Checking Fork Alignment

[triangleforge]

Dropped my Yamaha XT350 yesterday in a low-speed, sandy turn & rode home with a question that hopefully won't ever apply to my Monster (but could): is there a way to check fork alignment at home?

The drop was nothing remarkable for a dirt bike -- maybe 15-20 mph -- so I'm a little surprised there seem to be issues. The front tire washed out & the bike landed on the right handlebar & footpeg. All the way home, the bike didn't seem to want to track straight -- I was constantly giving it little countersteer inputs, right-left-right-left, just to stay on line. It seemed happier turning leaned over a bit, to the right or to the left, but still not very confidence-inspiring.

Back home, I visually inspected everything and the forks look straight, front & rear wheels appear to be true when I spin them.  The front tire doesn't really line up in the center of the front fender, but it's a 14 year old piece of dirt bike plastic that's spent a fair share of time in the Arizona sun, so I'd be shocked if that was much of a gauge of "straight" at this point. Headset bearings aren't loose, but turn freely.

Is there a way to check to see if I've tweaked the forks before I take it to the shop?

Thanks!

[rockaduc]

I bought a Fork-tru alignment tool from motion pro for just this issue.  I think it was $60 or $70.  It is pretty idiot proof, which is about the right speed for me  ;:|.

[Howie]

If the bike rides true and the forks work smoothly you are probably good to go. 

[darylbowden]

Dropped my Yamaha XT350 yesterday in a low-speed, sandy turn & rode home with a question that hopefully won't ever apply to my Monster (but could): is there a way to check fork alignment at home?

The drop was nothing remarkable for a dirt bike -- maybe 15-20 mph -- so I'm a little surprised there seem to be issues. The front tire washed out & the bike landed on the right handlebar & footpeg. All the way home, the bike didn't seem to want to track straight -- I was constantly giving it little countersteer inputs, right-left-right-left, just to stay on line. It seemed happier turning leaned over a bit, to the right or to the left, but still not very confidence-inspiring.

Back home, I visually inspected everything and the forks look straight, front & rear wheels appear to be true when I spin them.  The front tire doesn't really line up in the center of the front fender, but it's a 14 year old piece of dirt bike plastic that's spent a fair share of time in the Arizona sun, so I'd be shocked if that was much of a gauge of "straight" at this point. Headset bearings aren't loose, but turn freely.

Is there a way to check to see if I've tweaked the forks before I take it to the shop?

Thanks!

measure the distance form lower triple to axle, write it down.  Loosen triple tree bolts so that forks are able to move.  Reset them to the correct height and then tighten.  A lot of times, they get tweaked in a crash like that and you just need to loosen, measure and tighten and they're good to go.

[VisceralReaction]

measure the distance form lower triple to axle, write it down.  Loosen triple tree bolts so that forks are able to move.  Reset them to the correct height and then tighten.  A lot of times, they get tweaked in a crash like that and you just need to loosen, measure and tighten and they're good to go.

Now would this method conceiveably work with any bike? I dropped my ST last year in a very similar method and at a certain low speed
I get a wobble back and forth in the bars, like a head shake back and forth but very gentle small occilations.
M

[scott_araujo]

An easy way to check if the fork legs are parallel is to use a piece of glass.  Glass is nice and straight.  You want a piece of glass that you can lay across the two fork legs from side to side across a part where they are both flat.  If the glass lies flat the fork legs are parallel, if it rocks back and forth they are not.  If they are not, remove the front wheel and loosen all the triple clamp mounting bolts.  Adjust them until they are parallel again, retorque fasteners, check with the plate again.

If you think you bent a fork leg you'll need to disassemble the fork and then roll each leg down a large plat of glass.  If they roll smoothly they are straight, if they make tink-tink-tink noises as they roll they are bent.  You can use the same method to check pushrods to make sure they are straight.

Hope this helps,
Scott

[Norm]

For straightness, I rotate the bottom of the leg with a dial indicator attached. I'm looking for .005" or less, but most people won't notice if it's triple that. For alignment, Just fit the axle without the wheel. This is done by feel and is the ONLY way I know to get a perfect alignment (it's a Cary Andrews method).

[fasterblkduc]

An easy way to check if the fork legs are parallel is to use a piece of glass.  Glass is nice and straight.  You want a piece of glass that you can lay across the two fork legs from side to side across a part where they are both flat.  If the glass lies flat the fork legs are parallel, if it rocks back and forth they are not.  If they are not, remove the front wheel and loosen all the triple clamp mounting bolts.  Adjust them until they are parallel again, retorque fasteners, check with the plate again.

If you think you bent a fork leg you'll need to disassemble the fork and then roll each leg down a large plat of glass.  If they roll smoothly they are straight, if they make tink-tink-tink noises as they roll they are bent.  You can use the same method to check pushrods to make sure they are straight.

Hope this helps,
Scott

+1...You beat me to it. (saved me some typing! ) This is a great old school method that works well.

[darylbowden]

Now would this method conceiveably work with any bike? I dropped my ST last year in a very similar method and at a certain low speed
I get a wobble back and forth in the bars, like a head shake back and forth but very gentle small occilations.
M

Yes, about every time I've dropped my race bikes I've had to do this.  It just happens that they tend to get tweaked a bit - it's no big deal.

[Howie]

Assuming you are not wiggling the slider around in worn bushings, Norm's method is accurate and you don't need to disassemble the forks