Another thing guys on the front of the clutch there are allen key bolts that u can adjust the engagement or stall of the clutch.. u can definitely get 70 + with ease!! Congrats on your prodject .. do a compression test just to see whats the life of the engine . 2 strokes like to eat through piston rings as they get old.. u gained another subscriber.
Well high 50 mph, 70+ I don't think so, 70 + you need a new Rotax, aime, to achieve that, you need at least 27 hp to push it, that Yamaha should be 17 hp new and really tuned, but like I mentioned in another comment,,,,, have fun
Clutch has a high engagement RPMs because this 'racing' engine prolly doesn't make much power below 4,000 RPMs... although that is also common in 2 and 4 stroke high performance motorcycles/cars... a quieter muffle would make it more enjoyable for fun use...
Clutch sounds like its slipping on take. I'M not real knowledgeable about that type of racing clutch setup. It all depends on how the kart is setup. Its an awesome Kart guys congrats on getting it running. Have a great weekend God Bless!!!
centrifugal clutches are designed to slip to allow the wheels to catch up with the engine, but not with so much slip you roll away on launch. it should be throwing you into the seat.
You need a long road to tune the thing,and learn how to read a spark plug,balck to much gas,white it is about to blow up. Coffey double cream is the colour you are looking for. Buy several new spark pulgs, 2t like to foul them. The "v band" is just the way 2t's are they come into the power band when they are reving high and the port timming is most effective. That is a whole nother thing to learn about. Then you have clutch tuning to learn .Last check the crank seals , spray some carb cleaner at them and if it revs up they are shot and need to be replaced OR IT WILL BLOW UP. 2t motors are fun but need alot of attention to keep them right.
Reed valves in the bottom of the engine case are somewhat fussy also. The valve timing as it were is a function of the shape of the ports in the cyl and the piston skirt. If it looks like there has been die grinder work done, then it's been fiddled with! Not sure but it sounds somewhat tame compared to the stuff I was around years back. I don't think 70 is an unreasonable goal, iirc we ran 12tooth and a 48 maybe? (if that's way smaller than your rear sprocket then I'm full of it and ignore that!)
+Jeff Kephart yea, Reed valves ware out over time, but they are easy to check and change (much more simple than 4 cycle valves). It's all part of tunning, also jetting is very important as with any carb. lucky I live at sea level so I never had to deal with swapping spare jets during dirtbike/ATV mountain climbs( Just tune it, forget it, and rip!) I would just pull the plug, look at it and put it back after each ride... All of my 2 strokes ran as good or way better than my 4 strokes, and held a tune year round- hot/snow! One more big thing I did was top end rebuilds as maintenance, instead of waiting for it to blow and cause possible expensive damage (if the compression was low etc. I would pull the jug and hone/replace the rings, or bore/replace piston, better than a catastrophic failure). All the work is fast and easy on 2 cycles, you really can't beat em for a "fun" bike/ATV/cart.
All good advice here, specially on checking the crank seals if it's stood for a while as they can start to die soon after recomissioning. Definitely fit/repair the kill switch and learn how to do a plug chop/read the plug, pretty easy really just do a top speed pull and cut the ignition before you lift the throttle & then check the colouring as described above, rinse and repeat. :)
I think the clutch is okay as far as I can tell, and the “vtec” your feeling is the power band of a 2-stroke, it happens when the expansion chamber seen as a large swell in the exhaust can build up enough back pressure to help the engine run correctly and get enough fuel (its complicated). It is generally good practice to get the engine all the way through the rpm range before expecting performance or before tuning so that you can burn excess oil and basically “clear the engines throat”, this should help you tune. Lastly I will warn you that pinning the engine at very high rpm for more than about 2 minutes will complete lock up the engine. Good luck
Also sorry for writing a book but this is all good info for beginners so saying that in order for all kart motors to start you have to spin them so many rpm to get them to fire have fun be safe if you ever get to Indiana there is a race track there called Newcastle Raceway just east of Indianapolis (Indy) vintage karts hold there championship there and WKA has events there also I think Superkarts USA races there also
So glad you guys took advice on board! So happy to see you guys running it, motor sounds pretty strong. Sounds like the clutch is set up to engage at about 11000 rpm, usually you can adjust these until they reach the end of their tether so it may be on its last legs or might need adjusting, have a play with it, won't hurt it. Your front end needs adjusting also, looks like you've a toe rod slightly off, run the front end at 1 degree toe out either side, usually 0 camber to start and play from there. You'll do "60" easily with a 76 tooth sprocket, even 70-80 is achievable with right tune and sprockets. Have a blast lads*
Jarrad Powell i have a crg racing kart big al chassis and it has a rotax max 125cc . The left tierod is bend . Do i heat that area up and bend it back . Advice please
You need to slip clutch to 10k rpm with Dxl horstman oil and can run a Yamaha all day 14k rpm also put all clear tubing don't run a mixed line I ran Yamaha for over 25 years if you have any more questions hit me up also check out comet kart sales in Indiana they have everything you need
Chris yeah direct drive you get more out of them here in the Midwest of the states you have to use a Dxl clutch or or newer model I used to also run BM Atlas and Komet k55 k11 and k78 rototory valve I ran stock and modified
Clutch is made to kick in at higher RPM for more power. I would tweak it to come in earlier(lower RPMS) with slightly weaker clutch Springs The high jet on carb could be tweaked slightly leaner. For the most part running pretty good! 👍
I think you should name the cart JIIiiiiiiiiiiiiiiiimmmmmmmmmmmmmmmmmmmm! Takes me back to 1976 when brother in law ran a B101 McCullough on a funco cart. He was a pro engine builder for car bike and even 2 stroke, he was running fuel and I think he said he was getting around 40hp out of it on the engine dyno. It was ludicrous. Those race carts are wild, clearance to the track is like 1/2" (can't fit my hand under one). I don't know if they still make "Golden Spectro" synthetic 2cycle mix but that's what we ran, also BOSH plugs seemed to handle the heat and vibration far better than Chumpion or even NGK. I hit subscribe, will be following! cheers
Fantastic. So glad to see y'all got the go kart up and running. I'm not familiar with the KT100 motor but having raced dirt bikes for many years, I mixed my fuel at 50:1 using Motul 800 2T Pro Racing Premix (and it is common for 2 stroke motors to run at 32:1). It's a little bit expensive but keep in mind that you will be using less oil in your premix. Also would suggest you use a Ratio Rite measuring cup to calculate your oil to gas ratio. It easy to use, inexpensive, available at most motorcycle dealership, and will allow a more accurate mix. Wishing you continued success and have fun with your new toy. Also loved the music. Thanks for using it.
