Hi I have an old '72 XL250 that I'm thinking of building into a trials bike, similar to the Jefferies bike. Any thoughts on how the head angle was steepened? Im favouring heat bending the top tube but I'm open to suggestions. Thanks in advance Mart

I remember that the head angle was changed, only 1 degree or so, but not how it was done. Cutting and welding the frame I think. 

The Jefferies Honda had extensive changes to the original frame. The bottom section was cut out completely, and the engine also raised in the frame. A shorter swinging arm was used. I think the engine remained relatively standard but a smaller carb was used. 

In the end, it depends what you want. You won't end up with a Jefferies replica, such were the number of changes made, both major and detail. Neither will you get a competitive trials bike, it'll always be overweight, not properly balanced or suited to trials in terms of power delivery, and a cumbersome lump to move around (even the Jefferies bike didn't really suit many riders). 

In addition the '72 XL 250 is a truly historic bike in its own right as a trail bike, I'd think more worth restoring to a near-original state. It marked quite a turning point in the trail bike genre. It would really be a shame to try to change it from what it was into something else which may not be very good at all. Just my opinion, you understand!

Edited October 26, 20241 yr by cleanorbust

Are the forks parallel to the head stock ? They are frequently at least 1.5°  rake. New / different yokes to achieve parallel might be a quicker and cheaper alternative.

Thanks for the info. The forks appear to be parallel but I've yet to measure properly. A simple solution as you say. I 've just rebuilt 2 XL's and it cost me a fortune! I can't bring myself to do another one. Thanks