82 gs650L do the forks have air in them?

[Guest]

I was wondering what the fitting is that is at the top of the forks when you remove the plastic cap? It looks like a air fitting. I have not heard of air being in the front forks but I am new to motorcycle riding, this is my first bike and only have a permit. I also have a set of rear air shocks off a yamaha, about the same size. Can they be interchanged the length is within a half-inch. They look like they will bolt up but will they perform correctly? I was wondering about how much air to start with? Thanks for the help.

[Eli69]

my 650L doesn't have air fillers like my 1000's do but you might have different forks. if you can put air in them i wouldn't go over 12 to 15 pounds. there is a special pump that has a gauge and doesn't allow air to escape while you're removing the hose.

[rkubik]

Back in the 1980s, that fitting was there to add air as a kind of preload or extra spring. But that thinking on suspension became obsolete for motorcycles a long time ago, although bicycles still use it. If you do add air, use the small shock air pumps sold in bicycle shops - add about 8 pounds per leg. But generally it just leaks out or causes oil leaks from the fork seals.

New Progressive Suspension or Race Tech front springs are now the way to go for your machine. They are not much $$.

As for the rear shocks, are they 1/2 inch longer or shorter? If shorter, they may cause the tire to hit the fender on big bumps. If longer, raising the the rear end will make the bike turn quicker - it doesn't take much change in ride height to make a difference. Again, best to just get some modern shocks and springs in the right length. The Chinese ones currently marketed may not be that good, but they are inexpensive. Check here:

http://www.mikesxs.net/mikesxs-suspension.php?category_id=6.1

[scrapper]

They are a little longer but that may be because of the air in them. The shocks on my bike seem to bottom out easy? I am not sure if I can adjust them more or not. It seems that you need a spanner wrench type tool? how do you know how much to move it and with way? Would it be the springs and or the shocks that may be worn out? The air shocks are longer

[Steve]

The first thing to do when setting suspension is to get the spring rate and preload correct. You will need a helper for this. Measure the length of the shock with the bike on the centerstand and the shock fully extended. Now take the bike of the stand, sit on it, bounce around a bit to get it settled into riding posiiton. Try to get as much of your weight as possible onto the bike. A second helper can steady the bike while you sit on it. Now measure the shock length again. What you are looking for is to have no more than 20-25% of your available travle used up by just sitting on the bike. Most shocks have about 4 inches of travel, so you are only looking for about one inch of compression. If you get more than that, use the collars at the bottom of the spring to compress the spring until you acheive this. Although a spanner-type wrench is intended, you can also do it with large channel-lock pliers. Once the preload is correct, you will have to determine whether the rate is correct by hitting some dips and bumps. You should seldom bottom out.

One other factor in suspension is the damping. Many are of the opinion that by the time you get a new bike home from the dealer, the dampers (shocks) are worn out and need to be replaced. Certainly, after 25+ years, this would also be true. As mentioned before, the Chinese shocks that are available work, but aren't that comfortable. I got a set for my son's '82 650L, but they ride almost like a hard-tail. I can get the springs to move a bit, but the damping is so stiff, they don't like to respond to minor irregularities in the road. I moved the shocks over to my other son's '81 850 be cause he is ... errr ... dimensionally enhanced and can better appreciate the damping abilities of those shocks. Among the best (and most popular) shocks you can put on there are those from Progressive Suspension. Not cheap, but worth it. They have a selection of spring rates to accomodate various-size riders and riding styles, and they also have shocks in different lengths.

Front suspension recommendations are pretty much the same for setting preload, except that you have to open up the top and change the length of a spacer to adjust preload. Stock spring rates are not too bad, but a set of Progressive Suspension's fork springs are even better. When you use Progressive's springs, you will not need any air.

.

[egent]

Again, best to just get some modern shocks and springs in the right length. The Chinese ones currently marketed may not be that good, but they are inexpensive. Check here:
http://www.mikesxs.net/mikesxs-suspe...ategory_id=6.1

Which set of shocks are you talking about on the above page. There seem to be several different types, as well as two or three different lengths. I believe that my 82 GS1100L needs the 13.5 or 13 13/16 inch shocks, but still many different types to have an idea as to what to look at.

[STANDIGGITY]

I am interested in the progressive springs, however, for a gs300l 1983. What exact springs/shocks would I need (front and rear)? Links are greatly appreciated

[Flaggo60]

What rkubik said-I posed this question some time ago on this forum and the consensus was that the air forks were an outdated idea now that good products such as Progressive Suspension fork springs are readily available. No fuss, no fiddling, and they last the life of the bike. I've used them with total satisfaction for almost all of the 19 years I've had my 650.

[rkubik]

Details

When you replace the front springs with Progressive Suspension ones, you will find that the old ones are 540 mm long, while the new ones are 483 mm mm long. A spacer is needed. As a start, I made one 60 mm long just for round figures. More preload could be added by making it longer, but I have not found the need. L models are not real corner carvers anyway.

The PVC pipe generally used in other bikes is too big around in this application. That's because of the "ledge" partway down where the fork inner diameter increases. You can see it in this picture:



So not surprisingly the the space has to be the same diameter as the spring. What worked out quite well was the coupler for 3/4" copper plumbing pipe, plus a 60 mm length of pipe inside. In this picture, the inner pipe is the 3/4" pipe, with the larger coupler slipped over it (you just have to file away the little lugs inside to let it slide right over). Another short length of coupler (right side) is cut and stacked on make it complete.



Here's the spacer in place. It probably should have a steel washer between it and the spring - I need to find the right size ones.



So from the hardware store you need 3 couplers, a piece of 3/4" pipe, and one of those tubing cutters you clamp one and turn around and around. Lees than $20 all in and you're good to go.