Awesome video. So many people try to do a channel like yours but are total screw ups. I would describe piston slap as if your holding a deck of cards in one hand and use your other thumb to flick thru the top of the cards. Your spot on with nikasil cylinders, when i was 13 I desert raced a 77 yz250 and after you bored the cylinder it had to be rejetted every time. Then in 79 Honda came out with the chrome bore, never needed major jetting changes if any, it would last 5 or 6 pistons before changing unless you flat blew it up and gouged the bore. Then in 81 went back to a standard bore for the time KTM495. Lots of fun jetting it. Keep up the vids, you are one of the few people that truly knows how to show people especially the younger generation the proper ways to repair and diagnose bikes. Be safe and always enjoy the moment. 🙂👍👍
Thanks! Surely sounds like shuffling playing card lol. Thanks for the kind words and comments. I am trying my best to always live in the moment. Thats all we have right!. 13 on a 77 YZ250! You surely got to live through probably the best years of dirt bike riding. Lucky you! I was only 1 year old in 1977 lol. But by 1985 I could not get my mind off dirt bikes. Here I am today lol
Super good piston video. I learned a ton! I did my first rebuild on a 94 KDX 200 and sent my cylinder to power seal. They did an amazing job and it was a night and day difference.
Thanks! Congrats on the top end job! Yeah Power Seal did a great job on my cylinder too, so far it has about 30 hours on it and sounds as tight as new. Power feels good too!
What I find is that nikaseals cylinder glaze up, rather than the coating being worn off. You can use a aluminum oxide flex hone to deglaze them. Aluminum oxide is softer than that plating and can’t actually “hone” off the nikaseal but rather take off the glaze. The cylinder will look brand new after!
You should *never* hone a plated cylinder , the stones can damage the plating and impregnate grit into the plating. According to Slavens. Watch his video.
Oh I should have covered that. Yes a forged piston does require a little more time warming up to be safe. I usually run the bike on the stand for about 3 minutes and then make the first lap on the track a easy one, to let the heat soak in. Gotta do a sight lap anyway lol. A cast piston is not as picky about being warmed up and I believe this is why they come stock in our bikes.
Great review as always. I have an original cast iron 500 2 stroke still on its first piston sixe for now. Do you ever recommend putting nikosyl coating on a cast iron cylinder?
Thanks! I don't think they can plate on a cast iron sleeve. But if its a original cylinder with original sleeve thats good. Quality control on OEM sleeves is real good. I would just run it.
Bought a new OEM cylinder for my '05 YZ125 1.5 years ago (50 hours). Cylinder is a B size. Ran a ProX A piston (14.8 hrs), then OEM B piston (14.2 hrs), then OEM C piston (19.5 hrs), and the cylinder looked good inside every time except now, where after removing that last piston, there's what I believe to be a worn section of the Nikasil near the exhaust port. Piston looks worn right down the center where the exhaust bridge lines up. I installed a ProX C piston and will run it since I'm trying to at least get a little more life out of that cylinder since 50 hours doesn't seem old to me. Kinda thought I was doing the right thing by being super on top of my top end rebuilds w/o neglecting them, and was expecting to get maybe like 100-200 hrs out of a cylinder this way. Never honed it. Only ran Maxima 927 at 30:1, but I'm gonna try going up to like 24:1 from here on. I went ahead and ordered another OEM cylinder as well since at $395, it's barely cheaper than the $400 for Millennium to replate it.
Oh man bummer. Yes I wore my cylinder out around the exhaust port area at around 75 hours of lots of wife open throttle on fast sandy tracks. I don't think going up to a c or d piston has any real advantage as the cylinder wears. The rings are what cause most of the wear and the piston reaches areas the rings never touch, like the very top of the cylinder and below all the ports. My wife got 200 hours out of her cylinder but she doesn't work the motor nearly as hard as I do. I try to swap my pistons out on the yz125 every 20 hours, but it seems they may be safe up to 25 at my speed and pace. Do you ride the bike hard? That might be the reason you didn't get as many hours out of it as you would expect.
