Topic: Piston to final honed cylinder clearance

[Fasted]

Does anyone know what the piston to cylinder wall clearance should be after the final hone just prior to instalation of new pistons and rings?  1969 cb750 with new 2nd oversize pistons and rings.

Thanks,

ED

[oldfart]

You really need a manual, factory if possible, but the standard in-use piston-to-cylinder clearance on the SOHC 750 is between 0.0005 and 0.001 inch.  I have disassembled many of them that even after 50,000 miles were still under 0.001 inch, showing how low thrust loading is on these cylinders.

[Fasted]

Thank you.

My Clymer manual does not specify this.  It gives me about every other measurement but that one.

ED

[bryanj]

Basically you bore it to the standard size plus 0.5mm and the piston clearance will be right!

[mazingerzeca]

Hello. My Honda Shop Manual says that the minimum clearance between piston and cylinder at the skirt section is 0.0004-0.0016 in. (0.01-0.04 mm)

[nippon]

My clymer says the following:
(sorry for the poor scan)

nippon

[Fasted]

Thanks Guys,

I am going to have the machine shop use .0009" as the clearance.  I got the new ART pistons in and made them all the same weight to (+ -)
1/10th of a gram - best my scale could do.

ED

[Jim F]

I used wiscos 836 kit and bored these to "O" Clarence
I didn't use any oil to coat the pistons (started dry)
and immediately went to 7000 RPM and keep it there for 30 seconds

this was over 10 years ago and I still run 175 to 175 cranking pressure on all 4 cylinders

although I have to use race gas because of the pressure the bike is allot of fun to ride

enjoy

Jim