Well, I took the pistons & cylinders to the machine shop this morning. I carted along the service manual. Do you think we could find any mention (other than service LIMIT) of what the piston to cylinder clearances should be?
The answer is no. He says he's confidant that 0.002" would be a good clearance, unless I can provide any other specs. He's waiting on my reply.
Can anyone confirm 0.002", or have other specs?
Thanks....Mike C
Piston clearance
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bikeymikey748
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- Location: Montreal, Canada
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SteveG
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- Location: Skaneateles, NY
Re: Piston clearance
Mike -
FWIW, I was searching for exactly that tidbit of info to get my 900F bored out. The results of my search:
The 82 CBX, 1100F, and 750F manuals all have the dash (-) where the clearance should be listed.
The 900F manual lists piston to wall clearance as .0004" - .002".
All above manuals show a service limit of .004" (or .0039" in the 1100F manual)
I called Wiseco (putting in a 985 big bore kit
) and they specified .002".
My machine shop guy said the .0004" is tight, but he has done them that tight at the customers request, and it has worked but that he likes to go with .002".
I chose to use Wiseco's .002"
Steve
FWIW, I was searching for exactly that tidbit of info to get my 900F bored out. The results of my search:
The 82 CBX, 1100F, and 750F manuals all have the dash (-) where the clearance should be listed.
The 900F manual lists piston to wall clearance as .0004" - .002".
All above manuals show a service limit of .004" (or .0039" in the 1100F manual)
I called Wiseco (putting in a 985 big bore kit
) and they specified .002".My machine shop guy said the .0004" is tight, but he has done them that tight at the customers request, and it has worked but that he likes to go with .002".
I chose to use Wiseco's .002"
Steve
82 CBX, 82 CB900F Project, 81 CB900(985)F, 79 CB750(810)F, 06 Wee-Strom
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CopperCollar
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Re: Piston clearance
With aircooled engines I have always gone with .002, never had a problem with that.
Other's that have done more work on the CBX than I will chirp in here soon.
Mike
Other's that have done more work on the CBX than I will chirp in here soon.
Mike
When given the choice between being right or being kind; choose kindness. W. Dyer
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preston
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- Location: Dunnellon, Florida, USA
Re: Piston clearance
Using a Honda Spec book I was giver while a Honda Motorcycle tech back when shows the piston to wall clearance at 0.01-0.04mm. This is the assembly clearance not the service limit where parts are wornout. Using both Weisco and J.E. piston kits to bring back to stock oversize or to enlarge to a big bore clearances are different due to mostly the production of the piston itself.
Cast pistons swell differently than forged pistons, hence the difference in piston to cylinder clearances. Now these piston kits comming out of China recently appear to be cast pistons from the photos I've seen and may work with the stock specs unless the mfg. suggest differently.
Note: my specs are metric, as are all my precision measuring tools and the written info I work from and have been for over 35 years
Cast pistons swell differently than forged pistons, hence the difference in piston to cylinder clearances. Now these piston kits comming out of China recently appear to be cast pistons from the photos I've seen and may work with the stock specs unless the mfg. suggest differently.
Note: my specs are metric, as are all my precision measuring tools and the written info I work from and have been for over 35 years