Power_Man Posted December 3, 2015 Report Share Posted December 3, 2015 Picked up a bike that squeaked the left piston. Spark plug came loose, due to, Trying to determine why now) rider error or detonation. Right one looks good. No marks. Cylinders are being re-nikasiled now. Is it okay just to get one piston and rebuild? Or? Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted December 3, 2015 Report Share Posted December 3, 2015 What kind of cylds? If it's a mono then both sides will have new plating. It would be foolish to not put 2 new pistons in. Quote Link to comment Share on other sites More sharing options...
Power_Man Posted December 3, 2015 Author Report Share Posted December 3, 2015 Yeah CP cub cylinder. Here is picture of said good piston. It looks almost new. That's why I thought maybe rings and go for it. Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted December 3, 2015 Report Share Posted December 3, 2015 No. You're talking an 80 dollar piston. Replace both, carry the good used as a spare for a worst case rebuilder to get you through a weekend. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted December 3, 2015 Report Share Posted December 3, 2015 You can go broke saving money 1 Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted December 3, 2015 Report Share Posted December 3, 2015 Seen many "Mint" used pistons have skirts that were quite collapsed. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted December 3, 2015 Report Share Posted December 3, 2015 Have you figured out why that piston shit the bed? Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted December 3, 2015 Report Share Posted December 3, 2015 Seen many "Mint" used pistons have skirts that were quite collapsed. What exactly does a collapsed skirt look like? Quote Link to comment Share on other sites More sharing options...
possum Posted December 3, 2015 Report Share Posted December 3, 2015 (edited) Lean Edited December 3, 2015 by possum Quote Link to comment Share on other sites More sharing options...
Guest XDOVAYA Posted December 4, 2015 Report Share Posted December 4, 2015 I would replace both pistons at the same time..but that's just me however i am a specialized mechanic. Quote Link to comment Share on other sites More sharing options...
Bennett131 Posted December 4, 2015 Report Share Posted December 4, 2015 You mean retard.Yes. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted December 4, 2015 Report Share Posted December 4, 2015 What exactly does a collapsed skirt look like?Well that's the problem... It's not always so bad that you catch it with your eye. Quote Link to comment Share on other sites More sharing options...
Power_Man Posted December 4, 2015 Author Report Share Posted December 4, 2015 Have you figured out why that piston shit the bed? When he jumped off the bike after it started shutting down on him, the left plug was loose. The guy was a neighbor and he was just in the middle of a plug chop run. He was about to hit the kill switch when it just started getting tight. Looks like a blown crank seal..... id make damn sure to leak down that monster or you just wasted your money...... For sure, I'm not sure why he didn't right after it happened, but he was pretty sure it was due to the one spark plug. After its all re-assembled i will make sure it passes will no drop in PSI. Thanks for all your input. I'll grab a couple pistons and do it right. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted December 4, 2015 Report Share Posted December 4, 2015 Pistons gradually get smaller up the skirt , I start my measurements 3/8-1/2" from skirt bottom and work up keeping it square. I find a dial caliper is the the easiest and most effective, venir caliper is too Inconsistent IMO Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted December 4, 2015 Report Share Posted December 4, 2015 If it doesn't get smaller,skirt is collapsed Quote Link to comment Share on other sites More sharing options...
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