This is a serious problem

[Hzryder]

Hey thanks for the info. I just now saw it. As it turns out I ordered a jug kit on eBay that turned out being the yd jug so it is useless to me. But the piston is just right. Even has 12mm wrist pin. It came two days ago. So I threw the new piston in and it runs better that I've ever seen it run. . When I first started it though it was idling and was smoking all over the motor it seemed and had a minor seizure. Freed pretty easy be bumping rear wheel in reverse. But since that happened had no problems . I'm surprised at the motor. It's a beast. The 80cc kit I got cannot even get close to competing with the bt.so far so good but my fingers still stay crossed for now. Also I have a brand new yd cylinder paper weight I'll make a good deal on.

The yd100 bottom end is on Amazon for like 80 bucks

 

[Greg58]

After reading this thread and from what mapbike and I have noticed on the BT100 cylinder with the steel sleeve the bore is a little tight. I honed mine to get a little more clearance, the steel sleeve is very hard and takes a lot of work to cut the deck height down.

 

[mapbike]

After reading this thread and from what mapbike and I have noticed on the BT100 cylinder with the steel sleeve the bore is a little tight. I honed mine to get a little more clearance, the steel sleeve is very hard and takes a lot of work to cut the deck height down.

I would think that a lot of people who don't hone the steel sleeve cyl. before running it might have a seizure when the engine gets heated up, I have never had one of these engines that had as tight of a bore as this steel sleeve one.

Hoping we get a very long life engine build outta these.