Stalling after warmed up

[viggen]

Hello all,

I've been enjoying my 04 GS500F for 500 miles or so.  In the last 100 miles, it has begun to stall occasionally when I pull up to lights.  It happened about 4 or 5 times on my 109 mile trip home today.  Always seems to happen during moderate deceleration with the clutch pulled in. 

The bike has 5400 miles on it.  I'm not sure if the valves were adjusted at 4k miles.  I know I should probably just get in there and measure everything. 

I also filled up with 93 octane instead of my usual 89 this weekend for the first time.  This has never been a problem in my cars, but I don't know if the GS has any idiosyncracies when it comes to high octane fuel? 

In my searching since I got home, I've decided to try running with the petcock set on 'prime' next time I take her out.  Also will check out cleaning the tank vent system.

Thanks for any help you can give!
-Ed

[tt_four]

The valves do need checked, but I'd have a hard time believing that a bike with that few miles is stalling just because of the valves.

What type of gas is everyone else here usually using? just for reference. I think I usually go for 91, but I've been trying some different ones, but have had some ongoing problems with my bike anyway, so it's hard to gauge by just the gas.

Also, are you sure your idle is adjusted properly? It may just need turned up a little bit.

[jeremy_nash]

make sure the choke is fully disengaging, I had to adjust mine once for that same problem.  I always use 87 octane, and never had a problem with that.  higher octane fuel is just a waste on our bikes for the most part, as the compression ratio and timing doesn't require it.  and theoretically, the lower octane fuel would generally be fresher, as the majority of vehicles use it as opposed to 93 octane

[viggen]

The choke was pretty sticky when I first got her.  Will definately check that out.  I think the idle is usually about halfway between 1k and 1.5k, so I think it's ok but maybe I'll just turn it up a bit.  Got my Haynes manual on the way.  What RPM should idle be at?

Makes sense on the freshness of the 87 octane.  I'm gonna use this stuff up and go back to regular. 

Thanks for the quick responses!
-Ed

[mister]

Viggen,

Are you saying... as you are approaching a set of lights, you pull in the clutch and Keep it pulled in until you have stopped, essentially just Coasting to a stop?

My opinion is, do Not come to a stop this way. Always change down gears and let the clutch out, before pulling in again and changing down again. This way, your engine is helping you brake - PLUS - you are in the nearest correct gear should you need to suddenly accelerate away.

As for fuel, it isn't just the Octane you need to be concerned with but also the Brand.

In Aust we have three Octane choices - 91, 95 and 98. My MPG is roughly the same on 91 vs 95 (never tried 98) though the bike Sounds different on the different octanes and starts better in the winter on 95 than 91. AND, there is now a growing trend to put up to 10% ethanol in the 91. ALSO, I have found the bike gets worse economy running on Shell fuel. It runs best on BP fuels.

Michael

[viggen]

My opinion is, do Not come to a stop this way. Always change down gears and let the clutch out, before pulling in again and changing down again. This way, your engine is helping you brake - PLUS - you are in the nearest correct gear should you need to suddenly accelerate away.

I agree with you on being in the correct gear to accelerate away as it is also part of the MSF IIRC.  I have a heck of a time doing it smoothly while applying the front brake, but I know that's not an excuse.   Any good tips on getting smoother with this? 

I used to be decent with the heel-and-toe on my Viggen, but that's a completely different appendage.  Also, I decided that braking with half of my foot is fairly irresponsible in many situations.  Different on a motorcycle as your hand is not covered in a shoe 

I know that there are two camps on the engine braking idea in the car world, and I imagine it is the same in the two wheeled domain as well.  Anyways, I'll give it a try tonight when I go out for a cruise.

I've had good luck with Mobil gas in the car, so maybe I'll stick with that on the bike as well?

Thanks for all the replies!
-Ed

[Iroquois]

Stalling at stoplights for me turned out to be a loose clutch cable and dirty air filter. Try those.

[bill14224]

Viggen,

Are you saying... as you are approaching a set of lights, you pull in the clutch and Keep it pulled in until you have stopped, essentially just Coasting to a stop?

My opinion is, do Not come to a stop this way. Always change down gears and let the clutch out, before pulling in again and changing down again. This way, your engine is helping you brake - PLUS - you are in the nearest correct gear should you need to suddenly accelerate away.

As for fuel, it isn't just the Octane you need to be concerned with but also the Brand.

In Aust we have three Octane choices - 91, 95 and 98. My MPG is roughly the same on 91 vs 95 (never tried 98) though the bike Sounds different on the different octanes and starts better in the winter on 95 than 91. AND, there is now a growing trend to put up to 10% ethanol in the 91. ALSO, I have found the bike gets worse economy running on Shell fuel. It runs best on BP fuels.

Michael

I know nothing about gasoline in Australia but this seems illogical.  Octane requirement drops with temperature.  Using high octane gas in a low compression engine can make it hard to start in cold weather, not the other way around.  Our bike has 9 to 1 compression so "regular" gas should be fine if it's of good quality.  If our bike doesn't like "regular" something's wrong with the gas, not the bike.  Here in NY regular has an octane rating of 87 and my bike loves it.  Starts right up every time with no knocks or pinging when it's hot and climbing hills.  High octane gas has only ONE advantage, resistance to detonation.

[mister]

Viggen,

Are you saying... as you are approaching a set of lights, you pull in the clutch and Keep it pulled in until you have stopped, essentially just Coasting to a stop?

My opinion is, do Not come to a stop this way. Always change down gears and let the clutch out, before pulling in again and changing down again. This way, your engine is helping you brake - PLUS - you are in the nearest correct gear should you need to suddenly accelerate away.

As for fuel, it isn't just the Octane you need to be concerned with but also the Brand.

In Aust we have three Octane choices - 91, 95 and 98. My MPG is roughly the same on 91 vs 95 (never tried 98) though the bike Sounds different on the different octanes and starts better in the winter on 95 than 91. AND, there is now a growing trend to put up to 10% ethanol in the 91. ALSO, I have found the bike gets worse economy running on Shell fuel. It runs best on BP fuels.

Michael

I know nothing about gasoline in Australia but this seems illogical.  Octane requirement drops with temperature.  Using high octane gas in a low compression engine can make it hard to start in cold weather, not the other way around.  Our bike has 9 to 1 compression so "regular" gas should be fine if it's of good quality.  If our bike doesn't like "regular" something's wrong with the gas, not the bike.  Here in NY regular has an octane rating of 87 and my bike loves it.  Starts right up every time with no knocks or pinging when it's hot and climbing hills.  High octane gas has only ONE advantage, resistance to detonation.

Bill,

This winter I am experimenting with BP standard (91). Previous winter I used Shell standard and had the problems. I haven't finished my winter testing of Standard BP fuel so cannot fully comment on that.

Oddly, my previous bike ran better on Shell than BP. Though it too started better in Winter on Shell premium than standard.

Michael

[Toledo Jim]

..snip..
I know nothing about gasoline in Australia but this seems illogical.  Octane requirement drops with temperature.  Using high octane gas in a low compression engine can make it hard to start in cold weather, not the other way around.  Our bike has 9 to 1 compression so "regular" gas should be fine if it's of good quality.  If our bike doesn't like "regular" something's wrong with the gas, not the bike.  Here in NY regular has an octane rating of 87 and my bike loves it.  Starts right up every time with no knocks or pinging when it's hot and climbing hills.  High octane gas has only ONE advantage, resistance to detonation.

Bill, In the U.S they measure octane differently, in the U.S. 87 is called "regular", in Australia 91 is called "regular". They are equivalent.