Cutting out

[Keeper96]

Hi all, 

took my gsx600f for a decent run out today and all felt well until it suddenly went flat then cut out on the way home. 
I tried restarting it and it would start hesitantly then run but as soon as I let go of the throttle it would cut out again. 
 

I got recovered home and did some digging, I’ve checked the reg/Rec and it’s holding steady at 14.8v at around 4K rpm so I think that is okay? 
 

I checked the inline fuel filter and the in tank fuel filter, both look okay however the inline filter was empty when I first checked so I checked the fuel tap and that is working, no fuel through till I sucked on the vacuum line. Only thing I did notice is that the vacuum line at the tap end was slightly loose so I’ve added a jubilee clip to that just incase. 
 

ive got the bike running again but had to use the idle screw to hold the revs at around 1100 where it’s always idled. 
 

it’s sounding a bit rough now when it runs but I’m out of ideas. 
 

Can anyone point to why it may have cut out, why I’ve had to readjust the idle and why it sounds rough? 
 

could it be worth throwing some redex through it? 
 

the bike stood for 18 months but since putting it back on the road I’ve done 96 miles until it died on me so in my head the carbs etc. Won’t be clogged with varnish? 
 

I’m a fitter by trade but I work on diesels so petrol and carbs is all new to me! 
 

thanks 

 

Jamie 

 

[onesea]

Sounds to me like fuelling issue.

Particularly fuel filter being empty. Loose vacuums line could do it, on my trophy putting the fuel tap on reserve or prime negates the peticock valve leaving it open.

If the bike has sat idol how fresh is the fuel?

I would add a fuel additive. I used quicksilver a marine brand recently, it worked for my bike. 

You could have a bit of moisture in the tank, or crud in carbs.

So try vacuum line and fuel additive, or strip and clean carbs...

Edited December 15, 2020 by onesea
Typo

[Keeper96]

1 minute ago, onesea said:

Sounds to me like fuelling issue.

Particularly fuel filter being empty. Loose vacuums line could do it, on my trophy putting the fuel ratio on reserve our prime negates the peticock valve leaving it open.

If the bike has sat idol how fresh is the fuel?

I would add a fuel additive. I used quicksilver a marine brand recently, it worked for my bike 

You could have a bit of moisture in the tank, or crud in carbs.

So try vacuum line and fuel additive, or step and clean carbs...

Thanks for the input, I’ve reattached the vacuum line with a jubilee and I’ll try some additive tomorrow for the effort it takes. 
really want to avoid stripping the carbs

[WD-40]

If the in line fuel filter was empty I think the problem has to be before that filter not after it. Could be a kinked vacuum hose not allowing air into the tank, blocked fuel tap, corrosion on the vacuum side of the fuel tap, split vacuum line, blocked fuel filter in the tank, something like that. Is the fuel level low? Can you switch it onto reserve and see if it's better? Is it old fuel in the tank?

Edited December 15, 2020 by WD-40

[iangaryprice]

GSX600f should have a prime setting on the fuel tap marked "PRI" in this position the fuel will flow without vacuum.

Try it on this setting, if it now runs OK, the problem is in the tap. Try commecting a fuel line to the tap and see of fuel flows freely, first in the prime position, then try in the "main" and "res" positions. You will need to attach a pipe to the vacuum and suck on it to make fuel flow.

Are you sure you just didn't run low of fuel. From full my GSX600F can be onto reserve between 120-160 miles, reserve is about 5 litres.

[Keeper96]

13 minutes ago, WD-40 said:

If the in line fuel filter was empty I think the problem has to be before that filter not after it. Could be a kinked vacuum hose not allowing air into the tank, blocked fuel tap, corrosion on the vacuum side of the fuel tap, split vacuum line, blocked fuel filter in the tank, something like that. Is the fuel level low? Can you switch it onto reserve and see if it's better? Is it old fuel in the tank?

With the tank removed I sucked on the vacuum hose and had a good flow from the fuel tap,  I’d filled up in the morning from an Esso station and did 40 miles without issue. 
 

I tried on reserve and it was the same, I could start up but it died as soon as I let go of the throttle. 

[Keeper96]

2 minutes ago, iangaryprice said:

GSX600f should have a prime setting on the fuel tap marked "PRI" in this position the fuel will flow without vacuum.

Try it on this setting, if it now runs OK, the problem is in the tap. Try commecting a fuel line to the tap and see of fuel flows freely, first in the prime position, then try in the "main" and "res" positions. You will need to attach a pipe to the vacuum and suck on it to make fuel flow.

Are you sure you just didn't run low of fuel. From full my GSX600F can be onto reserve between 120-160 miles, reserve is about 5 litres.

