ok, the motor... 114 inch twin-cam, 10:1 CR, carbed, high output ignition (fire wide plug gap under compression).

is it crazy to think that my 160 lb soaking wet frame could start this even with compression releases installed? and what are some good compression releases for kickstart only bikes? thanks!

 

Yeah, it's crazy. Any manual compression release will work.

 

care to elaborate?

is it because the the CRVs are sized too small to get the cranking pressure down low enough? if I could get the effective starting CR down to 6:1- 5:1 range what do you think then?

can't find much hard data anywhere on this subject (making a big motor easy to kick)!

 

I misread your OP; thought the question was crazy = no CRVs. I am sure there is a mathematical way to calculate how much a set of CRVs will reduce the CCP. It's not static CR that is the problem, it is the cold cranking compression (CCP) which is a function of the head chamber volume, head gasket thickness and intake valve close timing. The size of the motor does not matter, the motor could be 70" instead of 114" but if the CCP was 200psi, you would not be able to kick start that motor. Comprende?

So, you need to calculate your CCP and then try to relate that CCP to say the CCP of an old Shovel that required kick starting. Then you would have to calculate how much a pair of CRVs would reduce the CCP to what would be possible to kick start.

Why do you want to kick start anyway?

 

I bought a new 74" shovel way back, with only a kickstarter. It cost extra to have one with an electric starter. I didn't make that mistake again! You will need a suitable ignition system that allows you to kick start - or see sense and fit a big starter motor. From first hand experience I can recommend ACRs.......