FJ Dragbike Project

[fj1289]

Well, there still might be some hope.  New Facebook post today - after further investigation and bringing in some experts and sponsors - sounds like they will try to make temporary repairs for this year.  Plan is to make the temp repairs and have some cars make test passes and see if they can safely run in that condition for this year.   The track said they should have results by May 6th ... fingers crossed

[joebloggs]

With any adjustable link or any link you swap or fab - it will only change the leverage ratio between the wheel movement and the shock travel.   

If you are going to use a different ratio linkage I would suggest leaving the stock spring on the shock (assuming it is fairly well matched to the shock damping).  If you swap a heavier spring but leave stock damping, the spring will overwhelm the shock - the linkage ratio won't effect just one aspect of shock performance - it will effect them all equally I assume...

On the Linkpro - the more you move the lower pivot point forward the stiffer the suspension gets.   The more you move the lower point to the rear the softer the suspension gets.

Tony Foale used to have some software for evaluating motorcycle suspension design and function.  Might be worth a google search. 

Good luck!   

I found a way to allow the use of the shock on with the stock linkage. I mounted the arm/shock without the dogbones in place and roughly marked where the spring contacted the brace on the arm. Using a flap wheel on my drill I removed some material, refitted the arm, checked clearance and repeated, was a long process but it fitted in the end.
 

[fj1289]

Sweet!  That's a similar method that was documented somewhere in the past - I think they used a mill - but same idea and result.