preface: this is my first post here so if this question has been asked/answered a million times already, apologies and kindly point me to the right thread.


Okay, Ill try and keep this short. I bought a 2005 F a year or so ago and it had about 8k miles on it. It now has about 10.5k and I've noticed a few things that are hopefully all interconnected.

First symptom: Occasionally when in a higher gear (typically on the freeway) and coming to a slow/stop I will pull the clutch in and instead of dropping down to idle it will completely die. And not die as if it sputtered or tried to stay alive, but as if I was driving and hit the kill switch. High revs, pull the clutch, drop to 0. Just like that. (Of course I'm on the freeway and watching this makes my heart-rate triple but so far I've been lucky and managed to either pop the clutch off quickly and "roll start" it, or have just hit the starter and it will start up again).

Second symptom: Basic clutch slipping. Sometimes I'll be cruising down the road (any speed really) and it will slip into a lower gear. I've noticed it happens more often when I've just shifted up but it has certainly happened in the blue when I haven't switched gears for quite some time (10-20 minutes of freeway riding).


Any help would be greatly appreciated! I really hope I can just replace the clutch plates or make a clutch cable adjustment and I'll be set! But generally I'm not that lucky when it comes to things like this.
Also note that in May of this year I had the carbs professionally cleaned so it likely has nothing to do with those (not that any signs were pointing that way, but still...).

Quote from: FreshGroundPepper on August 12, 2013, 02:12:38 PM

Second symptom: Basic clutch slipping. Sometimes I'll be cruising down the road (any speed really) and it will slip into a lower gear.

Do you mean your riding in 4th gear and all of a sudden the bike pops down into 3rd on it's own?

Hmmm.. First thoughts...

The puling in clutch and dying makes me think of tight valves. So, last valve check? 

The other sounded like you need try a 3 point clutch adjustment. 

- Bboy

When did the problem start?

The clutch doesn't do anything electrical to kill the bike. It has a safety switch, but that is just in series with the starter button.

One thing that will kill a bike is the side stand and neutral switch safety circuit. If your side stand is not up all the way or is bouncing, the bike can die because you can't be in gear with the side stand down.
Probably not that since you can bump start it while you're still moving. Still, good idea to check the side stand and be sure it stays up. You can bend the pin that holds the spring to get it to stay up tighter.

Does bike have normal power? What about when going on side streets? If weak or low on power, you might be running on one cylinder or the carbs are not synced correctly and you're running 75% one cylinder and 25% the other. That might cause a die at high speed as the momentum of the bike would keep a weak engine running until the clutch pulled in.

Possibly the floats are low so you have fuel starvation on the highway when fuel demand is high.

Did the problem start around the time the carbs were cleaned?

Quote from: Slack on August 12, 2013, 02:38:01 PM

Quote from: FreshGroundPepper on August 12, 2013, 02:12:38 PM

Second symptom: Basic clutch slipping. Sometimes I'll be cruising down the road (any speed really) and it will slip into a lower gear.

Do you mean your riding in 4th gear and all of a sudden the bike pops down into 3rd on it's own?

Yeah exactly like that.

Quote from: BockinBboy on August 12, 2013, 02:40:20 PM
Hmmm.. First thoughts...

The puling in clutch and dying makes me think of tight valves. So, last valve check? 

- Bboy

Never that I'm aware of. I bought it a year ago, have only been riding it regularly since about April and have only taken it in for a carb clean in May.

Quote from: adidasguy on August 12, 2013, 02:48:01 PM
When did the problem start?

The clutch doesn't do anything electrical to kill the bike. It has a safety switch, but that is just in series with the starter button.

True but it's not as though something was hitting a kill switch, it's as though it thinks it's in neutral when I pull the clutch but is actually in gear so it dies.

Quote from: adidasguy on August 12, 2013, 02:48:01 PM

One thing that will kill a bike is the side stand and neutral switch safety circuit. If your side stand is not up all the way or is bouncing, the bike can die because you can't be in gear with the side stand down.
Probably not that since you can bump start it while you're still moving. Still, good idea to check the side stand and be sure it stays up. You can bend the pin that holds the spring to get it to stay up tighter.

I can try but I've never had any issues like that in the past. I've never needed to re-kick the kickstand up if it wouldn't start or something along those lines.

