check/replace fork seal

Hi, I have a 2001 Yamaha 650 V star.
It was in storage for about 2 years. Took it out last year and all seemed fine.

Near the end of the season I thought I was hearing a bang noise when under hard braking. I thought it was my tool bag (with a can of bug spray in it) banging against the front fender.

This year, no tool bag on the bike, and I am sure the front forks are bottoming out when I am braking. Even seems when I am braking moderately hard.

My question is, how do I check and or replace my fork seals. Wondering if having it suspended up off the wheels for 2 years may have caused some problems.

Any help would be appreciated.
Thanks.
Hearts88

Keeping the bike lifted shouldn't hurt them, in fact it probably relieves some strain on them.

If leaking you'd see a lot of oil residue where the larger part of the fork slides along the smaller portion. There would probably be a dark ring of oily dirt buildup around it where the slider stops travel...

A very faint residue of oil on the sliders is normal, but shouldn't be enough to leave rings or drip.

It may just be that the fork oil is worn out....That one doesn't have an air ajustable fork does it? Old Yamahas did, they were prone to blowing air seals...I really don't think they use that anymore...

http://www.roadstarmagazine.com/modules.php?name=News&file=article&sid=237

Here's a good writeup on replacing fork oil, if that's what you need.

You can go one grade heavier with the fork oil if the fork seems to bottom easily or seems to rebound too quickly, a lot of bikes ride much better with a bit heavier oil in the forks.

If you need seals, you'll have to refer to the shop manual for your bike, there's lots of variations between makes.

You didn't change the preload on the rear shocks did you?

Too high can throw the weight transfer too far forward on braking...just wondering...

Hey jeff,
first of all thanks for the reply.

The front forks are not adjustable.

I left the rear mono shock on the "standard" setting. Right from day one I found this setting sufficient for single riding or even riding with my wife.

Are you saying that if the rear suspension is set too hard to could cause more dip in the front? I am understanding this correctly?

At any rate, I think I am going to look into putting a heavier oil in the front. I'm not really that big of a guy, 6'4", under 200lbs. Like I said when I 1st got the bike new, it never bottomed out. It's only after being stored for 2 years.

Anyway, difficulty level on doing the front forks? I have not really done anything on Bikes before other than basic mantainence. Plugs, wires, etc.
Lots more experience on Cars. Pretty much nothing on a car I won't do, and not much I haven't done.
I would like to do the work myself simply because I enjoy it and 'cos I don't like my local Yamaha dealer.

Thanks,
Hearts88

Yeah the bike's suspension reacts pretty profiundly to suspension preload changes. Heavier preload in the rear will bias the weight transfer more to the front under harder than average braking. Still shouldn't bottom out, but I just wondered if any changes had been made leading up to the problem.

Bikes have funny dynamics...problems that are perceived as coming from the front often originate with the rear...if you've ever had a rear tire going down or a bad swingarm bushing you know what I'm talking about...feels like the front end is wandering/sticking....

That's why using your brakes in a curve is such a bad idea...when you brake, you compress the front fork and transfer a lot of weight off the rear. The fork is now closer to it's lower limit of travel and tightly compressed, it's ability to be compliant over road irregularities is seriously compromised...and the rear is light and near the upper limit of travel. So you now have a two wheeled vehicle with two very different suspension rates and traction issues. You are flirting with a get-off. The ideal cornering situation always has the suspension in a state of balance, with both ends working in the middle third of their total travel.

Anyway, enough of that. I know you didn't ask about that, I just like talking about it.

Did you mean just changing the fork oil? That link I supplied has a great run-down on the procedure. It's not difficult, with your experience it should be no problem at all. Even replacing seals isn't bad, just have the right info for your model.

Make sure all your triple clamp and steering stem hardware is tight too...I bought a new '99 Vulcan 1500 and a few days after having it back to the dealer for first service I started getting a knocking noise in the front end over rough pavement when braking....and found the damn steering stem bolt (that holds the steering head bearings together) was loose! And part of the first service was to check all fasteners for proper torque! So much for that service...never again...I do my own work now....