Forks are crooked after asembly

[du907]

I wrecked my 907 last May. I've been putting everything back together over the winter. I had the forks straighten and the wheel straighten. I had to get a new axle too. After putting everything together I tried it out and the top triple clamp is slightly to the right when the bike goes straight down the road. I looked down and the lower clamp is turned about 5 degrees to the right when going straight down the road. When I put the forks in the triple clamps I had everything loose. The forks went in no problem. I'm wondering if the bottom clamp can be bent somehow. Just looking at it, it doesn't look like you could bend it. Does anyone have a method for aligning everything up? Maybe a how-to method.
Thanks
du907

[ducinthebay]

Check the bridge piece that holds your front fender. That is also a fork brace, and can pull things around if not straight.

Front ends are fickle. Only one bent bit will send the whole thing off. Put it up on the stand and take things apart one piece at a time. use a laser or the string method to check the bike for being straight.

Don't forget to check your rear wheel. Measure your axle to the pivot pin on both sides to see that the wheel is straight. Don't trust the hash marks on the swingarm until you can confirm that they are correct.

Start here:
http://www.motorcyclistonline.com/howto ... index.html


Good luck,

Cheers,

[Mc tool]

You could try , with bike on center stand and front wheel off ground ( make sure it cant roll forward off the centerstand) loosening the axle and axle clamp , the top and bottom clamp bolts and rotate the inner tube by hand (probly quite stiff ) and you will soon know if the fork is still bent .With the sides and the axle still loose try twisting the bars in the desired direction, whilst holding the front wheel still if they move and stay where you put them do up all the bolts and be happy , if they bounce back out of allignment ; ooooohh thats bad.
one thing to make sure of is that your eyes arnt lyin to you , what are you lining it up against , are you sure that whatever that is is not 5 degrees out? . you can pretty much discount the axle as its new .

[JWilliam]

Check the rear wheel alignment by placing a long straight tube against the side of the rear tyre and mark the tube end against the placing of the front wheel. Ideally the tube end will be 25mm each side of the front tyre. If the back wheel is misaligned by (eg) 5 degrees clockwise you will have to steer to the right to correct this. More serious is if the frame is bent and is no longer placing the front wheel properly on the road, either way you should be able to work this out by the above method. It is part of the UK MOT test now.

[du907]

Thanks guys for all the info. Will try it out. I took the forks apart and put a straight edge against the tubes and they are straight. So it's in the clamps. As I was riding down the street and saw the handle bars were not straight I looked down at the lower clamp and it waa cocked to right while going straight. So this time after taking the forks apart I pushed the forks in until they touched the upper clamp and looked down and it is obvious the axle is cocked to the left. So I'm thinking bottom clamp. Does anyone have a bottom clamp I can buy? I have two top clamps so I need just the bottom.
Thanks

[samandkimberly]

Thanks guys for all the info. Will try it out. I took the forks apart and put a straight edge against the tubes and they are straight. So it's in the clamps. As I was riding down the street and saw the handle bars were not straight I looked down at the lower clamp and it waa cocked to right while going straight. So this time after taking the forks apart I pushed the forks in until they touched the upper clamp and looked down and it is obvious the axle is cocked to the left. So I'm thinking bottom clamp. Does anyone have a bottom clamp I can buy? I have two top clamps so I need just the bottom.
Thanks

Bottom clamps usually bend (and straighten) easier than you'd think. If you put the clamp in a nice rigid vise you can probably straighten it using the forks themselves. As long as you don't start using cheater bars and the such you shouldn't hurt the forks.

Sam

[ducinthebay]

So, you have the bike supported, the forks are in, and the front wheel is off. Correct?
Make sure the fork brace is off also.
While you have the bike in this condition, here are a few things to try.
- make sure your axle bolts are loose. I sometimes drive a screw driver into the slot to loosen it up even more.
- slide the forks all the way up into the upper triple clamps, but don't tighten the top clamps.
- Snug up the pinch bolts on the lower triple clamps.
- make sure the pinch bolt for the upper triple clamp onto the steering stem is loose and the clamp can rotate on the steering stem.
--Now site down the whole system to see if the front axle is not straight. the only thing tight should be the lower triple clamp pinch bolts to the forks. This will tell you if the lower clamp is twisted or not.

