VFR 400 forks gone spongy

[fizzafulla]

Hi, my 1991 NC30 (50,000ks) is starting to bump me around a bit up front. It seems to have happened relatively suddenly. Seals look ok on quick inspection. When stationary and bouncing the front with the brake on it pops up quicker than it should with very little damping. Is this an oil issue or a spring issue? I use the bike on the road not track. thanks for any help.
Dan.

[James Deuce]

Change the oil and change the seals.

Bet you the oil is a dark grey colour with white froth floating on it.

[more_fasterer]

Yeah change the seals & oil (I found 10W to be a good improvement). Betcha it's still got the original fork oil in it.

[Robert Taylor]

Hi, my 1991 NC30 (50,000ks) is starting to bump me around a bit up front. It seems to have happened relatively suddenly. Seals look ok on quick inspection. When stationary and bouncing the front with the brake on it pops up quicker than it should with very little damping. Is this an oil issue or a spring issue? I use the bike on the road not track. thanks for any help.
Dan.

If its only oil Id be very surprised. The checkplate valving ( its little better than that ) has most likely got debris entrapped in it, holding it open. the damping mechanisms need a full strip, advisable on a 50,000 k 17 year old bike.

[James Deuce]

See above. Do that.

[fizzafulla]

Thanks for the replies.
Yes I might get a pro to take a look at it. My last bike was a fzr 250 and
changing the fork oil really didn't help the same problem.
I might PM Robert actually.

[F5 Dave]

With both bikes, esp if 400 is a jap import, the springs are likely way too soft & stiffer springs will be a large part of the issue. Changing oil in some forks isn't enough, they need a proper clean out. Clearly Robert will point you in right direction if he knows your weight etc.

[racefactory]

hi guys

if i take the forks off the bike... supply new fork seals and 10w fork oil.. how much can i expect to be charged to fit the new seals and change oil?

Cheers

[cs363]

hi guys

if i take the forks off the bike... supply new fork seals and 10w fork oil.. how much can i expect to be charged to fit the new seals and change oil?

Cheers

Probably best to PM Robert Taylor, he'll give you an unbiased quote based on best practice as opposed to cheapest cost (yes, the two are generally mutually exclusive!)
Be careful buying fork seals if non genuine as many of the aftermarket ones are crap and will either increase fork stiction or not seal properly (or for long). Also, don't assume 10w fork oil is the ideal - as Robert will tell you there is a lot more to it.....
Also, with the mileage your bike has done (and in that time it may have suffered unnoticed accident damage) it may well need bushes and other internal parts replaced.
Spending money on your suspension is by far the best money you can spend on your bike, not only will you enjoy the ride more, you'll most likely ride better and get better tyre life.

If the rear shock hasn't had any loving you'd be best to bite the bullet and send that down with the forks to CKT for an overhaul, believe me -you won't regret it.

Talk to Dr Bob!

[CookMySock]

hi guys

if i take the forks off the bike... supply new fork seals and 10w fork oil.. how much can i expect to be charged to fit the new seals and change oil?

CheersI was quoted about 150bux to do that, but not change the seals, and he provide the oil.

HTH,
Steve

[racefactory]

I was quoted about 150bux to do that, but not change the seals, and he provide the oil.

HTH,
Steve

hey man.. where did you get that done?