Author Topic: Aluminum Pro-X cylinder overboring (Read 4889 times)

mx250r91 · « **on:** July 07, 2013, 09:30:54 AM »

Here is a question I had but didn't want to ask on .net because of you know who. I have a Pro-X 260PV cylinder 68mm bore, all aluminum, nikasil plated. Could this be stripped and bored to 72mm then replated? There is plenty of material between the current edge of the bore and the inner o-ring gland. I heard these cylinders and the 310 were from the same casting so that got me thinking about this. I know the PV blade and dome would need to be modified for the bigger piston. There really is no cc limit in the current racing series by me anymore whether xc or mx so I figure why stay with a little 260 when all the four strokes are 450+ cc.

matt250r21 · « **Reply #1 on:** July 07, 2013, 09:46:35 AM »

I have the same cylinder as you, with a 68mm piston you are closer to 262cc. As far as boring up to a 72mm piston, I don't think you can safely. The aluminum sleeve at that bore will be to thin and brittle, the part of the sleeve that fits down into the cases will break off is what I'm referring to.

motofool250r · « **Reply #2 on:** July 07, 2013, 09:54:14 AM »

mx250r91, the only person i know that has done this and with success in the cpi cylinder is Pete at Hybrid im sure with a quick call he can tell you what your options are.

1bad88r · « **Reply #3 on:** July 07, 2013, 10:05:01 AM »

I have a 265 pv I have been wanting to bore and sleeve with a iron sleeve. Would Pete be a good option?

motofool250r · « **Reply #4 on:** July 07, 2013, 10:10:54 AM »

1bad88r you have an all aluminum/nikisil lined 265 you want to sleeve? or an iron sleeve 265 you want to re sleeve?

1bad88r · « **Reply #5 on:** July 08, 2013, 06:37:39 AM »

aluminum/nikisil lined I want to iron sleeve because the aluminum has a few nicks in it and would need fixed and recoated. Figured iron sleeve would be a cheaper route.

motofool250r · « **Reply #6 on:** July 08, 2013, 06:52:37 AM »

Quote from: 1bad88r;1758

aluminum/nikisil lined I want to iron sleeve because the aluminum has a few nicks in it and would need fixed and recoated. Figured iron sleeve would be a cheaper route.

iron sleeve will run around 400 total to install re nikasil about 200$ Millenium plating or us chrome can handle it. if you seek out rsss396 on here he gets some good pricing if you go through him

1bad88r · « **Reply #7 on:** July 08, 2013, 09:15:05 AM »

What about the cylinder repair? It has a few small Knicks on the bottom skirt and a small gouge by one of the ports.

motofool250r · « **Reply #8 on:** July 08, 2013, 09:46:08 AM »

Quote from: 1bad88r;1765

What about the cylinder repair? It has a few small Knicks on the bottom skirt and a small gouge by one of the ports.

millenium welded up some cracks in my cylinder and ported it back to where it was and stripped the plating and replated mine for about 400$