I’d brimmed it in the morning and only did about 40 miles, I’m confident that the tap is okay. 
 

the only suspect thing I found was the loose vacuum connection on the tap. That would explain why it cut out but not the rough running I now have and the fact I had to adjust the idle speed just to keep it running 

[Bender]

Has it fouled one of the plugs, does it feel like a miss or mixture problem

 

[onesea]

5 minutes ago, Keeper96 said:

I’d brimmed it in the morning and only did about 40 miles, I’m confident that the tap is okay. 
 

the only suspect thing I found was the loose vacuum connection on the tap. That would explain why it cut out but not the rough running I now have and the fact I had to adjust the idle speed just to keep it running 

Loose vacuum hose could be rough running, fuel starvation.

If I recall vacuums increases with revs so Less revs could equal miss fire due to fuel starvation and on the carb losing air to vaccum leak.

If it was running fine 18 months earlier I would look at vacuum & fuel system first.

[Keeper96]

Just now, onesea said:

Loose vacuum hose could be rough running, fuel starvation.

If I recall vacuums increases with revs so Less revs could equal miss fire due to fuel starvation and on the carb losing air to vaccum leak.

If it was running fine 18 months earlier I would look at vacuum & fuel system first.

Definitely a possibility, I’ve only had a few days but it’s been spot on until today haha 

[WD-40]

If the carbs ran dry from the loose vacuum hose maybe one of them hasn't refilled properly and the bike is running on three cylinders now. Try throwing some water on the headers and see if they all dry at the same rate or is one colder drying slower than the others. You could suck on the vacuum line on the tap and then open the drain screws on each carb and make sure you have good flow to each carb

Edited December 15, 2020 by WD-40

[fastbob]

Nothing much to add really . I'll go with it being a kinked vacuum line . This happened on my GSXR when I was a hundred miles from home so it is something that can happen to a vacuum line over time rather than being a result of some work that has been done . I just stuck the tap on Prime to get home . 

[Guest Swagman]

Sounds like blocked carb jets, check you have fuel in the bowls if so you may have fouled up carbs as it has been stood a long while, does it have a tank vent if it is blocked it will stop the fuel running also, try running it with the cap open.

[Keeper96]

I had a spare afternoon so I drained some fuel from the float bowls into a clean container and was greeted by lots of sediment. 
 

seeing this I stripped the fairing etc. Off and removed the carbs to strip them down. 
 

this was a learning curve for me so I pulled off 1 float chamber at a time and removed the float, needle and the jets before turning it over and removing the diaphragm and giving everything a good blast out with brake cleaner and compressed air. 
 

Each component was then cleaned and blown through prior to reassembly. 
 

with the carbs back on the bike took a while to start and was spluttering and stalling again so I wasn’t sure if I’d done something wrong but a bit of perseverance and playing with the choke had it running again and it now isles and revs smoothly. I can only assume that it took a little while for the carbs to refill with petrol? 
 

Tomorrow I’ll go for a local ride so I’m in within pushing distance of home just to make sure it’s all okay before venturing further. 
 

 

 

[bonio]

The sediment might have come from the tank. When you get a chance, might be an idea to drain it out.

[Guest Swagman]

2 hours ago, Keeper96 said:

I had a spare afternoon so I drained some fuel from the float bowls into a clean container and was greeted by lots of sediment. 
 

seeing this I stripped the fairing etc. Off and removed the carbs to strip them down. 
 

this was a learning curve for me so I pulled off 1 float chamber at a time and removed the float, needle and the jets before turning it over and removing the diaphragm and giving everything a good blast out with brake cleaner and compressed air. 
 

Each component was then cleaned and blown through prior to reassembly. 
 

with the carbs back on the bike took a while to start and was spluttering and stalling again so I wasn’t sure if I’d done something wrong but a bit of perseverance and playing with the choke had it running again and it now isles and revs smoothly. I can only assume that it took a little while for the carbs to refill with petrol? 
 

Tomorrow I’ll go for a local ride so I’m in within pushing distance of home just to make sure it’s all okay before venturing further. 
 

 

 

Have you cleaned out all the jets, this is the problems you get when bikes are laid up for a long time.

[Keeper96]

10 hours ago, Swagman said:

Have you cleaned out all the jets, this is the problems you get when bikes are laid up for a long time.

I think so, took the float bowls off and there where 3 things I’d identify as jets, all removed with a screwdriver and had small holes drilled straight through?

they all got blasting with brake cleaner and blown through with an air line

[Trooper74]

I've had similar symptoms on 2 of the bikes that turned out to be a blocked tank vent, the vent through the fuel cap ...

[Guest Swagman]

56 minutes ago, Keeper96 said:

I think so, took the float bowls off and there where 3 things I’d identify as jets, all removed with a screwdriver and had small holes drilled straight through?

they all got blasting with brake cleaner and blown through with an air line

Nice one hopefully that will sort it out.