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Old 09-05-2006, 03:31 PM   #1
laramie LC4 OP
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Fork Oil and Suspension Questions....

was doing some things on the LC4 the past few days and decided to check the oil level in my forks. i already had the fork out due to a steering bearing inspection so it only took a sec to check. i know my seals had been leaking over the past few weeks. they had a rough trip of 2000+ miles tied down on the trailer with the forks compressed so i wanted to make sure that my level wasnt low due to loss.

to say the least i was shocked when i saw the results. not so much the oil level but the condition of the oil.



this is a side by side comparision of the old oil and some new oil. i had no idea that fork oil could get so nasty! this oil has roughly 1 years worth of riding on it since it was last changed. granted a lot of it was wet and nasty, but i still dont think the oil should be that bad.

is this a sign of a problem with my seals? or something else?

either way, id recommend you check your oil soon.....

thanks,

laramie
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Old 09-05-2006, 03:40 PM   #2
drdave_2006
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Oil does not last forever. On my bmw it suggested changing the fork oil every 14k. In your hand book it should have something in there about changing it every year. Lots of hard riding would need to be done earlier. Gets hot just like engine oil. Thats what i think. See what other suggest as well.
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Old 09-05-2006, 03:40 PM   #3
laramie LC4 OP
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oops, now for the suspension questions,

1) how do you guys torque the valves on the bottom of the forks to 25nm? i got one by slightly pulling down on the piston but the other fork just spins. i dont want to bend the piston trying to torque the valve.

2) when measuring the fork oil level, you measure 25mm from the top of the "4 holes", or roughly 35mm from the top of the outer tube?

3) when reinstalling the springs, what is the trick to getting the rebound cap back on. i remember this being a bitch the last time i changed the oil and dont remember how i got around it.

thanks, im having some issues and want to ride tomorrow so your help is appreciated. ive done this before but im frankly not to sure if i did the measurements correct. i wanted to stiffen the front so i added an additional 10mm on the last service. my problem is i think i measured from the top of the fork because when i checked the level today i was way over.


laramie
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Old 09-05-2006, 04:15 PM   #4
Stobie
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Quote:
Originally Posted by laramie LC4
oops, now for the suspension questions,

1) how do you guys torque the valves on the bottom of the forks to 25nm? i got one by slightly pulling down on the piston but the other fork just spins. i dont want to bend the piston trying to torque the valve.

2) when measuring the fork oil level, you measure 25mm from the top of the "4 holes", or roughly 35mm from the top of the outer tube?

3) when reinstalling the springs, what is the trick to getting the rebound cap back on. i remember this being a bitch the last time i changed the oil and dont remember how i got around it.

thanks, im having some issues and want to ride tomorrow so your help is appreciated. ive done this before but im frankly not to sure if i did the measurements correct. i wanted to stiffen the front so i added an additional 10mm on the last service. my problem is i think i measured from the top of the fork because when i checked the level today i was way over.




laramie

1) With the caps off and the springs out, you can put a little side pressure on the damper assembly at the top, which will wedge it in place and let you torque the base valve (this is right out of the fork manual). Or, but the spring in and the cap back on, flip the fork upside down, put the axle through the bottom lug to use as a handle, and push down on the fork while you tighten. The spring tension will hold everything in place. I put a socket on the fork cap (I think it's a 24?) to protect the rebound knob.

2) Measure the fork oil level from the top of the inner fork tube. I'm not sure what the standard level is for the 43's, but I'm thinking 150mm from the top.

3) I hold the spring buffer by sticking my finger through the spring, then turning the spring like a bolt, so my finger lifts the spring buffer up to the where I can grab the top of the damper assembly.

I hope that made sense.
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Old 09-05-2006, 04:45 PM   #5
laramie LC4 OP
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Quote:
Originally Posted by Stobie
1)Or, but the spring in and the cap back on, flip the fork upside down, put the axle through the bottom lug to use as a handle, and push down on the fork while you tighten. The spring tension will hold everything in place. I put a socket on the fork cap (I think it's a 24?) to protect the rebound knob.
can you do this once the fork is back in the triple clamps and everything is back together?

