front forks bottom out over every bump

[nhanxsolo]

Ok, about to buy these.

Seals:
http://cheapcycleparts.com/products/218387-leakproof-seals-7239-forks-front-ends-standard-leak-proof-fork-seals

Oil:
http://cheapcycleparts.com/products/219132-bel-ray-94850bt1lc-fork-fluid-fork-oil-20w-1-liter

Anyone have any experience with either brands of products?  Anything else I may need for the job/make the job easier?

[Toogoofy317]

Other than taking my forks apart is there a way to tell if I have aftermarket springs in my bike. I have an '04 with 17,000 and I've never had my bike bottom out and it handles quite well.

Mary

[pandymai]

Other than taking my forks apart is there a way to tell if I have aftermarket springs in my bike. I have an '04 with 17,000 and I've never had my bike bottom out and it handles quite well.

Mary

you dont have to take them apart so much as.. pop the bike up on the center stand. loosen ONE fork's triple clamps. then unscrew the fork cap. make sure to go slow and careful as it could bounce out. as long as you only open one fork, the bike wont dip or drop down because the other fork will still be compressed. once you open one fork, pull out the spacer. the stock spacer is probably about 8 inches long or something ridiculous like that. if yours is anywhere between .5-1.5 inches than you probably have aftermarket springs.

[burning1]

You only need to loosen the upper triple on one side, and then, you only loosen it so that you can get the fork caps off without damaging the threads.

[burning1]

Toogoofy317,

If I were you, I wouldn't worry so much about whether or not you have aftermarket springs. What I would do is measure the static and rider sag to make sure that you have the correct springs.

Start by identifying the fully extended length of your forks. Put the bike on it's center stand, and measure the distance between the fork body and the lower triple clamp.

To measure static sag:

Take the bike off the center stand, and have someone hold the bike upright. Measure the distance between the fork body and the lower triple clamp. Subtract this measurement from the fully extended length of your forks. This value is the static sag.

IIRC, for a street bike, 10-20mm is a good static sag value.

To measure rider sag:

Sit on the bike, and try to put all of your weight on the bike (a front wheel chock would be ideal here...) Have an assistant measure the distance between the fork body and the lower tripple clamp. Subtract this value from the fully extended length of your forks.

If I recall correctly, 30-40mm is a good value for rider sag.


- If you have enough rider sag, but too little static sag, it means you have too much preload on the forks bike, and that you need need stiffer springs.
- If you have too much rider sag, but not enough static sag it means you need stiffer springs, and perhaps a touch less preload.
- If you have too little rider sag, and enough static sag, it means you need softer springs, and perhaps more pre-load (not going to happen on a GS, unless you buy a bike modified for a heavy rider.)

If static and rider sag are in the correct range, your springs are perfect.

[Toogoofy317]

Wow thanks so much for the specifics guys! 

Mary

[Eric_in_OR]

You don't need special fork oil, I used regular 15w40 that I had laying around and it worked great. The forks will never get hot, so the first viscosity number is all you need worry about.

[Trwhouse]

Hi all,

Sorry, Eric, but you are wrong on this.  You've had 49 whole posts and you are an expert on fork maintenance?

One does need to use real fork oil for the forks. Fork oil has special moly lubricants that help keep seal stiction minimized.
I would never recommend using multi-weight engine oil in the forks.
Don't just use whatever you have laying around in the garage.
That's lazy.
I used to buy Kal-gaard Fork Oil, but can't find it anymore. Belray or PJ1 are fine fork oils.
I run 10 weight or 15 weight.

And to the original poster:
And NEVER use thicker oil to try to slow down a leak like someone else wrote.
Just fix the forks, replace the seals, and do it right.
Oh, another thing, "Leakproof" seasl don't work.
Go with OEM Suzuki seals.
Fork seals are not universal. There are different sizes for every fork.

Good luck,
Trwhouse

You don't need special fork oil, I used regular 15w40 that I had laying around and it worked great. The forks will never get hot, so the first viscosity number is all you need worry about.

[black and silver twin]

And NEVER use thicker oil to try to slow down a leak like someone else wrote.

I did not say that as a fix, rather as a temporary band-aid until the seals are replaced. his forks were very low and he was going to put fluid in, so I suggested 20w just to slow the leak and give better/safer damping until he fixes the seals. sorry about the confusion 

[Trwhouse]

No problem, and thanks for the clarification.

We're good.

Trwhouse

[burning1]

...The forks will never get hot...

Spoken like someone who's never ridden at track speeds on cold forks. 

Fork oil definitely heats up. On the GS, the right viscosity fork oil is way too thick when cold.

[black and silver twin]

I wish I could get 25w oil sometimes maybe even 30w, 20w is far better than stock 10w but its still soft. then again I still have stock springs.

[burning1]

You're really better off installing stiffer springs -  I'm sure you could find a pair for less than $100. Thick oil will make the suspension feel firmer, but you'll still have the same cornering clearance issues, and your bike won't track as well over rough surfaces.

[marc]

Did you replace the fork seals yet?

I've just done the job and I might help.

I plan to write a howto.

[Deros514]

We've got some good detailed write-ups on this but pics are a plus...I was planning to snap a few but the job was a little messy.

[nhanxsolo]

Did you replace the fork seals yet?

I've just done the job and I might help.

I plan to write a howto.

Not yet, I am actually looking to upgrade.  Had a few interests in the bike, but if it doesn't sell soon I'm gonna keep it for now and do the swap.  I may just do it anyway even if I sell it just to learn.  Either way, insterested in your DIY!  Make sure you get pictures for us.