Riding in sandy terrain need to clean/replace and oil heavily the air filter or at least inspect every ride. Wearing out piston rings in 20 to 25 hours isn't normal. The piston has almost no effect on cylinder wear. The wear happens from the hardened steel rings. The aluminum piston riding inside the plated cylinder doesn't wear the cylinder unless dirt is present.
@@jaysonhoulihan9808 Right on. I clean and oil the filter every full days riding. I dont change out pistons due to ring wear, I change them out because the piston itself wears after a while.
Hello. If its a steal sleeved cylinder yes. But if its a nickel plated cylinder its not really needed. On nickel plated cylinders its easy to spot when its worn past due by paying attention to the original cross hatching. When the original cross hatching wears completely away its about due for a replate.
So I have a question for you. My yz125 has a wiseco with nikasil cylinder. I wouldn't say fresh but less than 40hrs. ..I have a similar rattle but at 3/4 throttle. Wot is fine...idle is fine. I dunno.
Hello. At 40 hours I would just start by doing a top end and then see how it sounds. Also check the rod bearing and crank bearing while in there. 40 hours is about the max I would suggest on a 125 piston by a slower rider. And faster riders 20 to 25 is about the max.
@@UpAllNight91 OH ok. I have 3 RM 125's with much more hours that sound and run perfect. I just had the yz apart to replace some transmission parts but everything looked and felt great so I just slapped the same piston back in it being it was replaced (if I had to guess somewhere around 25-30hrs) somewhat recently. Everything mic'd perfectly and the rod felt great. Probably time to just go through it again with replated cylinder and pro x top and bottom. Thanks for the vid man....your content explains soo much.
@@brainstain22 Your welcome! Some bikes can get pretty worn out before making noise and some do it with just a little wear. The KX85 will start making piston rattle sounds in just 20 hours but the KTM 85sx can go further before making any piston sounds.
Love your knowledge. Honda off road I ride. Mainly because we have more Honda dealer here. But we also have a Yamaha dealer. I always wanted Yamaha but never owned one except on road bike
@@stravis3269 Thanks! Honda are good. Actually can go wrong with any of the 4 japs bikes, as far are build quality and parts availability. I can say I have had all 4 japs brand but yet to own a KTM variant.
@@UpAllNight91 yes sir, I'm in same boat. Never touched a ktm. They always caught my eye. Something dif. Great bikes as I never heard anything bad about KTM
@@stravis3269 Yeah I may try one in the future but it will most likely be a 2 stroke because the parts are pretty expensive when it comes time to rebuild one of their 4 strokes.
So I have a question for you. I have a piston to replace on my Sizuki rm 250 96 and am wondering if i should buy tools to measure the cylinder accurately and calculate what the piston size should be based on the piston to cylinder clearance or should i just open the engine up and see what size it is now and put the same size piston? My compression is 150 psi with very hard kicks and my symptoms are that when the bike is in gear can't reach its max rpms(11-12000) it stays on 8000 rpms on full throtlle. It starts work well when reach high temperature when i am climbing hils. When it is in neutral hits 12k rpms(i am using hourmeter that shows also the rpms), but when im in 3 4 5ft geat i cant hit the top. greetings from Bulgaria!
Hello. If the piston was too tight or loose it wouldnt effect how high its able to rev as much as it would just wear out very very fast and you would know you have a issue within a few hours of run time. 250 2 strokes dont rev much past 8 to 9k under load. That is normal. You may be able to get it higher neutral but gear 8000 to 9000 is about as high as they go.
@UpAllNight91 What about new piston size. Should I get measurement tools and measure it or just buy the same size piston. I want to do a top end, I think the problem is in it.
If its a oem nickel plated cylinder then its pretty plug and play, just buy a oem sized piston and run it. But if its been replated or it has a cast iron sleeve then you will surely want to measure the cylinder and size the piston to the cylinder
Hello. If the exhaust bridge is crack it will need to be replated after the repair. I do know Power Seal can repair the bridge and then replate it. It will cost about $350 though.
@UpAllNight91 I'm going to hold onto it until I get the resources and information to do it safely myself I only paid 800 for the bike I think it would be a neat learning experience even if It doesn't work at all.