Quote from: adidasguy on August 12, 2013, 02:48:01 PM
Does bike have normal power? What about when going on side streets? If weak or low on power, you might be running on one cylinder or the carbs are not synced correctly and you're running 75% one cylinder and 25% the other. That might cause a die at high speed as the momentum of the bike would keep a weak engine running until the clutch pulled in.

That's certainly a possibility though I'm fairly certain they were synced when I had them cleaned in May. As for the side-street/lower power question, I'm not 100% certain but I believe it has happened before on normal roads (i.e. not the freeway), the high speed/power may not have anything to do with the issue.

Quote from: adidasguy on August 12, 2013, 02:48:01 PM
Possibly the floats are low so you have fuel starvation on the highway when fuel demand is high.

That might be the issue for freeway riding? But goes against the last answer I just gave of this occurring on side-streets. Either way, is there a fix for this? Even if it's just driving change?

Quote from: adidasguy on August 12, 2013, 02:48:01 PM
Did the problem start around the time the carbs were cleaned?

No, before. That's actually the reason I had them cleaned as I thought that might help resolve the issue.

Possible dirty gas cap vent. To test that idea: ride with the cap loose. If no issues, then the cap vent is dirty not allowing air into the tank.

Possible dirty fuel filter screen. Look down in the tank and look for it at the bottom left side. Can try getting some dirt off of it when you fill with gas: squirt the gas down there to the left to try to flush off the stuff.

Possible water in tank. Ethanol separating if bike not ridden much. Old gas is bad. add good fuel additive like SeaFoam to help get it out of the tank. You can drain carbs in case there is stuff in them.

Possible dirty frame petcock. You can try running in reserve and prime. If one works better, then you can clean out the frame petcock. Turn off gas under the tank first. Then usually easier to remove the frame petcock and clean it on your work bench. Remove metal clip noting how things fit as you take it apart. Clean all passages and careful not to poke in and puncture the diaphragm. Reassemble and you should not have petcock problems.

OK. There are 4 possibilities.

Oh, dirty or missing air filter? any hoses missing off the air box (air box drain, valve cover vent hose?)

Quote from: adidasguy on August 12, 2013, 03:37:06 PM
Possible dirty gas cap vent. To test that idea: ride with the cap loose. If no issues, then the cap vent is dirty not allowing air into the tank.

Possible dirty fuel filter screen. Look down in the tank and look for it at the bottom left side. Can try getting some dirt off of it when you fill with gas: squirt the gas down there to the left to try to flush off the stuff.

Possible water in tank. Ethanol separating if bike not ridden much. Old gas is bad. add good fuel additive like SeaFoam to help get it out of the tank. You can drain carbs in case there is stuff in them.

Possible dirty frame petcock. You can try running in reserve and prime. If one works better, then you can clean out the frame petcock. Turn off gas under the tank first. Then usually easier to remove the frame petcock and clean it on your work bench. Remove metal clip noting how things fit as you take it apart. Clean all passages and careful not to poke in and puncture the diaphragm. Reassemble and you should not have petcock problems.

OK. There are 4 possibilities.

Oh, dirty or missing air filter? any hoses missing off the air box (air box drain, valve cover vent hose?)

I will look/try all those tonight after I get home! I'll report back tomorrow!
Thanks again.

Quote from: FreshGroundPepper on August 12, 2013, 02:12:38 PMOccasionally when in a higher gear (typically on the freeway) and coming to a slow/stop I will pull the clutch in and instead of dropping down to idle it will completely die. And not die as if it sputtered or tried to stay alive, but as if I was driving and hit the kill switch. High revs, pull the clutch, drop to 0. Just like that.

When this happens to me it's usually because I left the choke on after the engine warmed up.  Are you sure the choke lever is all the way forward AND that the business end of the cable is attached correctly?  I'm wondering if it's always under a little tension.... 

Quote from: Kerry on August 12, 2013, 05:58:28 PM

Quote from: FreshGroundPepper on August 12, 2013, 02:12:38 PMOccasionally when in a higher gear (typically on the freeway) and coming to a slow/stop I will pull the clutch in and instead of dropping down to idle it will completely die. And not die as if it sputtered or tried to stay alive, but as if I was driving and hit the kill switch. High revs, pull the clutch, drop to 0. Just like that.