I do remember the first time i was driving an 2stroke 100ccm racing kart. same as you! my whole body was shaking... :D But with more seat-time, you get used to it. I would get rid of the clutch and connect the engine directly to the axle... these things are meant to be directdrive! After that, start the kart by pushing it and then jump in.
Looks like a kid's racing kart from the 90's or so. It looks really familiar. A lot of these were push start direct drives. Not sure of the actual mechanics but basically you started them by running and dropping them. There are videos of karts like that online; old fashioned by today's standard but really, really quick machines.
Its called coming on the pipe. When the port timing in the cylinder hit its optimal RPM range in conjunction with the expansion chamber create a big jump in power. Thats a cool little Kart!
On a racing yamaha you do your tunning with the low end needle and set high needle to about 3/4 turns the low end needle you start about 1 turn out maybe 1 1/4 . On your dt6e digitron gage head temperature shouldnt exceed 370 degrees no more than 14k rpm keeping that in mind you can run them half a racing season before you have to have new piston and ring or rings it might have one or 2 also use a 2cycle oil like klotz or redline wit about 2o% caster oil in the oil i recommend klotz super oil it already has the caster and far more forgiving on tunning with racing caster
I raced one of these back in the early 70's....though it was a Cheetah....Yamaha brand came later. Ran a McCullah 90cc motor...and AvGas (aviation gas...HI Octane) is what we burned. The kart with the right sprocket could hit 70 mph. I started when I was 7.
Sounds like it was running lean at first. If you open the throttle and it Boggs you need to add fuel. Read the spark plug as others have said bc running lean will kill a 2stroke in all kinds of ways
My son's 70cc 2t race cart does 85mph @ 16k revs. My Gilera 180 t2 scooter does 100mph. Once you get hooked on a 2t powerband, few 4 stroke engines will give you the same thrill.
That kart is good for 70-80 mph, with carb tuned right, and clutch not slipping. Check for air leak around carb, and intake with wd40?. That clutch is either wore out, or out of adjustment, watch some videos on adjusting carb, a little to rich is OK, but too lean, and you smoke motor.
Please , I race karts, to make 70 in that kart, I have a crg with a Rotax 125 tuned and is not easy to do 70+, it will but you need space, shifters will do easy but we are talking over 30 hp
Late 1980s, I raced my Emmick chassis in Senior classes with the Yamaha KT100 engine with a Horstman wet clutch. Even on a small track like the one that used to be on the beach in Oxnard, it could hit 80 at the end of the straight just in front of the bleachers. My recollection is clutch coming in around 9000 rpm and 14,000+ rpm at the end of the straight. It was thrilling, to say the least. My kart was initially set up and tuned by the legendary Jim Hall Racing in Oxnard. Damn those were fun times!
You don't kill the engine by pulling the spark plug wire off. Just Full chock the carb with you hand. You seem to running to rich. Close both needles Open low speed one turn out open high speed 7/8 turn out & if it is 4 cycling on top turn high speed in till you just take it out. Maybe 3/4 turn out from closed. Clutch is over slipping a bit. Looks like a Horsman. or burco. Check the oil & be sure you have the right oil for either clutch. They use different clutch oil. If it is a horseman you can adjust the springs with a allen wrench threw the cover. only loosen 1/8 turn of each spring each time to adjust. If it is a burco clutch You must pull side cover & add weight to each shoe. Hope I helped
Clutch is stuffed guys. The 2 smokers are predator eaters lol sounds awesome great work on geting it running. Fine tune it more an it will be a killer racing kart 😁 take care Mark
You need to lean out the high end needle a bit more like an 1/8of a turn at a time till u get peak power and then back of 1/8 so you not to lean.. Bare in mind each day u ride you will need to fiddle with the needles... Air temp plays a big roll on those carbs. Best of luck to you and don't loose it round a corner and crash into ur truck
I don't have any experience wit go cart clutches, but with snowmobiles the engagement on the clutch is typically around 4000 rpms. Although some guys change spring rates and weights to get them to engage higher for better acceleration off the line. 2 strokes don't make power at low rpm and they rev high. There should be some way to adjust that clutch to get it to engage a little higher or lower depending on what you're looking for. With the way it's acting down low, I would think you would need to raise the engagement rpm so you're farther in the power band when it engages.