Quote:
2) Measure the fork oil level from the top of the inner fork tube. I'm not sure what the standard level is for the 43's, but I'm thinking 150mm from the top.
from the WP manual, "Now compress the piston-rod and outer-tube fully down, and fill the forkleg with oil till about 25mm under the 4 holes of the inner-tube. Move the piston-rod and the outer-tube at the same time several times up and down over the entire stroke. Push the piston-rod and outer-tube fully down and adjust the oil level (airchamber) with T137S."

so its definetly not 150mm, i just wish they would make this easy and say, " its this far down from the top of tube. whats this 4 holes down crap? can you measure the 2 and give us a real, useful number?


Quote:
3) I hold the spring buffer by sticking my finger through the spring, then turning the spring like a bolt, so my finger lifts the spring buffer up to the where I can grab the top of the damper assembly.
even with the inner piston fully extended it doesnt come close to reaching the top of the spring. id have to reach down, between the coils and grab it, and then getting the cap on would require me compressing the springs considerably which always causes the inner tube to fall back in. its kinda like chasing your tail. plus i dont know how small your hands/fingers are, but mine dont fit and then cover them with fork oil and its a lost cause.....

thanks for the input, ill keep trying but its not looking good for tomorrow.


laramie
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Old 09-05-2006, 08:00 PM   #6
meat popsicle
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If you still have questions, there are some OLD WP repair manuals in my Yahoo Briefcase (indexed) that might have some tips for assembly. More likely they just note some custom tool that is required...
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Old 09-06-2006, 05:17 AM   #7
Stobie
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Laramie,

I got an email notice that you had more questions, but I couldn't get back on the site for some reason. Had I thought about it, I would have PM'd you through KTMtalk.

Quote:
can you do this once the fork is back in the triple clamps and everything is back together?
Run a tie-down from one side of the handlebar, through the wheel, then to the other side of the handlebar, and cinch it down to compress the forks a little.

Quote:
from the WP manual, "Now compress the piston-rod and outer-tube fully down, and fill the forkleg with oil till about 25mm under the 4 holes of the inner-tube. Move the piston-rod and the outer-tube at the same time several times up and down over the entire stroke.
This is just the initial fill-and-purge. The "25mm under the 4 holes" thing just gives you enough oil in the fork to do the second step, "Move the piston-rod and the outer-tube at the same time...", which just purges all the air from the damper assembly.

The next step,

Quote:
Push the piston-rod and outer-tube fully down and adjust the oil level (airchamber) with T137S.
is where you set the oil level to 150mm or whatever. The stock level is listed in your owner's manual, in a table toward the back where all the stock suspension settings are listed. I don't have it in front of me, but I think they actually call it "Fork Oil Level", and it's measured from the top of the inner tube, although they don't tell you that part. For my bike with the 48's, it's 120mm.

Quote:
even with the inner piston fully extended it doesnt come close to reaching the top of the spring
Are these the stock springs? It sounds like they are too long. If the piston rod doesn't come close to reaching the top of the spring, you're putting hella preload on the spring when you re-install the fork cap. Preload numbers are usually in the mid-single digit millimeters. If the springs are what you typically find for the USD 43's, they are the 520mm long springs used in the RFS bikes. The LC4's have less travel in the front and use shorter springs (485mm for the 48's).

Sorry I couldn't get back to you last night. I hope you get to ride today.
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Old 11-25-2010, 08:55 AM   #8
StepOnIt
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690e forks for 690r forks

Hi
First post
I have a friend at least i hope he is, but he just bought a 690r and was going to change his forks from his old bike 640 adventure (had a lot of work done to them) so is there any problems changing out my E forks to the R ones. I find the guy who had the bike before me messed them up and are way too stiff. Any thoughts out there or should i just get them re-valved???
thanks
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Old 11-25-2010, 09:02 AM   #9
wrk2surf
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he might have just put stiffer springs in it.. more than likely you can adjust the level of the fluid or weight .. if you do a fluid change the forks should have a mark of what rate the spring is on the end of it... if you have a suspension comany in mind it is common for them after a revalve to change the valving for free if you are unhappy or get fatter during the life of the forks they do.. not a problem swaping em either..
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