YZ125 piston ring and boring issues.

Payterrr125
Profile picture for user Payterrr125
Posts
37
Joined
4/3/2015
Location
Fitchburg, MA, USA
Payterrr125
Edited Date/Time 5/7/2015 4:09pm
Okay I'm a bit stuck on this boring and piston ring sizing. The piston was measured at 55.7. Next the cylinder measured at 56.3 and were going .04 over. What piston and ring combo would fit?
|
markit
Profile picture for user markit
Posts
2641
Joined
1/10/2013
Location
Bogalusa, LA, USA
markit 4/28/2015 6:13pm
4/28/2015 6:13pm Edited Date/Time 4/28/2015 6:18pm
Stock bore for a yz125 is 54mm, your 2 mm over. Im gessing ts bored to a 144 piston kit? You cant go over 2mm over stock bore, can you be a little clearer?
mxrose3
Profile picture for user mxrose3
Posts
2380
Joined
8/17/2006
Location
Delmar, DE, USA
mxrose3 4/28/2015 8:22pm
4/28/2015 8:22pm
you didn't specify what year YZ125 or if it had a boreable sleeve installed already.
Pre-1994 YZ125's were 56mm bore by 50mm stroke. 94' and up are 54mm bore by 54mm stroke.
Payterrr125
Profile picture for user Payterrr125
Posts
37
Joined
4/3/2015
Location
Fitchburg, MA, USA
Payterrr125 5/6/2015 3:58pm
5/6/2015 3:58pm
It's a 87' the clyinder is boreable. Sorry for the late comment, my phone broke
markit
Profile picture for user markit
Posts
2641
Joined
1/10/2013
Location
Bogalusa, LA, USA
markit 5/6/2015 10:44pm
5/6/2015 10:44pm
So you boring it up to 56.34 or its 56.30 and you want .04 clearence?

The Shop

See All »
Payterrr125
Profile picture for user Payterrr125
Posts
37
Joined
4/3/2015
Location
Fitchburg, MA, USA
Payterrr125 5/7/2015 12:01pm
5/7/2015 12:01pm
The machinist said he can bore it up to anything so were going .04 over is what he recomended so that's what we're going to do.
markit
Profile picture for user markit
Posts
2641
Joined
1/10/2013
Location
Bogalusa, LA, USA
markit 5/7/2015 1:32pm
5/7/2015 1:32pm Edited Date/Time 5/7/2015 1:41pm
You need to get the piston kit first then have him size the bore to the new piston. just make sure the piston is larger than 36.34 (what hes saying will clear i guess) say like mabe a 36.4 he may have to take more than .04.
Payterrr125
Profile picture for user Payterrr125
Posts
37
Joined
4/3/2015
Location
Fitchburg, MA, USA
Payterrr125 5/7/2015 4:09pm
5/7/2015 4:09pm
Sorry this is my first time doing any of this. But it's a 56.3 why are we going down to 36.4?

Post a reply to: YZ125 piston ring and boring issues.