fork woes - Wrist Twisters
 
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post #1 of 12 Old 09-05-2010, 06:19 PM Thread Starter
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fork woes

Hey guys, off recently ive been hearing a clunking sound coming from my front end and well i assumed it was the steering head bearings. Took it to a mates house (very knowledgable on bikes) and he checked both the steering and wheel bearings and said they were absolutely fine. He then moved the forks up and down and a clunking sounds appeared. He then checked the dampening and compression adjustments at the top of the forks and found the dampener was wound all the way up. He readjusted it and the sounds was significantly less, but its still there. Could this have damaged the forks inside, and if so, what is that clunking noise in there. I fear a hefty bill coming my way.

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post #2 of 12 Old 09-05-2010, 07:15 PM
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are you holding the front break while compressing the forks? cus mine has the same small clunk... but im pretty sure its the small slop back and forth of the brake pads in the calipers.

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post #3 of 12 Old 09-05-2010, 07:20 PM Thread Starter
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that noise when i lift the bike off and push the forks up and down. i do also get the sound yer talking abt when i push down on the forks with the brakes on.

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post #4 of 12 Old 09-06-2010, 12:26 AM
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Possibility 1: Noise is coming from a uneven spacing from left to right side in the triple clamps. Double check the torque on the lower triple clamp.. then loosen the top triple pinch bolts and re-torque. The torque ain't much.. like 44 for the lowers and like 14 or 25 for the upper. Check your manual of course.

Possibility 2: Something above the valve body is broken or bent or hanging up. I recommend removing the forks completely from the bike.. but, you can remove the handle bars.. leave all the controls attached and lay forward onto a towel over the gauges or back onto tank.. pad it real well. Do only one side at a time unless you can lift the front of the bike by the frame or from the lower steering stem with an appropriate stand. Back off all the pre-load if so equipped, remove the cap, & again.. one side at a time here unless the front suspension is unloaded. You can then fish out the spacers/washers and even the spring with a magnet on a stick. Inspect it all. If the clunk is at the top.. that is above the spring .. then it will be obvious.. there will be wear marks or some physical damage to the washers or spacers etc. You might even find a busted spring or the rebound adjustment shaft/screw if they are 2004 or later forks. Inspect everything thoroughly.

Possibility 3: the stanchion tube bushings are worn out. They would allow the fork tubes to knock side to side, front to back and up and down if they are pretty worn. This is a completely plausible possibility. I had to replace the bushings in the forks I rebuilt... too many wheelies and hard landings will do that trick. I imagine high miles, rough roads, bad seals, contaminants such as water, dirt and so on would lead to this. Forks have to come off bike and come completely apart to change. The good news you will be getting new seals and oil... and the bushings are really cheap if I remember right.

Possibility 4: Unlikely, but the screws that hold the valve body down in the fork case could have come loose. Seems it would be leaking all over if that was the case tho. You will have to remove the front wheel.. actually need the axle out of the way to gain access to those screw heads. They are internal Allen head.. 6mm I think. Again.. its very doubtful these would be loose without a shit load of oil pissing all over.

Possibility 5: Something is busted in the valve bodies. Good luck there. I don't know how the noise would even resonate up and out for you to be able to hear a clunk sound... but could be the case I guess?

Honestly, it's hard, if not near impossible, to diagnose this without seeing & touching it. If it is in the forks they are a fairly straight forward component and easy enough to tear into and replace the parts that are the culprit. I tore some 03 and 04 forks apart side by side once and took pics. I laid the parts all out, so you can tell what goes where in what order. Refer to this POST for these pics. I never claim to do "how to" write ups and this is no exception. I assume you have basic mechanical skills and tools and more importantly know when you are in over your head. I know when I am in over my head and seek an expert when necessary. That said, if you have basic mechanical skills, the correct tools and a little patience you can easily tear into your forks for repairs and upgrades.

- Rev. CYCHO -

tires.... it's what's for dinner!
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post #5 of 12 Old 09-06-2010, 01:57 AM Thread Starter
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wow thanks for the elaborate reply motocycho, this is why WT members are amazing.

