My GS550E is stalling unpredictably.

[Ira]

Last night, with the bike running, I sprayed carb cleaner on the outside of each intake boot. As soon as I hit it with a good blast, the bike stalled.

My bike is clearly sucking the liquid through the boots, or through the o-ring, so it looks like I found my answer. This happened on all four boots.

The bike is also starting to stall more and run badly, so I'm leaving it in the garage until I replace everything between the carbs and engine.

I'll report back if this fixes it.

[spyug]

Sorry to be late to the party and I'm glad you've found it as that is exactly what I encountered with my 550 last year. Leaking O-rings.

Now you should obviously replace the O-rings and boots if you determine they are bad too but in a pinch, a dab of silicone sealant around the O-rings will tied you over. If the boots are cracked and you can't readily get replacements, you can "paint" the exteriors with liquid electrical tape available from most auto stores.

Now these are just stopgap measures but they can buy you a little time if needed.

Good luck and let us know when its fixed.

[Ira]

Thanks, I may try those tricks for the short term. It's looking like around $120 to get all of the stuff (boots, o-rings, and clamps) from Boulevard Suzuki.

Anyone have a better price?

[cowboyup3371]

Orings from www.cycleorings.com are pretty cheap - only $4

[Ira]

Orings from www.cycleorings.com are pretty cheap - only $4

Thanks for the tip; I ordered a set of rings and new fasteners.

[Ira]

I ordered boots from Boulevard Suzuki this week, and the o-rings are arriving tomorrow.

[Ira]

These came off with an impact driver and a little persuasion. Looks like I found the vacuum leak

[koolaid_kid]

Actually, the leak is at the o-ring. The plastic covering has nothing to do with it. But it is always good to have fresh boots on a 30 year old bike.

[Ira]

I can definitely peel the rubber from the metal with my fingers, and I'm pretty sure that's bad.

[Ira]

I installed a new set of carb boots, along with new viton o-rings and stainless allen hardware.

Everything went together easily, especially the way the carbs clamped into the new boots. Luxurious!

I had previously sized-up my idle jets (due to my ignorance of the air leak) so I went back down a size before installing the carbs.

I warmed up the bike and rode around the neighborhood for about 15 min. I intentionally came to complete stops and released the throttle, trying to copy the behavior that would stall the bike in the past.

I couldn't get it to stall!

The idle is a bit rough, so I'm going to readjust the mixture screws and do a vacuum sync, but doing a very basic form of maintenance fixed a very annoying problem!

[tom203]

Great and thanks for update- it's sure to help convince others with similar problem.

[Ira]

Update: I rode this bike to Milwaukee and back and after a good half hour of riding, the idle issues were back. Bike seemed to run great in the mid and high revs, but coming down to idle it was rich - burbling idle, fuel smell, stalling and backfiring.

I got home and tried to adjust the mixture screws with no luck. I went through the carbs and made sure the passages were all still clear, and sized the idle jet down to stock. I could not adjust the air screws to a steady idle, and the bike wanted to stall most of the time.

The idle was still showing rich characteristics, which makes no sense with the stock idle jet and aftermarket K&N filters.

While I had a plug out, I checked the spark against the engine case, and it looked bad. It seemed reasonable the coils were not doing their job, and the fuel mixture was not fully combusting. Does that make sense?

[koolaid_kid]

Please define "looks bad". Was the color not blue or white, but red or yellow instead? Was it intermittent? What color was the plug tip, center electrode and ceramic?
Let us know, please.

[BigD_83]

What is the voltage at the coils?

Have you had a chance to go through the electrical? You should have less than 1V drop at the coils compared to your battery voltage.

How are your plug caps and leads? What resistance readings do you get across them?

[Ira]

Please define "looks bad". Was the color not blue or white, but red or yellow instead? Was it intermittent? What color was the plug tip, center electrode and ceramic?
Let us know, please.

The spark isn't quite red, but definitely purplish. Not a fat, healthy blue.

The plug looked like the mid-range was optimal, but the high and idle are rich. I haven't noticed any real high rpm issues though.