Raoul Posted May 18, 2007 Report Posted May 18, 2007 Any advice is welcome. I'm in the process of rebuilding my banshee motor. I'm just about done, I've got the pistons left to do. I have stock (standard) pistons. I ordered a set of stock (standard) piston rings from bikebandit. I put the rings on, and they were way too thick. I measured the pistons and rings with a micrometer, and this is what I came up with: The piston diameters measured 2.515". OK. I checked my Clymer manual, and that is the measurement of a stock piston. BOTH the old rings measured .038". The new rings I ordered measured .047" and .058". I put them on, the thicker one in the top ring slot, and it was obvious that they were incorrect. I cross-referenced the part number on the piston ring box, and it shows up correct, that they are standard size piston rings. I just don't get it. Why are these rings not the right size? Why don't they fit correctly in my pistons? Is there any way to cross-reference the stencilled numbers on the tops of the piston domes? I thought maybe somebody put the wrong rings in the box at the company, but both boxes? Unlikely. There is a possibility these aren't stock Yamaha pistons, cause I bought the bike used, but they sure do look like stock Yamaha pistons. I'm really curious about the writing on the tops of the pistons. Anybody got any hints? Quote
badassbanshee479 Posted May 18, 2007 Report Posted May 18, 2007 what is the numbers on the tops of the pistons?? stockers do not have numbers, and the stock pistons do have different size rings top and bottom. Where as a wiseco piston, both rings are the same. Quote
Raoul Posted May 21, 2007 Author Report Posted May 21, 2007 what is the numbers on the tops of the pistons?? stockers do not have numbers, and the stock pistons do have different size rings top and bottom. Where as a wiseco piston, both rings are the same. The pistons do have some numbers stencilled into the tops of the domes, but I think I've got this figured out. They must be aftermarket pistons, I just don't know what kind. Definitely not Wiseco. So I went ahead and bought some Wiseco pro-lites for it. Screw it, now at least I know what I have in there, and its good product. Thanks Quote
BigRed350x Posted May 21, 2007 Report Posted May 21, 2007 (edited) I'm guessing you have wiseco pistons and you are trying to put stock rings on them. which just wont work. -Jared Edited May 21, 2007 by BigRed350x Quote
racer Posted May 21, 2007 Report Posted May 21, 2007 Screw it, now at least I know what I have in there, and its good product.Thanks Indeed, that piece of mind may be well worth the money. Quote
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