Lateral Gas Porting on a 2 stroke to gain hp
HTML-код
- Опубликовано: 6 фев 2025
- Lateral gas porting was taught to me by Matt Kneen. He built winning snowmobiles for years and used this technique in them. If you want to read a thread he is in this is a great one.
www.mopedarmy....
I do this to all of my personal builds and see a great improvement with increased compression, lower temps, and larger carbs.
If you want some micro bits, I use these are they are good. but expect to break a couple because they are so small. - amzn.to/3sR5vV6
#2stroke #Enginetuning #Mopeds
My Gear Links
Main Camera amzn.to/3qw1Cnt
Main Lens amzn.to/3qsSOPf
Wide Lens amzn.to/3pwmOdQ
Portrait lens amzn.to/32ooNbv
Mic amzn.to/3HgkBch
Light amzn.to/3qw2SXJ
360 Camera amzn.to/3euCkjV
Selfie stick amzn.to/3pxJGJK
2 stroke master here. Gas porting works best on 4 stroke motors. This has been tested by yamaha and Suzuki in the 1990s, the Turbulence on the ring when it's exposed to the transfer and exhuast ports with the gas ports created ring flutter and also on the way down the rings would get snagged by the ports creating cylinder scratching. And ring failure. Not to mention a loss of 0.2 hp
Drag racers have been gas porting pistons for decades because of very thin rings with little tension. Gas pressure at ignition really forces ring into cylinder wall. Keystone rings work well too.
Been running my polini for 2 seasons. I’ve followed several build guides but have never seen this. it always looks perfect when I check it But I’m def getting flutter! Hopefully this will help. Keep up the good work man.
Do it up! Check out spark plug side gapping too!
@@Corn-ped OIL MIX 33:1 IS OK ?
I like to run less oil. 50:1 or 60:1 full synth
I think to get the most out of my Jawa, plus it likes to soft seize. I think I need to do this. All I can do to make this little wh**e get to 45mph.
Ok gonna do this before I slap it back together.
Your channel has really helped me. Thank you.
Get that JAWA GOING!
@@Corn-ped spoke with Josh at BillBunes today. This cylinder is on its way out this afternoon. 🥵🥵
I've been porting chainsaws for years and never would've thought about piston porting and probably v wouldn't have heard about it if i didn't see your video it's brilliant and most husqvarna saws use a single ring
Give it a try! Pair it with a side gap spark plug!
@@Corn-ped I never heard of a side gap plug either I'm going to watch that video now
Dynosheet before and after?
Where is the dyno test?
Awesome!
That induces carbon buildup creating stuck rings in 2000 miles. The Piston seizes up at the bottom skirt area. From overheating from lack of lubrication/lean mixture. Only drive it at night😅😅😅😅 or do what someone did in the 70s that is drill approximately.020 deep divots on both piston skirts to catch oil. 1/4 drill you can drill them evenly spaced in a pattern if desired at least five divots no need for more than 10 on each skirt. Then you can haul ass Non-Stop
Thank you CornPed!!! I did the gas porting and the plug side gapping you showed and OMFG the polini is so fast! I'm not joking bro its insane paired with a proma circuit pipe. Thanks bro you are the shiz😎
Can you or someone else explain the mechanism of how his "works" and how this creates more horsepower, also, applications to chain-saw and other small engines like an Echo 2400 - 210 series of lawn equipment. TIA
@@peterdarr383ringland porting the TOP ringland on the piston causes the top piston ring to act like a dykes ring creating a better seal and more power plus helps cool the piston since more mix can get around the top part of the piston
@@thomaspeffer3885sweet ! Gunna try it on my old ms290 piston before I put it back in . I wanted to drill holes for the transfer port bridges but the piston has a cut away on each side of the piston . It’s amazing how this stuff works let’s alone how it was discovered. every herd of the one where the drill small hole through the top of piston or was my leg being pulled ?
Very Nice video! Keep up the good work man
Thank you!
Awesome, Bro
Thanks for the info . Interesting! only seen it on 4 stroke car engines
In which direction does the gas flow through piston ring land holes?
YT really supports your channel recommending 2-year-old videos . your doing something right.
