2 stroke scooter tuning & ryan are spot on with coments. Also I advise you to rich up the mixture on the main jet, as i've seen the colour of the piston crown and sqishband of the head... Great and educational video as always!
That coating won't fall out dont worry. Have seen cylinders with whole chunks missing running just fine for years. As long as its beneath the exhaust port roof height you won't have performance decrease. Good to see it back together, good for 2 thousand more miles!
I hope you can read this in time. Piston edge- is detonated and you need to run higher octane OR when the head gasket blew from a loosening head bolt lowering the compression. Use blue lock tight. The seal is made on the head by that O-ring.feal with fingernail around inside of cylinder to check for scratches (looks fine). That chip in the nickel sodium carbide coating is from a casting and boring flaw and fine. Never use sandpaper and a finger on the inside of the connecting rod, you’re making it out of round. Lmk if you appreciate the insight or think I’m just a hater (and I’ll stop).
I appreciate insight. Sometimes I wonder if comment makers have any idea what's going on, but this doesn't seem to be the case. You know, like telling me that the TPR won't last 1000 miles when I'm at near 2,000 stated many times in the video and title. I also thought detonation at first, but I believe it was Eric Gorr that talked about coolant leaks doing just this and actually leading to ring sticking in one of his publications. I don't claim to know the cause for sure, but the description that I recall about the coolant leak was almost exactly what I found. I did find a crack in my airbox (replaced) so maybe there was something going on? Normally, I hear detonation. I have never heard it with this kit. No sandpaper on the conrod. Just cloth and polish. The sandpaper was just to clean some rust off of the crank wheels. Kinda pointless since I can't get in there to clean everything, but I suppose it made me feel better. I do realize that there is a totally technically correct way to do things and then sometimes how things actually go. I didn't even measure the conrod small end diameter TBH, because I saw no signs of needle rollers eating in or anything of that nature that I've seen with other conrods. At this point, the head is either screwed because of the broken walls around the o-ring or it's will probably work OK. I could toss the whole thing (head and piston kit etc... would end up being near total replacement cost) or just see if I can get more use out of it first. The reason that I have not used a thread locker on my studs is that my initial experience with torque specs was with automotive cylinder heads. Most of which specify a lubricant, often motor oil or an overpriced specialty lube. These scoot manufacturers and aftermarkets don't bother, but I've been in the habit of using motor oil and generally it's not a big issue if I re-torque after heat cycling. I don't make any claims of being an expert and always correct. Thanks.
@@49ccscoot dont worry about torqing nuts on head/studs, just use coper washer under nuts and torq to the specific values. M6/M7 bolts and nuts 12~14nm. Never used locktite, just coper washers, never had a problem.
@@49ccscoot Don´t worry too much , the Tp thropy 70 ccm (castiron) in my vespa is already lasting near 45000km on the second piston.But my setup is very low rev on the ET2.(9gr rollers and sito plus exhaust) As long as you maintain it well it should keep going until a pistonring snaps or the engine runs dry.
I'm glad T2 is up and running again and the cause wasn't anything major. I'd watch very closely the coolant levels from now on. As usual I really enjoy your videos. Keep up the good work man.
Yeah, I'm concerned that it's going to leak again. Replacing the head and the piston would mean I might as well do the whole kit so I figured I might as well try it and hope it works for a while. Thanks.
Another great video my friend, so my guess would be that my stock 50cc engine is in great shape as far as compression goes. I’m getting 130 psi of compression. I think I’ll replace the crank seals, I just haven’t been feeling motivated to do anything but now I’m ready. Thanks for posting, ride safe.
I got heat problems,before I replaced a new 60cc cylinder.From stator\alternator wich broke down 100km later.I`m not so precis,but new cylinder had at least 1-2 mm clearance from piston.The cylinder shrinked 2 mm after perhaps 10 000km.New,2 times better 60cc,you can drop piston right trough.The old has to use force,it has shaped\melted around the piston(wich also are oval from heat).And I mixed more fuel,2.5 turn to new cylinder,wich dont mix with old stator,and new plug turned blue.COMPRESSION:lost 2 tries in non-egr high compression 70cc.First cylinder bolts,was to tight,and squeezed into soft metal casing,impossible to unscrew now.2.attempts the treads inside cylinder nuts was ripped out.New naraku performance crank,wich need 2 top-gasket,it touches the valves.
Hope your cylinder holds for a while, the chip and the scratch in the cylinder wall does make me suspicious about the cause the cause why your piston ring got stuck because it does add more and uneven friction, the rust could only have come from a coolant leak indeed (or the scoot would have taken a dive a in a pond 😉) the breaches between the two stud holes on the head would for me mean replacement, if it had an aluminum crush gasket I would have taken the chance but with a rubber o ring gasket I wouldn't, but time will tell how this plays out. I would check up on the cylinder, piston and head in a short time. Please keep making these video's i find them really enjoyable to watch. 👍👍 Now back to wrenching myself so my old Honda MT-5 can hit the road again after 20+ years!
