Hate to do it but I agree with sloth^
Bpb, I wasn't saying a big bore 4mm is a bad idea. I was just trying to show that an extreme sized piston could potentially be an issue, but after looking at a bunch of different cranks, it seems that the 4mm HotRods rods are about as durable as anything, so maybe I'm just putting my foot in my mouth.
Idea. If you are serious about building a few race bikes, why not throw a few 421 cubs together. Just shelf stock with poor man's CPI's and used sets of 35 PWK's. Lease the bikes.....
You can get fancy, but why if they're just bikes you're selling. Really you are gonna take a loss unless you start just buying used motors to toss in them or something. Building a good cub costs about the same as what guys are getting for decent complete bikes. Maybe just build a few stock stroke draggers. Send a few motors off at once and possibly get a deal. Have the cylinders done and stock heads re chambered, cranks checked and welded with new bearings, cheap used VF3's, used sets of 34mm PJ's.