Testing for fork straightness?

[CZroe]

I recently bought two sets of bent forks and will be getting all four tubes straightened. While I'm at it, I might as well check my other sets to see if they need straightening. The thing is, I don't have the best eyes for eyeballing these things. Short of removing them from the bikes and holding them up to each other, what else can I do?

[cuong-nutz]

A small straight edge but that's even tough with everything in the way.

[Motofool]

Any machine shop can verify that for you.

If they freely roll on a flat surface, they are straight.

If the bent is too severe, the section of the tube will become oval, which cannot be fixed by straighten them up.

That deformation could lead to seal leak.

[CZroe]

Originally Posted by cuong-nutz

A small straight edge but that's even tough with everything in the way.

I guess I could at least drop them. That's probably worth doing if there's no easier way.

Originally Posted by Motofool

Any machine shop can verify that for you.

I keep hearing that but my experience these last two days says otherwise. Two disassembled forks in my trunk, 8 shops, and many gallons of water in my trunk later (did you see what the weather was like in the southeast today?!) and I've found that they usually aren't even willing to talk to you. I must've heard "We don't do anything like that" more times than I can count today. One shop even tried to blow me off by saying that they were only set up for automotive applications, as if motorcycles weren't automotive!

Originally Posted by Motofool

If they freely roll on a flat surface, they are straight.

Yeah, but the problem is that I don't want to take apart forks for curiosity's sake! It just so happens that the ones I want to know about were rebuilt a year ago (bad seals) and never used since so it would be a horrible waste. I hit a curb with them and didn't go down so it didn't occur to me that they might be bent when I still had them apart. Now I hear that curb encounters often result in bent forks, so I want to check without taking them apart.

Originally Posted by Motofool

If the bent is too severe, the section of the tube will become oval, which cannot be fixed by straighten them up.

That deformation could lead to seal leak.

Yep. Already understood. Thanks.

[cuong-nutz]

Another thing you can do too, is drop the forks and get a piece of glass from the hardware store and lay it on top of the forks.

[Motofool]

Originally Posted by CZroe

.....I keep hearing that but my experience these last two days says otherwise.......I've found that they usually aren't even willing to talk to you.....

That is really shocking; any decent machinist would do it with minimum effort.

If they were so pathetic, it was better that they didn't attempt doing the work.

If bent, the kink should be located somewhere above the seal of the fork, since the suspension should have had some sag due to the weight on the front end at the time of impact.

What do you have that could be used to measure any bent?
Pipes, tape measure, ruler?
We could engineer a simple gauge with what you have.