[jnscott90]

I'm playing the "Which Part is Bent?" game again...forks or triple tree on a CB450sc

Hello all,
A while back I had some issues with a bent frame up near the head tube of my 83 nighthawk 450. 8 months and almost $600 later that problem is solved. The guy did an awesome job at straightening and powder coating my frame, and yes I know I've probably paid him at least half of what the thing is worth to fix it. Yet I've run into another snag in the front end: it still doesn't line up right...now that the frame is straight it's better, but something is still bent and I'm leaning towards the triple tree/steering column. Here's why. When I slide the right fork through the right side of the tree, it binds quite a bit once the top of the fork protrudes through the upper portion of the tree. However, the left side is smooth as butter all the way through. I thought, maybe a bent fork? In theory (at least what makes sense to me), if a fork was bent, by switching the forks from right to left I should get the same bind from the right fork in the left side of the triple tree, and the same smoothness from the left fork on the right side, if the triple tree was not bent, right? Wrong. When I switched the forks, the left fork bound up at the top of the right side and the right fork was smooth through the left side. From a side view, the right side is raked in a few degrees more than the left. They should be even right? And it doesn't matter which fork is where either, the right still looks pushed in. Has anyone else experienced this? Fork problem or triple tree problem? Is there an easy way to repair this or do I just need to throw a few more fifties into the fire?
Thanks!

 

[outobie]

Roll the fork tubes on a flat surface like a kitchen countertop and it will become obvious if they are bent
same with the triple trees... Take them off And sit them so the openings are on a flat surface for both the top and bottom, and inspect one at a time. You'll probably need some blocks to sit them on ...try a level

 

[jnscott90]

Forks look ok. Right fork has about a millimeter of bend in the top tube. I don't know if that is enough to make a difference. But the trees are warped. I took the top off and set it on a level surface and I could see that the right side is twisted downward by a few millimeters. Probably not bending it back either because it's aluminum. Off to ebay I go...

 

[outobie]

you can straighten minor bends in the fork tubes and if you tube is in good shape otherwise it is highly recommended (as in it isn't all rusty)

it requires a press and some thick heavy Oak V blocks.

you can get a 10 ton press at harbor freight for less than the cost of a new fork tube.

identify the exact location of the bend on the fork tube then put two V blocks under on either side of the bend with the bend up. then put a third V block on top of the bend in the center and use the press to push it down.

do it very slowly a little bit at a time. remeasure the tube after each application of force. you'll find that you'll need to press the bend slightly beyond straight and allow the metal to spring back to the final at rest position.


aluminum trees can also be straightened in a similar fashion (using flat oak blocks) but you will need to heat them up with a torch to prevent cracking...this is more tricky but not too difficult