Vintage Dirt Bike Q & A

I've scoured ebay and have found only just a couple of pistons for 73-74 elsinores, but they are for stock bore. I've found dozens of Wiseco pistons in both single and double ring variations but they say they are for 75-77 years.

Are they really different, and if so what's the difference?

Someone posted a link to a chart that shows parts cross-references but it's got "No Data" in the boxes for 73 and 74 bikes

Buy a wiseco piston for a 73-74 cr250m same thing for the mt250. The difference has been explained before I think it was the cutaway but dont remember. I have a heavily modified wiseco in my mt250 and it works fine. It was only modified because I spent a lot on a port and reed valve setup and the piston had to match it now has four windows cut into it. The 75-76 cr pistons wont work only 73-74 will and all mt pistons will work as far as I know.

Thanks! That's pretty much what I'd surmised. I just find it puzzling that the 75 MT250 pistons are so readily available and the 74 MT250 pistons are so scarce!

If your talking about ebay a lot of people dont know much about what they are selling. I one time bought a set of carbs for a 350 and they were from a 200. The guy got really irate and said I didnt know my ass from a hole in the ground. I had to get a signed statement from the local bike shop to prove I was right before ebay gave my money back. He never admitted he was wrong and even quit accepting paypal so no one could get there money back from him. So be careful when buying stuff on ebay its not always what its supposed to be. If I were you I would just get a wiseco cr250m piston from a reputable dealer.

Thanks all! I decided on a Wossner piston for it. I have a coworker who has used them in his flattrack bikes and loves them. For the price it's worth a shot