Had my 360 jug bored .25mm over

[NewHavenMike]

Hey guys!

Long story short, my bike had a seized engine. I bought a used 360 cylinder and NOS oversize pistons and all the other hardware..

The piston are for the first re-bore and hone, which is .25mm.

When i went to pick the jug up, the guy said he bored them to spec within .003'' tolerance.

I picked up the Haynes manual so I can have all the info I need at hand, and that guide says tolerances should be within .002"

against my will and lacking proper tools, I gently slid the piston in its cylinder and there is a slight play.

Now, Ive worked on my watercooled VW and that thing has some serious piston play and ran perfectly....

My question is, without getting into more details, do you think I should be fine when I seal up the engine? Will compression suffer and give blow by?

Will heat expansion take up the slack?

 

[Wolfe_11B]

That's perfectly fine. You'll notice play all around, these are full floating pistons. Just gap and set the rings properly per the manual (machine shop should have checked rings, but make sure). Break the rings in, very important on that first startup after the fresh build (trust me).

 

[drewpy]

when i ran-in my 400 resto, i used cheap mineral oil and gave it some throttle without labouring the engine for 20 miles then dropped the oil and used semi synth.

used that bike over 6 years and never had any smoking issues