What to do first

[B Evil]

First the vitals: 1981 GS 550 L

Ok, here's the thing. I bought this bike for cheap last winter and put in a little time and money to get her going right. I was able to ride almost all season last year but then she started running like crap. Seems like the plugs fould out within just a couple mile ride. Looking at the plugs, it looks like a couple run rich and a couple run lean so I need to balance the carbs. The previous owner chopped off the stock mufflers and now it's just straight pipes and no baffles. I've heard they will still run fine like this as long as you re jet the carbs. Well I don't know too much about working on carbs so it never got done. Could this also be a reason the plugs are fouling out so quickly? Will replacing the pipes with the stock mufflers remedy this so I don't have to re jet the carbs?

The petcock is also about due for replacement as she only runs on 'run' and nothing on 'prime'. I had someone say she may need the valves adjusted. Again, this is something I've never done but think I probably could but I'm not so sure that she needs it.

So basically these are the things that I think she needs

New Petcock
Carbs Synched
Oil and Filter Change
Spark Plugs

And Possibly
Adjust the Valves
Replace pipes with Stock Exhaust

What I'm wondering is, is there any sure way to know if the valves need adjusting without really opening her up? From what I've said so far, any thing else you guys with all the wisdom might think of that needs to be done?

She's a great bike with only 12,000 and she ran great most all last year so I want to try to hang onto her a little longer but with how she's running right now, I don't want to invest too much more money if I'm going to keep having problems.

Any and all help is greatly appreciated

Thanks,
Bradley

[TheCafeKid]

First of bro, adjusting the valve adjustment is a must do, at least check the clearances, see if they need adjusting (prolly do) Its cake. Seriously. Secondly, running a straight thru pipe will indeed mess with your carburation, how much, i dont know. Some say that a rejet is uneccessary, that it should be able to be dialed in with the mix screw(s) However, some would say differently. Is the stock airbox still on it? Cleaning the carbs would probably be a good idea as well, and there is an excellent tutorial on that in the "Garage" section on the main GSResources page. Again i cant stress how important it is, however, to check those valves. Taking the valve cover off is cake, and you can usually keep the gasket intact (try to keep it with the motor, and not with the cover) If your valves are too tight, they wont close, inturn the bike will run like crap.

[chef1366]

If it started running bad in a day check your battery.

[B Evil]

Yes it still has the stock air box. I considered switching to the pods or cones whatever you want to call them but I've also heard this is going to mess with the carbs more. So I'm trying to keep everything as close to stock as possible. I did clean the carbs last spring, but as I said before carbs are definitely not my speciality so I'm sure it was a single cheek job. I will for sure pull them back off and clean them out again following the tutorial. Thanks for that tid bit. How can you tell when they need rebuilt and how hard of a task is this for someone who has very little expierence with carbs?

It didn't start running bad in just one day though. It progressively got worse. It's too the point that as soon as I touch the throttle it chokes out cold or warm. Battery is practically brand new.

If the valves need adjusted do I pick up new shims at the dealership?

Thanks for the info.

[hampshirehog]

If it bogs as soon as you touch the throttle then there's a strong chance your carbs are in need of attention (though could be fuel delivery and you've already id'd the petcock). The carbs are easy enough to strip - there's an excellent tutorial on here -and maintain absolute cleanliness - some of those holes are pretty small.

[Smokinapankake]

Single cheek job. So funny I almost fell off the chair!
I'd be suspecting the carbs/fuel valve issues. Carbs are super easy to clean, just do one at a time and yes, absolute cleanliness is imperative. Carb cleaner will clear out every orifice on that bike if it's had gas through it in the last year. I cleaned carbs to spotless on a GPz 750 that had sat for 8 years using nothing but carb cleaner.
I imagine that exhaust (or lack thereof) may be somehow related to your problem, but probably not too much. Must be loud enough to wake the dead.

[Nessism]

Pull the carbs and replace the rubber O-rings with a kit from Robert Barr http://cycleorings.com/

While the carbs are off replace the intake pipe boot O-rings.

Check the valves while everything is apart. You are going to have to buy a shim tool (about $20) and some different shims. Z1 sells the various parts if you can't find a dealer to trade shims with you.

Check the air filter while you are at it and clean it as needed. They tend to crumble after 20 years or so don't neglect.

Good luck.

[TheCafeKid]

Nessim has said a mouthful. Z1 for shims if the dealer doesnt have them (chances are, he'll say We have to order them, 12.50 each, its gonna be a couple days. Screw that, Goto Z1, still a couple days, 5 bucks each.) OR if you only need a couple, I live not TOO far from you, and i have a decent collection of shims here.

[B Evil]

Thanks for all the advice guys. Helps more than you can imagine having other people who have probably had the same issues agree on what needs done. I found a factory set of pipes on ebay for 20 bones so I guess I'll go ahead and swap those out at the same time. After looking through the carb cleaning section it definitely looks like something I can tackle. Wasn't too sure at first, but I'm glad all the pics are there. Still not too sure on the valves though. But I guess there's only one way to figure out if I can do it or not. And if not, I'm in your area 4 or 5 days a month Cafekid so I might just have to throw her in the bed and bring her along sometime. Thanks again for all the advice.

There wouldn't happen to be a step by step valve job picture walk through around here is there? I just don't want to end up doing a single cheek job on it either.

Where can I find the intake boot o rings that had been mentioned? Are those also on cycleorings?

[TheCafeKid]

yup cycleorings carries those, as well as nifty stainless allen bolts to replace those evil phillips head ones that are on there now. Highly suggest those as well. i bought carb rings, intake rings and the bolts, think it cost me a total of 15 bucks maybe?? Highly worth it.

[robertbarr]

Valves:

http://www.cycleorings.com/gs850valve_adjust.pdf

... courtesy BassCliff.

[B Evil]

Ok, I've got a pretty good idea of what to do now thanks to all you GSperts.

One more thing though, I'm already a little worried about trying to adjust the valves myself but feel confident I can takle the jobs with everything you guys have presented here BUT . . . how will I know if I have a burnt valve? I had mentioned everything I have set out to do to a fellow co worker and the mentioned the possibilitie of a burnt valve. Any easy way to find out for sure without having to take the head off? I was really hoping I would be able to do this all myself without tearing into it too much but I'd really hate to adjust the valves and everything else then find out I still have valve issues.

As always any and all help is greatly appreciated.

[Steve]

A burnt valve would show up in a compression test. One cylinder would have readings drastically lower than the others (unless all cylinders had burnt valves ).


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