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bent forks?


betanz
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Hi there,

I have just had a crash out in the paddock in which i tried to go up a bank with nearly no run up (bank is vertical) and the bike got up the top and managed to do a flip while I watched from to bottom, when i picked it up everthing in the front end seemed bent or out of place so i came back to the garage and loosened all the triple clamp bolts and axle pinch bolts and wigled it around and it made no difference so i kept it all loose and took the mudgaurd and brake caliper off and then proceeded to take the front wheel out and it took a lot more effort than normal to get the axle out but it eventually gave in and out came the front wheel aswell, then i slowly turned the axle in my hand and up at the light to see if it was bent and it is fine, so i then went to take out the forks and as you would normally i grabed the stantions and pulled down aswell as twisted them and they would not budge at all so i took the top triple clamp off the top and the forks came out the bottom of the lower clamp normally. then i held a ruler against the stantions of both forks and you can see a gap between the edge of the ruler and the fork stantion about 5 cm up from the outer fork, but only on the left hand side one, the one without the spring. so my question to you is: Are my forks or well.. fork bent or not? and if your not sure any other ideas to test it? also if it is bent is it possible for the fork stantion to be taken out and straightened? (obviously not by me lol)

Note: my bike is a 2001 beta rev 3 250 with the paoli forks.

Really need urgent help!!!

Cheers Brad.

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Best way to check is to put the stanchions in two v blocks and rotate with a dial guage in place.

It doesn't sound like they're badly bent, if at all. If they are you place the stanchion in two v blocks locate the highest point upwards and use a hydraulic press to gently push dowm. You'll need to do it several times but gently, gently little bit at a time is the game.

I'd suggest getting Tony27 to give you a hand (but he's a bit far away) but any decent engineering shop will do.

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If you can see a gap when holding a straight-edge against the tube, it is bent

Whether it can be straightened depends on how badly bent it is and if there are any creases or is it bent into a gentle curve.

Another test is to hold the slider still (by carefully clamping it to something solid) and rotate the tube. You will see any run-out as the tube rotates.

Are you sure only one is bent? I would be having a close look at the other one while the front end is apart.

You should also check for bending/twisting of the triple clamps.

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Hi Brad

Take the forks apart and just roll the tubes along a flat surface, you will see if they are bent. The safest way to straighten the tubes is have them rolled between 4 other rollers, with the bent tube in the middle. I dont know where you could have this done in Timaru, Just ring engineers and ask if they have tube straighting service. Good luck.

Pete

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Hi Brad

Take the forks apart and just roll the tubes along a flat surface, you will see if they are bent. The safest way to straighten the tubes is have them rolled between 4 other rollers, with the bent tube in the middle. I dont know where you could have this done in Timaru, Just ring engineers and ask if they have tube straighting service. Good luck.

Pete

Hi pete, All I did is i took them to my engineering tutor at polytech and he helped me straighten them, so now I have straight forks and more engineering knowledge.

Cheers Brad.

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Good to hear you got them fixed, engineering tutors love it when you can bring something in thats slightly out of the ordinary to use as a demonstration.

Hopefully you get an apprenticeship with a firm whose boss lets you do home jobs, you learn so much more that way

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Good to hear you got them fixed, engineering tutors love it when you can bring something in thats slightly out of the ordinary to use as a demonstration.

Hopefully you get an apprenticeship with a firm whose boss lets you do home jobs, you learn so much more that way

haha yea, an aprenticeship would be awesome!!!! :)

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  • 3 weeks later...
 

Well done Brad. Welcome to engineering. It is fun. Catch up with you some time to chat. Ralphy

Cheers Ralphy. My tutor is going to get my some hydraulic work experience, which should be awesome as hydraulics is the best out there i reakon :thumbup: . Yes catch up some time, that would be good.

Cheers Brad.

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