The gas flows from the top of the piston down the cylinder wall, into the ringland and then under the ring and down the piston to cool the cylinder wall and piston.
Absolute loving your videos. Keep up the amazing work!!
Thank you! Ill keep em coming!
Could you make a porting video for beginners
Could you please make a video with a comparison of the stock piston, compared to this one... It all sounds great, but there´s 100 YTers doing they same, and also never showing any plausible results... It could all also be just fairy-tales...
this
Ever presented any testresults?
Cool video, can't wait for the next one.
Thanks Wayne!
@@Corn-ped Just giving you my opinion :-)
Re-watching this video one month later, would it be some sort of not good to put a lateral gas port on the piston where the exhaust port is?
So it’s a single ring piston…
Do you put the piston ring back on after you drill the holes???
Good video I look forward to your videos
Thank you!
SUPER RIGHTEOUS ! Great video!
Glad you liked it!
keep making videos like this please, im a beginner in bikes engine modifications and want to open my own bike's repair garage, so yeah really need to learn alot about bike engine because that is the harder part for me. tq😊 and im subscribed.
Thanks bro
can anyone explain to me what the purpose is of the 2 blind big gaps above the pistonpen? i guess it has to do with cooling or some sort? cant find any info on that
I build little 2-stroke engines for a living, (don't have those cavities), but I am not totally sure why either. I can see 2 things it can do though.
1) Lighten the piston to a better balance weight.
2) Connect the front and rear transfers to help equalize the pressure in them.
That's all I have.
Tq bro..❤
How does it increase compression,?
So doing this will increase performance and run cooler? But why is having the second piston on not a good idea? Didn't quite understand that
If you run the second ring, the premix cant get by it and cool the cylinder wall/ piston.
I've seen this done to pistons in the 70's.
Love your video's!!!
Thank you!
Cool concept. How deep are you drilling?
I jave a ktm 125sx It is a double ring piston what do I need to do just not install the bottom ring
Yeah only run the top ring
It will still run I am sure with no lower ring. But you will have a passage (the lower empty ring groove) from the transfer ports to the exhaust port near the bottom of the stroke when the cases are pressurized on the down stroke. It will probably lose some fuel charge out the exhaust port, and slightly reduce the primary compression (in the cases). On the up stroke, (now creating a vacuum in the cases to open the reeds), the passage can allow burnt exhaust gasses in the exhaust port tunnel to flow the opposite way into the transfers, and the reeds may open up a tad later, (less charge entering the bottom end if the reeds open later.), due to less suction. You will probably lose a bit of power. If you can pick up a single ring piston from KTM or a company like Weisco, you can try this mod. But I would ask this guy to run his hard for you first. :)
Also is it true that if my cylinder has a chip or dip below or above the cylinder ports that it’s still good to run or something along them lines?? Just wondering your thoughts strange thing is that this engine ran fine until the main drive sprocket broke I will say I did have quite a bit of oil spitting out the back of the silencer so is that also known as blow by??
yeah if you have a chip/dip and it doesn't have sharp edges for the ring to catch you should be good.
Blow by is when the premix leaks past the rings into the crank case. oil spitting out if your pipe is from running to rich.
Can we do this in the lower ring, in the two ring piston?
Pressure Paths in compression rings
Would it be good on snowmobile application
That's where I learned about it. From 50cc racing sleds
This is the thing though , people are watching this thinking this applies to all two strokes when it doesn’t . If you got all the biggest power strokes you’d find not all have this. Every two stroke design is different
Different strokes for different folks
Hey love the info is it possible that you could get a zoomed in image of what it looks like after I have a older Franco morini s5 engine that all use the same bottom end but the top end uses different cylinders and to of the top ends have double piston rings but I have one rope end that only uses one ring if you could up load a image or send me an image of what it looks like when done and you probably answered this already but if I may ask how come this wouldn’t work on double ring basically double the holes and offset them just wondering
Ill post a photo in the community section for ya. www.youtube.com/@Corn-ped/community
I'm new at the game, is 'ghosting' the same as ring flutter ? Thanks., You picked up a new subscriber.
hmm I have not heard of ghosting?
