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Low Side, maybe Bent Fork Tubes - some questions

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I had a low speed, low side. Noob to knobbies on pavement, and too much throttle twist, leaned over on sand-covered tarmac. Oh well...

We went down fast / hard, but did not slide much. Left Barkbuster (and my hip) absorbed all the road rash.

Now, front wheel points one way, handlebars and lights point another. I'm evaluating the various parts to determine what's bent.

I've gleaned these instructions (below) from previous threads and posted here for consolidation helpful to others, and have just a couple questions:

I'm a skilled shade-tree, and I'm confident I'll find all the bent stuff, but I dont know if I'm competent enough to un-bend them (the fork tubes, if they are bent).

Do you think a shop will do it, if they're already off the cycle? (They are not removed, yet).

Is there anything else I should pay attention to (thats not already in the instructions, below)?

Thanks...

 

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Wisdom from other threads:

Handlebars:

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Lay it flat on a table. The horizontal tube and the mid segments should all be in one plane. If they are not then it is bent.

If they do lie in the same plane then measure the vertical distance from the table surface to the bar ends. If it is not the same they are bent.

The bar clamps have rubber inserts in the top triple clamp, this could be the issue. your forks could be straight, but the bars could be slightly off center without being bent because of the rubber inserts.

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The holder on top of your bars may be bent. it's weaker than the bar. lay it down on a flat surface and check

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Check for alignment of the handlebar clamps. Rubber mounted ones may be twisted.

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As far as the handlebars, either the bars are bent themselves and/or the forks are twisted in the clamps.

Is the handlebar parallel to the upper triple clamp? If not its bent, either bend it back yourself or buy a new one.

Now with the front wheel pointed straight, is the handlebar perpendicular to the bike? If not the forks are twisted,

loosen up the triple clamp pinch bolts, hold the front wheel and turn the bars back to proper alignment and tighten back the pinch bolts.

You can also use a piece of plate glass against the fork tubes to verify their alignment (hold it flat against tubes).

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Forks:

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Loosen all the top and bottom clamp pinch bolts that hold the forks.

Twist bars to straighten (may need to hold front wheel between knees).

Re-torque bolts.

After that I would also loosen pinch bolts that hold axle.

then hold front brake and bounce suspension to align front wheel.

That should do it.

If after riding, it returns to miss alignment you my have a bent bottom

or top clamp.

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Also loosen all the axle bolts, and the steering neck nut. Then let everything kind of fall back into place as you tighten each one just a bit at a time.

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I wouldn't loosen everything unless it was really wacked out but I reckon it's more thourough to do so as long as you put it all back together properly.

If doing it this way remove the front wheel first. Then loosen the fork clamps. Loosen the center bolt on the upper tripple only if needed. The order isn't really critical other than I would for sure take the wheel off first rather than just loosening the axle clamps because otherwise you'll be trying to fight both forks and the wheel all at the same time once things are loose.

To assemble - Position one fork at the desired height and snug the lower triple clamp on that fork only. Position the opposite fork at the same height and snug the lower triple clamps on that side. (At this point I prefer to use a couple of low tech winding sticks (wood workers term, not going to go into it here) to sight down the forks to see if there is any twist and if there is then tweak the triples as needed to eliminate it. Once the triples are true and the forks in the same plane I torque both the upper and lower clamps on ONE side only.

Now take the front axle and see if it easily slips through the forks. If not, and you have set the triple properly, then the issue is fork height. Loosen the lower clamp on the fork you did not torque down and very gently move the fork up or down as needed until the axle runs smoothly through both fork legs. Now torque the upper and lower triple clamp on this fork leg.

Now install the wheel. Tighten the axle to spec. Leave the pinch bolts loose. (At least the ones on the large end of the axle). Bounce the front suspension deep into it's compression stroke a couple of times and then torque the axle pinch bolts.

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If the forks are twisted then undoing the triple clamps alone won't fix this but it will make it easier to manually straighten them.

To make absolutely sure you need to un-tighten the stem nut so that the top clamp can twist freely wrt to the bottom clamp (good time to check the stem bearings for grease if not already done). If you do loosen the stem nut to help alignment . when its time to tighten everything back up, leave the stem nut for last.

I had my moments where I'd straighten the front then torque down the stem nut first only to find that when I did ,it twisted the forks back up .

 

Axle:

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The fork position may or may not be right . The best way to tell is hoist onto a stand, take the front wheel off, and slide the axle back in place and spin it with your hand in the middle where the tire would be . Can you spin it all? does it feel like theres allot of resistance ?. the idea is to be able to turn the axle with the least resistance .

the best way to do that is to loosen the floating side fork from the triple clamps and move slightly up or down turning the axle till the axle turns really easy with the least drag then tighten the triple clamp bolts back up .

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Sounds like the forks twisted, I doubt a crash like that would permanently damage them. When I dump my bike and the forks twist, I like to go alongside a wall, put the front wheel against it and use leverage from turning the handlebars into the wall to get the wheel back on plane. As far as the bars go, they could be bent. If they are only a minor tweak I would just ride it as is. If they are badly bent, then a replacement is in order.

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ya my bikes been wrecked on the street 8 times, from 2-55mph, and everytime i just loosen the forks bolts, and kick the tire in the desired direction,until its all straight with the fender..

go down the road slow, and weave back and forth (like your warming tires) and see if it turns the same both ways, might take 2-3tries(loosening and kicking the tire straight) but it worked for me everytime

Edited by 707LAKE

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Have to agree with the above posts.

Unless you hit something head on you won't bend a fork in a low side.

I bent a lower triple in a 80mph low side but the forks were fine.

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This is all certainly good news. My other cycles would be begging for about a bill's worth of parts and labor about now.

This a big help, thanks.

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So, I got a chance to try these things.

Yup, loosened all triple tree bolts, then hold front wheel between knees, and twist handle bars until wheel points straight ahead. Snug up the triple tree bolts, and bounce the front end up 'n down. Go for a check ride.

All good, it worked out. No parts to order, and did not remove the fork tubes, (like that other fellow, who is now having so much trouble after doing that).

Thank You for the great advice!

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So, I have a follow-on concern. I dont think I'm gonna let it bother me, but I'll post and ask if it should bother me.

The cycle behaves normally, steering wise. I have no issues with the way it handles.

But... when I sight down the cycle's center-line, from front-to-back, with the front wheel centered, side-to-side (ie: it points straight ahead).

The front wheel does not "center", left-to-right, laterally down the frame center-line. Looking at it, from the front to the rear, it rests to the viewer's "right", slightly off-center-line (hard to say how much, maybe a half-inch from center).

It does this when a rider is seated and compressing the front end at rest, and it does this when fully extended on a lift, while on a stand, and while on the side-stand.

At each point, the fork tube ends-to-lower triple tree clamp distance measurement is equal on both tubes (ie: one tube is not "longer" than the other), and the fork tube top ends are equal in the top triple tree (ie: they're mounted as equal in trees).

I have not checked the front wheel axle, but the wheel spins freely without binding, and with no "wiggle" lateral or vertical, and since the fork tubes are equal distance, length-wise, in the trees and measured to the fork ends. So, I do not suspect the axle.

My other DRZ400's front wheel centers correctly down it's center line, and I expect this one should, too.

I thought of moving the "left" side (again looking front-to-rear, viewer's left) fork tube up in the clamps to center-line the front wheel, but that presents potential problems with axle alignment, (and mebbe other things, not sure).

But, the cycle steers and handles fine.

Should I let this go, or is there something I should pay attention to?

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