I got to 01:36 and heard something about fuel magically flowing uphill. Pressurize the tank or raise it above the motor cuz below the carb is where that fuel will stay (at the exact level as in the tank and no higher). Have fun!
the yamahas arent tuned to have a noticeable powerband its more likely jetted wrong or sparkplug is on its way out. they should pull smoothly from about 6-7k to 17k
i have a kt100se which is unrestricted. I race this kart every month or so and the motor is great. the reason why you are having a few problems on start up would just be carb settings, i only touch mine when the motor gets up to temp. id also suggest getting it on a dyno and having a pressure test because a big problem with these motors will be seals and they will rob you of hp. my seals were pretty much stuffed and it had about 8 hp after the seals and a top end rebuild it made 18 and it flys. hope this was helpful. oh and the clutch is definitely slipping so id suggest making it either direct drive or investing in a new wet or dry clutch.
"VTEC" LOL, welcome to the world of 2 strokes! Look up 2 stroke power band, expansion chamber exhaust, and learn how to tune it... then image a modern liquid cooled 125cc (or 250 if you're insane) w/ a power valve! Good start, and good idea about trying out some of those extra pipes (a tuned pipe can make a HUGE difference)
The clutch is slipping badly, when it locks in that is the feeling you described as vtec lol, some kart clutches used organic friction material and can go bad sitting over time. I used to set my clutch to come in at about 3k and lock up within 3-4 seconds. With the different types and brands of clutch having different tuning options, I'd suggest that you Google it.
Build Break Repeat, no problem, I got out of race karts years ago, now i prefer off-road karts just to screw around. Racing got to expensive and time consuming lol. Those things are very fun, hope yall enjoy it!
I raced as well never 2 stroke ran meth carts and they would spin on take off and still hit 60 so that motor should be way meaner id say. Keep up research and youl all have a screaming deamend
Okay guys. I raced Yamaha's in the late 80s sprint and enduros. Looks like you have a sprint gearing ratio. Maybe a 9tooth top 68 tooth axle sprocket or close to it. Here's what to do the cheapest way. Don't change the Clutch sprocket. Find an axle Gear around a 52 to 56 tooth axle gear. You should have a longer stretch because it will take longer to max out. You maybe able to reach 65 to 70mph with this gearing on the cheap. Also, set your carb around a turn and a half on your low side and around 2 turns on the high side to start. You'll tell if it's to lean. Then if on your top speed if the engine blubbers then turn in a quarter at a time turn till it stops blubbering. (Note to start) adjust both carb needles all the way in then adjust outwards to my suggestions. Good luck.
Tuning top high speed needle is done while riding like you were I'm pretty sure. I think that clutch might be slipping a little bit. I saw you said you had a rebuild kit. although they could be made to run like that at high speeds. since your not slowing down much on a track. can't wait up see how it runs after you rebuild it. looks like a fun cart! Have fun with it.
Yea as you can hear when the clutch engages it more happy and it goes i race dirt go Karts. There should be screws on the inside to adjust the timing of when it engages ur looking to engage around 2800-3000 rpms
I think you are not even close to this kart's limits. I am sure 60 is likely. It definitely is not coming up on the pipe as quickly as it should yet, and it does seem like the clutch is likely shot and needs a rebuild.
Use non synthetic trans fluid the synthetic ATF is causing the clutch plates to slip hence the hesitation. That thing is really unique definately an awesome kart. 👌🇺🇸🇺🇸
I'm beside myself I just can't believe you got that Kart for $400 if I had to walk a hundred miles I would to get that cart for $400 there's just no words for that none
The idle most racers don't even use it adjusting carb with the low end needle run the high end around 3/4 of a turn the low end you want to just leave a fante trail of smoke when racing it here in Indiana they still race the Kt 100 look up Newcastle raceway around
I honestly think the Clutch is loose or something. It's taking way to long to get up and go. Might want to make some adjustments or something. Either way, nice work on it.
The different expansion pipes will give you maximum power at different RPMs so they are made for using on different tracks. If you want the 'fastest' one then I guess whichever one gives you power band at the highest RPM will give the most power.
I think your chassis is a Margay. If you look on the right spindle hanger is a number. Contact Margay and they should be able to tell you the exact model. To me it’s a late 80’s early 90’s Lynx.
Don't know how far you wanna take this, but Yamaha is one of the cheaper classes out there, restoring it for track use should be very cheap. If you have a track near you, you can get a license there so you have people to race with. I do recommend a larger tank if you wanna race though, 5 liters(1.3 gallon) is pretty common.
I am so glad that you got the two-stroke go cart going. My love of two stroke come my RD-350 and a Titan 500 so much fun, also had a friend rode with go cart Honda 405(?) motor with shifter. pretty cool. I got one question its in your promo film of a go cart pulling a wheelie. what vid is that from?
