Sticky suspension ??

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#1
I recently had my suspension services by a local tuner. New springs and oil and seals. When the bike is on the stand ( forks fully extended) I marked the postion.Then took the bike off the stand ( under its own weight)it sinks 3/4 of an inch.Then if you push on the bike (compress the forks and release)it sticks about another 3/4 of an inch below the of the line of it under its own weight ? Any ideas ? I did loosen all pinch bolts and axle bolts, checked fork height in the clamps, and turned top tubes 180 degrees and stil the same problem.
 
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#2
I see a lot of Yamahas with this problem. It is the fork bushings. Even though they may look perfect, replace them and i am sure your problem will be solved.
 

marcusgunby

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#3
dbrace-do you think bad/old oil is damaging the bushes??ive seen a few perfect looking bushes that cause this-almost like they loose the very top coating of teflon(not able to be seen with the naked eye?)
 
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#4
I dont think so. I have seen it happen on bikes that were only a few months old. I normally advise my customers to ride their bikes a few times to bed everything in and the break-in contamination can then also be removed when serviced/revalved. Perhaps bushing need to be replaced at the same time even though they look perfect. Another problem i see is that you dont notice it when you push on the forks when they are out of the bike and verticle. You only notice it when the forks are at an angle installed on the bike. 90% of my work is suspension only -no bike.
 
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#6
Sorry where's my manners .Thanks for the reply . Good call on the bushings..I took the wheel off and there is a little play in the fork.Thanks again.Why couldnt this be diagnosed(sp?) off the bike ?
 
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#7
Because most suspension tuners don't take the seals & bushings out during servicing or revalving. A lot of times the bushings will get detroyed when taking them out if the seal area isn't heated up some so, if the seals aren't leaking they don't need to come out. The best way to feel if they are bad is when the forks are on the bike. Grab the frt. brake and pull up (top out) the forks. Let go of the brakes and the forks should settle approx. 30-35mm's. If they are bad the forks will stick at the top.


doc
 
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#8
You should be aware that a little play is absolutely necessary. If there is not enough you will have a sticky fork, and if there is too much your fork will leak.
 

DEANSFASTWAY

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#9
I think those bushings kinda get bent ever so slightly when disassembling. heat definitely helps some . I always like to clean out the seals but on a brand new fork sometimes ill skip it . You know what I like to use and you guys might try it is Moly spray on the new un oiled seals . Spray them then oil them up and they feel like they have less drag than just oiled. I get it at gun shops or like McMaster/Carr. MTRIDER: if the guy that put the seals in used those leak proof seals or even leak proof with moly then that could be alot of the stickiness. Ive seen these seals actually melt away on street bikes. Way way too much drag ,You called him a tuner so I guess hes using good parts. New Suzuki spec'd KYB Rm250 forks have good redesigned seals but youve got to be sure to use new style wipers or else theyll tangle with each other. They seem very durable. GLMF
 
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#10
Dean, I use Torco's (red) engine assy lube on seals with great results. I will get some Moly spray tho and try it.



doc