GS1000 fork air pressure spec

[DaveR]

The front end of the 79 GS1000N is disassembled for inspection, cleaning and servicing. There is a discrepancy between the info on the warning decal on the left lower fork tube and the service manual.

The manual states it should be 11.4 psi (0.8 kg/cm2). The Suzuki decal states the fork air pressure should be 35 psi (2.5 kg/cm2).

Are these forks not original?

[Agemax]

standard pressure is 11psi, Maximum pressure is 35psi.

[hampshirehog]

35psi is 'do not exceed'.

[DaveR]

I am so fortunate to be able to rub shoulders with some smart guys. Thanks!

[bccap]

I use around 10 and do it with a bicycle shock pump.......

[bwringer]

The correct air pressure is none (technically, atmospheric, or no added air pressure if you want to be pedantic).

Install upgraded fork springs (I use and highly recommend Sonic Springs), set the correct preload, and use no added air pressure.

Air pressure is an unreliable bodge; a shameful band-aid for the low-rent weak-suck fork springs the factory installed for mysterious reasons.

[Steve]

I agree with the use of proper springs and no additional air.

One of my bikes has Sonic springs, the rest of them use Progressive springs.

The best price on Sonic is from Sonic. Owner Rich Desmond is a member here.

The best price on Progressive is from Z1 Enterprises. Owner Jeff Saunders is a member here.

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[DaveR]

Good supplemental info guys. Did not know that. This $500. and a $1000. budget project (about $1300 USD) will have to use the stock springs until I know what I have next summer. Info noted in the shop log. Thanks.

[Guest]

Good supplemental info guys. Did not know that. This $500. and a $1000. budget project (about $1300 USD) will have to use the stock springs until I know what I have next summer. Info noted in the shop log. Thanks.

Since you have to use your stock springs for now, you could up the fork oil weight to a 20 or even a 30 w fork oil.

[Steve]

Heavier fork oil does NOT help hold up the front of the bike. It only keeps the response down, making for a VERY stiff ride.
Not stiff as in "heavy-duty springs", but stiff as in non-compliant with road irregularities.

A better approach would be to measure the "sag" of your front suspension. Get a helper. Put the bike on the centerstand, measure the distance from the top of the lower fork tube to the bottom of the lower triple clamp. Take the bike off the stand, get on it. Bounce the front end a couple of times to settle the suspension, have your helper measure the distance from the top of the lower fork tube to the bottom of the lower triple. Ideally, the "sag" is 20-25% of the total travel. Most of our bikes only have about four inches of travel, so you are looking for 3/4 to 1" of sag. If you have more than that, pull the tops off the fork tubes (block up the front of the engine so the front of the bike does not crash), remove the tops of the forks. Pull out the spacers, measure them. Make new spacers of PVC tubing that are a bit longer. Add the amount to the spacers that you want to raise the forks. If your sag was 2" (1" more than desired), add 1" to the spacer. Put it all back together, install the proper amount of 10w or 15w fork oil (depending on your weight and riding style), repeat for the other tube.

Even better, pull your stock springs out. You will see that they are either a two-piece setup or progressively-wound. If they are two-piece, Just remove the smaller, lighter section. Make your new spacer the length of the stock spacer + the length of the lighter spring + the amount of sag you want to remove.

If your springs are progressively-wound, cut off most of the tightly-wound end, make sure to cut off the same amount off each spring. Make your new spacers the length of the stock spacer + the length of the spring you cut off + the amount of sag you want to remove.

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