Guys looked like it was running rich by the amount of smoke you were putting out. You want the clutch engaging around 10,000 rpm, that's what I used to set mine up at. If you put a 9/60 gear ratio on with a good length road you should get to 100 MPH but make sure you wear proper protected gear full race suit decent boots and gloves. Don't stop the motor by pulling the HT lead off (if it over revs that won't stop it) Choke it to stop if you don't have an on/off switch connected.
like somebody else said here I think those clutches have adjustment bolts on them to make the clutch pack tighter or loosen it up....its not grabbing all the way on 'take off' u shud b able to barley tap the gas pedal n that shud take off quickly lol!!...adjust ur clutch n that thing will fly a lot faster....the clutch dialed in with the engine u shud b push'n close to 80mph idk if those do 100mph without blowing up the top end I haven't been in 'carting' for years now I do know those Yamaha 100's kick ass tho when 'dialed in' correctly.....
Now this can go several ways but normally in some cases it is the sprockets, there are one in the engine bay, and the one in the axle, if you want more speed you would lower the sprocket size(say 78 to a 60). Now if you have too much sprocket on front it over streches the ratio of the driveshaft speed to the speed of the wheels, also this can involve the engine setting. If it takes too long for the engine to reach its powerband even though it has high sprockets then the engine is too lean. If it is almost chugging about while acclearation then lower the rich setting. But mainly read the colour of the spark plug, brownish is ok for what your using it for. Hopefully this might help you
Doing lots of that stop and go stuff is really hard on the clutch, gonna burn it up if you keep doing that, and set the idle so it dies, so when you stop it will shut off automatically and you don’t have to pull the spark plug wire.
First you need to get your gas mix correct 4 ounces of oil per gallon 32 to 1 great baseline to start and then tune from there you guys got a nice cart right there!!
Depends on the oil you are using, on the hand grenade motors in the 70's used to run 12.5 to 1. some of the latest generation oils are now being used at 50 to 1.
A good CORDLESS DRILL or IMPACT, would make for an easier staring device. That way you can ditch the cable's, and carry it with you on the cart. think of it as a really big key
One of the things about high octane fuel is evaporation and heat .adding alcohol in the fuel mix decreases heat in combustion and should not decrease oil efficiency
Hey I have a go kart just like the one you guys have and I was wondering if you guys know if where I can get a starter because I am having trouble finding one. Thanks
Another thing guys on the front of the clutch there are allen key bolts that u can adjust the engagement or stall of the clutch.. u can definitely get 70 + with ease!! Congrats on your prodject .. do a compression test just to see whats the life of the engine . 2 strokes like to eat through piston rings as they get old.. u gained another subscriber.
BighomieJ5x - Ok cool, didn’t know about the clutch thanks.
id recommend checking the piston to see if this has been sized before it happens all too often on 2 strokes (coming from a 2 stroke motorcycle rider)
Well high 50 mph, 70+ I don't think so, 70 + you need a new Rotax, aime, to achieve that, you need at least 27 hp to push it, that Yamaha should be 17 hp new and really tuned, but like I mentioned in another comment,,,,, have fun
Your clutch is fried and it is a little rich. Put a spring on the idle screw to stop it from moving.
Clutch has a high engagement RPMs because this 'racing' engine prolly doesn't make much power below 4,000 RPMs... although that is also common in 2 and 4 stroke high performance motorcycles/cars... a quieter muffle would make it more enjoyable for fun use...
Clutch sounds like its slipping on take. I'M not real knowledgeable about that type of racing clutch setup. It all depends on how the kart is setup. Its an awesome Kart guys congrats on getting it running. Have a great weekend God Bless!!!
yes, needs a new one or a tunning i use to race in a 2T zanella sol 50cc and customize de clutch with new springs
They do slip on take off my kart does and the engine is 1 hour old
centrifugal clutches are designed to slip to allow the wheels to catch up with the engine, but not with so much slip you roll away on launch. it should be throwing you into the seat.
Tj Reeve a fresh clutch isn’t gonna be really grabby until it’s broken in a little
It is supposed to do that How would you else take of if u have a direct drive kart. It will stall otherwise
You need a long road to tune the thing,and learn how to read a spark plug,balck to much gas,white it is about to blow up. Coffey double cream is the colour you are looking for. Buy several new spark pulgs, 2t like to foul them. The "v band" is just the way 2t's are they come into the power band when they are reving high and the port timming is most effective. That is a whole nother thing to learn about. Then you have clutch tuning to learn .Last check the crank seals , spray some carb cleaner at them and if it revs up they are shot and need to be replaced OR IT WILL BLOW UP. 2t motors are fun but need alot of attention to keep them right.
Yes definitely good advance about reading the plugs! probably the most important thing to know about 2 cycles (after you get them running).
Reed valves in the bottom of the engine case are somewhat fussy also. The valve timing as it were is a function of the shape of the ports in the cyl and the piston skirt. If it looks like there has been die grinder work done, then it's been fiddled with! Not sure but it sounds somewhat tame compared to the stuff I was around years back. I don't think 70 is an unreasonable goal, iirc we ran 12tooth and a 48 maybe? (if that's way smaller than your rear sprocket then I'm full of it and ignore that!)
+Jeff Kephart yea, Reed valves ware out over time, but they are easy to check and change (much more simple than 4 cycle valves). It's all part of tunning, also jetting is very important as with any carb. lucky I live at sea level so I never had to deal with swapping spare jets during dirtbike/ATV mountain climbs( Just tune it, forget it, and rip!) I would just pull the plug, look at it and put it back after each ride... All of my 2 strokes ran as good or way better than my 4 strokes, and held a tune year round- hot/snow! One more big thing I did was top end rebuilds as maintenance, instead of waiting for it to blow and cause possible expensive damage (if the compression was low etc. I would pull the jug and hone/replace the rings, or bore/replace piston, better than a catastrophic failure). All the work is fast and easy on 2 cycles, you really can't beat em for a "fun" bike/ATV/cart.
