CCS / ASRA Racing Forum

All the other stuff => Wrenching => Topic started by: Kal on October 18, 2004, 05:34:48 pm

Title: Bent Forks???
Post by: Kal on October 18, 2004, 05:34:48 pm
I recently had a low side and the bike slid into the grass and cartwheeled 4 or 5 times.  The fairing stay took the brunt of the front damage.  It's completely crushed.  The forks don't look bent, but is there anyway to tell without taking them in to an expert?
Title: Re: Bent Forks???
Post by: Super Dave on October 18, 2004, 08:27:35 pm
Well, they need to be straight.

You'll really need to take them out of the triple clamps.  They usually bend at the lower one.  A straight edge of any kind will help you.

Obviously, a really bent one might have a real noticeable kink.  

Others might just be a mild bend.

That help?
Title: Re: Bent Forks???
Post by: WebCrush on October 19, 2004, 05:51:45 pm
note that if you bent your forks, its extremely likely you bent the frame to boot.  

the forks on most modern bikes are stronger than the steering heads on them
Title: Re: Bent Forks???
Post by: Kal on October 19, 2004, 08:49:45 pm
Yea, I can't tell yet but the forks were a little hard to get out of the tripple.  When the bike came down on the front, it impacted more on the fairing stay and crushed the key in the ignition.  I'm not sure if the triple is bent either.
Title: Re: Bent Forks???
Post by: RidgeRider on October 20, 2004, 07:22:10 am
It might be that the triples are just out of alignment.  Try this:
1. remove the forks
2. loosen the steering stem nut
3. insert one fork leg and align the upper/lower triples so the leg slides freely up and down
4. insert second fork leg - if it also slides freely - things are aligned and straight (at least the upper part of the fork legs)
Title: Re: Bent Forks???
Post by: INSANESTEVE777 on October 20, 2004, 08:08:15 am
Usauly the triple will bend before the forks. to check the forks take them off ans grab the caliper mount with a vise,wrap the caliper mount with a shop towel to keep your forks pretty. Now spin the slidder portion of the fork and it will be easy to see if its bent. Use a refrence on the wall or table behind the fork while you spin it and if its off or bent you mark will show you. Once your forks are straight you can check your triple. Set one of the forks straight up and now measure the other forks location and angle. If these are bent more than likely so is your axle. to check this just roll it on a table and see if it wobles,if its not noticable check it again on a vise. open the vise slightly so the axle can sit on top and not roll off,now spin it and look or mark a refrence on the vise to see if the bad boy is bent.
Hope this helps a bit. hope you have a gsxr 600 if they are bent . those front ends are cheap on ebay!!
Title: Re: Bent Forks???
Post by: Kal on October 20, 2004, 12:03:18 pm
Thanks, I'll try it and hope for the best!
Title: Re: Bent Forks???
Post by: r6_philly on October 21, 2004, 08:07:15 pm
ok the best way to tell if your forks are bent or not (I know this from a very extensive experience...) is to measure the distance between the to axle holds.

Loosen your upper and lower triples, but do not let it so loose for the forks drop off.

keep the fork tubes leve at the top, then twise one leg at a time, 1/4 of a full rotation. Measure the distance between the to fork bottoms. Keep twisting and keep measuring. If your forks are even slightly bent, the distance between the 2 legs will change as you turn.

I found this out when I can only install the front wheel with OEM spacers when my forks are pointed certain way  ;D in the other ways there isn't enough space, or there is too much space.

Of course you can always put the fork leg in a vice and use a dial indicator to measure the tube while you turn it. If you have the equipment.
Title: Re: Bent Forks???
Post by: MELK-MAN on November 14, 2004, 07:33:51 am
Quote
note that if you bent your forks, its extremely likely you bent the frame to boot.  

the forks on most modern bikes are stronger than the steering heads on them


I don't agree. Very VERY easy to bend forks without damage to the frame. Especially on non-inverted forks. However..this guys bike did FLIP 5 times so the thing could be tweeked pretty good. :(
Title: Re: Bent Forks???
Post by: MELK-MAN on November 14, 2004, 07:36:41 am
Quote
ok the best way to tell if your forks are bent or not (I know this from a very extensive experience...) is to measure the distance between the to axle holds.

Loosen your upper and lower triples, but do not let it so loose for the forks drop off.

keep the fork tubes leve at the top, then twise one leg at a time, 1/4 of a full rotation. Measure the distance between the to fork bottoms. Keep twisting and keep measuring. If your forks are even slightly bent, the distance between the 2 legs will change as you turn.

I found this out when I can only install the front wheel with OEM spacers when my forks are pointed certain way  ;D in the other ways there isn't enough space, or there is too much space.

Of course you can always put the fork leg in a vice and use a dial indicator to measure the tube while you turn it. If you have the equipment.


Good idea! .. Yes, even a little bend will be MAGNIFIED at the bottom of the tubes as the forks are a few feet long. turning 180deg will show measuring at the axle pinch area as he indicated
Title: Re: Bent Forks???
Post by: dwilson on November 15, 2004, 06:19:23 am
If you're near Philly I have a machinists straight edge you can check them with.