@@Corn-ped Some of the newer model Stihl Chainsaws ( MS362 specifically ) experience a problem which has become known as ghosting. An unexplained phenomenon which has yet to be properly diagnosed or even existing (By Stihl ). It is a high frequency vibration within the saw.
@@thomasgronek6469 hmmm. I would think that has more to do with an unbalanced engine or part.
@@Corn-ped Thanks.
I broke my top piston ring ...Will the bike run with out it
yeah it will run fine. I would swap that bottom ring up to the top.
I assume you didn't drill a hole were you marked the first marke because the pin? That's why you said 7 holes. But there's eight. Thanks for the vid gunn try it on a couple I have while there apart
Yeah, don't do it at the pin
@@Corn-ped so really , you making the same “ notch “ as the pin “ hole “ correct ? I’m trying to vision what I have to do … lol I was first thinking you drilled right through the piston . But then I see that you say “ notch “ so really you make it look like the top only of the pin hole
@@steveZ1turbo yes. Only notch it to the back of the ringland. Do not go thru.
Does this work for iron cylinders? Plz let me no I need to no looks really hard to do
Yeah totally!
what the
Dark sorcery!
What if ya remove the ring from a two ring piston and try this?
Same concept!
@@Corn-ped what about compression, will the single ring with the "dimples" seal just as good as two rings?
I removed the bottom ring on the RD-375 long rod motors I raced. The piston had a keystone ring and I never saw blow-by below top ring so I removed the second ring. Keep in mind that the rings help the piston shed heat of combustion so you have to keep an eye on the underside of the piston for oil burning onto bottom of crown.
very neat. do you have a still picture of that close up so we can see how much material is coming out?
yeah, its not much. I can post it in the community tab.
How much would it cost to sell me? One of them premeet by you to put on my punch mopet engine ??
yeah I could. $20?
Great videos! What is the origin of the name Cornped? Do the gas porting grooves need to go all the way to the top of the piston? Looking at the pics in the link to MA that you posted, his ports are like half moon shaped.
They do NOT need to go up like a half moon. That guy did HUGE ones with a drill bit. You only need a notch. Back when people started doing it, no one knew about micro bits so people were using the smallest drill bits they could find.
CornPed came from my name Maize which means corn and mopeds, Ped. Its not that original. I made a blog like 15 years ago and at the time someone was calling me CornFace, so I decided to call the blog CornPed. I could choose a different youtube name but I havent thought of a better one.
@@Corn-ped are the porting grooves the same depth as the ring groove?
@@rexsheler1321 yes. it goes all that way in.
Here in Iowa we're all corn fed.
hello! I'm gonna try this but what is the difference between this and vertical gas porting when you drill through the top of the piston? would that also work on a 2 stroke? also why don't these holes cause blowby? to me drilling these holes sounds like bypassing the ring? and also does it matter when drilling if it nicks the ring land itself as long as it doesn't hit the lower part you said? and why do you drill on the top and not bottom?
Do you go all the way trougt
No. Only to the back of the ring land.
What tou mean, that less oil increases power? I thought and heard its opposite to that..
You heard wrong. Fuel burns better than oil, Adding oil is purely for lubrication it slows down a motor
Lean is mean. lean fuel 👍 but will burn up the motor . More oil not to much more. makes more power . 4.5 oz oil to one us gallon works great on my honda af16 with 72 cc polini .
More lubrication less oil burnoff from heat and helps "diesel" any leftover thats why you get more power with a little bit more oil 👍👍👍
Using any more oil than needed for lubrication will promote detonation. If you jump from a small ratio (50:1) to large (16:1) make sure you richen the jetting up as the oil takes up space in mixture. I used 40:1 in the RD375's and 16:1 in the TZ250 as the TZ's liked the extra oil for cooling.
@@postulator890 super kart dudes use way more oil. Why is that? Allmost same engines than 2-stroke GP bikes.
I was gonna build a setup with a polini kit on my free spirit pretty soon do you have any other tips for polinis?
Parts I have:
Polini kit
Estoril sidebleed
17 tooth gear (free spirit 1 speed so 35 in the back) should I go with a bigger rear sprocket?