Thanks. For me, by the time the head and piston kit were replaced, I might as well get a new cylinder kit totally. Figured I might as well try it and see what happens.
This is why I advised the Klotz Super Techniplate it leaves a protective film that protects the motor when you shut it off and it stays there this is why wear is so little with the Klotz oil and again it runs a bit smoother than the amsoil me and you had a chat about this before and you said you loved your amsoil even after i linked you the info saying it wasn't designed for motorcycles and such it was designed for weed wackers and chainsaws this is why they removed the support from the amsoil bottle for motorcycles / quads / and snowmobiles and such.
Wrong AMSOil. I used to use Saber Pro. Now I use Dominator. They did change their recommendations on Saber and that is when I switched over. Who knows, maybe I'll try something else after I go through a case and a half of this that I have. I've been pleased with it though.
I've had the same issue with a 50cc TPR set. You really need to torque the bolts to the right spec in a cross. Especially with water cooled cylinders, otherwise you get coolant leaks in your engine. I had them too many times engine wasn't running good at all. I gave up and switched to Polino but Polini also isn't the best... Had issue with the thermostat that didn't fit had to use a Dremel to make space for it because of casting imperfections.. Anyways Polini has better seals compared to TPR imho. Needs to be sealed otherwise you might end up with this bullcrap and need ro rebuild it again because the big end can damage and the main bearings, they all don't like H2O !
Your content is superb. The piston looks like there was detonation, but the rust makes it confusing. I would say it is detonation because it's evenly around the piston edge. Also because of plating chipping. I think if it was just a coolant leak, it would leave signs only at a single spot on the piston face. That said, you better do some adjustment changes to prevent the detonation, otherwise the engine will break sooner or later and fun stops 😀 It may detonate at part throttle. It's a common issue of racing two strokes. btw, almost 2000 miles with a racing kit and that high rpm is already unbelievable..
I believe it was one of Eric Gorr's writings that talked about coolant leaking in and eroding the crown edges and leading to ring sticking. The rust and lack of oil residue on anything is a dead giveaway that coolant was surely in there... aside from the indications on the cylinder deck. Detonation will do something similar, but I'm not sure that's what it was in this case. It does seem odd that it would be around the edges so evenly with coolant that was likely coming from 1 to 2 points, but IIRC whatever I read about coolant leaks also eluded to a ring around the outer edge. I make no claim to be an engine failure diagnosis pro. I have not heard detonation yet. I've never not heard it before and found signs of it. Not saying that it isn't happening though.
14:48 Nikasil-coating-purpose is to lower cyclinder-piston-friction, but does the piston ever reach that high in the cyclinder, where the chipping and flaking has started? Was that chipping/flaking an indirect (not caused by the piston directly) mechanical damage? Cause the nikasil-coating-edge is the weakest link in the whole coating? 24:47 The weakest link is the original adhesive, u should use the other (cheap-adhesive-free) side of the pad for the good 3M-adhesive, or clean off the cheap adhesive. I would at least suggest... Great work as always, most similar channels don´t make any sense...
The ring will never reach the edge of the coating up top. If it does, I've got bigger problems. I'm just not used to coated cylinders and flaking can be an issue at rough edges. I'm hoping it's fine. Thanks.
Go to the store you buy your gas at fill a mason jar up and cap it off. Bring it home and put it on a shelf to rest. Ethanol is atracted to water and bonds with it and will seperate the ethanol and sink to bottom of jar. You will see a line where it changes from gas to water/ ethonal. This can cause rust in case on 2 stroke engines.
Pretty much everything is 10% ethanol here, so I know there is ethanol. Could have had more water in a batch, but I still think coolant got into the cylinder.
1800 miles on a single ring piston? Wow you did well buddy, my ring usually needs changing between 700 and 1k miles. That’s only revving to 10k too! Ported Airsal T6 (Piaggio) mine is AC though, probably harder on the ring.
Do you have an idea of acceptable ring gap for a 50mm bore? Fro a 139 qmb? I opened the gap up slightly, slightly more than I was aiming for, I guess the rings are a softer iron than I'm used to, I build Chevy v8 engines mostly, I'm not used to such tiny engines! But I plan on getting a bit crazy with one of these eventually! Stroker big bore, with big valve head and cam! Great video
Bookmark this page : www.49ccscoot.com/calculators.html There are calculators there for 2T and 4T piston rings and many other useful things. As long as you aren't planning to use a bunch of nitrous or anything too crazy, the gaps those calculators produce usually work well.
