I need some help/advice.

Who can tell me the differences or similarities between a UL rigid frame and a FL rigid frame?

Or links to where I can find this information.

My UL has been customized - I have bought as it looks right now - photo attached - now I am looking to have an extended front fork on her - for this I need to know details about the frames as is might have a front fork that is approved for FL, but not UL. So if I can prove the frames are similar, I might be able to use this fork.

Thanks in advance
Peter/Denmark

 

Think you attached the wrong pic. Looks like an EVO or Twink in the pic...

But to your question...


There are 2 basic catagories of Big Twin rigid frames: the 1936 61 and 1937-1947 frames, commonly called the Knucklehead frame, and the 1948-1957 frame referred to as the Panhead frame. Although the Knuckle frame is for the Knuckle head motor, it is also the same frame used for the 1937-1947 74 and 80 SV motors.

Any 1936-1947 OHV and 1937-1947 SV motor will fit into any year Knuckle frame without modification. Any 1948 SV motor and all 1948-1957 OHV motor will fit into the Panhead frame without modification.


Hope this answers your question.

 

Thank you panz4ever.
The engine is an S&S Shorty/EVO, but frame is an UL '47.
Your reply helped me a lot - thanks again.
/Peter