Jump to content
Sign in to follow this  

Piston ring thickness?

Recommended Posts

So I purchased this piston ring

 

http://www.ebay.com/itm/171120907743?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648

 

to replace the one on this 86 yz 125 im restoring (See the rollin turd comin through thread in the 2 stroke forum :) ). Its at standard bore which is 56 mm. I got the ring today and tested the end gap in the cylinder and its golden. Perfect out of the box. But, I go to install it to the piston and it doesnt seem to want to slip fully into the groove which makes it impossible to compress to fit the cylinder. It seems to be sitting on the outside of the groove, not the inside. Im installing it with a piston ring installer and not rolling it on with my fingers. There werent (arent) different thicknesses of these rings are there? If I match the new ring with the old ring, they look identical and I can put the old ring back on with no issue. It slides right in the groove. Im not sure whats up. Anyone run into this before?

Share this post


Link to post
Share on other sites

Are you using a wiseco piston??? Is it the correct ring for the piston by part numbers?? If so It sounds like the new ring is a dyke's style ring that is tapered upwards from the inside to the outside edge. The stock ring was probable a flat ring. If you put them on some thing flat compared the inside edges to each other, then compare the outside edges to each other. I will bet the out side edge is thicker.

 

OR

 

I had this happen once in my life. The ring will not compress over the pin. Lay your two rings on top of each other at the ring end gap and see if the cut away notch for the pin are the same. If not you will need a new ring or modify the one you have.

Edited by Zrt1200

Share this post


Link to post
Share on other sites

Definitely sounds like the ring is not correct for the piston you have. I'm not a fan of mix matching parts, especially with pistons. Chances are the piston is worn anyways so Just buy a piston kit and be done with it

Share this post


Link to post
Share on other sites

Definitely sounds like the ring is not correct for the piston you have. I'm not a fan of mix matching parts, especially with pistons. Chances are the piston is worn anyways so Just buy a piston kit and be done with it

 

 

Yeah Im still on the oem piston....I was trying to save some dollars as I just sent my 400 to the shop for a head rebuild. I may just wait and buy a new piston kit. Either that or send this back and buy the OEM ring from TT store :)

 

I was just under the impression that as long as the bore size was the same, the ring would fit. Learn something new every day!

Edited by ShsFunny

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×