The 2 stroke oil your using (amsoil ) is your issue not a coolant leak the coolant leak wouldnt do what your seeing the rust again is alack of oil sticking to the parts the reason bottom end is fine is because botton end get direct spray upper doesn't get that coolant getting in the combustion cylinder wouldn't rust just 1 end of the rod and it would fill bottom of motor so there would have been alot of rust in the bottom end.
If you go back to my 1,000 mile checkup, you will see that it came apart coated in oil. There was no coolant leak at that point. Same oil. Same mix ratio.
hello, I come back with another question, I have a TGB Delivery 50cc scooter and I want to mount a minarelli motor, the TGB stator has 5 wires and the one from minarelli only 4, how to connect, I searched the whole internet I can't find the electrical diagram from TGB. Thank you .
Great video, I have couple questions, If compression is an issue with a scooter, or even is the bike runs erratic and you have tried everything else, does rebuilding the top, say going to a 100 BBK fix the compression issues and possible issues with the way the bike runs? 2. My 50cc today will not crank, tail light and horn work, new battery, but no cranking sound, dead when you hit start button, if I touch the starter relay with screwdriver it make a small cranking sound, is it the starter relay or the button, where should I start to troubleshoot? DO you know of any diagrams that show full electrical wiring of most chinese scooter? TY for everything
1) You can install a BBK instead of repairing the existing top end. 2) 49ccscoot.proboards.com/thread/2556/wiring-diagrams & 49ccscoot.proboards.com/thread/340/manuals-documents
Great information for all the scooter guys/girls. Going to get my build going this winter, for the Zuma has anyone done the conversion for liquid cooled? how has it went?
I flushed it. It's not ideal. As said in the video, I don't like the idea of any sort of abrasives being in the crankcase. Technically correct would be to disassemble the whole thing.
It looks to me that it is running to hot. Look under the piston and if dark it means running to hot you need to add another rad or a tank to increase you water capacity.
My belief is that it would likely be fine, if they hadn't machined the head a bit off center to make those 2 thin walls around 2 o-rings. The o-rings seemed to work well enough till whatever happened to those walls.
A few things. I'm really glad to see that you caught it when you did and she's breathing again. Also, I have had the same kit on the shelf for a few months waiting for cooler weather to get started on it. It's hot in SE GA this time of year. So, do you think that the issue you had is something that I should take precautions to avoid? I honestly haven't unboxed it except for the cylinder because my friend in the Philippines wanted to see it. Last, do you feel like cutting my cases for me since you did a fine job on yours? Not free of course. I'd like to do build videos like yours if this particular build since the last one was lost due to the end of zumaforums.net. And thank you, again, for documenting your struggles along with your successes.
My opinion is that the failure would not be likely if the bore and stud o-ring spacing was more even. 2 o-ring grooves were closer to the bore than the other 2. Those 2 with thin walls are what failed. If your kit is in the box, look it over. If never used and you have the same issue, then maybe you can get the head replaced. Could be something that happened in one head or batch of heads and never again. I always advise people to do their own cases. I don't think it's worth it to ship them back and forth and I don't really like taking the risk that I ruin someone's cases. I'm not a confident machinist and it stresses me out. I did all of mine with flap wheels or carbide burrs till recently.
@@49ccscoot I'll get a look. And I totally understand where you're coming from. You did a great job on your cases but I understand. People think that I'm good with computers but I'm not. I'll work on mine and sometimes things work out. I'm definitely not going to touch anyone else's. I'm a member of the forum and I'll try to get some documentation of my build there.
Ah get rid of that cylinder and put a Barikit 77cc jug in there .. try gluing your teflon gaskets in place with contact adhesive before you tighten down the head, so you know they stay in the position they are meant to be in when they are not visible
what squish were you running? i have no idea why people in the comments are suggesting to run a larger squish clearance, detonation can't occur if there is no fuel/air to go bang!
@@49ccscoot that's very conservative, fine for low power long life road bikes, and for manufacturer's butt covering. I ran 0.7mm on a 64x52 (bigger piston, more rod stretch) on your engine i'd aim for 0.6mm and only back off if the piston kisses the head while off throttle at high RPM.
@@TerraRoot It was 1.1mm. I had to shave the head to get it to their spec. I've stuck with it there because this is a road scoot, whether it should be or not.
@@49ccscoot full disclosure i'm a tiny bit of an armchair warrior having only tuned up two 2t engines, but everything i've read (mostly wayne wright's contributions) indicates 0.8 is the absolute maximum. i know you had detonation probably more from the coolant leak effecting the octane than the size for your squish, but if the squish was tighter the detonation wouldn't have been there in the squish area.