All good advice here, specially on checking the crank seals if it's stood for a while as they can start to die soon after recomissioning. Definitely fit/repair the kill switch and learn how to do a plug chop/read the plug, pretty easy really just do a top speed pull and cut the ignition before you lift the throttle & then check the colouring as described above, rinse and repeat. :)
P Kuudsk 78
Back to school learning and researching the type of engine you have first of all along with the type of clutch,, sooo much to learn,,
I think the clutch is okay as far as I can tell, and the “vtec” your feeling is the power band of a 2-stroke, it happens when the expansion chamber seen as a large swell in the exhaust can build up enough back pressure to help the engine run correctly and get enough fuel (its complicated). It is generally good practice to get the engine all the way through the rpm range before expecting performance or before tuning so that you can burn excess oil and basically “clear the engines throat”, this should help you tune. Lastly I will warn you that pinning the engine at very high rpm for more than about 2 minutes will complete lock up the engine. Good luck
You guys deserve more viewers for the hard work you put into enjoyable videos.
Also sorry for writing a book but this is all good info for beginners so saying that in order for all kart motors to start you have to spin them so many rpm to get them to fire have fun be safe if you ever get to Indiana there is a race track there called Newcastle Raceway just east of Indianapolis (Indy) vintage karts hold there championship there and WKA has events there also I think Superkarts USA races there also
So glad you guys took advice on board! So happy to see you guys running it, motor sounds pretty strong. Sounds like the clutch is set up to engage at about 11000 rpm, usually you can adjust these until they reach the end of their tether so it may be on its last legs or might need adjusting, have a play with it, won't hurt it. Your front end needs adjusting also, looks like you've a toe rod slightly off, run the front end at 1 degree toe out either side, usually 0 camber to start and play from there. You'll do "60" easily with a 76 tooth sprocket, even 70-80 is achievable with right tune and sprockets. Have a blast lads*
Jarrad Powell i have a crg racing kart big al chassis and it has a rotax max 125cc . The left tierod is bend . Do i heat that area up and bend it back . Advice please
You need to slip clutch to 10k rpm with Dxl horstman oil and can run a Yamaha all day 14k rpm also put all clear tubing don't run a mixed line I ran Yamaha for over 25 years if you have any more questions hit me up also check out comet kart sales in Indiana they have everything you need
I raced the yamaha and rotax when i was a teenager we would get the yamaha up to 18k in competitions, they ran it direct drive here.
Chris yeah direct drive you get more out of them here in the Midwest of the states you have to use a Dxl clutch or or newer model I used to also run BM Atlas and Komet k55 k11 and k78 rototory valve I ran stock and modified
Clutch is made to kick in at higher RPM for more power. I would tweak it to come in earlier(lower RPMS) with slightly weaker clutch Springs The high jet on carb could be tweaked slightly leaner. For the most part running pretty good! 👍
I think you should name the cart JIIiiiiiiiiiiiiiiiimmmmmmmmmmmmmmmmmmmm!
Takes me back to 1976 when brother in law ran a B101 McCullough on a funco cart. He was a pro engine builder for car bike and even 2 stroke, he was running fuel and I think he said he was getting around 40hp out of it on the engine dyno. It was ludicrous. Those race carts are wild, clearance to the track is like 1/2" (can't fit my hand under one). I don't know if they still make "Golden Spectro" synthetic 2cycle mix but that's what we ran, also BOSH plugs seemed to handle the heat and vibration far better than Chumpion or even NGK. I hit subscribe, will be following! cheers
Fantastic. So glad to see y'all got the go kart up and running. I'm not familiar with the KT100 motor but having raced dirt bikes for many years, I mixed my fuel at 50:1 using Motul 800 2T Pro Racing Premix (and it is common for 2 stroke motors to run at 32:1). It's a little bit expensive but keep in mind that you will be using less oil in your premix. Also would suggest you use a Ratio Rite measuring cup to calculate your oil to gas ratio. It easy to use, inexpensive, available at most motorcycle dealership, and will allow a more accurate mix. Wishing you continued success and have fun with your new toy. Also loved the music. Thanks for using it.
34bartm I raced kt100s for years at national level in the 90s. Everyone ran 16:1 helps you lean out the motor with the needles to go faster
2 stroke = massive powerband !!
I do remember the first time i was driving an 2stroke 100ccm racing kart. same as you! my whole body was shaking... :D
But with more seat-time, you get used to it.
I would get rid of the clutch and connect the engine directly to the axle... these things are meant to be directdrive! After that, start the kart by pushing it and then jump in.
Looks like a kid's racing kart from the 90's or so. It looks really familiar. A lot of these were push start direct drives. Not sure of the actual mechanics but basically you started them by running and dropping them. There are videos of karts like that online; old fashioned by today's standard but really, really quick machines.
Excellent job guy's!! She should be fun!
I saw that truck on Preston...knew who it was right away. Good video!
kz6fittycent Aye that’s sick. Thanks for watching.
''vtec'' its called ketchup-effect, normal for twostrokes. At first comes nothing and then everything kicks in and you are flying
Pirate Fade haha that’s dope. Thanks.