When this happens to me it's usually because I left the choke on after the engine warmed up.  Are you sure the choke lever is all the way forward AND that the business end of the cable is attached correctly?  I'm wondering if it's always under a little tension.... 

I usually ride with the choke on for quite a while because my bike takes so long to warm up (and therefor, obtain the ability to sit at idle with 0 choke). I can confirm that this symptom happens when the choke is still on.

Is there some reason why my bike would take so long to warm up? I've had the choke on to keep the thing idle at about 3k for as long as half an hour before I feel comfortable taking the choke off completely.

Well I went to check the air filter and found a hose not connected to anything... is this normal? Maybe my preface in my OP should have added that this is my first bike and I don't really know what I'm doing when it comes to repairs. The end that wasn't connect didn't have any fluid on it and looked dry so I didn't just do that when taking the tank off. It did have a little connector piece that was used to attach to the air filter screws to keep it in place

Here's what it looked like when I lifted the tank



This is the other end (it's connect to the 'T' in the middle of the picture (background)



Highlighted in red

Yeah that hose is your carb vent tube. Doesn't connect to anything, but it should be routed to terminate between the airbox and battery, out of the wind. If wind catches that tube, it will slow fuel flow to the carbs. So just make sure it gets routed there when you button it back up and ensure it doesn't get kinked or pinched.

Sounds like you been having hard starting issues which is another tell tale sign for tight valves. I'd get those checked ASAP.

Kerry did bring up an prime possibility though. If the bike is on choke or partially choked once warmed up, it will want to stall or die when he clutch is pulled. This is typically paired with rough idle in neutral with the same conditions though, but not always. Make sure your choke cable isn't getting caught up and the mechanism is working properly at the carbs.

- Bboy

If you "feel the need" to ride your bike on choke, I suspect your idle revs are set too low.
Turn the idle screw a bit clockwise.

I for example turn the choke down as soon as the bike starts up (ok, maybe five or six seconds later), even on the coldest day.

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I never recommend leaving your bike idling on choke at 3k! I start my bike up on choke and set it to 1500rpm then ride for a couple of minutes then turn it off.

It sounds like your valves need adjusting and possible carb clean/sync but you can't adjust the carbs until the valves are in tolerance.

As for clutch slip, it wont cause the bike to change gear, it will cause the revs to rise and the bike to not accelerate proportionally to the revs. Seems like you have a gear selector fork issue or some other gearbox issue.

Quote from: mjj4 on August 13, 2013, 03:23:03 AM
I never recommend leaving your bike idling on choke at 3k! I start my bike up on choke and set it to 1500rpm then ride for a couple of minutes then turn it off.

The GS500 manual actually states full choke at around 3000rpm for 30 secs.

Try setting your idle speed a little higher and getting off choke sooner, should fix your engine dying problem.  Engine can die from choke being on too long as well as from not enough choke to start.

The dropping down a gear problem could be due to gears only being partially engaged.  Work on making positive full stroke movements of the shift lever every time you shift.

Wow this is starting to make sense now! Awesome. Then I suppose I should mention my bike does seem to run quite poorly cold, I would turn the choke off after only a minute or two but I have done that in the past and it just falls down to normal idle but then dies. I would set the idle higher but when the bike has warmed up (after about a half hour of 3k rpms...) I'll turn the choke off and the idle is fine. Should I just up the idle even though it runs okay at the current setting when it's warmed up? Currently it is set at about 1.2k

Thanks for everyone's help!

Hm, 1200 rpm ought to be just fine.
There must be something else.

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If it is indeed a valve adjustment, would that cause it to run so poorly cold but then run fine once its warmed up? And would it also cause it to take forever to warm up?

If the exhaust valves are tight, yes. They'll loosen up a bit as it warms up. They'll also make it seem like it takes longer to warm up, when it's really just not exhausting properly and bogging down the motor.

Quote from: JAS6377 on August 13, 2013, 09:09:42 AM
If the exhaust valves are tight, yes. They'll loosen up a bit as it warms up. They'll also make it seem like it takes longer to warm up, when it's really just not exhausting properly and bogging down the motor.

+1 

Thanks for covering that for me... was on my phone when I was replying earlier and was hard to get everything explained from my phone.

- Bboy