Fuel Cock Troubles

[Spamulaspam]

Hi guys and gals.
Have recently managed to get hold of a GZ250 after upgrading from a GZ125. After riding it home I noticed the idling speed was all over the place. Anyhow, to cut a long story short the fuel cock is not restricting fuel flow and is still free-flowing when in the on and reserve position.
As parts are very hard to find in England, I was wondering if anyone knows if any other fuelcock from another motorcycle fits the GZ?

[jonathan180iq]

The petcock for the 125 and the 250 are the same, aren't they?

I know it's the same fuel tank. Should be the same petcock. Is the 125 easier to get a hold of?

Either way, since you say the petcock is flowing properly, then it's not your problem.
Check for vacuum leaks in the hoses that run from the back of the carb into their little ports. Also check the "S" hose that runs from the crank case to the air box.

Finally, make sure you have a good clean carb. And if none of that works, maybe check your valve adjustment.

Is the bike hard to start when it's cold?

[Spamulaspam]

Thanks very much for your swift reply.

No, unfortunately the 125 Petcock and the 250 are different. The 125 does not use a vacuum hose and the fuel just runs freely into the carb. I wish they were the same as it would certainly make things a little easier as I still have hold of my 125!

I maybe did not make things clear enough on my last post. The petcock is running freely when the hoses are disconnected. It is my understanding that fuel should only run through when the engine is running and when disconnected the fuel flow should stop as it makes it easier to remove the petrol tank without draining all the fuel.

Have removed the petcock and low and behold the "smiley face gasket" (dont know the technical term, excuse me im female :whistle: ) is a little shredded and is leaking fuel into the prime outlet on a permanent basis.

I was wondering if any other petcocks fit the GZ250 or does anyone know the part number for the "smiley face gasket" and if indeed can you actually buy them without having to purchase a complete assembly?

[blaine]

You are correct if the petcock is in the "run" position,if the petcock is in the "pri" position the fuel can run all the time.
:) :cool:

[Spamulaspam]

Yeah, the tap was in the run position.

Parts are so hard to find in the UK for the 250 but they are 10 a penny for the 125 :(

[blaine]

If it fits,you can use the non-vacuum (125 petcock).You would just need to remember to shut the fuel off when you shut the bike off.The (250 petcock) does the work for you by shutting the fuel flow off.You would also need to plug the vacuum line.
:cool: :)

[Spamulaspam]

Hmmm... Thats certainly something to think about if all else fails. Thank you very much.

I would much rather replace the gasket though if I could find one as I know I would probably forget and leave the fuel turned on :whistle:

Just wish I knew if any other motorcycle petcock gaskets fitted the GZ as I could probably find one on Ebay over here. The GSF 600 one looks very similar on picture but im not sure of the dimensions and I dont want to waste money purchasing one and finding out it doesnt fit.

[Water Warrior 2]

You could do a search on Ronayers.com in their micro-fiche section. You may find a matching part # from another bike that is fairly common in your area.

[Spamulaspam]

Thanks Water Warrior.
I'll check that out now.

[Road_Clam]

If it fits,you can use the non-vacuum (125 petcock).You would just need to remember to shut the fuel off when you shut the bike off.The (250 petcock) does the work for you by shutting the fuel flow off.You would also need to plug the vacuum line.
:cool: :)

Yup, agreed. and let us reiterate "you need to remember to shut the fuel tap off when the bike parked. " Raw fuel can gravity feed dribble into the cylinder and you can potentially "hydo-lock" the engine attempting to start it. I've see first hand piston connecting rods bend from a hydro-lock !

[Fausto]

The petcock for the 125 and the 250 are the same, aren't they?

I know it's the same fuel tank. Should be the same petcock. Is the 125 easier to get a hold of?

Either way, since you say the petcock is flowing properly, then it's not your problem.
Check for vacuum leaks in the hoses that run from the back of the carb into their little ports. Also check the "S" hose that runs from the crank case to the air box. Finally, make sure you have a good clean carb. And if none of that works, maybe check your valve adjustment.

Is the bike hard to start when it's cold?

Is that 'S' also a vacume hose? I have a problem with my bike too, in the Run positions it dies out after a few min of running, I move it over to prime and it starts up again. I check the hose that goes from the petcock to the carb and it is fine. I am at a loss right now. Close to dishing out some doe and taking it to a shop. Thank you

[Water Warrior 2]

The petcock for the 125 and the 250 are the same, aren't they?

I know it's the same fuel tank. Should be the same petcock. Is the 125 easier to get a hold of?

Either way, since you say the petcock is flowing properly, then it's not your problem.
Check for vacuum leaks in the hoses that run from the back of the carb into their little ports. Also check the "S" hose that runs from the crank case to the air box. Finally, make sure you have a good clean carb. And if none of that works, maybe check your valve adjustment.

Is the bike hard to start when it's cold?

Is that 'S' also a vacume hose? I have a problem with my bike too, in the Run positions it dies out after a few min of running, I move it over to prime and it starts up again. I check the hose that goes from the petcock to the carb and it is fine. I am at a loss right now. Close to dishing out some doe and taking it to a shop. Thank you
Sounds like the vacuum line to your fuel petcock is porous or collapsing. Any auto parts store will have a new vacuum hose. Just take in the old hose as a sample.
The "S" hose is a crankcase ventilation hose and is likely a vacuum hose too. I doubt that it is the problem. Try the new petcock vacuum hose first.

[Fausto]

The petcock for the 125 and the 250 are the same, aren't they?

I know it's the same fuel tank. Should be the same petcock. Is the 125 easier to get a hold of?

Either way, since you say the petcock is flowing properly, then it's not your problem.
Check for vacuum leaks in the hoses that run from the back of the carb into their little ports. Also check the "S" hose that runs from the crank case to the air box. Finally, make sure you have a good clean carb. And if none of that works, maybe check your valve adjustment.

Is the bike hard to start when it's cold?

Is that 'S' also a vacume hose? I have a problem with my bike too, in the Run positions it dies out after a few min of running, I move it over to prime and it starts up again. I check the hose that goes from the petcock to the carb and it is fine. I am at a loss right now. Close to dishing out some doe and taking it to a shop. Thank you
Sounds like the vacuum line to your fuel petcock is porous or collapsing. Any auto parts store will have a new vacuum hose. Just take in the old hose as a sample.
The "S" hose is a crankcase ventilation hose and is likely a vacuum hose too. I doubt that it is the problem. Try the new petcock vacuum hose first.
I will. I already have it removed. I did notice that one end of the hose is larger then the rest of the hose. Thanks Water Warrior.