Build Break Repeat no problem! Can i send you a picture. If so, where?
Pirate Fade U can dm us on instagram. @build.break.repeat
Its called coming on the pipe. When the port timing in the cylinder hit its optimal RPM range in conjunction with the expansion chamber create a big jump in power. Thats a cool little Kart!
Power band
That Vtec feel is the powerband, keep the engine in that rev range
On a racing yamaha you do your tunning with the low end needle and set high needle to about 3/4 turns the low end needle you start about 1 turn out maybe 1 1/4 . On your dt6e digitron gage head temperature shouldnt exceed 370 degrees no more than 14k rpm keeping that in mind you can run them half a racing season before you have to have new piston and ring or rings it might have one or 2 also use a 2cycle oil like klotz or redline wit about 2o% caster oil in the oil i recommend klotz super oil it already has the caster and far more forgiving on tunning with racing caster
Those 2 strokes always had good power bands on them.
I raced one of these back in the early 70's....though it was a Cheetah....Yamaha brand came later.
Ran a McCullah 90cc motor...and AvGas (aviation gas...HI Octane) is what we burned.
The kart with the right sprocket could hit 70 mph.
I started when I was 7.
Sounds like it was running lean at first. If you open the throttle and it Boggs you need to add fuel. Read the spark plug as others have said bc running lean will kill a 2stroke in all kinds of ways
You just got to love it you guys are very very lucky he could have easily got 1200 for that package without blink of an eye just unbelievable
OMGGGGG😍😍😍😍 THAT VINTAGE 2 STROKE SOUND....
My son's 70cc 2t race cart does 85mph @ 16k revs. My Gilera 180 t2 scooter does 100mph. Once you get hooked on a 2t powerband, few 4 stroke engines will give you the same thrill.
That kart is good for 70-80 mph, with carb tuned right, and clutch not slipping. Check for air leak around carb, and intake with wd40?. That clutch is either wore out, or out of adjustment, watch some videos on adjusting carb, a little to rich is OK, but too lean, and you smoke motor.
Please , I race karts, to make 70 in that kart, I have a crg with a Rotax 125 tuned and is not easy to do 70+, it will but you need space, shifters will do easy but we are talking over 30 hp
Late 1980s, I raced my Emmick chassis in Senior classes with the Yamaha KT100 engine with a Horstman wet clutch. Even on a small track like the one that used to be on the beach in Oxnard, it could hit 80 at the end of the straight just in front of the bleachers. My recollection is clutch coming in around 9000 rpm and 14,000+ rpm at the end of the straight. It was thrilling, to say the least. My kart was initially set up and tuned by the legendary Jim Hall Racing in Oxnard. Damn those were fun times!
You don't kill the engine by pulling the spark plug wire off. Just Full chock the carb with you hand. You seem to running to rich. Close both needles Open low speed one turn out open high speed 7/8 turn out & if it is 4 cycling on top turn high speed in till you just take it out. Maybe 3/4 turn out from closed. Clutch is over slipping a bit. Looks like a Horsman. or burco. Check the oil & be sure you have the right oil for either clutch. They use different clutch oil. If it is a horseman you can adjust the springs with a allen wrench threw the cover. only loosen 1/8 turn of each spring each time to adjust. If it is a burco clutch You must pull side cover & add weight to each shoe. Hope I helped
Clutch is stuffed guys. The 2 smokers are predator eaters lol sounds awesome great work on geting it running. Fine tune it more an it will be a killer racing kart 😁 take care Mark
I feel like that clutch is worn out
It sounds like my traxxas t-maxx nitro rc car. Nice build.
You need to lean out the high end needle a bit more like an 1/8of a turn at a time till u get peak power and then back of 1/8 so you not to lean.. Bare in mind each day u ride you will need to fiddle with the needles... Air temp plays a big roll on those carbs. Best of luck to you and don't loose it round a corner and crash into ur truck
not bad should rip more than that when it running better or new clutch...got my vintage race kart up to 52mph with a modified 5hp briggs raptor..
They engage at high RPM, also make sure to keep atf in the clutch.
Get some aviation gas at your airport. The Macs loved that stuff. Can you add weights to the clutch shoes? Sweet kart.
We used to run Klotz fuel.... kinda expensive but makes them 2 cycles git it and go...
plan on some spare horstman DXL friction plates when you go to a smaller driven sprocket!
and go easier on it when you first start out.
I don't have any experience wit go cart clutches, but with snowmobiles the engagement on the clutch is typically around 4000 rpms. Although some guys change spring rates and weights to get them to engage higher for better acceleration off the line. 2 strokes don't make power at low rpm and they rev high. There should be some way to adjust that clutch to get it to engage a little higher or lower depending on what you're looking for. With the way it's acting down low, I would think you would need to raise the engagement rpm so you're farther in the power band when it engages.
I got to 01:36 and heard something about fuel magically flowing uphill. Pressurize the tank or raise it above the motor cuz below the carb is where that fuel will stay (at the exact level as in the tank and no higher). Have fun!
Very common on two strokes, they hit that sweet spot, often referred to as 'coming on the pipe', its quite a rush.