The bushings sound like it, since the internals of the forks feel like they have abnormal mvements. I do have some mechanicals skills, and like you, i know where my limit is too so if anything i will be contacting the experts. I guess the next step is to pull it apart and see if there is anything abnormal.

I guess this would be a prime opportunity to consider doing a racetech/ohlins rebuild?

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post #6 of 12 Old 09-06-2010, 08:00 AM
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remove the wheel/axle and check every fork individually. Find which fork makes the noise and take it apart.
It's easier than you think. If you want to upgrade your forks, that would be the time to do it.
if you have 04+ forks, get new springs rated for you and change shim stack for your existing valves, don't bother with RT gold valves or Ohlins UES kit unless you get them really really cheap somehow.
If you do find a good deal, get just a compression kit, don't even waist your $ on rebound kit for 919 forks, just rework shim stack on existing valve

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post #7 of 12 Old 09-06-2010, 08:38 AM
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Quote:
Originally Posted by nd4spdbh View Post
are you holding the front break while compressing the forks? cus mine has the same small clunk... but im pretty sure its the small slop back and forth of the brake pads in the calipers.
Thats the floating rotors you're hearing. If your brake pads moved enough to to make that kind of noise, you would be having serious issues with your brakes.

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post #8 of 12 Old 09-06-2010, 03:43 PM Thread Starter
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Quote:
Originally Posted by zaq123 View Post
remove the wheel/axle and check every fork individually. Find which fork makes the noise and take it apart.
It's easier than you think. If you want to upgrade your forks, that would be the time to do it.
if you have 04+ forks, get new springs rated for you and change shim stack for your existing valves, don't bother with RT gold valves or Ohlins UES kit unless you get them really really cheap somehow.
If you do find a good deal, get just a compression kit, don't even waist your $ on rebound kit for 919 forks, just rework shim stack on existing valve
simply awesome information zaq123, checkin each fork for the noise would be an excellent idea. thanks you guys for the help. I shall update this thread soon with my findings. Thanks once again

And has been racer, i learnt something new today

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post #9 of 12 Old 09-06-2010, 03:53 PM
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Quote:
Originally Posted by hasbeenracer View Post
Thats the floating rotors you're hearing. If your brake pads moved enough to to make that kind of noise, you would be having serious issues with your brakes.
ah... ur probably right, its one or the other... i know the pads have just a little forward and back slop... but not much, never thought bout the floating rotors!

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post #10 of 12 Old 09-06-2010, 04:13 PM Thread Starter
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Quote:
Originally Posted by nd4spdbh View Post
never thought bout the floating rotors!
me too!!

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post #11 of 12 Old 09-06-2010, 04:56 PM
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Quote:
Originally Posted by veEnom View Post
me too!!
Im sure your knowledgeable mate (as you said it your 1st post) will be able to figure out if it's your semi-floating rotors that make the noise. If indeed it turns out to be your semi-floating rotors, I would look and re-look real careful into fork adjustment he did on your bike.

It's very easy to check, take your calipers off and see if it still makes a sound on compression.

Here is what 919's semi-floating rotors sound like when moving:



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post #12 of 12 Old 09-06-2010, 07:11 PM Thread Starter
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[QUOTE=zaq123;411750]Im sure your knowledgeable mate (as you said it your 1st post) will be able to figure out if it's your semi-floating rotors that make the noise. If indeed it turns out to be your semi-floating rotors, I would look and re-look real careful into fork adjustment he did on your bike.

hahaha, nah nah we took the calipers off and secured them.

motocycho provided me with a link of the fork internal part list so once i diagnose which fork is making that sound ill open it up and go from there.

i knew something was not right when i changed the fork oil last week and found one fork's fluid to be a 100 fold darker in colour when compared to the other fork. somethin sketchy about this i thought.

Btw, just in case anyone pulls me up on this, the noise was there long before i changed the fork oil. shud have seen to it earlier. QUOTE]

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