crankshaft stroke questions

[gearhead1]

Got a engine question and am probably posting in the wrong section.

Back in 07 I added a 95" stage 2 kit. I've been looking at the SE performance book and it reads like I could change the crank and get 103" just by adding the crank.

Would this require pistons with different pin location or is there enought room on the stroke to add the 3/8" increase? The increase in stroke would add 3/16" more piston travel at TDC. How much clearance is in there? How much would this increase compression?

I'm considering the crank change because I feel the stock crank balance is not very good, lots of viberation at 4200 RPM and up. I talked to a cert. wrench and he felt the SE cranks were a lot better for balance.

Appreciate any input.

 

[Bud White]

You would need to change the pistons also .. the pistons on the 96 are different from what the 95 and 88s were because of the longer stroke .. it was the bottomes of the pistons that were the big difference. skirts were shorter and something else i cant think of right now

 

[TQuentin1]

Got a engine question and am probably posting in the wrong section.

Back in 07 I added a 95" stage 2 kit. I've been looking at the SE performance book and it reads like I could change the crank and get 103" just by adding the crank.

Would this require pistons with different pin location or is there enought room on the stroke to add the 3/8" increase? The increase in stroke would add 3/16" more piston travel at TDC. How much clearance is in there? How much would this increase compression?

I'm considering the crank change because I feel the stock crank balance is not very good, lots of viberation at 4200 RPM and up. I talked to a cert. wrench and he felt the SE cranks were a lot better for balance.

Appreciate any input.

If you are getting vibration now, I would suggest that you have the run-out checked. You may have a twisted crank already, and that knowledge might guide your thinking about when and what to do. See here:

Chain Driven Cams And A Twisting Crank - Harley Davidson Community
Crankshaft Runout (videos) - Harley Davidson Community

TQ