Terry- Possibly, but not sure. I never gutted any of these "unit" engines for the piston; just used those pistons that happened to be in rebuilt chain saw engines. I'm told this piston is still a current Tecumseh part! It has a wide groove running down from each wrist pin hole- probably for better o...

Terry- Those lower ports were in a new kart cylinder, with the big outer exhaust ports and the pipe plugs. The white cylinder looks to be identical to the chain saw cylinders that are in my shop. I like the ports higher up for high RPM and less chance of free porting that the snowblower pistons I us...

Youre right, Brian. I just found out these came off Navy surplus engines for small generators. Hank found the port timing identical to the regular cylinders. But my other question must have been missed by the gurus. Why are this kart cylinder's ports nearly 3/32" further down the barrel than the por...

Hi- I was priming a new kart cylinder and noticed that the exhaust ports were noticeably lower down in the bore than those in a chain saw and white cylinder. .08 to be exact. Was this kart cylinder made for an AH 61, or did the AH 58 and 61 share the same one? I wound up with three white cylinders, ...

Hi- there' s a lot of stuff on the Vintage Kart site about the correct spark plug for an early 580. I can' t log on there, but I think some of you visit that site. Anyway, my very first engine was a 580, and it came from the factory with an Auiolite AL5x. This is close to a Champion H8j. Both plugs ...

thanks, Louie! The only clue in my manual is an exploded view of a Super showing what seems to be the closed end of pin towards flywheel side { Tecumseh split crankcase models}. I wasn't sure if this alone was enough info. Shown on the last page, by the way, is a listing of speed items you could ord...

hi- should the closed end of the wrist pin face the exhaust port in a stock AH 58? Please clue me in, as these kinds of details are not always in the manuals.
Thanks, Bill

thanks, Steve. I thought we were on the right track because the seal was a good press in the big 45 counterbore. The matching numbers made me feel better, as the letter prefix looks more and more like the company's ident.- (i.e. CR- Chicago Rawhide).
Bill

Help, MAC gurus- is seal # CB-078-137-8 correct for the mc 45? Also on it is 010000. The seal seemed tighter than usual around the shaft, even though well lubed and the step on the shaft smoothed. I hope your Thanksgiving was a good one!
Thanks, Bill

Yes, the Big Bear had a WB 580. This was my first minibike, the one I raced at Bridgehampton. I thought it was the first mini ever, not knowing 'till now that Bug came a week earlier. Its steering head was the weak link, with only the single top tube and down tube butt welded to it. The frame would ...