Hello. I dont suggest honing nickle plated cylinders. They come honed when the plating is fresh and if the honing wears away to the point you cant see it anymore then its about to wear through the plating all together. And honing a used plated cylinder will only speed up the wear. The video that best explains it is on this link right here th-cam.com/video/vaFp8aYkHNA/w-d-xo.html
I have a rm 125 1993and I have a la sleeve are they really that bad to use. The cylinder is to far gone to nicasil what do you think I should do. The port timing is giving me a red flagg
They can be. Its hit and miss. Next top end check and see how lined up the iron sleeve is to the ports. If there's any misalignment thats a red flag. But of course picking up a good used cylinder and having it replated is the best option overall
Question I did a top end on my 2023 yz125 yesterday 21 hrs on it it had 1 small scratch very slight couldn't feel it with your finger but just a tad with your nail I went ahead and reused it should I buy new or run with it runs good at the moment thanks
Thanks man I whish I could figure out how to send u a pic of it super Kool u reasoned back I watch your shows just about every night I have Learned so much and yea it's running good I honestly replaced the top end just for matiance I had no running issues all though I did find my old wrist pin bearing was on it's last leg u can shake the old one and hear all the needled moving I am thinking they are the failure point to the new yz 125
@@TimmyStasny-ow3hl Hello. You can email it to me at upallnight91@hotmail.com . For sure its good to get in there and replace the piston and wrist pin way before it goes out. On my 125 I change them out about everything 20 hours, my brother does his every 30 hours. But I wouldnt go over 30 hours.
Yea I did mine at 21 hrs seemed to be a good time for sure your a excellent teacher man the way u explain things in detail just sinks in thank u for takeing the time to post all these videos we all appreciate it
the differences between Nickel Plate and an iron sleeve: Nickel Plate (Nikasil): Composition: Nikasil is a nickel-silicon carbide coating applied to the inner surface of aluminum cylinders. Purpose: It enhances durability, wear resistance, and heat transfer. Advantages: Wear Resistance: Nikasil plating wears better than cast iron. Heat Transfer: Aluminum, with Nikasil plating, transfers heat more efficiently than iron. Ring Seal: Improved ring seal over time due to the harder coating. Reusability: Nikasil-coated cylinders can be rebored and reused. Considerations: Adhesion: Nikasil doesn’t always adhere well to cast iron sleeves, leading to bubbling or flaking. Application: Typically used on aluminum cylinder bores without a sleeve12. Jetting: Contrary to a myth, jetting isn’t affected by liner material. Iron Sleeve: Composition: Cast iron sleeves are tough and resilient. Advantages: Durability: Cast iron can withstand significant abuse. Cost-Effective: Economical and widely used. Considerations: Heat Transfer: Iron is not as efficient at transferring heat as aluminum. Ring Seal: May not provide the same long-term ring seal as Nikasil. Jetting: Proper jetting is achievable with iron sleeves. In summary, while Nikasil-coated cylinders offer better heat transfer and wear characteristics, cast iron sleeves remain robust and cost-effective. The choice depends on specific engine requirements and preferences. ive been doing 2 strokes since 1992 and prefer a iron sleeve with wiseco piston and total seal rings. i only use motul 800 2t with sunoco 260 gtx 98 fuel.thats my opinion and like a ass we all have one . lol
Awesome video. So many people try to do a channel like yours but are total screw ups. I would describe piston slap as if your holding a deck of cards in one hand and use your other thumb to flick thru the top of the cards. Your spot on with nikasil cylinders, when i was 13 I desert raced a 77 yz250 and after you bored the cylinder it had to be rejetted every time. Then in 79 Honda came out with the chrome bore, never needed major jetting changes if any, it would last 5 or 6 pistons before changing unless you flat blew it up and gouged the bore. Then in 81 went back to a standard bore for the time KTM495. Lots of fun jetting it.
Keep up the vids, you are one of the few people that truly knows how to show people especially the younger generation the proper ways to repair and diagnose bikes. Be safe and always enjoy the moment. 🙂👍👍
Thanks! Surely sounds like shuffling playing card lol. Thanks for the kind words and comments. I am trying my best to always live in the moment. Thats all we have right!. 13 on a 77 YZ250! You surely got to live through probably the best years of dirt bike riding. Lucky you! I was only 1 year old in 1977 lol. But by 1985 I could not get my mind off dirt bikes. Here I am today lol
Super good piston video. I learned a ton! I did my first rebuild on a 94 KDX 200 and sent my cylinder to power seal. They did an amazing job and it was a night and day difference.