I have a question about 50cc engine, what is a normal compression. My 2004 cpi gtr50 have 4285km and it run fine 84psi coold 115psi hot. how many km can a 2-stroke engine run before making repairs? and its a good idea to put a 70cc engine with the original conecting rod (50cc) because I have a very good chance of changing it for a 70cc this winter. Just my 50cc engine is hover boosted ot can go maximum 95km/h. thank you for reading my comment.
Compression will vary. I saw one service manual specify 198psi for a stock 1E40QMB, which is ridiculous. I would really like to see 120-150psi for something like that. There's a lot of room for error with testers and sealing too. 84psi cold does not sound like something that should be running great. If possible, see if you can try another tester if you've got friends with more or maybe even a loaner tool from a parts store just to see if it changes. Sometimes I've had better luck removing the rubber ring and using the washer from a spark plug on the tester's fitting. Engine longevity will vary. There are stock Yamahas with over 20,000 miles on them. Nothing that I own is going to do that because it will be modified and ran hard, but it is possible. 70cc is fine with a stock crank, up to a certain point. Sport kits work very well for many miles with stock cranks in my experience. When RPM gets elevated, then it may be a problem.
Hello i need an advice, I have Yamaha Aerox with DR 70cc cilinder, stage6 variator, stage6 fan, stage6 clutch and stage6 clutch bell and i am using technigas next r exaust pipe. Is the leovice gp a better pipe for my set up? Or shoud i buy a leovince tt??
The GP is very mild, like 8500RPM. I don't know much about the DR 70. TT is likely better, but you may want to check out Yasuni exhausts. They have a great reputation for performance and offer pipes like the Z and R for lower revving setups and the C16 is really popular for a bit higher revving stuff and makes great power.
I know. I think anyone that doesn't do videos like this would probably be surprised just how much time it takes from adding a bunch of time to the actual work playing with cameras to editing and all of that. The big channels have a crew to film and edit and so on. It ain't like that here. It's just me. I'm literally hoping to get back to the SSR today, but it will be a longer process to get the next vid out for it because I have to work on something, then see how that goes so I can research and order other stuff and I'm at a part that to me is the most difficult of it. It's not forgotten.
Hi, I have a little question, I have a Malaguti F10, with original engine, I mounted a 47mm engine set, but after 4 km the engine stopped running and restarted but after it lost power and after another 3 km it stopped, since then it doesn't start, should the quality of the set be too bad?
Could be a quality issue, but also may be tuning. It could be running lean and soft seizing. It could be that it needs time running easy to break-in because of tight clearances.
If you go back to my 1,000 mile checkup video, you'll see that it came apart coated in oil. There was no coolant leak then. Same oil. Same mix ratio (32:1).
RUclips should automatically create English subtitles. Then it can be automatically translated. It may not happen immediately and I don't know if they do Polish or not.
Please continue with your vids, they are just one of the best out there.. So helpfull in many cases.. Love your vids..
the piston is detonation to smal squish or to mutch pre ignition the rust is just coolant leak
2 stroke scooter tuning & ryan are spot on with coments. Also I advise you to rich up the mixture on the main jet, as i've seen the colour of the piston crown and sqishband of the head...
Great and educational video as always!
That coating won't fall out dont worry. Have seen cylinders with whole chunks missing running just fine for years. As long as its beneath the exhaust port roof height you won't have performance decrease. Good to see it back together, good for 2 thousand more miles!
I hope you can read this in time. Piston edge- is detonated and you need to run higher octane OR when the head gasket blew from a loosening head bolt lowering the compression. Use blue lock tight. The seal is made on the head by that O-ring.feal with fingernail around inside of cylinder to check for scratches (looks fine). That chip in the nickel sodium carbide coating is from a casting and boring flaw and fine. Never use sandpaper and a finger on the inside of the connecting rod, you’re making it out of round. Lmk if you appreciate the insight or think I’m just a hater (and I’ll stop).
I appreciate insight. Sometimes I wonder if comment makers have any idea what's going on, but this doesn't seem to be the case. You know, like telling me that the TPR won't last 1000 miles when I'm at near 2,000 stated many times in the video and title. I also thought detonation at first, but I believe it was Eric Gorr that talked about coolant leaks doing just this and actually leading to ring sticking in one of his publications. I don't claim to know the cause for sure, but the description that I recall about the coolant leak was almost exactly what I found.
I did find a crack in my airbox (replaced) so maybe there was something going on? Normally, I hear detonation. I have never heard it with this kit.
