A friend of mine picked up a Loncin Desert Storm ATV250 and it's been sitting in the open with the plug out and the piston is stuck in the bore. He want's me to rebuild it for him, I'm having trouble finding a cylinder that will fit it. The engine looks identical to a yamaha 250 Timberwolf and I was wondering anyone knows whether the jug and piston from the Yamaha will fit the loncin motor. Luckily the piston was nearly at TDC and the exhaust valve was open, so most of the water went in the pipe and very little was in the crankcase.

 

I have the same type of atv. Its a Baja wilderness 250 that was made by London. Yes the parts are very similar but just enough for it not to fit
I have a Yamaha dealer by my house and every time I needed a part it always looked the same in pictures but side by side you would find it was casted slightly different or holes were off set etc etc. When I need parts now I resort to my local Baja dealer eBay or the many Chinese atv suppliers online for the best match. London parts are pretty easy to find online...
Hope this helps

 

Well that sucks...lol I had a rebored piston/cylinder kit found for a timberwolf for $200. I was hoping I could find a kit with the piston, cylinder and gaskets online. I find them for about every 250 chinese motor but this one, and the heads seem readily available. I only find the cylinder on a few websites, and by the time I buy all the pieces I need to get it together, it's looking like around $300 and by the time I get labor on it, I don't think he's gonna want to put that much money in it, and it was missing the coil as well, so it's hard to tell what else is wrong with it until it turns over and does or doesn't make spark.

Thanks for the info.

 

You should be able to pick it up here, OEM....
Loncin.ca Your Loncin Distributor for US and Canada plus Loncin Parts for Bikes, ATV's and Dune Buggies

Try soaking the top end with PB Blaster or Marvel Mystery Oil and turning the crank by hand back and forth. It worked on an old boat motor for me. If you can free it up, it may be runable with out a tear down (nothing to lose trying).

Hope this helps...
Denny