I have a guy wanting to trade me some twin cam stuff, including cases for some shovel parts, I am new to this modern stuff, but been doing some research.


the engine will be bolted into a hard tail frame, & hooked to a ratchet top 4 speed, planning for open 3" belt drive kick only.


the cases are the early style, 99-05 one of my questions is in reguards to a crank, since I will have to purchase one if I do this trade, can I use a later crank to effictively stroke the engine? what are my options for stronger rods? I would plan to have crank welded no matter which crank I go with.


I have tried to read as much as I can find, & see that there is a spline difference, as well as centering location for clutch drum from early to late, but didnt see anything that addressed when using it stand alone with an open belt drive primary to early shovel style trans.


I am versed in building older bikes, as well as some jap & british stuff, just never been around any twin cams, except for riding a few buddies.

 

From what I have read they have said the new cranks 07 and after I believe won't fit the 99-06 cases

 

I can't say for sure but with all the main bearing changes and oil pump, cam plate, comp. changes from 88 to 96 I wouldn't think its that easy if it is possible at all. Look for a 07 to 10 bottom end if your after the stroke and save yourself a lot of aggravation.

 

I know if one wanted to install a later crank in an early model, the interfaces between primary and secondary would be challenging and expensive to address. However, in your situation, if you can address the interface between primary and secondary in the fabrication process, I don't see why you couldn't use the longer stroke crank. But you really need to think through the primary/secondary interface as that is where the issues are. There are no issues with fitting the late crank to early cases as long as the correct main bearings are used.

Hoban Brothers (AKA Darkhorse) sells a beefed up connecting rod.

 

ok I appreciate the responses, the cases I will be getting are aftermarket S&S cases brand new, & I am trading some old shovel parts I dont need for them


I know I am going to have my work cut out for me, lol.


I know I have read the rods are weaker in the later cases? what are my options there if I try to build this stroker, unless go with the early crank with the stronger rods?

 

As djl has already mentioned, I do not see a major issue with what you plan, as the open primary will be the saving grace as long as you can configure a belt length for that combination.
Scott

 

Since you need to purchase a crank wouldnt it be easier to buy an S&S 4 3/8 crank for a 99-06? It wont need to be welded and will bolt right in. Then there is no guess work.

 

That would be a more straight-forward approach.
Scott