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Suspension/from end help

1K views 18 replies 7 participants last post by  TurboBlew 
#1 ·
I had a slow low side about 10-15mph, the frame slider took 95% of the damage but I did notice that the front forks where slightly off so I did what I do to my dirt bikes. I loosened the front axel, cowl and lower triple tree. I then compressed the forks and tried to straighten them. I tightened everything up and rode the forks are now straight but around 35 mph the whole front end/bars shake, the faster I go the more violent it gets. At this point not knowing anything about suspension what do I need to look over and evaluate, fork seals are good and brakes have lost the stiffness in the lever. I plan on bleeding them soon. Any advice on the wobbling?
 
#5 ·
If the bars are shaking back and forth that can cause the pistons to retract. That would cause the lever to go soft, since you're needing to displace more fluid to bring pistons back out.

At this point, if it were me, I'd remove the wheel, loosen both triple clamps/clip-ons, remove each fork tube, and roll them on the edge of a flat surface looking for run-out at the axle end. It won't roll straight (different diameters at the clamp points), but you'd still be able to see any significant run-out at the bottom of the axle casting.

To reassemble, loosen the stem nut on the top of the upper triple clamp, slide each fork tube up through into position, clamp the LOWER triple first on each tube, and then clamp the upper. Then tighten the center stem nut. This will ensure that the triple clamps are aligned.

Reassemble the rest and test ride again.
 
#7 ·
Okay I've done some research on "run out" but i am still struggling to understand what it is, I am guessing it is the distance the fork would rotate if it was bent? like if you have a bendy straw then another straw around it and if you where to spin it you could see the bend for the inside bendy stray coming out of the inside?

something of that nature? I'm hoping I didn't tighten my axle enough.... some thing simple, and the brakes aren't tightening up even when she isn't moving leading me to believe that when she went down air got in the lines.
 
#8 ·
With the axle out you should be able to see the cartridge holding bolt in the bottom of the axle casting. If that bolt appears to wobble as you roll the fork on a flat surface you have bent forks. If it spins on center your problem is elsewhere.

Your straw analogy is close i think, but let's simplify it. When it comes out of the wrapper it's straight (for our purposes). If you rolled it on a table the bendy end doesn't wobble. If you then put a slight bend in it and again roll it on the edge of the table the bendy end is wobbling pretty good. That's run-out. Same concept.

Air typically doesn't get into brakes in a crash, but it's a simple fix if it does. Bleed them.
 
#10 ·
Ok I am about ready to take this bad boy apart, but one question how do you guys normally lift the front I've seen a few threads where they lifted the front by putting a floor jack on the headers then a video where there was an actual stand to lift up the front. What is yalls input?
 
#12 ·
Yes fork legs bend! You should probably get them checked by a suspension shop. They can bend by 1/16th of an inch and it stops them working smoothly and will f**k up the handling.

I use axle stands under the crash protectors to lift the front end. If you haven't got crash protectors you can put a steel bar through the frame at the front of the engine.
 
#13 ·
So I found it. I don't know why this would apply to my brakes but I lifted the front to check the rotors it make sure they aren't the problem....they aren't the problem the problem is a bend in my front rim its minuscule but enough to the see the Bend when I was spinning the front tire by hand. I'm guessing new rim which I'm happy it's not the forks but is there a tolerance for a bend in the rim? What are my current options?
 
#16 · (Edited)
If the rim is truly bent your best option is to just replace the rim. You can get great deals on used rims on ebay, just make sure you read through the ad to make sure they are not selling you a bent rim in replace, haha. I went through the same issue just recently, where i had a noticeable wobble in the wheel when spun on a stand and pulsating brakes, so just got a wheel off ebay with rotors for $200 shipped.
 
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