It's called power band
the yamahas arent tuned to have a noticeable powerband its more likely jetted wrong or sparkplug is on its way out. they should pull smoothly from about 6-7k to 17k
Call bullshit it's power band 100%
Now is Sure Name: Tatsache the! Race Kart Run be'cose the 100 CC come on IT nice show.
i have a kt100se which is unrestricted. I race this kart every month or so and the motor is great. the reason why you are having a few problems on start up would just be carb settings, i only touch mine when the motor gets up to temp. id also suggest getting it on a dyno and having a pressure test because a big problem with these motors will be seals and they will rob you of hp. my seals were pretty much stuffed and it had about 8 hp after the seals and a top end rebuild it made 18 and it flys. hope this was helpful. oh and the clutch is definitely slipping so id suggest making it either direct drive or investing in a new wet or dry clutch.
casey phillips Ok cool, a dyno would be sick
Your the only RUclips channel I enjoy watching
Ingraving on the cylinder is gonna be the shop who did head work on it in betting it's been ported
"VTEC" LOL, welcome to the world of 2 strokes! Look up 2 stroke power band, expansion chamber exhaust, and learn how to tune it... then image a modern liquid cooled 125cc (or 250 if you're insane) w/ a power valve! Good start, and good idea about trying out some of those extra pipes (a tuned pipe can make a HUGE difference)
The clutch is slipping badly, when it locks in that is the feeling you described as vtec lol, some kart clutches used organic friction material and can go bad sitting over time. I used to set my clutch to come in at about 3k and lock up within 3-4 seconds. With the different types and brands of clutch having different tuning options, I'd suggest that you Google it.
Evil Me Ok, the kart came with a rebuild kit when we bought it, I’ll have to do some research thanks.
Build Break Repeat, no problem, I got out of race karts years ago, now i prefer off-road karts just to screw around. Racing got to expensive and time consuming lol. Those things are very fun, hope yall enjoy it!
I raced as well never 2 stroke ran meth carts and they would spin on take off and still hit 60 so that motor should be way meaner id say. Keep up research and youl all have a screaming deamend
Kart engines run 20to1 oil no less. Believe me on that, I was a Yamaha kart dealer & you take a chance of sticking that engine running less.
Are those engines easy to get parts for seems badass if I build a go kart It will definitely be a two stroke
Okay guys. I raced Yamaha's in the late 80s sprint and enduros. Looks like you have a sprint gearing ratio. Maybe a 9tooth top 68 tooth axle sprocket or close to it. Here's what to do the cheapest way. Don't change the Clutch sprocket. Find an axle Gear around a 52 to 56 tooth axle gear. You should have a longer stretch because it will take longer to max out. You maybe able to
reach 65 to 70mph with this gearing on the cheap. Also, set your carb around a turn and a half on your low side and around 2 turns on the high side to start. You'll tell if it's to
lean. Then if on your top speed if the engine blubbers then turn in a quarter at a time turn till it stops blubbering. (Note to start) adjust both carb needles all the way in then adjust outwards to my
suggestions. Good luck.
I hit 90 miles an hour with a McCulloch in 91 B1 on k l o t z s racing fuel against Michael Andretti have a great great night
there's defo some clutch slip going on there but hey... you got it running!!
Tuning top high speed needle is done while riding like you were I'm pretty sure. I think that clutch might be slipping a little bit. I saw you said you had a rebuild kit. although they could be made to run like that at high speeds. since your not slowing down much on a track. can't wait up see how it runs after you rebuild it. looks like a fun cart! Have fun with it.
Lance Shank Thanks, yeah that’s what I’ve heard about the clutch.
Two strokes like it when you give it full throttle on start up just to get it started though
Put a spring on the idle screw and it will stop vibrating out as you ride it
Yea as you can hear when the clutch engages it more happy and it goes i race dirt go
Karts. There should be screws on the inside to adjust the timing of when it engages ur looking to engage around 2800-3000 rpms
Centrifugal clutches are designed to slip obviously but, she sounds pretty loose. Prob need to do some spring swapping at best.
These 'racing' engines make no power below 4,000 - 10,000 RPMs... depending on how radical the tune is... so clutch has a 'high stall RPMs'...
Now you know, predators are a joke compared to a strong two-stroke
GT1Man Yeah, just depends on how much money you want to spend lol.
I think you are not even close to this kart's limits. I am sure 60 is likely. It definitely is not coming up on the pipe as quickly as it should yet, and it does seem like the clutch is likely shot and needs a rebuild.
GT1Man Yeah, we have some other sprockets too, 70 is the goal lol. Thanks.
2 strokes are gay😎😎😎
Will is just mad that he has tons of videos and no views. Whos gay now!
Air mixture can be a pain but get started won't be to bad
Use non synthetic trans fluid the synthetic ATF is causing the clutch plates to slip hence the hesitation. That thing is really unique definately an awesome kart. 👌🇺🇸🇺🇸
I'm beside myself I just can't believe you got that Kart for $400 if I had to walk a hundred miles I would to get that cart for $400 there's just no words for that none
That jerk of power is the power band
The idle most racers don't even use it adjusting carb with the low end needle run the high end around 3/4 of a turn the low end you want to just leave a fante trail of smoke when racing it here in Indiana they still race the Kt 100 look up Newcastle raceway around
Ik this is years ago but I have the same kart and I need to put a clutch on it and I want to put a starter as well which ones do I need 😅
I honestly think the Clutch is loose or something. It's taking way to long to get up and go. Might want to make some adjustments or something. Either way, nice work on it.
