80 GS550L won't idle, occasionally stalls

[jmill050]

Hello everyone

I recently picked up a GS550 in order to see how much better I like bigger bikes compared to my little GN400. The guy who had it before had it sitting around for a while because he lost his license from a DUI. The bike has two issues now.

I was riding down the freeway for about 20 minutes when the bike started to lose power. Gradually, Over about a minute, I lost all power and had to pull off into the shoulder. Not knowing what to expect, I put down the centerstand and started checking oil and trying to figure out what went wrong. After a bit, I sat back down, cranked it for a while, played with the choke, and got it to fire up. I then rode the rest of my trip with no problems, about 30 minutes. This was about a month ago. I got it back out again yesterday to work things out with a new battery (the old one was just about gone), and things seemed to work fine. Maybe I'm a glutton for punishment, but I took it back out again. I rode around all day, multiple stops, cool downs, and starts. All in all probably just under two hours riding time. At the end of the day I was on my way home (once again, on the freeway), and I started to open it up a little bit on the onramp. About 5 minutes later, the power fluctuation started again, and I lost everything. Suspecting something similar, I waited, and tried again, but to no avail. Luckily I called my friends with a truck into action as soon as I got into the shoulder, and we were able to get it home. My instincts tell me it's a problem in the fuel system somehow. Ideas?


Also, the bike has an issue with idling. I've played with the idle screw, but it seems to have two different modes. It either idles very high, or slowly fizzles out and dies. I thought it was bad gas at first, but then it continued after a new tank. Thoughts?

I feel like it's relevant information that the bike has pod filters. I do not know when they were added, or more importantly, if the carbs were rejetted to compensate for that. Could either of these problems be related to that? Is there a way to tell if the proper carb tuning was done? I'm fairly handy, but I avoid carb work at all costs. Too many little pieces for me.

Thanks in advance.

James

[Nessism]

Hi James,

Welcome to GSR!

Please check the Newbie Mistakes thread linked in my signature. You are making several, but it's not too late to get on track.

Enjoy!

[BassCliff]

Greetings and Salutations!!

Hi Mr. jmill050,

The only way to ensure that the bike is jetted properly is to first remove the carbs and have a look at the jets comparing them to the stock sizes. Then you should perform plug chops and read the plugs to check the fuel/air mixture at different throttle openings. If it hasn't been jetted to compensate for the pods then you stand a chance of melting your motor. Well, burning valves at least. Speaking of valves, they should be adjusted too. Anyway, it's all in your "mega-welcome".

Have a good look at the maintenance lists and procedures in the links below. You've got a 30 year old bike that probably needs 20 years worth of maintenance.

Let me dump a TON if information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. Now let me roll out the welcome mat for you...



Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[mike_of_bbg]

You need to start from square one and get a good baseline.

First, are they good pods (APE or K&N)? If not, get good pods or find a stock air box to put back on that puppy. Lots floating around on eBay.

If they're good pods, then you need to verify the jetting. You can do this when you clean the carbs. Since it's an 80 running CV carbs, what you really need to have in there is a Dynojet kit. It's not just the size of the jets: the taper of the needle is very important.

Here's a nice article on the subject of pods, pipes, and jetting:

http://www.mediafire.com/?7ttgomzmmjz

Valve clearances are too often neglected. Check and adjust.

The idle variations are likely caused by hardened and cracked o-rings between the intake boots and the heads. Check the boots to be sure they're in good condition.

Dying after a while at high speeds sounds like fuel flow - blocked venting at the cap is a likely culprit. Carry an extra spark plug though, and check spark on all 4 the next time it dies and won't restart (hold plug sideways against head to ground and connect wires one at a time while cranking).

[1_v8_merc]

Check your Charging System!!!
(sorry don't mean to yell)

Get a multimeter and check the battery cold(bike off)
How many volts?

Now start the bike, and check the voltage again.
What does it say?

Now rev the bike to around 3-4k and get a voltage reading.
What's it say?