Clone 15 bing (might switch to the mallosi 4 petal and a mikuni vm20)
Running stock points
Treatmetric 3 shoe clutch
Let me know what you think and if I should change my setup at all. I was running an airsal kit with a biturbo pipe before and it caught a ring on the exhaust port unfortunately. I was looking for about 50mph but I haven’t switched out my front forks or changed any suspension components so that might be a little aggressive. Thanks
Maybe switch out the front sprocket to a smaller one, like a 13. Ive heard that shorter chain is better so ye. And about the bing, make sure you use original 2.17 atomizer and original jets for it
I would use a real bing 15 carb or a larger one. Oko carbs are great, Mikuni VM 18 or 20, Del 21.
I would also go to 16x40 gearing. Thats my favorite.
Marty has a great gearing calculator if you want to mess around with gearing and speeds.
A stock polini revs to around 10K. you can get them to rev out to 13 if you go nuts.
toolbox.martysgarage.info/
@@Corn-ped thank you for the response that gear ratio calculator is very helpful.
I'm going to try this on my 2 stroke 78.5cc 80/100 bike engine. Using just 1 ring with reliefs. Oh, it's a reed valve engine
Is there any relationship between the cylinder ports and where the ringland ports go? Like centered in the ports or only on cylinder wall or just evenly around the whole piston?
I have tried both and not noticed any difference.
So i have to drill through all the way inside the piston ?
No! Don't touch back side of ring groove as he explains in video.
I have only side gapped my plug on the stock 50cc eaton bimmer3 I roll as my daily. Major difference.. 7-8 mph top end gain. Not a super fast bike to begin with but cruising went from 28-30 to 35 easily. Top speed gain similar at 45 mph up from 37-38. More importantly just finished my street build gas porting the 70cc kit i have and ill definitely side gap the plug too. Its already pretty ridiculous but I hope it it will run cooler with the pipe and carb setup I have. It was running 55 mph. Would like to see over 60 without soft sieze and I believe this will do the trick. Gas and fuel oil mix already "tuned"
yeah man! Get that 60!!!
I can’t even see what u did. Can u zoom in?
I did post a photo in the community tab on my channel.
What effect does it have on reed action and longevity though?
None
What size bit was that from The set?
oh man I dont know. Its small. it fits into the ringland but doesn't hit the bottom.
Oh wow. You weren’t kidding. So you basically drill a half circle in 7 spots flush with the ringland and only run one ring if two ring piston?
yeah. you just put little notches on the upper ring land and run a single ring. you do NOT drill THRU the piston. Just lil notches.
Need to give us an up close shot of exactly what you did I couldn't tell so that made this video useless to a mid mechanic but still not understanding what you just did so please show an up close shot when doing anything else like. 🙏 Thanks
Why wont this work on more than 1 ring?
As I understand this, this porting mod is to force the piston down on combustion and seal faster, and possible better. (pushing out and sealing better)
Hence it will not work on the 2nd ring.
And then it will give you get better compression and a better 'yield' of the compression giving you a potensial for better performance.
@erikeggenbakstad Ok so it will work using 2 rings but mod is only for first. Maby do opposite side on second ring since that ring seals from other side (below).
Been building engines 44 years laterally gasporting to stroke piston huuuuu hels cooling huuuuu. 1 that's done on 4 strokes that use thin low tension rings to help sealing nothing to do with cooling. #2 in 30 minutes then holes will be getting stopped up with carbon. 3 kinda worse for cooling on a twostroke you just screw up the purpose of sqish gap good vid just wrong type engine
Couldn’t really see what you were doing..
So that pushes the ring tighter to the cylinder?
Would it not be even better to make channels all the way to the upper edge of the piston for even more gas flow around top of the piston?
some people do that on 4Ts. I think on a 2t they might gum up quick?
TOTAL BS !!!@@Corn-ped
Most rings behave like dikes until they go below the exhaust port
REMOVE THE LOWER RING 😮 😂😂😂😂😂😂😂😂 just remove the ring nothing else 😞
Wusste nicht das unge auch tunt
Maybe next time you can actually show what you did. You tried tho.
What part do you want to see better?
@@Corn-ped can’t see the porting you did
Are there circumstances where you wouldn't want to do this?
Not really
DO NOT DO THIS MOD !!!
Yeah? How come?