No sandpaper on the conrod. Just cloth and polish. The sandpaper was just to clean some rust off of the crank wheels. Kinda pointless since I can't get in there to clean everything, but I suppose it made me feel better. I do realize that there is a totally technically correct way to do things and then sometimes how things actually go. I didn't even measure the conrod small end diameter TBH, because I saw no signs of needle rollers eating in or anything of that nature that I've seen with other conrods. At this point, the head is either screwed because of the broken walls around the o-ring or it's will probably work OK. I could toss the whole thing (head and piston kit etc... would end up being near total replacement cost) or just see if I can get more use out of it first.
The reason that I have not used a thread locker on my studs is that my initial experience with torque specs was with automotive cylinder heads. Most of which specify a lubricant, often motor oil or an overpriced specialty lube. These scoot manufacturers and aftermarkets don't bother, but I've been in the habit of using motor oil and generally it's not a big issue if I re-torque after heat cycling.
I don't make any claims of being an expert and always correct. Thanks.
@@49ccscoot dont worry about torqing nuts on head/studs, just use coper washer under nuts and torq to the specific values. M6/M7 bolts and nuts 12~14nm. Never used locktite, just coper washers, never had a problem.
@@49ccscoot Don´t worry too much , the Tp thropy 70 ccm (castiron) in my vespa is already lasting near 45000km on the second piston.But my setup is very low rev on the ET2.(9gr rollers and sito plus exhaust) As long as you maintain it well it should keep going until a pistonring snaps or the engine runs dry.
I'm glad T2 is up and running again and the cause wasn't anything major. I'd watch very closely the coolant levels from now on. As usual I really enjoy your videos. Keep up the good work man.
Yeah, I'm concerned that it's going to leak again. Replacing the head and the piston would mean I might as well do the whole kit so I figured I might as well try it and hope it works for a while. Thanks.
Another great video my friend, so my guess would be that my stock 50cc engine is in great shape as far as compression goes. I’m getting 130 psi of compression. I think I’ll replace the crank seals, I just haven’t been feeling motivated to do anything but now I’m ready. Thanks for posting, ride safe.
I got heat problems,before I replaced a new 60cc cylinder.From stator\alternator wich broke down 100km later.I`m not so precis,but new cylinder had at least 1-2 mm clearance from piston.The cylinder shrinked 2 mm after perhaps 10 000km.New,2 times better 60cc,you can drop piston right trough.The old has to use force,it has shaped\melted around the piston(wich also are oval from heat).And I mixed more fuel,2.5 turn to new cylinder,wich dont mix with old stator,and new plug turned blue.COMPRESSION:lost 2 tries in non-egr high compression 70cc.First cylinder bolts,was to tight,and squeezed into soft metal casing,impossible to unscrew now.2.attempts the treads inside cylinder nuts was ripped out.New naraku performance crank,wich need 2 top-gasket,it touches the valves.
Such a pleasure to watch you work. Well done as always.
Sincerely,
Alicia.
Thank you so much 😀
Lean mixture/ignition, look at the piston.. All the best from Sweden..
Hope your cylinder holds for a while, the chip and the scratch in the cylinder wall does make me suspicious about the cause the cause why your piston ring got stuck because it does add more and uneven friction, the rust could only have come from a coolant leak indeed (or the scoot would have taken a dive a in a pond 😉) the breaches between the two stud holes on the head would for me mean replacement, if it had an aluminum crush gasket I would have taken the chance but with a rubber o ring gasket I wouldn't, but time will tell how this plays out. I would check up on the cylinder, piston and head in a short time.
Please keep making these video's i find them really enjoyable to watch. 👍👍
Now back to wrenching myself so my old Honda MT-5 can hit the road again after 20+ years!
Thanks. For me, by the time the head and piston kit were replaced, I might as well get a new cylinder kit totally. Figured I might as well try it and see what happens.
I had the same issue till I started using pro boost now fine.
This is why I advised the Klotz Super Techniplate it leaves a protective film that protects the motor when you shut it off and it stays there this is why wear is so little with the Klotz oil and again it runs a bit smoother than the amsoil me and you had a chat about this before and you said you loved your amsoil even after i linked you the info saying it wasn't designed for motorcycles and such it was designed for weed wackers and chainsaws this is why they removed the support from the amsoil bottle for motorcycles / quads / and snowmobiles and such.
Wrong AMSOil. I used to use Saber Pro. Now I use Dominator. They did change their recommendations on Saber and that is when I switched over. Who knows, maybe I'll try something else after I go through a case and a half of this that I have. I've been pleased with it though.
