Whoa!, three months later and I finally got the ATC185 running right. I’m sure nobody really cares, however I figured I would finish the story.

First of all the cylinder and piston were from a 200S, the piston rings were 185S.. I’ll bet you could guess that the rings didn’t really work. The head was a 185?.. I’m not sure if it makes a difference. Anyway the compression was way to high.. yep even with piston rings that were too small. The little engine was near impossible to pull over.

That’s the basics of what I discovered when I did the autopsy on the engine, furthermore there were chunks of aluminum floating around in the engine case. I figured they were from the previous piston that had exploded.

Anyway I had the engine/transmission completely apart and cleaned everything up. I reassembled the engine with the correct 200S piston rings and used /new cam and bushing.

With the new piston rings, the engine was nearly impossible to start. The compression was outrageous. I’m still not sure it there is a difference in 185 and 200 heads. I finally did get the engine to start and It was crazy powerful. It made lots of noise and just didn’t feel right.. The little three wheeler eventually snapped the drive chain. I guess I did too many wheelies.

I just didn’t feel right about how the engine ran, so I tore it apart again and replaced the head with a 200S. Well that was the trick! The compression felt normal and the engine now starts with one or two pulls. No effort!.

Perhaps the old 185 head was different or it had been milled, I’m not sure what was the story. The bottom line is my bargain three wheeler was no bargain. My total cost is $480.00 and a lot of work. I’m glad I didn’t give up though.

End of story.

Jim.