First things first, to use this cylinder, or not to?






It does have what I see very often in motorcycles, is the sharp edge of the piston skirt wore the cylinder a little.  Get a new one or use this one?  If I can use this one I'll be putting in a stock bore wieseco piston.  If I need a new one I'll probably get a cylinder works 488 big bore as it's only a few pennies more than an OEM piston, cylinder, & related parafanilia.

i dont know if that cylinder is good or not. but let me tell you if you go big bore make sure you get a better crank and connecting rod!

i bought a crf450r with 490 big bore kit and the owner didnt replace any of the bottom end and the rod blew out front of the engine

The ONLY way to know is to do a service limit measurement.
From your mediocre photos it's hard to tell.

Get a manual.

The nikasil on these cylinders is so hard that they rarely go out of spec before the rest of the engine is beyond rebuilding. I'd just give it a quick deglaze with a standard hone or a scotchbrite pad with soapy water and go

Edited by Lead Head, 29 May 2012 - 10:04 PM.

Lead Head, on 29 May 2012 - 10:01 PM, said:

agree.
MLW, even with these photos, why do you have any reason to think that cylinder is bad? it looks very very good. Lots of nice crosshatching. Be safe and measure for spec, clean it up, RUN IT!
I have a thread i posted a year or so ago, my 04 cyl was the ORIGINAL cylinder with no fewer than 900 hours. Still in spec, never had a motor issue, kept good pistons in it (oem only), rotella oil, lots of harescramble wins, sold it and someone else is STILL using that cylinder. I bought a new one just cause..

Edited by MELK-MAN, 30 May 2012 - 07:49 PM.