Progressive fork springs question

[24flinchin]

If I put progressive fork springs in my 83 gs650, does that eliminate the need for air and oil or just one or the other or neither? Also, what should I notice by installing these as far as improvements? Thanks

[waterman]

Generally speaking, most people who use progressive springs, do not use air. The oil is still required.

I find the biggest improvement is noticeably less front end dive while braking and better ground clearance. The ride is different, big bumps don't seem to hit as hard yet it is still relatively complaint. The front end feels more planted on rough roads. My opinion only.

I am thinking of dropping back to 15 weight oil in my forks as the 20 weight I am currently running isn't quite as plush a ride as I would prefer.

[chef1366]

20 weight!? That's some thick stuff
The difference you will feel is control over your motorcycle and not diving when braking.
Fork oil is always needed. Make sure the level is equal in both forks.

[24flinchin]

Great, thanks for the replies. Guess Ill order a set, any recommended brands?

[salty_monk]

"Progressive" is the brand

http://www.progressivesuspension.com/

[spokexx]

im assuming 15 is the stock weight in my '81 GS650G according to this thread. How much goes in each tube? (oz/ml/cc)?

thanks, drew

[Hammered]

I havent replaced my springs in the 650 yet but my 1980 750 called for 8 weight oil. I pressurized the forks when I was done to 10 lbs as well to check for leaks. After a week of holding pressure I released the air back into the wild where it belongs. I know thats probably not the best means to test, but it held fast at 10 for a full 7 days so....

[ryonker]

im assuming 15 is the stock weight in my '81 GS650G according to this thread. How much goes in each tube? (oz/ml/cc)?

thanks, drew

You can find this in your manual or go to Basscliffs site and look it up.

Rick

[buddha]

I just installed Progressive fork springs (#1106) in my GS650GL a few weeks ago. I can give you these pointers from my experience:

1. Don't use 20WT! It's way too thick. I used 15WT (stock spec) and it's just about right...almost too heavy. I might even try 10WT once I have some other details sorted out.

2. Choose your spacer length carefully. I weigh about 190lb and used a 60mm spacer, but it was about 5~10mm too long, so I get a little bounce during cruising. I will be shortening it soon. I'm not sure if you're riding a G, E, or GL, but you need to follow the instructions for the spacer length calculation (based on preload). It will be a different length for you if you don't have the GL (GL forks are longer than G/E/etc...).

3. When using the progressive springs, it is best to determine the fork oil amount by oil level instead of volume since the progressives take up more space inside the fork tubes. I basically compared the progressive instructions to the service manual spec, and used the lower of the two levels (larger number). So far, I haven't had any hydro-locking issues.

Feel free to ask if you have any additional questions. This work is still fresh in my memory.