Thanks! Congrats on the top end job! Yeah Power Seal did a great job on my cylinder too, so far it has about 30 hours on it and sounds as tight as new. Power feels good too!
What I find is that nikaseals cylinder glaze up, rather than the coating being worn off. You can use a aluminum oxide flex hone to deglaze them. Aluminum oxide is softer than that plating and can’t actually “hone” off the nikaseal but rather take off the glaze. The cylinder will look brand new after!
Right on
I don't usually have to de-glaze but honing is good for that
You should *never* hone a plated cylinder , the stones can damage the plating and impregnate grit into the plating. According to Slavens. Watch his video.
Thoughts on a forged piston needing to be warmed up before you start riding full tilt?
As always, such good info. Kelly
Oh I should have covered that. Yes a forged piston does require a little more time warming up to be safe. I usually run the bike on the stand for about 3 minutes and then make the first lap on the track a easy one, to let the heat soak in. Gotta do a sight lap anyway lol. A cast piston is not as picky about being warmed up and I believe this is why they come stock in our bikes.
Great review as always. I have an original cast iron 500 2 stroke still on its first piston sixe for now. Do you ever recommend putting nikosyl coating on a cast iron cylinder?
Thanks! I don't think they can plate on a cast iron sleeve. But if its a original cylinder with original sleeve thats good. Quality control on OEM sleeves is real good. I would just run it.
Great video - thanks for all the info
Yes sir!
I’ve had a really good experience sending out my cylinders to powerseal
So far my power seal replate has been great. 22 hours on it and just did a top end. No wear on the plating at all!
Bought a new OEM cylinder for my '05 YZ125 1.5 years ago (50 hours). Cylinder is a B size. Ran a ProX A piston (14.8 hrs), then OEM B piston (14.2 hrs), then OEM C piston (19.5 hrs), and the cylinder looked good inside every time except now, where after removing that last piston, there's what I believe to be a worn section of the Nikasil near the exhaust port. Piston looks worn right down the center where the exhaust bridge lines up.
I installed a ProX C piston and will run it since I'm trying to at least get a little more life out of that cylinder since 50 hours doesn't seem old to me. Kinda thought I was doing the right thing by being super on top of my top end rebuilds w/o neglecting them, and was expecting to get maybe like 100-200 hrs out of a cylinder this way. Never honed it. Only ran Maxima 927 at 30:1, but I'm gonna try going up to like 24:1 from here on. I went ahead and ordered another OEM cylinder as well since at $395, it's barely cheaper than the $400 for Millennium to replate it.
Oh man bummer. Yes I wore my cylinder out around the exhaust port area at around 75 hours of lots of wife open throttle on fast sandy tracks. I don't think going up to a c or d piston has any real advantage as the cylinder wears. The rings are what cause most of the wear and the piston reaches areas the rings never touch, like the very top of the cylinder and below all the ports. My wife got 200 hours out of her cylinder but she doesn't work the motor nearly as hard as I do. I try to swap my pistons out on the yz125 every 20 hours, but it seems they may be safe up to 25 at my speed and pace. Do you ride the bike hard? That might be the reason you didn't get as many hours out of it as you would expect.
Riding in sandy terrain need to clean/replace and oil heavily the air filter or at least inspect every ride. Wearing out piston rings in 20 to 25 hours isn't normal. The piston has almost no effect on cylinder wear. The wear happens from the hardened steel rings. The aluminum piston riding inside the plated cylinder doesn't wear the cylinder unless dirt is present.
@@jaysonhoulihan9808 Right on. I clean and oil the filter every full days riding. I dont change out pistons due to ring wear, I change them out because the piston itself wears after a while.
do you think it’s worth it to purchase a nice bore gauge and micrometer to check cylinders for wear?
Hello. If its a steal sleeved cylinder yes. But if its a nickel plated cylinder its not really needed. On nickel plated cylinders its easy to spot when its worn past due by paying attention to the original cross hatching. When the original cross hatching wears completely away its about due for a replate.
