4 or 7 mm crank questions

[30years]

So i have everything that u could possibly bolt on for performance on my shee. It's a 66mm bore, pro d cool head, 34mm carbs, v3 reeds, k&n, moose racing clutch plates and springs, clutch lock up, + 4 timing, and cpi inframes. The cylinders i just put on are full drag port by RDZ. I got it broke in, took it out for a few passes, and after the fourth pass it was making all kinds of racket. Shut it down. Kicked it over by hand, and it sounds to be a main crank bearing or connecting rod bearing. I haven't torn it down yet. I would really like to know if i should just repair the damage if possible and put it back together, or go for a 4 or 7 mill. I don't know what is involved in stroking the motor. Can i just use everything i've got with a spacer plate and a new crank, or what? Thanks

[dirtydownunder]

the port is prolly to drastic to turn into a 4/7mm. id pull yours down, see whats up and go from there.

 

if you wanted to stroke it, youd need cylinders, crank, pistons , domes and gaskets (and a port job) (and with a 7mm crank, you need to trench the cases) seems a bit too much, if alll you need is a crank and bearings... hopefully.

 

strip it down, see where ya at.

[johndeere10]

i would go with 4 mill and ask rob if he can save your cylinders and set the port timing for a 4 mill ...4 mill crank is cheap no trenching to the case ..

[Coupelx]

there a pretty good chance that being a drag port, they could not be ported for a bigger crank. 7mil stock cylinder bike would be fun. i was originally going to build one.

[30years]

What are the best shops in michigan other than rdz that i can talk to about my options. Where is the best place to buy parts? I see rdz offers a couple of motor kits, and override trans. I'm thinking about going all out, but i really don't wanna just scrap everything i've got and start over from scratch.

[SLOPOKE21]

Either you want to go FULL drag now or you want to keep a "duner". I had that problem before, and my bike is a handful to handle on anything but a track. Oh, and its only a 7mil.