No power when pulling away

[zedhead]

Hi this is probably a real obvious problem [hopefully]...but here goes.

I have a 1995 GPz500s it will start and idle but when i go to pull away the revs rise to about 2.5k and then all power just dies off. The choke is off and the bike is running smoothly at idle.

I am thinking it's got to be fuel.So i have checked,it has a good supply from the tank.

The choke is shutting off correctly and there has been no signs of misfires or anything before this point.

One thing i did notice on the carbs is that they are joined together with two metal tubes one on the bottom to the floats which has the flexible pipe from the tank connected and supplying the fuel. The other is at the top and seems to connect the two diaghram housings,this also has a flexible pipe which goes nowhere and seems to be a vent is this right ? Or is this a total red herring?

I have also cleaned and checked the plugs.

This problem just surfaced with no warning out of the blue.

Anyone got any ideas?

Cheers Zedhead

[Fozzie]

You should have a bowl drain point which can have a tube coming off it, should have a fuel supply and an overflow which lets extra fuel drip out of it.

The problem sounds like the fuelling is incorrect. Has the bike been stood as it sounds like a carb problem to me.

Do the easy stuff like making sure there is sufficient fuel pressure getting to the carbs, and that there are no blockages in the pipe and filters are all clear and work in.

Get to the carbs and clean them out and make sure none of the jets are blocked up, reset them to a factory setting then balance them.

Thats covered most of the fuelling so if you still have problems after that it gets a bit more tricky

[Tango]

Is the air filter OK? is there anything that could be restricting the air passage into the airbox?

[zedhead]

Fozzie the bowls have drain points on the bottom like most carbs the pipe to nowhere i mentioned is at the top coming of the diaghram housings.But thanks for the thoughts on the fuelling,stripping the carbs may be the way to go. The bike has been stood for a while but has been regulaly and ran perfect at all revs until this problem appeared.

Tango thanks for that idea something i will investigate. I cant help but think this problem is simple [like me] and staring me in the face.

[Tango]

Just be aware of what can happen if your bike is laid up for a while:

http://www.themotorbikeforum.co.uk/view ... hilit=nest

This was from before I owned the bike as I've run it pretty much consistently since getting it......but strange things can happen.....

[Roadtorque]

Hi this is probably a real obvious problem [hopefully]...but here goes.

I have a 1995 GPz500s it will start and idle but when i go to pull away the revs rise to about 2.5k and then all power just dies off. The choke is off and the bike is running smoothly at idle.

I am thinking it's got to be fuel.So i have checked,it has a good supply from the tank.

The choke is shutting off correctly and there has been no signs of misfires or anything before this point.

One thing i did notice on the carbs is that they are joined together with two metal tubes one on the bottom to the floats which has the flexible pipe from the tank connected and supplying the fuel. The other is at the top and seems to connect the two diaghram housings,this also has a flexible pipe which goes nowhere and seems to be a vent is this right ? Or is this a total red herring?

I have also cleaned and checked the plugs.

This problem just surfaced with no warning out of the blue.

Anyone got any ideas?

Cheers Zedhead

 

Don't know the bike or the carb set up,, You say diaphragm housing,, if the carbs are diaphragm controlled then that would be the first thing I would look at , sounds like they're leaking air into the vacuum side,,,,,,,,

[zedhead]

RoadTorque

I checked the diagphrams both are in perfect condition.But if as i mentioned this tube which appears to exit from a metal tube linking the two diagphram housings that may be affecting the running. On the same note what causes the slides which are attached to the diagphrams to move is it a vacuum? if it is then this wayward pipe i have should go somewhere.

[megawatt]

Vacuum pipes should only be connected to a vacuum! So that's the connection at one of the cylinder head inlet stubs, the fuel tap or the carbs. A vacuum pipe should never be open ended!!!

[zedhead]

If it helps the flexible pipe coming out of the diaphgram housing connecter tube is in fact a Carb breather pipe. So should have no bearing on the no power pulling away problem.

as seen here

http://www.ex-500.com/wiki/index.php/Wh ... oses_go%3F

the green pipe

though this knowledge still doesn't get the power coming on again

cheers

[eastanglianbiker]

if it is idleing ok and just wont pull or rev over about 2500-3000rpm then i would say look at main jet in the carbs or the fueling mixture

[zedhead]

Sucess!! after being sidetracked by getting my kids bikes through there MOT's i finally got to strip the carbs down. Both main jets were blocked .Gave it a good clean put them back in and voila! took 10 minutes to start [vacuum petrol tap] then vooom caught and ran perfectly . Took it down the road this afternoon and it ran sweet.

Thanks for all the suggestions, kept me going.

[Tango]

Great news Zed......

Always nice to hear back when a fault is fixed....adds to the collective knowledge here.....

Happy Days......