Forks leak air

[joeysr20det]

I've got a 79 XS1100 SF. My front forks won't hold air, and I've never rebuild the forks on a motorcycle. Is there anything common to look for? How hard are they to rebuild?

[bikerphil]

First, make sure they are not leaking from the valve core. Pump 'em up a bit and spray some soapy water around them and observe. If that isn't the case, the seals probably need replacing. Option 1: Replace the seals with genuine Yamaha with the extra lip for air forks. Option 2: Go with the Progressive spring upgrade (about $65) and air is no longer needed. IMHO, I'd go with the new springs. You will notice a great improvement in handling. The forks are pretty simple to work on, consult your service manual.

[joeysr20det]

I read about the progressive springs, and I was thinking of going that route. Do I have to get different fork caps and stuff though?

[bikerphil]

No need for new caps. You just won't be adding air anymore. Might be a good idea to change the seals and fork oil while you're in there. JMHO

[Gyrogearloose]

Just done the forks (air over oil) on my 80 special. Be very careful when replacing the caps. Trying to compress the springs while starting the threads on the caps is a bugger and the caps are aluminum and cross thread very easy. I had to use a file the dress the threads a coupla' times. Use this forum to find other members ways of doing this. Using the palm of your hand to press the cap down and try to start it is painful. I used a big crescent wrench to provide a flat spot for my palm and the handle on it was convenient to start it turning. Good luck.

[b.walker5]

Option 2: Go with the Progressive spring upgrade (about $65) and air is no longer needed. IMHO, I'd go with the new springs. You will notice a great improvement in handling. The forks are pretty simple to work on, consult your service manual.

Thoroughly recommend this option rather than trying to keep air in something that seems to be designed to leak. I changed to progressive springs about 4 years ago and still love the difference it made on my 80SG. Cost me a whole bucket load more than 65 bucks here in New Zealand but if thats what it costs in your neck of the woods then go for it, you wont regret it.