Fork pressure

[racquetman]

1981 GS850GL. Can anyone tell me what the proper air pressure range (min and max) should be for the forks? Thanks

[Steve]

It has been a while since I have seen actual numbers, but I seem to remember a max of 15psi.
The minimum is whatever it takes to maintain no more than 1/4 of the travel being used up when you sit on the bike.

A couple of options, if you don't want to keep messing with air, are to increase the length of the preload spacer that is in the forks already or to just get new springs from Progressive Suspension (or some other supplier) and not use any additional air in the forks.

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[Nessism]

Instead of adding a spacer, which increases ride height but not spring rate, take the springs out and chop off a few inches of coils (replace the lost stack height with a PVC spacer). This will increase the spring rate and save you the money of buying Progressive springs.

[Steve]

Good point, but you might still have to put a longer spacer in there than the length of the spring that you removed.

Not suggesting actual lengths here, just throwing out some numbers: let's say there is a stock spacer of 2 inches and you cut off 3 inches of spring. I would start with a 6 inch spacer. That would replace the original spacer and the cut-off spring and add another inch. If you find that 5 1/2 inches is better, it is easier to cut off half an inch than it is to add it.

To check for proper preload adjustment:
Find a helper. Put the bike on the centerstand so the forks are fully extended. Measure from the top of a lower fork leg to the bottom clamp. Take the bike off the stand, sit on it, get as much of your weight as possible on the bike, just like you are ready to ride. Have your helper measure from the top of the lower leg to the bottom clamp. Most of our bikes have about 6 inches of travel. You are looking to use up no more than 1/4 of that distance, or about 1 1/2 inches. If you "sag" more than that, increase your preload, and vice versa. Don't be surprised if the bike does not sag any under just its own weight. That is normal. It shouldn't start moving the suspension (front or rear) until you get on it, if it's set up correctly.

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