The best top end replacement for a stock crank?

[spurdy]

There's a lil more to it than just throwing a 4 mill crank in though. U can't just throw one in and slap it back together. Depending what rods are on it you'll have to get the right pistons. Then you'll either have to have the head recut for the extra stroke or run a cheesy spacer plate under the cylinder. If ya don't really bad shit happens. So there's a lil more cost involved with it than it sounds at first.

 

Then there's the matter of port timing. To really take full advantage of the extra stroke the cylinders need to be ported for it. It'll run but prob wouldn't notice a difference.

 

So what I'm sayin is unless your crank is toast or you just wanna spend more cash I'd get what you already have tried and welded. Doesn't sound like you want to get too involved or spend any more money than you have too. Goin 4 mill is more. One of these days I'm goin to do a stockish bike again. I'm not going to do a 4 mill. Just have the crank trued and welded. Run some pipes, small carbs, reeds, pipes, and prob a head and call it good.

 

If you wanna go with a serval I don't think there's much difference in hp between a stock stroke and a 4mill. I think if you start talking about crank changeout you need to look at longer rods also. That's another conversation about rod angle and all that though. Good luck.

 

Don't think I could have said it better, Dave. Just always assume everyone knows what goes with a bigger crank. Andy put together a stock stroke serval last year that Zac ran. I do think the 4 mil serval nets more power though.

 

None the less, if the 4 mil crank isn't set up right with the right pistons, domes/cut head etc, it will grenade or just not run. If short cuts are taken it may not even perform as well as a stock stroke.

 

SP