- Now loosen one of the forks pinch bolts and rotate the fork leg while peering down the leg. See if you have any variation in location at the end of the leg. (keep the axle in for this) This will tell you if your fork legs are indeed straight. tighten up that fork in the lower triple clamp, and try the other one.

If it is still crooked after all this, then I will gladly sell you a lower triple clamp.

The last thing you need to check is to see if there is any binding in the travel of the forks, which makes the ride horrible, and will wear out fork bushings quickly. Put the whole front end together, wheels, brakes, everything. Support the bike, take off the fork caps and pull out your fork springs. Lift the front wheel to confirm that the travel is smooth throughout the entire stroke. Its not easy, but since everything is now suspect, it should be checked.

Of course there is the whole tightening sequence to putting on a front wheel which I won't go into.

Lots of little bits to cross you up in the build.

Cheers, Phil

[du907]

Phil,
Thanks for all the help. I've been trying out some of the things mentioned in everyone's post. I measured from the rear wheel and I'm sure the right front axle centerline is forward of the left. I remember the first time I put the forks back in after having them straighten, the left side went right in (I had not loosen the top clamp bolt to the steering stem) but the right side didn't want to go, so I pushed it a little to make it go in. So i'm thinking the right side is the side that is tweaked.
My friend who is an airline mechanic and motorcycle mechanic/racer (in his younger years) says what you say about bending the bottom clamp. He said use my forks and we could bend the side . . . . and I said whoa. I just paid $110 to have the forks straighten (only one was bent according to the shop that did the work) so I was not interested in using MY fork to bend the bottom clamp. He said he had an old fork we could use. So that might be an option. I'm trying to get it ridable by the end of the month so my patients is wearing out.
How much do you want for the bottom clamp? I have another top clamp and some other pieces you might could use.

Below is some pictures. I have tried to show some reference points to show how far off things are. I think the pictures with the head light might exagerate things a little. The other pictures are the tubes and how far off they are when compared to the top clamp.












I'm confident that the fork tubes are straight. I bought a brand new axle, so good there.
Thanks eveyone
du907

[ducinthebay]

Yeah, that doesn't look right at all. Something is hinky up there.
Send me a pm with your address and I'll send you the bottom clamp. If it works, its $50. If it doesn't solve things, send it back.

Cheers, Phil

[angelix]

is that upper clamp right?

looks to me that has been modified somehow?

[streetsurfer]

Does anyone else use this during a front wheel mounting or fork/steering stem work? Once you have everything assembled but just prior to final tightening, you spin the front wheel by hand, then apply the brake. I doubt that is enough force to straighten what needs to be straightened on your bike but it is a method to help align things before torquing down the pinch bolts. Does something like put the centirfugal force of the wheel and the fork legs on plane I guess.
Settles them into the clamps where they'd naturally want to ride, and probably relieves any stress between parts from assembly?

[Derek]

Does anyone else use this during a front wheel mounting or fork/steering stem work? Once you have everything assembled but just prior to final tightening, you spin the front wheel by hand, then apply the brake. I doubt that is enough force to straighten what needs to be straightened on your bike but it is a method to help align things before torquing down the pinch bolts. Does something like put the centirfugal force of the wheel and the fork legs on plane I guess.
Settles them into the clamps where they'd naturally want to ride, and probably relieves any stress between parts from assembly?

I usually do it by loosening all the clamps on bottom yoke and wheel spindle but keep the clamps on the top yoke tight. then push the wheel against a wall and bounce the forks up and down a few times. This should bring everything into line and then I tighten all the clamps.

[Desmo_Demon]

I usually do it by loosening all the clamps on bottom yoke and wheel spindle but keep the clamps on the top yoke tight. then push the wheel against a wall and bounce the forks up and down a few times. This should bring everything into line and then I tighten all the clamps.

I do a similar ritual when remounting a front wheel. It helps align the fork legs and prevent binding of the fork tubes during their travel. To align them this way, it is necessary to leave the right side (brake side) axle pinch bolts loose, as the axle threads into the left leg and will remain stationary.

As for the triples, they usually align themselves when installed with the forks run up through them. With one tube installing easily and the other not, I would suspect the lower triple is bent, also. Personally, I'd probably prefer to replace the lower with a known straight replacement. I assume a 750 lower would work? If so, those are fairly easily available and fron non-wrecked bikes, as it seems most people would rather part out a Paso 750 than sell it complete.