Honda TRX700XX Forum - Club700XX banner
1 - 9 of 9 Posts

·
Registered
Joined
·
528 Posts
Discussion Starter · #1 ·
today i was measuring my specs for my 11:1 CP piston and cylinder... below are the measurements i got, i need to know if they are acceptable. the reason i ask is bcause the CP piston kit came with a paper that lists certain tolerances, and they differ from the service manual tolerances.i want to make sure i have a second opinion before i grind on a ring.

below are actual measurements
Cylinder:
0.004 out of round
I.D. 4.018(skirt sides)
4.014 (end of pin side)

Piston:
O.D. 4.014
top ring end gap: 0.016
2nd ring end gap: 0.012

cylinder to piston clearance is 0.004 at the biggest part.


below are the service manual specs:

cylinder:
I.D. (4.0157-4.0163)
out of round (0.004 max)

Piston:
O.D. (1.014-4.105)
top ring end gap( 0.010-0.014)
2nd ring end gap(0.016-0.022)

cylinder to piston clearance: 0.0004-0.0022

below are CP specs
these specs came on the paperwork with the piston.

top ring end gap: 0.020
2nd ring end gap: 0.024

cylinder I.D: 4.0157
cylinder to piston clearance: 0.0020
piston O.D. 4.0137


im making an excel cahrt now to get a better idea of what i need to do and i already know what needs to be tweeked but i want to have a second opinion.
 

·
Premium Member
Joined
·
2,932 Posts
You would use the CP clearances, Neither cylinder you have had a better piston/cylinder clearance?
 

·
Registered
Joined
·
528 Posts
Discussion Starter · #3 ·
im going to check my original one tomorrow, i just got the crank assembly in and put the piston in my old cylinder and it is tight, like stock tight, im thinking just my piston was worn.
 

·
Registered
Joined
·
1,561 Posts
I would use the piston suppliers recommendation. What are you measuring with?

Smooth, just curious why the 2 wouldn't work great on the clearance? Something about CP pistons?
Edit: Nevermind, I read it again.
 

·
Premium Member
Joined
·
708 Posts
you need to set your rings to what cp says i personally like .018-.020 on top and and extra .002-.004 on the 2nd ring .012 is to tight

.002 per side is not bad when i had custom pistons made up a had them make them with a little extra room like that when you dont have the anti friction coating on them they need some extra oil room.
 

·
Registered
Joined
·
528 Posts
Discussion Starter · #6 ·
i know i have to gap the rings which i am not afraid of and your preference is pretty much exactly what i came up with..the piston to cylinder clearance is 0.004 right now on the skirt side, on the adjacent edges it is more like .0004...this worries me so im going to mic the other clinder i have tomorrow. we were using snap guages and mic tools that our machinist use al work to spec cmpressor pistons and such, tomorrow im going to try it with a digital micrometer to see if i get any different numbers.

i wantr this hing perfect when it goes back in, i dont want any issuse with it anymore.
 

·
Registered
Joined
·
528 Posts
Discussion Starter · #7 ·
eric, your comment just made me realize something, there is a 0.004 difference in the piston and cylinder diameter but that is a 0.002 clearance on all sides, which puts it within spec, with that being said everything will be spot on after i gap the rings today.thanks for your help, the smallest input can sometimes solve a problem.i guess with all of the measuring i was doing, i overlooked splitting the difference for the wall clearance.
 

·
Registered
Joined
·
1,561 Posts
eric, your comment just made me realize something, there is a 0.004 difference in the piston and cylinder diameter but that is a 0.002 clearance on all sides, which puts it within spec, with that being said everything will be spot on after i gap the rings today.thanks for your help, the smallest input can sometimes solve a problem.i guess with all of the measuring i was doing, i overlooked splitting the difference for the wall clearance.
That is too good!
 
1 - 9 of 9 Posts
Top