Suspension overhaul: 77 GS750

[hannibal]

The time has come to address my worn out suspension. The fork seals are leaking, the front and rear sag under my weight, and the front dives significantly when braking.

For the rear, I'm planning to go with the entry level Hagon Type A shocks from Dave Quinn. His site says the slimline springs can rub the shock body so he recommends with wide springs. Any experience with this? I'm also considering go with 13.5" shocks instead of the stock 13" (I think). I think I read longer shocks speed up steering but reduce straight line stability. Any advice on shock length?

For the front, I thinking Sonic Springs. The calculator shows I'm right on the line between 0.95 and 1 kg/mm springs so I think I'll go with the stiffer springs. I also need to replace the fork seals and rings (part# 8 and 9). My dust seals look good but they are probably 40 years old. Should I spend the $30 for new ones? Any other parts need replacing when doing seals?

Thanks!

 

[hannibal]

I know the topic of springs and shocks have been beat to death. Any advice on fork seals and parts to be replaced? The seals obviously but retainer ring and dust boots too?

 

[RichDesmond]

The time has come to address my worn out suspension. The fork seals are leaking, the front and rear sag under my weight, and the front dives significantly when braking.

For the rear, I'm planning to go with the entry level Hagon Type A shocks from Dave Quinn. His site says the slimline springs can rub the shock body so he recommends with wide springs. Any experience with this? I'm also considering go with 13.5" shocks instead of the stock 13" (I think). I think I read longer shocks speed up steering but reduce straight line stability. Any advice on shock length?

For the front, I thinking Sonic Springs. The calculator shows I'm right on the line between 0.95 and 1 kg/mm springs so I think I'll go with the stiffer springs. I also need to replace the fork seals and rings (part# 8 and 9). My dust seals look good but they are probably 40 years old. Should I spend the $30 for new ones? Any other parts need replacing when doing seals?

Thanks!

The slightly longer shocks will balance out the front nicely, you'll have less sag with the new springs so the front will ride a bit higher. You'll need to go with the 1.0s, we don't make a 0.95 in the size that the 35mm forks use.
I'd replace the dust seals.

 

[RichDesmond]

I know the topic of springs and shocks have been beat to death. Any advice on fork seals and parts to be replaced? The seals obviously but retainer ring and dust boots too?

If the retainer is in good shape I reuse it, if it's all rusty (common on old bikes) I replace it. Almost always replace the dust seals, only time I don't is if I know that they are relatively new.

 

[hannibal]

Thanks for the advice Rich. I'll go ahead and buy the retainers and dust boots just to make sure I don't have wait for parts if they turn out to be in bad shape. Planning to order your springs (and everything else) in the next week or so.

Unfortunately, the Hagons with the Suzuki lower clevis mount only come in a 13" version (according to Dave Quinn). But since this is the only bike I've owned, any new parts will be an improvement.

 

[Steve]

Have you ordered the Hagons yet? If not, double-check the spring rates. Dave can select between a few damping rates and spring rates. Might ask about getting a spring rate that is about half a notch heavier than most would want. That would minimize the sag at the rear, keeping it about the same height as the "proper" spring rate on a longer shock.

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