help, im all forked up

[gsBert]

i just noticed something funny and uncomfortable today when trying my bike out. and when i say uncomfortable, i mean in a colonoscopy sort of way.

so im driving around the parking lot trying to warm up my bike to see if it'll stop smoking all sorts of colours (im real unlucky with it so far) when i squeeze the front brake ever so lightly...

this is what happened: there was a clunk and the front dove down REAL FAST and lots. my balls still hurt...

then the suspension comes back up after im stopped, but it now always does this (clunk followed by sharp dive). makes it real easy to lock up the wheel...

i added more preload to no avail, and maxed out the compression damping with an equal amount of unsuccess....

any ideas? could my fork oil have dissapeared somewhere? how do i drain/fill these things anyways? and what oil should i put in and how much?

oh, it's a 1989 gsxr 1100 fork. and i have no money to fix it if its broken, so if it is ill be updating you on a TL1000 inverted fork transplant.

thanks

 

[Billy Ricks]

Bert,
It sounds like something may have gone wacked with the preload adjusters to where they are no longer having any effect on the springs. If that's actually what has happened you not only have no preload, the springs are extended to their max. If you drain and fill it needs to be done with forks off the bike. Just slide each tube out of the triples. The only way to remove the oil is to invert the forks. Flush them out a few times with kerosene before replacing the oil and reassembling. You want to use an oil intended for cartridge forks. It only comes in one weight. You'll need to search the internet for how they come apart and oil level. It easy but you need to have something for reference.

 

[joe.d]

if there anything like my forks on my GS1150, I have Gixer 92 usD they come apart easy but you have to do the process in order, undo the Hex bolt on the bottom of the forks, then undo the top nut where the preload adjuster is, then it slips apart easy, to remove the fork tube from the leg, you will have to unclip the spring clip above the fork seal then pull, dont forget to drain the fork oil, I used a non corosive can of degresser to flush, and filled the fork leg with 380ml of 7weight fork oil.

 

[gsBert]

nah, theyre 89 gsxr 1100 forks. they're not inverted.

but i got aset of inverted TL 1000 forks lying around, and i'm probably going to put those on to fix my problem and add to the cool factor.

how do your forks perform compared to the stock items joe?
my usd have ball bearings in them, is this what yours have? can i fit this in my steering head? what am i going to have to mod?

 

[joe.d]

Mine were off a 1992 Gixer and they bolted right up, they use the same taper bearings

 

[gsBert]

yeah well yo'ure one lucky smurf...
i'll trade you your forks for my more modern (but ball-bearinged) tl-1000, wanna go for it?
didnt think so, oh well, i tried...

 

[Dink]

The ball bearing and tapered bearings interchange, ball bearing is supposed to give a lighter steering effort.
Dink

 

[Billy Ricks]

Bert,
One other thing you might need to look for is a warped rotor. It doesn't make sense for the wheel to be locking if the fork is at fault.

 

[mark m]

One other thing you might need to look for is a warped rotor. It doesn't make sense for the wheel to be locking if the fork is at fault.

Unless the fork is bottoming and jamming the wheel against the front of the motor/oil cooler, etc. That would produce a really nice lockup in no time.


Mark

 

[gsBert]

nah, i really feel the lockup is caused by the abruptness of the forward weight transfer combined with really grabby brakes... (actually, the front comes down so fast that the brake lever goes in just from wind resistance, just kidding) its really hard to modulate a brake when the weight doesnt transfer forward linearly you know...
but thanks and ill look into those 2 possibilities (rotor and tire contact)

a friend of mine who's a bicycle mechanic is gonna take a look on sunday and see whats wrong. he seems to think he can fix it. lol, i dont care, it's my excuse to put on that nice inverted TL1000 fork.