The different expansion pipes will give you maximum power at different RPMs so they are made for using on different tracks. If you want the 'fastest' one then I guess whichever one gives you power band at the highest RPM will give the most power.
I think your chassis is a Margay. If you look on the right spindle hanger is a number. Contact Margay and they should be able to tell you the exact model. To me it’s a late 80’s early 90’s Lynx.
Don't know how far you wanna take this, but Yamaha is one of the cheaper classes out there, restoring it for track use should be very cheap. If you have a track near you, you can get a license there so you have people to race with. I do recommend a larger tank if you wanna race though, 5 liters(1.3 gallon) is pretty common.
Sounds rich
I agree two strokes does like rings more you run them and harder means more rebuilds but that what two strokes are for
Clutch def. Sounds like its Slipping really bad?? But idk mch about them things.. but you would think it would burn the tires off..
I am so glad that you got the two-stroke go cart going. My love of two stroke come my RD-350 and a Titan 500 so much fun, also had a friend rode with go cart Honda 405(?) motor with shifter. pretty cool.
I got one question its in your promo film of a go cart pulling a wheelie. what vid is that from?
my go cart was 13 to 72 gear ratio. A mach 1 told me I was doing 70, I couldn't keep a clutch on it. Had the sprocket welded to the crank.
Have a look into two stroke tuning, it is rather critical.
Did you adjust the spark plug gap before using it? They are usually used in more than one type of engine so adjusting to the right gap may help a bit.
Guys looked like it was running rich by the amount of smoke you were putting out.
You want the clutch engaging around 10,000 rpm, that's what I used to set mine up at.
If you put a 9/60 gear ratio on with a good length road you should get to 100 MPH but make sure you wear proper
protected gear full race suit decent boots and gloves.
Don't stop the motor by pulling the HT lead off (if it over revs that won't stop it) Choke it to stop if you don't have an
on/off switch connected.
If I’m correct it hits power band my Suzuki rm80 hits it and it’s like vtec it kicks in hard
like somebody else said here I think those clutches have adjustment bolts on them to make the clutch pack tighter or loosen it up....its not grabbing all the way on 'take off' u shud b able to barley tap the gas pedal n that shud take off quickly lol!!...adjust ur clutch n that thing will fly a lot faster....the clutch dialed in with the engine u shud b push'n close to 80mph idk if those do 100mph without blowing up the top end I haven't been in 'carting' for years now I do know those Yamaha 100's kick ass tho when 'dialed in' correctly.....
badass kart
You guys should take it to a race meeting
You need the gas tank to be higher than the line going into the carb so try mounting it higher near the steering wheel
Nope, the carb has a diaphragm pump. The tank is in the correct place.
Now this can go several ways but normally in some cases it is the sprockets, there are one in the engine bay, and the one in the axle, if you want more speed you would lower the sprocket size(say 78 to a 60). Now if you have too much sprocket on front it over streches the ratio of the driveshaft speed to the speed of the wheels, also this can involve the engine setting. If it takes too long for the engine to reach its powerband even though it has high sprockets then the engine is too lean. If it is almost chugging about while acclearation then lower the rich setting. But mainly read the colour of the spark plug, brownish is ok for what your using it for.
Hopefully this might help you
Doing lots of that stop and go stuff is really hard on the clutch, gonna burn it up if you keep doing that, and set the idle so it dies, so when you stop it will shut off automatically and you don’t have to pull the spark plug wire.
Two strokes usually have that feeling of the power band
Clutch is warn and 2 stroke engines hit a power band which can feel like boost at high rpm
First you need to get your gas mix correct 4 ounces of oil per gallon 32 to 1 great baseline to start and then tune from there you guys got a nice cart right there!!
All depends on the Oil being used, get it wrong and Motor goes Bang. 20 to 1 for a KT is about right
20.1 That's way way way to rich for any two stroke
Depends on the oil you are using, on the hand grenade motors in the 70's used to run 12.5 to 1.
some of the latest generation oils are now being used at 50 to 1.
A good CORDLESS DRILL or IMPACT, would make for an easier staring device. That way you can ditch the cable's, and carry it with you on the cart. think of it as a really big key
Zax Garrison I hope they get to see this comment
Zax Garrison That’s a good idea, especially when we have to push it back to the truck when it dies lol.
One of the things about high octane fuel is evaporation and heat .adding alcohol in the fuel mix decreases heat in combustion and should not decrease oil efficiency
For sure need some clutch work it should kick sideways burn outs
Nice work guys.
2strokes have a power band up top where the power valve opens and lets more airflow for more power. it cannot open at low rpm or it will bog out.
KT100 is a Piston Port motor, has no power valve
Aaa sounds like you need to check on the clutch because of the 2 stroke there should be some clutch slippage
Clutch seems a little late in kicking in a good tune on the clutch
And you need a bigger fuel jets and injector's and a little tuning and it will be super fun and fast
2 strokes are the best !
runnin lean boys
Hey I have a go kart just like the one you guys have and I was wondering if you guys know if where I can get a starter because I am having trouble finding one. Thanks
I have a vintage kt100. My drill just isn’t enough to turn it over as the clutch will not engage when pushed.
Might want to check the gap on that plug.
Put an 8 oz bottle of baby oil in the tank, add it to the pemix, it'll turn up a little higher
hey guys you need to put a carb kit threw it and a proper tune up cause they need to be tuned properly so they can rip better