+10 pistons for 850 Commando

Anybody know a source for +10 pistons for an 850. Prefer Hepolites if possible but anything considered.
Thanks in advance.

Mark.

Good luck finding them

Remachine +0,020 and get rings made - totalseal is a good source.

Mark F said:

Anybody know a source for +10 pistons for an 850. Prefer Hepolites if possible but anything considered.
Thanks in advance.

Mark.

Click to expand...

If I may offer some machining wisdom, boring to .010 over and leaving enough to hone to finish is simply impractical and on the other hand honing to bring to .010 over is possible but will easily leave an inconsistent bore. A professional honing machine will do it, yet for the reasons stated above, .010 over pistons are basically rare. I have seen and had .030 overs (a .010 increment) but that was for a bad stock bore that need to go past .020 over.

Don't play games with these things. Do it right!

I have seem a left side only at British Only so there is hope. Here is a link that may help you to attain info.
http://www.britishonly.com/estore/categ ... pagesize=5

Hi Mark,
The only companies that I know of that manufactured +10 pistons were Yamaha and Wiseco, I don't know if Wiseco ever made anything for Norton, although I do believe they can custom make whatever you want.
The problem is that in order to true or repair any cylinder damage 0.010 of an inch typically isn't enough.

GB

.010" over pistons certainly used to be made by Hepolite and were called out in the manuals but now I believe pistons are mainly only available in .020" steps.

I have also had the experience that usually a machine shop will want to go to .020" rather than .010".

I replaced my pistons once but not because of wear in the cylinder. It was because the ring lands on the piston were worn. Still on standard bore at 36,000 mi.

Hi, I had been told that as few Commando were not accuratly bored (not parallel) , some dealers wre used to rebore them on new bikes to minus 0.010, thus the supply of such pistons , at least one french dealer did that ........it was in 1974 when I bought my new 850 from him (no charge for that.......happy times!)

Hmmm. Sounds like I might be looking for the proverbial needle in the haystack which I thought might be the case but always worth a try. +20's it is then. Thanks.