So I have a question for you. My yz125 has a wiseco with nikasil cylinder. I wouldn't say fresh but less than 40hrs. ..I have a similar rattle but at 3/4 throttle. Wot is fine...idle is fine. I dunno.
Hello. At 40 hours I would just start by doing a top end and then see how it sounds. Also check the rod bearing and crank bearing while in there. 40 hours is about the max I would suggest on a 125 piston by a slower rider. And faster riders 20 to 25 is about the max.
@@UpAllNight91 OH ok. I have 3 RM 125's with much more hours that sound and run perfect. I just had the yz apart to replace some transmission parts but everything looked and felt great so I just slapped the same piston back in it being it was replaced (if I had to guess somewhere around 25-30hrs) somewhat recently. Everything mic'd perfectly and the rod felt great. Probably time to just go through it again with replated cylinder and pro x top and bottom. Thanks for the vid man....your content explains soo much.
@@brainstain22 Your welcome! Some bikes can get pretty worn out before making noise and some do it with just a little wear. The KX85 will start making piston rattle sounds in just 20 hours but the KTM 85sx can go further before making any piston sounds.
How many hours on your worn yz250 cylinder and how many hours on your piston before you change.
135 hours. Expected more out of it but is what is was lol
Love your knowledge. Honda off road I ride. Mainly because we have more Honda dealer here. But we also have a Yamaha dealer. I always wanted Yamaha but never owned one except on road bike
@@stravis3269 Thanks! Honda are good. Actually can go wrong with any of the 4 japs bikes, as far are build quality and parts availability. I can say I have had all 4 japs brand but yet to own a KTM variant.
@@UpAllNight91 yes sir, I'm in same boat. Never touched a ktm. They always caught my eye. Something dif. Great bikes as I never heard anything bad about KTM
@@stravis3269 Yeah I may try one in the future but it will most likely be a 2 stroke because the parts are pretty expensive when it comes time to rebuild one of their 4 strokes.
So I have a question for you. I have a piston to replace on my Sizuki rm 250 96 and am wondering if i should buy tools to measure the cylinder accurately and calculate what the piston size should be based on the piston to cylinder clearance or should i just open the engine up and see what size it is now and put the same size piston? My compression is 150 psi with very hard kicks and my symptoms are that when the bike is in gear can't reach its max rpms(11-12000) it stays on 8000 rpms on full throtlle. It starts work well when reach high temperature when i am climbing hils. When it is in neutral hits 12k rpms(i am using hourmeter that shows also the rpms), but when im in 3 4 5ft geat i cant hit the top.
greetings from Bulgaria!
Hello. If the piston was too tight or loose it wouldnt effect how high its able to rev as much as it would just wear out very very fast and you would know you have a issue within a few hours of run time. 250 2 strokes dont rev much past 8 to 9k under load. That is normal. You may be able to get it higher neutral but gear 8000 to 9000 is about as high as they go.
@UpAllNight91 What about new piston size. Should I get measurement tools and measure it or just buy the same size piston. I want to do a top end, I think the problem is in it.
If its a oem nickel plated cylinder then its pretty plug and play, just buy a oem sized piston and run it. But if its been replated or it has a cast iron sleeve then you will surely want to measure the cylinder and size the piston to the cylinder
My exhaust bridge is cracked on my yz125 i would like to fix it but have no aluminum welder atm.
Hello. If the exhaust bridge is crack it will need to be replated after the repair. I do know Power Seal can repair the bridge and then replate it. It will cost about $350 though.
@UpAllNight91 I'm going to hold onto it until I get the resources and information to do it safely myself I only paid 800 for the bike I think it would be a neat learning experience even if It doesn't work at all.
@@Qb450r right on
Hey! Curious about your thoughts on honing a nikasil plated cylinder. Heard a lot about it from both sides. Is it actually useful or not?
