My zenoah enforcer has a full circle crank. I have read about how the "lamb chop" cranks are modded how would a full circle crank be modded?
Gordon
EDIT:


EDIT #2
This picture is a WHH full circle crank.
Removed the air cooled crank pictures. How or can the WHH crank be modified?

None of the engine builders waste time modifying crankshafts. If it runs true that's all you need. Any rewards would be tiny compared to the benefits. Spend time on pipes and porting. By the way, we've played with full circle versus dog bone cranks and can't find any performance difference we can measure. The only issue was when the clearances in the crankcase were reduced as much as possible. That change reduced power despite increasing crankcase compression. I believe that was mostly due to an increase in viscous drag.

Lohring Miller

Thanks for the reply and the info.
Gordon

I, for one person, agree. Pipe and porting is where the biggest gains are found IMO.
I have a question for you though. To use a full circle type air cooled Zenoah crank in PUM (with a special flywheels I have for the shorter crank shaft), I have to mill the crank case bore bigger because the Zen full circle cranks do not fit in PUM cases stock. I have been cutting .020" clearance per side. If you don't mind sharing what you found (and I would not blame you if you do), how tight of clearance have you found to actually cause more parasitic/viscous drag?

The crank is NOT an air cooled rc car crank, it is NOT an RMCK crank. I use stock PUM parts. As far as I know the case is a stock Zenoah case. When I blued my stock Zenoah PUM crank, Tony accidentally sent me an air cooled crank. I know the difference. What Tony shipped the second time was a direct replacement for the stock PUM crank. I will take measurements of my crank. since the crank is no longer on WHH website. Thinking it is lost to the sell of WHH, unless Bonzi' has the stock.
Gordon

Here are pictures of my case with crank installed


front of engine case flywheel removed


back side of flywheel


Zenoah serial number on case

My crank is identical to the one in the first post.


rear of case with flex adapter


looking down into my case showing crank and transfers
My crank is identical to the picture in the first post.

my case split into halves




my crank removed no shims





I'm guessing at this because I have not talked to Tony C, but I think one of the reasons that he used the full circle cranks is so that he did not have to use special Zenoah bearings.