An excellent video and production. There are a number of excellent 2 stroke engine sites out there any you are clearly one of them. Your approach is clear, concise and a professional approach to showing the viewer the points your are raising. As a 52 year earthmoving mechanic I have learnt today so much of the Teflon coating. I now realize a piston replacement is best due to some Teflon abrasion and not just rings and a cleanup hone I was considering. Well done and goodonyou. Keep up the good work
I definitely agree. I had a 21 140rf that i rode daily and hard on weekend ( technichal terrain ) but i seldom hit the rev limiter. Then my cousin got a 22 140rf and his bike is 6 months newer than mine and rides the bike only on weekends. But every time he got stuck on the trails he just locks the throttle on the rev limiter and pushing bike to get unstuck. His piston only lasted about 8 months and it started to smoke. My bike is more than 2 years with only issue is the clutch, wheel bearings and linkage bearings. Opened the top end. Piston and rings are in great shape. Removed the carbon deposit and the bike is still healthy. I also check the valve every 4 months. And only adjusted it 2x i 2 years
By far one of the most informative and yet simple videos on piston clearance! Keep up the great videos 👍 What is your opinion on deglazing with a hone a Nikasil cylinder to get a new cross-hatch? I've seen mechanics say it's fine, other say you shouldn't touch the Nikasil.
so you are just measuring piston clearance in the beginning to establish an understanding of wear. BUT if rebuilding an engine you simply go to the cylinder and gather measurements with dial bore gage and then subtract the spec'd clearance referenced in owners manual and that helps you decided which piston to purchase no?
Not sure. I bought them years ago. My bore gauge shows half thou increments which is close enough for checking clearance but not accurate enough for boring. Micrometers are just 2”-5”.
Size depends on what you’re working on. There are several reputable brands with Mitutoyo holding the top spot. You don’t need to spend Mitutoyo money in most cases though. If you don’t read a micrometer on a regular basis it may make sense to buy a digital one in the size you need. Reading a manual one takes a bit of getting used to.
If a piston still measures within spec and you decide to re-use it, should new rings be fitted while it's all apart? Or piston and rings should only be replaced together?
I’ve done both. I check ring end gap for that. Most often when I have a top end apart I change both though because I deglaze the cylinder. Any time the nikasil is worked on the rings should be replaced.
I always use a new base gasket because if it leaks it’s potentially catastrophic and time consuming to change. I’m not as picky with head o-rings because it’s immediately obvious if one is leaking. That being said, the o-rings come in the kit so I do change them during a top end job.
An excellent video and production. There are a number of excellent 2 stroke engine sites out there any you are clearly one of them. Your approach is clear, concise and a professional approach to showing the viewer the points your are raising. As a 52 year earthmoving mechanic I have learnt today so much of the Teflon coating. I now realize a piston replacement is best due to some Teflon abrasion and not just rings and a cleanup hone I was considering. Well done and goodonyou. Keep up the good work
Excellent video Chuck, well explained like always. Keep on post videos like this.
Man I'm so happy I've found your videos. Thanks!
Great video! Went from what i theorized to what actually happens. Thank you!!
I definitely agree. I had a 21 140rf that i rode daily and hard on weekend ( technichal terrain ) but i seldom hit the rev limiter. Then my cousin got a 22 140rf and his bike is 6 months newer than mine and rides the bike only on weekends. But every time he got stuck on the trails he just locks the throttle on the rev limiter and pushing bike to get unstuck. His piston only lasted about 8 months and it started to smoke. My bike is more than 2 years with only issue is the clutch, wheel bearings and linkage bearings. Opened the top end. Piston and rings are in great shape. Removed the carbon deposit and the bike is still healthy. I also check the valve every 4 months. And only adjusted it 2x i 2 years
Dam your good
By far one of the most informative and yet simple videos on piston clearance! Keep up the great videos 👍
What is your opinion on deglazing with a hone a Nikasil cylinder to get a new cross-hatch? I've seen mechanics say it's fine, other say you shouldn't touch the Nikasil.
so you are just measuring piston clearance in the beginning to establish an understanding of wear. BUT if rebuilding an engine you simply go to the cylinder and gather measurements with dial bore gage and then subtract the spec'd clearance referenced in owners manual and that helps you decided which piston to purchase no?
Almost. Piston listings show the size. I set the bore gauge to a new piston size & measure the difference. Same results. Just different procedure.
@@ChuckfromTrueTech and you do this in this order to make sure cylinder is not past wear point?
What fowler bore gauge did you buy? Im interested in getting one. Same with your micrometer set. Thanks.
Not sure. I bought them years ago. My bore gauge shows half thou increments which is close enough for checking clearance but not accurate enough for boring. Micrometers are just 2”-5”.
What brand micrometer and bore gauge along with sizes do you recommend?
Size depends on what you’re working on.
There are several reputable brands with Mitutoyo holding the top spot.
You don’t need to spend Mitutoyo money in most cases though.
If you don’t read a micrometer on a regular basis it may make sense to buy a digital one in the size you need. Reading a manual one takes a bit of getting used to.
If a piston still measures within spec and you decide to re-use it, should new rings be fitted while it's all apart? Or piston and rings should only be replaced together?
I’ve done both. I check ring end gap for that. Most often when I have a top end apart I change both though because I deglaze the cylinder. Any time the nikasil is worked on the rings should be replaced.
Do you recommend using new gaskets every time when re-installing cylinder and head?
I always use a new base gasket because if it leaks it’s potentially catastrophic and time consuming to change. I’m not as picky with head o-rings because it’s immediately obvious if one is leaking. That being said, the o-rings come in the kit so I do change them during a top end job.