piston and ring issues

Can any body Tell me if another over sized piston will work in my 85 vf700f
I need to bore it out and cannot find over sized piston and rings was thinking
about putting in the ones for a 87 vf700f2.
cheapcycleparts and bike bandit do not list. Thanks in advance.

 

Ross Racing Pistons /// 625 South Douglas Street, El Segundo - (310) 536-0100
Deves Piston Rings /// 137 Nevada St El Segundo CA, 90245 (310)322-8483
Have used them for everything from Austin Healey to Honda CR500.:wink:
Sorry, don't have any references for East Coast...

 

You need to find out the compression height of each piston. (center of pin to top of piston) From looking at the factory manuals the 87 piston pin bore is .039" smaller. This can be bored to .708 size of the 85 piston pin, which you will have to use. The factory provides up to 1mm (.040") oversize piston. So if need be you can at least bore to that safely.

Both the 85 and 87 pistons are the same OD size basically (2.755"). Use the rings designated for the piston you use. There should be .100 valve to piston clearance. Should check for sure. Your compression height can vary by .010 easy. So any piston that comes real close to yours can be used. General statement there. Have to check valve cutouts and if any dome. You can raise or lower your compression by adjusting the piston up or down a few thousands. Provided all else is fine. With just an over bore your compression will raise some normally.

This should give you several choices for pistons. Check with Ross, Wisco or JE and see what they have in those piston sizes and pin bores. Or you may be able to find another Honda piston that is with in 2mm (.080) OD, close compression height and pin bore to use (same or smaller). If needed most piston tops can be milled .030-.050.

You most likely can use the 87 pistons with just little alterations. Just need to do some measuring.

 

Thank You when it comes time I am going to call the places above and see if they can help me
before i order the 87 vfr700f2 p&r.
It will be awhile because I am on a real tight budget so it will be early next year before I can let
you know how I make out.:sad: