1982 GS400, progressive fork springs

[Guest]

Hello and greetings from Canada,

Last year i bought my first street bike and used it to get my motorcycle license.

Now in the off season i want to do some much needed maintenance.

I would like to order a pair of progressive rate springs to replace the soft stock units while replacing the fork oil and oil seals up front. The challenge i am having, and have had since purchasing the bike, is online retailers do not have my model listed in their buying options. The online retailers i frequent require me to choose my make, year, and model before being redirected to the correct parts. Unfortunately my bike is never listed.

ie, they have good options for bikes similar to mine in make and model or year but not mine specifically, so i end up always having to roll the dice and hope what arrives will fit.

So, does anybody know if parts will fit from a more common bike of that vintage?

Thanks for reading!

1982 Suzuki GS 400 TZ

IMG_8403.jpg

[Nessism]

Check Sonic Springs. The founder is a member here, Rich Desmond. Even if they don't show a specific spring for your application it's easy to calculate the correct spring rate using their online calculator. Then you just need to know the proper diameter of the spring. Spacers are made from PVC pipe that take up any extra space if the spring is shorter than the originals.

[RichDesmond]

Sonic won’t have them (they don’t carry springs for fork tubes that small) but Race Tech should be able to help.

[Euripedes]

Thank you to Nessism and to RichDesmond for those replies. I have the forks off, apart, and cleaned up. The oil that came out of the forks was really ugly and not much of it. I think at this point I will leave the springs as is and install 15w fork oil to improve the damping at least. I'm planning a road trip in the spring and the writing is on the wall that I will need a bigger bike. Regards,

[John Park]

Euripides - check your PMs...may have some springs for you.

[Steve]

I think at this point I will leave the springs as is and install 15w fork oil to improve the damping at least.

If you had virtually NO fluid, I think you would be making a mistake going straight to 15w oil.

My suggestion would be to use 10w oil, AFTER cleaning the internals in the fork. I would also highly recommend changing the seals. Poor seals just might be the reason there wasn't much fluid in the forks.

.

[LAB3]

My 450t has 2" spacers in the forks to firm them up a bit and I run 10w. I'm 200lbs and carry about 100lbs of gear most of the time and adding the spacers to the original springs made a huge improvement.

[Hokano12]

Late reply, but progressive suspension carries fork springs for gs400 and gs425 which are basically the same bike (most parts between these models are interchangeable). I just put a set in my gs425 with 1" PVC spacers (included in the kit) and Motul 10w fork oil and the bike handles much better. I like my forks a bit more stiff and the 1" spacers are perfect.