Some general fork rebuild questions from a first-timer?

[Guest]

Looking to tackle a fork rebuild as the next job on my 81 GS 1100E. They are functional as-is, other than a slow leak from the air-pressure system (got o-rings on order for that) and the damping adjustment dials at the bottom are super soft/mushy (pretty easy to spin, the 'detent' for each setting is very vague). But my guess is the fork oil hasnt been changed in many years, nor the level checked. And I figure while I have the forks pulled off the bike might as well do as much of a refurb/rebuild/upgrade as I can.

Only problem is, I've never had motorcycle forks apart before. I'm a gearhead, rebuild motors and carbs and transmissions and such, but never tackled this job before so its's all new to me. I've got a factory service manual as well as a clymer manual for the bike, and a well-equipped garage. Between that and the various guides and videos I've found for GS forks very similar to mine, I'm not too worried about being able to do the work, but I have some questions related to exactly what work I could/should be doing. Specifically:

1. Beyond replacing the oil, what other wear components should be replaced as part of a complete rebuild? Other than the obvious o-rings and seals, the parts diagrams show a variety of nuts, washers, springs, slides, pistons, rings, oil locks etc. My guess is some of these are perfectly fine to re-use unless broken, but some should/could be replaced? Are there "rebuild kits" out there that have all the needed components bundled together?
2. What are the spring upgrade options? I see reference to Progressive brand springs (presumably they are progressive-rate springs?), are these generally considered superior to the stock (fixed-rate?) springs? Are there other aftermarket alternatives to Progressive (either fixed-rate or progressive-rate)? Pros/Cons?
3. What are other potential upgrades while I have the forks apart? I have seen reference to Gold Valves or Emulators (I think these are the same thing). Seems to in effect act like a compression orifice that changes size as a function of compression speed (stiff damping/small orifice at low speed compression for anti-dive and non-mushy ride, but larger orifice at high compression speed for reduced harshness at higher-speed or 'sharp' impacts like potholes and such). Am I understanding what they do correctly? Are these generally considered a big improvement? Pros/Cons? How would this work in conjunction with the factory compression damping adjustment mechanism, or would it replace that system?

Bottom line, I'm in the planning stages of a fork rebuild. Never tackled this job before and not really sure about what exactly I need to be replacing, and what potential upgrades are worth considering while I have things all apart. Any info is appreciated. Thanks guys!

 

[oldGSfan]

I replaced the bushings, top and bottom, you probably can examine and see how worn they are. They are #8 and #10 here: https://www.partzilla.com/catalog/suzuki/motorcycle/1982/gs1100e/front-damper-gs1100ez I guess they're out of stock on #10 which they call a 'piston'. I also put new #26 and #31 O ring seals in and of course fork seals. I hate leaks. I don't know of any kit, bought individually.

Progressive springs used to be the thing, and yes their rate is progressive, but seems they are now out of fashion. Mine has them and they seem to work just fine for my riding, no reason to replace. People on this forum are fans of single rate springs like Race Tech I think. If mine had stock ones and they were sacked or just too soft (which I think they are), I might go with those.

I can't speak to #3, I am happy with my GS1100E and GS1000 as they are, with progressive springs and all else just stock and wear items replaced as needed. Of course upgrades are great but I never really feel like the front end lets me down. Maybe I'm not riding hard enough.

Oh, I blocked off the anti dive and plugged the air holes, I don't miss either.

 

[Rob S.]

Most guys go with straight rate springs. I had Race Tech .90 springs installed a few years ago; I probably should have gone with 1.00 springs, especially considering I'm now almost 20 lbs heavier.

The seals need to be replaced practically every time you look at them, and most remove/bypass the air system. Emulators might be overkill, depending on how hard you charge. Pictures of the bike will score you points. Good luck.

 

[Rich82GS750TZ]

Member RichDesmond in the former owner of Sonic (straight-rate) Springs and has helped set up many here with what they need in upgrade fork springs. Send him a message or wait for him to chime in.

 

[Maddevill]

When you get them apart, take a good look at the chrome tubes. Any rust, nicks or pits can cause future leaks.
A little steel wool or gentle Scotch Bride and some lube should take care of anything minor.

Mad

 

[RichDesmond]

When you get them apart, take a good look at the chrome tubes. Any rust, nicks or pits can cause future leaks.
A little steel wool or gentle Scotch Bride and some lube should take care of anything minor.

Mad

That's a very important point. Extra fine steel wool with a bit of fork oil on the tubes is my preferred method, but others work well also. Just be very careful not to go through the chrome. You don't have to make the pits and nicks disappear, just knocking the high points and sharp edges off is enough.

On the springs, straight rate is better than progressive. The problem with the stock springs is that they're way too soft.

 

[Who Dat?]

I replaced my stock springs several years ago with Sonic Springs. Also replaced the seals (OEM seals are highly-recommended and not much more expensive, if any) and used 10w oil. The difference in the ride was amazing. Later added the emulators that everybody likes so much, really could not tell much difference. Took the emulators out, verified proper settings (which I didn't do the first time) and put them back in. Still can't tell much of a difference. I don't feel they are doing much for me, but it's not worth the effort to remove them.

 

[Maddevill]

When getting the bottom fork bolts out, use a NEW good quality Allen socket and an impact gun. Leave the fork caps on to keep
the spring loaded to help prevent the inner rod from rotating. The LAST thing you need is to strip the head out of those bolts.
They can be very tight.


Mad