I've had the same issue with a 50cc TPR set. You really need to torque the bolts to the right spec in a cross. Especially with water cooled cylinders, otherwise you get coolant leaks in your engine. I had them too many times engine wasn't running good at all. I gave up and switched to Polino but Polini also isn't the best... Had issue with the thermostat that didn't fit had to use a Dremel to make space for it because of casting imperfections.. Anyways Polini has better seals compared to TPR imho. Needs to be sealed otherwise you might end up with this bullcrap and need ro rebuild it again because the big end can damage and the main bearings, they all don't like H2O !
Thank you for sharing this experience, very nice and helpful content!
Your content is superb. The piston looks like there was detonation, but the rust makes it confusing. I would say it is detonation because it's evenly around the piston edge. Also because of plating chipping. I think if it was just a coolant leak, it would leave signs only at a single spot on the piston face. That said, you better do some adjustment changes to prevent the detonation, otherwise the engine will break sooner or later and fun stops 😀 It may detonate at part throttle. It's a common issue of racing two strokes. btw, almost 2000 miles with a racing kit and that high rpm is already unbelievable..
I believe it was one of Eric Gorr's writings that talked about coolant leaking in and eroding the crown edges and leading to ring sticking. The rust and lack of oil residue on anything is a dead giveaway that coolant was surely in there... aside from the indications on the cylinder deck. Detonation will do something similar, but I'm not sure that's what it was in this case. It does seem odd that it would be around the edges so evenly with coolant that was likely coming from 1 to 2 points, but IIRC whatever I read about coolant leaks also eluded to a ring around the outer edge. I make no claim to be an engine failure diagnosis pro. I have not heard detonation yet. I've never not heard it before and found signs of it. Not saying that it isn't happening though.
14:48 Nikasil-coating-purpose is to lower cyclinder-piston-friction, but does the piston ever reach that high in the cyclinder, where the chipping and flaking has started? Was that chipping/flaking an indirect (not caused by the piston directly) mechanical damage? Cause the nikasil-coating-edge is the weakest link in the whole coating?
24:47 The weakest link is the original adhesive, u should use the other (cheap-adhesive-free) side of the pad for the good 3M-adhesive, or clean off the cheap adhesive. I would at least suggest...
Great work as always, most similar channels don´t make any sense...
The ring will never reach the edge of the coating up top. If it does, I've got bigger problems. I'm just not used to coated cylinders and flaking can be an issue at rough edges. I'm hoping it's fine.
Thanks.
Go to the store you buy your gas at fill a mason jar up and cap it off. Bring it home and put it on a shelf to rest. Ethanol is atracted to water and bonds with it and will seperate the ethanol and sink to bottom of jar. You will see a line where it changes from gas to water/ ethonal. This can cause rust in case on 2 stroke engines.
Pretty much everything is 10% ethanol here, so I know there is ethanol. Could have had more water in a batch, but I still think coolant got into the cylinder.
i called it when you broke down i said lack of compression so i bet ring :D
good to see its back running again long live t2 :D
Yeah. It felt wrong and sounded wrong, but lucky me I had no spark and no compression. Could have been worse though.
@@49ccscoot I know lucky the crankshaft was good after a clean tho . Tpr kit 1.8k miles is great for a hyper kit as you know
1800 miles on a single ring piston? Wow you did well buddy, my ring usually needs changing between 700 and 1k miles. That’s only revving to 10k too! Ported Airsal T6 (Piaggio) mine is AC though, probably harder on the ring.
I swapped out the ring at 1,000 miles because I had a spare on hand, but it had barely worn and didn't require replacement at that point.
Thanks for the info bud ,great video, keep up the great, awesome
☆☆☆☆☆
Also go up a tiny bit on the main jet.
Do you have an idea of acceptable ring gap for a 50mm bore? Fro a 139 qmb? I opened the gap up slightly, slightly more than I was aiming for, I guess the rings are a softer iron than I'm used to, I build Chevy v8 engines mostly, I'm not used to such tiny engines! But I plan on getting a bit crazy with one of these eventually! Stroker big bore, with big valve head and cam! Great video
Bookmark this page :
www.49ccscoot.com/calculators.html
There are calculators there for 2T and 4T piston rings and many other useful things. As long as you aren't planning to use a bunch of nitrous or anything too crazy, the gaps those calculators produce usually work well.
The 2 stroke oil your using (amsoil ) is your issue not a coolant leak the coolant leak wouldnt do what your seeing the rust again is alack of oil sticking to the parts the reason bottom end is fine is because botton end get direct spray upper doesn't get that coolant getting in the combustion cylinder wouldn't rust just 1 end of the rod and it would fill bottom of motor so there would have been alot of rust in the bottom end.
