Engine Problem/Almost Wiped Out

int15

Well-known member
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Hi,

Something really unpleaseant happened yesterday. I was out riding when I started feeling the engine lagging. It was behaving like I was opening and closing the throttle, but I made sure to keep it at a "static" position. A little later, things got worse. The engine was running at really low RPMs, so I downshifted to get the engine to rev up. That didn't work so well: Instead the engine stalled. The back wheel locked up and started to skid side-to-side.

I was able to control the skid and pull over to the side of the road, but the bike wouldn't start again. I waited a few minutes, turned the petcock to reserve and got it to start (there's a half tank left). I made my way home with the bike running really sluggish and stalling two more times. I just repeated that sequence and made it back in the garage.

I also noticed that the bike now idles around 2000 RPM! That's almost double what it used to idle at. Might be a red herring, but I can swear I could smell gas in the garage all week.

Here's the setup:
- The bike is fresh out of the shop for spring maintenance
- Oil is new, not even 70KMs on it
- Gas is new Esso Ultra (no fuel stabilizer left in the tank)

Any hints would be greatly appreciated. I don't really feel comfortable to ride it to a shop considering I almost wiped out.

Thanks.
 
Are you riding with the choke on?
 
No, the choke was completely shut off.
 
No, the choke was completely shut off.

It sounds like it might be a weak battery? (Mabey) I found that my bike would get harder and harder to start and would only idle high. It would seem your bike is getting gas or it would not run at all. Test your battery first. It's quick to do and you can just eliminate that as a problem right away.

Sent from my Nexus One using Tapatalk
 
Check that the choke really is off (not just at the lever). The cable may be sticking.


/rs
 
Do those bikes have a tps sensor on the carb?
I had to google it, but according to this post on GSTwins, it looks like it does have one.

Check that the choke really is off (not just at the lever). The cable may be sticking.
Good point, another thing to check this week.

Thanks for the pointers!
 
Did you drain the carbs before storage? Are those screws tightened back up?

No. I put fuel stabilizer in the tank and went for a ride to run the mix. Sorry, not sure what screws you're talking about. But the carbs were adjusted as part of the spring maintenance.

Thanks.
 
Does the shop receipt list what was done? It could be a poor adjustment to the idle mixture screw. If it just came out of the shop, I'd give them a call/take it back.
 
Does the shop receipt list what was done? It could be a poor adjustment to the idle mixture screw. If it just came out of the shop, I'd give them a call/take it back.

I probably should give them a call, but I made sure I looked at the RPM at idle. It has been between 1100 and 1300 since the maintenance. Before, the engine would idle around 900-1000.
 
Could be a sticking float valve, that would explain the gas smell as the engine loads up with fuel.
 
Make sure the fuel tank is venting properly ... Make sure the vent hose isn't kinked.

Start the engine and ride/run it until it displays the symptoms, then switch it off and quickly open the fuel cap. If you hear a strong suction sound (or if you can't get the cap open!) you have a tank-venting issue.
 
Does the shop receipt list what was done? It could be a poor adjustment to the idle mixture screw. If it just came out of the shop, I'd give them a call/take it back.

Agreed. Had an issue maybe similar to yours - bike would lag and just cut out if gave it too much throttle. Adjusted my idle mixture. Think my mix was too rich - once had it reset properly I.e. Idle RPM when warmed up - bike runs fine now.
 
sounds like the battery, one night my gs500 kept stalling on me randomly, as the night went on the lights flickered and 1st gear was really jerky, as if the throttle was on and off. it also died randomly when idled. gave the bat a full charge and it was fine from then on. give it a try
 
Could be a sticking float valve, that would explain the gas smell as the engine loads up with fuel.

I'm afraid checking this is outside my current skill set.

Make sure the fuel tank is venting properly ... Make sure the vent hose isn't kinked.

Start the engine and ride/run it until it displays the symptoms, then switch it off and quickly open the fuel cap. If you hear a strong suction sound (or if you can't get the cap open!) you have a tank-venting issue.

Easy enough to test. I'll give it a try.

sounds like the battery, one night my gs500 kept stalling on me randomly, as the night went on the lights flickered and 1st gear was really jerky, as if the throttle was on and off. it also died randomly when idled. gave the bat a full charge and it was fine from then on. give it a try

Mmmm, the symptoms are similar. Makes me hopeful this is the case, as it can be replaced easily (by me) if the battery is not keeping it's charge. I didn't notice flickering light as this happened in full sun. Anyhow, I hooked up the battery to my tender this morning.

Thanks everyone, I'll try to go through all the suggestions I can do myself. The bike has always been reliable since I got it. It needs some "love" starting in cold weather, but once warmed up it runs (well used to) like a charm.

Much appreciated guys.
 
Make sure the fuel tank is venting properly ... Make sure the vent hose isn't kinked.

Start the engine and ride/run it until it displays the symptoms, then switch it off and quickly open the fuel cap. If you hear a strong suction sound (or if you can't get the cap open!) you have a tank-venting issue.
was just about to suggest this ... seems similar to what a friend experienced on there bike years ago ...
 
why are you running ultra (assuming ultra 94) in a gs500? it calls for 87.
 
why are you running ultra (assuming ultra 94) in a gs500? it calls for 87.

I know. It was a tip from the mechanic, about trying to avoid ethanol in the gas. I was thinking the octane might be too high. I can siphon the tank and use it in my car and run some regular as I always did.
 
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