Rebuilding a 1991 GS, my experience thusfar...

[The Wreck]

Well it's been fun, the GS (a friends bike) is literally a joy to work on compared to my 1993 ZX7 and my current ride, a 2002 CBR954RR. That said, I've run into a few interesting things that I'd like your feedback on.

First of all, the front brake caliper was sticking badly, making it nearly impossible to push the bike. When I removed the caliper and began tearing it down I found that the seals were literally FUSED to both pistons frezing them solid in their bores. I managed to free the pistons with compressed air but they're toast. The caliper body is okay and we've ordered the parts to rebuild it from Suzuki. I've rebuilt lots of calipers before and never run into anything quite like this. I'm thinking that at one time or another somebody used the wrong fluid in the front system or is this common on the GS???

Next issue was that the carb boots (plenums between the carbs and cylinder head) had dessicated and become extremely brittle. I know that gasoline can damage rubber but am I correct in thinking that this has more to do with the heat from the air cooled engine and that this is a common GS issue?

Thanks, Jamie

[starwalt]

Hello Jamie!
I am rebuilding a 90 GS, ebay non-runner, but do not have a problem with caliper sticking. Also on my projects list is a custom 3 wheel car using m/c engine and auto suspension. The Triumph Spitfire front calipers I have sound like your GS's. I ended up ordering a caliper rebuild kit and new pistons.

It is difficult to say that a particular brake fluid causes that problem. I think it is more neglect and rust due to the hygroscopic nature of brake fluid. The DOT fluid Suzuki specs for the GS is DOT4. Some have experimented with DOT3. Good maintenance and care would have prevented the problem you found.

My carb boots, or intakes as some have called them, are in fine shape. I noticed a pair on ebay for $19.99 starting bid that have some minor rust. There are several days left on the auction. You are the first I have noticed with this problem although my experience here is just since the fall of '04. I am sure others will chime in soon enough.

Take some pics for us and post here. If you do not know how (as I didn't at first), we will help.  

[Jared]

They aren't expensive for new ones ( new intakes ).....

I bought a new set not long ago...don't think they were that much. Worth it in my opinion.

Just a little info on getting bikes with stuck brakes rolling... take a chunk of wood and tap on the caliper body... often thats enough to release the brakes enough to let you move the bike.

[The Buddha]

I have had intake boots go bad. On one bike (not mine) when I tried to pull the carbs off the intakes split in 1/2 ... anyway, the piston can be sanded and checked if its useable but more than likely weather and neglect more than fluid choice ...
Cool.
Srinath.

[DerekNC]

The air intakes also have o-rings that can go bad. The o-rings in mine were smashed completely flat, not round like they're supposed to be. It would be a good idea to replace them as well.

Derek

[knowlsey]

well here is the start of my rebuild, doing the paint and tidy till i get the output shaft and flywheel

http://bikersgrove.clickhere2.net/page6.html