If you go back to my 1,000 mile checkup, you will see that it came apart coated in oil. There was no coolant leak at that point. Same oil. Same mix ratio.
i would probably increase the sqish or lower the compression and keep the timing where it is
Reduce the squish. A.G Bell recomends minimum of 0,6mm for 50cc
What kind of oil are you using seems to be doing its job great great video as always
Thanks. I'm using AMSOil Dominator Racing 2T pre-mixed at 32:1. It smokes quite a bit, but I know it's lubed.
hello, I come back with another question, I have a TGB Delivery 50cc scooter and I want to mount a minarelli motor, the TGB stator has 5 wires and the one from minarelli only 4, how to connect, I searched the whole internet I can't find the electrical diagram from TGB. Thank you .
You don't cross tighten your cylinder head bolts?
I do a crisscross pattern.
Great video, I have couple questions, If compression is an issue with a scooter, or even is the bike runs erratic and you have tried everything else, does rebuilding the top, say going to a 100 BBK fix the compression issues and possible issues with the way the bike runs? 2. My 50cc today will not crank, tail light and horn work, new battery, but no cranking sound, dead when you hit start button, if I touch the starter relay with screwdriver it make a small cranking sound, is it the starter relay or the button, where should I start to troubleshoot? DO you know of any diagrams that show full electrical wiring of most chinese scooter? TY for everything
1) You can install a BBK instead of repairing the existing top end.
2) 49ccscoot.proboards.com/thread/2556/wiring-diagrams
& 49ccscoot.proboards.com/thread/340/manuals-documents
Great information for all the scooter guys/girls. Going to get my build going this winter, for the Zuma has anyone done the conversion for liquid cooled? how has it went?
Check out the forum. There are multiple LC conversions, some of which are Zumas.
wouldn't sanding in a case like that without cleaning contaminate it?
I flushed it. It's not ideal. As said in the video, I don't like the idea of any sort of abrasives being in the crankcase. Technically correct would be to disassemble the whole thing.
It looks to me that it is running to hot. Look under the piston and if dark it means running to hot you need to add another rad or a tank to increase you water capacity.
Super clean under the piston.
The o rings in the head look too thin. What's to stop it leaking again.
My belief is that it would likely be fine, if they hadn't machined the head a bit off center to make those 2 thin walls around 2 o-rings. The o-rings seemed to work well enough till whatever happened to those walls.
A few things.
I'm really glad to see that you caught it when you did and she's breathing again.
Also, I have had the same kit on the shelf for a few months waiting for cooler weather to get started on it. It's hot in SE GA this time of year. So, do you think that the issue you had is something that I should take precautions to avoid? I honestly haven't unboxed it except for the cylinder because my friend in the Philippines wanted to see it.
Last, do you feel like cutting my cases for me since you did a fine job on yours? Not free of course.
I'd like to do build videos like yours if this particular build since the last one was lost due to the end of zumaforums.net.
And thank you, again, for documenting your struggles along with your successes.
Also, I love the sound effects!
My opinion is that the failure would not be likely if the bore and stud o-ring spacing was more even. 2 o-ring grooves were closer to the bore than the other 2. Those 2 with thin walls are what failed. If your kit is in the box, look it over. If never used and you have the same issue, then maybe you can get the head replaced. Could be something that happened in one head or batch of heads and never again.
I always advise people to do their own cases. I don't think it's worth it to ship them back and forth and I don't really like taking the risk that I ruin someone's cases. I'm not a confident machinist and it stresses me out. I did all of mine with flap wheels or carbide burrs till recently.
@@49ccscoot I'll get a look. And I totally understand where you're coming from. You did a great job on your cases but I understand. People think that I'm good with computers but I'm not. I'll work on mine and sometimes things work out. I'm definitely not going to touch anyone else's.
I'm a member of the forum and I'll try to get some documentation of my build there.
Ah get rid of that cylinder and put a Barikit 77cc jug in there .. try gluing your teflon gaskets in place with contact adhesive before you tighten down the head, so you know they stay in the position they are meant to be in when they are not visible
What is a good compression for a 70cc aluminum kit air cooled ??
I like to see ~150psi anyway, but if building to a spec I would use corrected compression ratio and aim for 7-8:1 for a street scoot.
what squish were you running? i have no idea why people in the comments are suggesting to run a larger squish clearance, detonation can't occur if there is no fuel/air to go bang!
0.9mm (TPR's recommended squish).
@@49ccscoot that's very conservative, fine for low power long life road bikes, and for manufacturer's butt covering. I ran 0.7mm on a 64x52 (bigger piston, more rod stretch) on your engine i'd aim for 0.6mm and only back off if the piston kisses the head while off throttle at high RPM.
@@TerraRoot It was 1.1mm. I had to shave the head to get it to their spec. I've stuck with it there because this is a road scoot, whether it should be or not.
