YZ 125 Top End Deglazing

[A-310]

I'm putting a new piston and ring set on my top end and wondering if I have to give the cylinder a lite hone so the new ring will break in? I'm told you don't have to with the nickesil coating. can anyone verify this?

[ossagp]

Many of us don't do anything, I am one of those. If you have an area that needs attention, I use nothing more abrasive than a scotch pad. No oil or very lightly oiling the cylinder is the best way of making sure that the rings will seat. (oil your bearings and wrist pin of course). Years back, factroy mechanics were following leads from such sources as "Detroit" when trying to find ways to make a racing engine ready to race sooner. Forgoing the heavy oiling seemed to be the trick.

My guess though is you will get a few imaginative responses here. Companies such as Wiseco publish their suggestions. Your manual will have some too.

[Blue 250]

I wouldn't even use any hone. I just had bad experiance when doing the same thing youre doing. My dealer used a finger hone which wrecked the plating. If anything a scotch-brite pad will work best.

[beefydog]

Even if you don't do it right, or anything at all, you will probly never know the difference. I just did the topend of my KX, what I did was have the cylinder in a bucket of hot soapy water and used a combo of a scotch brite and a stainless steel little wire brush and tryed to scrub in cross hatches. Bike runs fine now, I believe I read in Eric Gorr's book that the scrotch brite is all you need.