Topic: CB550 racer - what piston to cylinder clearence and finishin stone #?

[vintage_racer]

Hello,
My CB550 racer is being rebuild and the cylinders have to be bored for the +0.5 pistons.
What clearence (bore to piston) should I use?
What finishing stone should be used to finish the cylinders?
Pistons and rings are ART NOS so probably same material as Honda stocks.
Thanks,
Dan

[Bill/BentON Racing]

Stock clearance is .0004-.0016 in.The shop/person should have stone part under control,crosshatch usually @ 60-70 degrees.Good Luck,Bill

[kos]

400 grit stone finish is best.


KOS

[bwaller]

I quess you have your answer Dan. I understand you had a catastrophic result in North Bay?

[vintage_racer]

Hey Brent
I broke my camshaft (not the chain the shaft!) at N.Bay so used Doug's P1 CB350 which I had never rode before, otherwise would have finished second in my class for the season also finished second in the heat race on Sat.
My new camshaft is at WebCam now, should be ready this week, then will put the motor back with the new pistons, will have to make valve pockets on the intake side, the exhaust side has more than enough clearance as it is.
I decided to totally split the cases, got a new camchain and primary chain (not cheap) from Honda, all transmission and bearings were inspected and measured, all looks like new after 6 to 7 intensive seasons, this Hondas are made so tough!
Also bought a CB500T to race in P1, not sure if I will manage to race 2 bikes but will give it a try.

[bwaller]

Sounds like you'll be busy Dan. Is the twin already modified to race or is this a project?

[vintage_racer]

This CB500T is very well prepared, high compression, valve spring conversion, duel spark plug on a Boyer ignition, some porting, megacycle cams.
Also beautiful fiberglass tank and tail section, good shocks, forks, 4 leading show front drum, etc.

Bike should handle much better than my CB550 and should make about the same power.
Dan