Getting bike back on the road: some general tuneup issues

[twelvepoint]

Hello. This is my first post here, although I've lurked for a bit. Some great technical resources here.


My deal is that 4 summers ago, I began riding and bought a '94 GS500E. It ran great for the season, and then sat in the backyard (covered) for a typical New England winter. At that point I really didn't know much about winterizing a bike, so other than covering it, I didn't do anything else.

The following spring I started it up and it ran really rough. I cleaned out the carbs but couldn't get it idling right. So it sat for 2 more winters.

A couple weeks ago I decided I was gonna try and either revive it or junk it. To my surprise, it started and actually idled ok, although it seemed the vacuum on the petcock was causing issues with starving the carb bowls. So I followed some advice here and plugged the vacuum fitting on the petcock, cut away the diaphragm, and capped the vacuum lines on the carbs. This seems ok so far. The bike idles nicely using a temporary fuel tank.

The trouble I'm having now is with acceleration. As I'm sure anyone here knows, the right side Mikuni carb is directly connected to the throttle cable, and it couples to the left side carb with a couple metal tabs and a set screw. When first accelerating, from idle, it looks like the right carb opens up slightly ahead of the left, then the tabs hit and throttle motion gets transferred to the left carb. Is that normal operation? Because by the time the left carb starts opening up, the overall engine power starts to sag and stall. However, if I don't use the cable throttle, and carefully open up both carbs by hand at the same time, acceleration is quite smooth. I assumed I should try and get the tabs closer together, but with the adjustment screw fully clockwise, the separation was still too great. Does this make sense?

I assume this is related to synching the carbs? I did look at some previous posts about this in FAQ, but I think some images had been subsequently removed. I don't mean to annoy anyone reintroducing a topic that's been discussed already, but I think if I can get past this issue, I'll be able to get this back on the road.

Thanks,

Chris

[joshr08]

IIRC there is a screw there to set the sync on the carbs.  i always bench sync and to do this just look through the carb body and adjust the screw until the opening on both are the same. does this make sence? some times its hard to explain 

[twelvepoint]

Ok, I have the Clymer manual in front of me now and maybe I can describe the issue better:

The throttle shafts on the carbs are coupled with an adjustable fitting. Looking at the manual, I now see there should be a spring inside the coupling. Without the spring, the left carb will not open right away and it takes about 20 degrees of motion before the right hand piece makes mechanical contact with the left. I must have lost the spring when reassembling the carb a couple years ago.

So I put in a spring and now both sides are moving as they should and acceleration, while not completely smooth, is good enough to get the engine running almost normally.


A couple other questions before I put the bike together:


1) The gas tank has some rust inside it. I would say it's dotted with rusty areas and not really uniformly rusty. Should I bother to kreem the tank, or is it ok just using inline fuel filters?

2) The chain is rusty, and there are spots where it's not very flexible. Should I replace the chain, or can I take a shot at cleaning it to an acceptable point? I understand the chain has o-rings, which might affect maintenance, is that correct?

Thanks again,

Chris

[joshr08]

inline filter should be fine and i would replace chain and sprockets so everything wears in the same.

[JAY W]

Hi Chris,not all GS`S will have an O`ring chain,but if you look inbetween the outside of the link and the roller the o`rings should be visible.if iso and has tight spots its f****ed,if its an ordinary chain try boiling in oil.

[joshr08]

you could boil in oil if you dont care if you live or die but for me 60-80 bucks for a new chain is well worth it compaired to leaving my family early because the chain snaps at speed and raps around the wheel causing you to crash in front of that semi thats fallowing you. if the chain is tight i would replace it no questions asked.  but your the one riding it not me.

[twelvepoint]

Point taken. Is there a recommended online source for a chain and sprockets? And what's the verdict about replacing sprockets? Is that something people do as a matter of course, or is it more discretionary? The bike has about 90K on it, by the way.

Also, I should get the right spring for the carb linkage. Again, is there a good online source, or should I ask my local Suzuki dealer?

Thanks for the advice with this. Sorry for the dumb questions!

-Chris

[joshr08]

stock chain is 520-110 sprockets are 16/39 i got all my stuff at http://www.chaparral-racing.com
for the carb part either your local dealorship or online at bikebandit.com or ronayrs.com is a good place some people dont like bike bandit some do i have never got anything from either places.

[twelvepoint]

Am I able to replace the chain without separating links and rejoining it? (This is assuming I'm replacing sprockets, as well)

[twelvepoint]

Just a quick follow-up to anyone playing along at home:

I ordered up a DID 520/110 O-ring chain, JT 39+16 sprockets, a Motion Pro riveting tool and a couple little bits for the carbs.

I'm also going to replace the brake fluid, which has been sitting for a few years. (The calipers seem to work fine)

Should I also replace the motor oil? Probably a good idea, right?

Any other advice? My desire is to get the bike to a point where it runs reasonably well and is safe. I'd prefer to ride first, then address finer tuneup issues (like carb syncing, valve adjustment, etc) as-needed.

Thanks.

[twelvepoint]

Just an update- bike is now running, registered and insured. Seems to be running well so far, but I'll probably do a valve and compression test in the near future.

Thanks for the help. Great site here.

[pandymai]

awesome to see the return of a rider!

i hope, since last, that you DID replace the oil.

happy riding!