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mxrose3
4/7/2018 9:34am
4/7/2018 9:34am
Edited Date/Time
4/24/2018 2:18am
I just picked up a project 89' YZ490. The bike runs and starts, but it seemed a little down on compression (for a 490), so I took the top end off expecting to see a worn out piston/cylinder. The guy I bought it off of said it was on the original bore (yeah right!). Measured it, and its at 1.50mm oversize. Bore measures within specs, but the rings were worn. This time, i'm not going to bore it - I'm just going to throw a new set of piston/rings in. But since I've only got one bore left on this cylinder, my question is:
Has anyone here tried to get there steel liner coated with nikasil so it lasts longer? Pluses and minuses of it?
Has anyone here tried to get there steel liner coated with nikasil so it lasts longer? Pluses and minuses of it?
If all you can get are chrome rings then you certainly can't run it. Easy if the dimensions are shared with a nikasil plated bike though as you can just run the rings intended for those bikes. No idea why as I'm not a Tribologist. I guess it would be an issue with stiction.
I have read that some tuners nicasil the ironsleeve, but i think that is for getting a small power gain and with a 490 power should not be a problem
Also, where are steel liners available at for that matter? I don't see one listed by LA Sleeve.
The Shop
They do Iron, Steel or Aluminium liners. The original will likely be steel if it's chrome plated.
I don't see anything listed on their website for a YZ490.
I read alot of online opinions on plateing an iron bore and some were that the plating would flake after a while so I got to calling around asking questions on it. Apparently the process has changed in recent years and its common practice now without issues. In more poking around Ive found alot of vintage racers doing this witb there cylinders. If its as durable as Ive been told its a win win in my book to have a plated cylinder in this big bore of mine.
Check out these guys for alu sleeves. Also Millennium, Powerseal or US Chrome or another plating place might know. I still think that would be trickest. better heat transfer and expansion rates.
I talked to a buddy that has done several nicasil on iron cylinders and no issues after several years of racing. He thought the piston and ring wear was greatly reduced. He used Powerseal.
There aren't any stories on the net where people have had it done and it has failed. Maybe that's a good sign and I should try it.
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