Originally Posted by VENICE BOY
Why do you think you'll need a 3-piece crank in the first place???
The in frame 4-stroke kits that I have seen, come with a special wider 1-piece crank to clear the engine.
The 4 stokes are a wider engine than the 2 strokes, so the wider crank is necessary. They engine kit contains a three piece "crank set" (two crank arms, and chain sprocket) which requires the "square shaft bottom bracket" to mount the crank set on. Most (practically all) of the bikes I looked at have the one piece cranks on them and that renders the three piece crank set that came with the kit useless. I know my terminology is not the best, and I'm probably not explaining myself in the most accurate way as well.
At any rate, I need the square shaft type bike to bolt my crank set onto.
The Ashtabula type one piece crank will not work for my 4 stroke engine.