forks

[Ionatan]

Hi everyone, I looked in the manual but couldn't find anything about how to check if the forks are working properly, I don't know why but mine look very compressed when I sit on the bike. How should I check if they are alright?

[GSnoober]

If you weigh 150 pounds or more, the forks DO compress a lot when you sit on the GS, but there is a good reason for that... the stock fork springs SUCK!

There is a LOT of information here about servicing the forks; it is scattered in various places, but there is an excellent How-To that you can read and learn from... it is in the FAQ section:

http://gstwins.com/gsboard/index.php?board=7.0

Written by Alpha, former GSTwinner, no longer an active member, which is a shame:

http://gstwins.com/gsboard/index.php?topic=25706.0

Read through it SEVERAL times, to be sure that you understand all that is involved. It doesn't matter if you're not going to do this work now or soon; what matters is that you understand fork service and assembly, and how not to do something that will soon make you bounce on your head...

Also, read this thread:

http://gstwins.com/gsboard/index.php?topic=57022.0

Some good information there; now read this one:

http://gstwins.com/gsboard/index.php?topic=4287.0

which will help you understand how to measure the air gap (the "air gap" is the distance between the top of the fork LEG and the top of the fork FLUID). Measuring the air gap is the best way to figure out how much oil is in each fork leg. Setting the air gap properly is CRITICAL to the function of the fork, so learn how to do it right. The air gap acts as a spring (since a gas can be compressed); get the air gap wrong and you WON'T like the results.

Other links which might interest you:

http://wiki.gstwins.com/index.php?n=Upgrades.FrontForks

about how to upgrade the entire front end, and:

http://gstwins.com/gsboard/index.php?topic=7084.0

which will show you how to build a fork tool which works on the OLDER (GS-E) models; Suzuki changed the fork internals back around the time they introduced the GS-F...

One more thing to consider; if you have stock forks, the stock springs are junk right from the factory. IIRC, I've read somewhere on here that those springs are rated for a 45 pound rider, though I don't know if that is accurate or not. I swapped mine for Progressive Suspension springs the first week after I bought the GS; I tend to ride hard in the local canyons (also in the not-so-local canyons), and that stock front end was a JOKE! I can't imagine running a GS with a stock suspension on a racetrack; you'd be spit off in no time. The rear shock works well enough if you're in the bantamweight / flyweight / paperweight class, but the stock fork springs are overwhelmed just by the weight of a tank bag... or a full tank of gas.

I don't know how old your GS is, but if the forks are low on oil (it escapes by seeping past the fork seals), you'll need to refill it and replace the seals, so you might as well upgrade the springs while you're at it. Better springs and the right amount of fork oil = MORE FUN!

EDIT: To replace the WRONG link with the RIGHT link...

[adidasguy]

The statements about factory springs sucking is partly true.
In some year, they upgraded the springs - still somewhat sucky but not as bad as they used to be.
This photo shows:
top = Sonic 0.85
Middle: OEM springs from a 2009 (Seems same part number starting in 2004)
Bottom: OEM springs from an older bike. (Is this even a real spring?)

Maybe someone knows what year they changed springs? They changed the top cap in 2008. The parts lists show a change in the spring and spacer part numbers effective 2004. So maybe in 2004 they beefed up the front springs? Maybe they did it just for the added front weight of the fairing. Still not as good as after market springs. Put 0.85's in Suzi Saturday and she no longer bottoms out when going into the parking lot at the gym (just a small bump). I'm only 170 lbs so imagine someone heavier.

Checked again - part for spring seems the same until 2004. Non-US market has a different spring and spacer 2004-2006. Spacer for US bikes has been discontinued-even for a 2009. WTF? Spacer still available for non-us bikes and again WTF?

[mister]

For a quick visual...

If you see rings around your fork tubes, it is usually where dust and crud gather in the oil which is left there. Wipe with finger to see.

Have a look at the Back of your forks. Do you see any marks of leakage past down the back? If so, your seals need doing.

Some people will ride with a slow leak for ages. But ask yourself what Could happen? Leak into the break pads. Now you're up for new brakes as well. If it lets go suddenly it will go everywhere including the front wheel - whoopsie involved now.

Michael

[adidasguy]

For a quick visual...

If you see rings around your fork tubes, it is usually where dust and crud gather in the oil which is left there. Wipe with finger to see.

Have a look at the Back of your forks. Do you see any marks of leakage past down the back? If so, your seals need doing.

Been there....
Junior had a bad right fork seal. Saw oil on the tube and a line of gunk down the fork, fender and onto the brake.
Fork oil on the brake is NOT a good thing.

Bought that nice set of 2009 forks on fleabay for a hundred bucks. Put in progressives I bought off this board and now Junior has pretty new 2009 forks. Just added Denali fog lights to him. Just to be safe, also put on a clean 2009 front caliper so I wouldn't have the worry of fork oil in the front brake. (Cheaper and easier than taking a 1994 caliper apart, cleaning and rebuilding it.)

Now with the expertise of nonfiction (Scott) , we're rebuilding a bunch of sets of forks. It was amazing that an 18" paint roller (left over from the floor for the cave) is perfect for setting fork seals. Exactly the right size. Then with the tool Scott made, we're all set to rebuild a set of forks in under an hour.

FYI: Dealer wants about $150 plus parts to redo the fork seals. That's when they're NOT on the bike. We can do it so fast, maybe we should start a business just rebuilding forks 

If you hit a bump and the front goes CLUNK - maybe you're bottoming out the forks and time to fix them. At least put in better springs.