Hello. I dont suggest honing nickle plated cylinders. They come honed when the plating is fresh and if the honing wears away to the point you cant see it anymore then its about to wear through the plating all together. And honing a used plated cylinder will only speed up the wear. The video that best explains it is on this link right here th-cam.com/video/vaFp8aYkHNA/w-d-xo.html
I have a rm 125 1993and I have a la sleeve are they really that bad to use. The cylinder is to far gone to nicasil what do you think I should do. The port timing is giving me a red flagg
They can be. Its hit and miss. Next top end check and see how lined up the iron sleeve is to the ports. If there's any misalignment thats a red flag. But of course picking up a good used cylinder and having it replated is the best option overall
Question I did a top end on my 2023 yz125 yesterday 21 hrs on it it had 1 small scratch very slight couldn't feel it with your finger but just a tad with your nail I went ahead and reused it should I buy new or run with it runs good at the moment thanks
If its running good and holding up I would say its good to go.
Thanks man I whish I could figure out how to send u a pic of it super Kool u reasoned back I watch your shows just about every night I have Learned so much and yea it's running good I honestly replaced the top end just for matiance I had no running issues all though I did find my old wrist pin bearing was on it's last leg u can shake the old one and hear all the needled moving I am thinking they are the failure point to the new yz 125
And i meant to say the cylinder had a small scratch right above the exaust port it got a new pistion and yes is running well
@@TimmyStasny-ow3hl Hello. You can email it to me at upallnight91@hotmail.com . For sure its good to get in there and replace the piston and wrist pin way before it goes out. On my 125 I change them out about everything 20 hours, my brother does his every 30 hours. But I wouldnt go over 30 hours.
Yea I did mine at 21 hrs seemed to be a good time for sure your a excellent teacher man the way u explain things in detail just sinks in thank u for takeing the time to post all these videos we all appreciate it
Apakah ada untuk kx 85, sorry saya dari Indonesia
Hello. I do have a video on the kx85. Here is it... th-cam.com/video/0kCDF8CEGsM/w-d-xo.htmlsi=L-wiq3p4Fb4JDwox
Well could a guy take his cast iron slightly worn out jug and have it nickle plated?
As far as I know they dont nickel plate steal lined cylinders.
Prices for nikasil are getting crazy, A mew bore job runs you half that price
It is getting more expensive. But also the cost of a bore job has gone up too. guess everything is going up
the differences between Nickel Plate and an iron sleeve:
Nickel Plate (Nikasil):
Composition: Nikasil is a nickel-silicon carbide coating applied to the inner surface of aluminum cylinders.
Purpose: It enhances durability, wear resistance, and heat transfer.
Advantages:
Wear Resistance: Nikasil plating wears better than cast iron.
Heat Transfer: Aluminum, with Nikasil plating, transfers heat more efficiently than iron.
Ring Seal: Improved ring seal over time due to the harder coating.
Reusability: Nikasil-coated cylinders can be rebored and reused.
Considerations:
Adhesion: Nikasil doesn’t always adhere well to cast iron sleeves, leading to bubbling or flaking.
Application: Typically used on aluminum cylinder bores without a sleeve12.
Jetting: Contrary to a myth, jetting isn’t affected by liner material.
Iron Sleeve:
Composition: Cast iron sleeves are tough and resilient.
Advantages:
Durability: Cast iron can withstand significant abuse.
Cost-Effective: Economical and widely used.
Considerations:
Heat Transfer: Iron is not as efficient at transferring heat as aluminum.
Ring Seal: May not provide the same long-term ring seal as Nikasil.
Jetting: Proper jetting is achievable with iron sleeves.
In summary, while Nikasil-coated cylinders offer better heat transfer and wear characteristics, cast iron sleeves remain robust and cost-effective. The choice depends on specific engine requirements and preferences.
ive been doing 2 strokes since 1992 and prefer a iron sleeve with wiseco piston and total seal rings. i only use motul 800 2t with sunoco 260 gtx 98 fuel.thats my opinion and like a ass we all have one . lol
Right on. I have used cast iron sleeves before but I do enjoy the plug and play of nickle plated cylinders.
Your bike has roing rattle or oisron slap
Hello I put a new piston with a new plated cylinder in the bike and it got ride of that sound.
4 strock kx valve are noise
They are noisey? I dont understand?
Wifes bike is good forba nother 100
Yeah, that bike is at about 350 hours now lol. Still original crank!