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How does this cylinder plating look?

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Can anyone give me advice on this cylinder? It was replated at the last top end, I can still see the cross hatching and it should cleanicon1.png up even better. There is a shinny spot between two ports, does it look the plating wore off here? If so will it be safe to run for another top end or could it be a problem? I want to put my money into the bottom end now not the top.

 

Thanks 

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2013-09-03_21-58-06_673.jpg

Edited by crmaverick

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It's wore but acceptable.  You should measure it and don't expect a long piston life.  The shiny spot between the ports is where a grinder was used to add extra clearance to prevent them from rubbing on the piston while hot.

Edited by 1987CR250R

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It's wore but acceptable.  You should measure it and don't expect a long piston life.  The shiny spot between the ports is where a grinder was used to add extra clearance to prevent them from rubbing on the piston while hot.

Cool thanks, Ill clean it up with scotch brite. 

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You said in another post that you had the cylinder replated.  That looks like a US Chrome replate job.  I had them do my CR 250.  I was not happy with the results the cylinder looked just like that and the bike would eat pistons every 20ish hours.  No break-downs just had to replace them regularly.

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You said in another post that you had the cylinder replated.  That looks like a US Chrome replate job.  I had them do my CR 250.  I was not happy with the results the cylinder looked just like that and the bike would eat pistons every 20ish hours.  No break-downs just had to replace them regularly.

 

You nailed it, US chrome job. The previous owner had is done at the previous top end. 

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I have run both Millenium and US chrome finsish's on our race snowmobile engines. US chromes are a harder coating than Millenium's coating. I have seen Milleiniums coating be not hard enough and have had to replate several times because of there plating. I personally dont like milleniums coating as it is always a crap shoot if you end up with chatter marks in the bore because of there pore plating. This is just my experience with sled engines but I have built a lot of prostock drag engines and I prefer US chrome as i know it will be hard enough to last.

 

Now one thing you guys can do to help when having to re-plate is to hone, or bore to +.010. It will give you .005 per side of plating VS the .0012-.0015 as a stock bore. The finish will hold up a lot better and last longer as well.

Edited by Zrt1200

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