@@49ccscoot full disclosure i'm a tiny bit of an armchair warrior having only tuned up two 2t engines, but everything i've read (mostly wayne wright's contributions) indicates 0.8 is the absolute maximum. i know you had detonation probably more from the coolant leak effecting the octane than the size for your squish, but if the squish was tighter the detonation wouldn't have been there in the squish area.
Same thing happen to my 2 stroke it broke down and now it won't turn on it has spark
Compression test and making sure it has fuel would be next on the list.
hi, i did 15 tests on different bikes and i always get 75 psi, why? im using aliexpress compression kit
Most likely your compression tester is not working properly and/or not sealing. Borrow another one if possible and try it.
Silkolene pro boost octane booster will cure all that detonation
Nice!
I have a question about 50cc engine, what is a normal compression. My 2004 cpi gtr50 have 4285km and it run fine 84psi coold 115psi hot. how many km can a 2-stroke engine run before making repairs? and its a good idea to put a 70cc engine with the original conecting rod (50cc) because I have a very good chance of changing it for a 70cc this winter. Just my 50cc engine is hover boosted ot can go maximum 95km/h.
thank you for reading my comment.
Compression will vary. I saw one service manual specify 198psi for a stock 1E40QMB, which is ridiculous. I would really like to see 120-150psi for something like that. There's a lot of room for error with testers and sealing too. 84psi cold does not sound like something that should be running great. If possible, see if you can try another tester if you've got friends with more or maybe even a loaner tool from a parts store just to see if it changes. Sometimes I've had better luck removing the rubber ring and using the washer from a spark plug on the tester's fitting.
Engine longevity will vary. There are stock Yamahas with over 20,000 miles on them. Nothing that I own is going to do that because it will be modified and ran hard, but it is possible.
70cc is fine with a stock crank, up to a certain point. Sport kits work very well for many miles with stock cranks in my experience. When RPM gets elevated, then it may be a problem.
@@49ccscoot thanks for this info :D now i care less about the connecting rod. and yes when it is cold it does not stay on the idle.
Hello i need an advice, I have Yamaha Aerox with DR 70cc cilinder, stage6 variator, stage6 fan, stage6 clutch and stage6 clutch bell and i am using technigas next r exaust pipe. Is the leovice gp a better pipe for my set up? Or shoud i buy a leovince tt??
The GP is very mild, like 8500RPM. I don't know much about the DR 70. TT is likely better, but you may want to check out Yasuni exhausts. They have a great reputation for performance and offer pipes like the Z and R for lower revving setups and the C16 is really popular for a bit higher revving stuff and makes great power.
Thanks :)
The DR 70cc is basically rebadged Top Performance black trophy cast iron 70cc
@@Sensey9383 I would think maybe the Yasuni Z, but a LeoVince TT would be OK too.
ey ... but what happened to the SSR project ? :D cmon ....
I know. I think anyone that doesn't do videos like this would probably be surprised just how much time it takes from adding a bunch of time to the actual work playing with cameras to editing and all of that. The big channels have a crew to film and edit and so on. It ain't like that here. It's just me. I'm literally hoping to get back to the SSR today, but it will be a longer process to get the next vid out for it because I have to work on something, then see how that goes so I can research and order other stuff and I'm at a part that to me is the most difficult of it. It's not forgotten.
The roughness on the piston and top part off the cylinder edge as you call it is not corrosion, but detonation!
Look like you need to tune your carb again
so chief .. the bottom problem was a faulty gassket ? :D sry my english kinda sucks ..
I think it is because of the broken o-ring grooves in the head allowing coolant into the cylinder.
I always imagined a really skinny super tall guy... wierd
great
Hi, I have a little question, I have a Malaguti F10, with original engine, I mounted a 47mm engine set, but after 4 km the engine stopped running and restarted but after it lost power and after another 3 km it stopped, since then it doesn't start, should the quality of the set be too bad?
Could be a quality issue, but also may be tuning. It could be running lean and soft seizing. It could be that it needs time running easy to break-in because of tight clearances.
I know on a chainsaw that usually means not enough oil
If you go back to my 1,000 mile checkup video, you'll see that it came apart coated in oil. There was no coolant leak then. Same oil. Same mix ratio (32:1).
looks like the ignition is to advanced
👍👍☝️
Start using #10 spark plugs trust me!
I have since day 1.
go to #11
Not enough oil
Hi do have Instagram I want ask you questions
Tpr junk only last 1000 miles if your lucky
Okay what cylinder kit performs just as good or better then the tpr with more reliability?
fajne by były napisy po polsku :(
RUclips should automatically create English subtitles. Then it can be automatically translated. It may not happen immediately and I don't know if they do Polish or not.
Buy stage6 tpr is garbage
stage 6 to śmieci