Reserve Tap not working ZZR250

[ncrn]

Something is wrong with my ZZR250's fuel line. When I switch to reserve it doesn't let fuel through properly the bike jumps and jerks, and dies repeatedly. I've looked into the tank and there is plenty of fuel. The fuel tap is a vacuum tap.

Recently when I took the tank off of the bike the line was pissing fuel out instead of not letting any fuel through like it should.

I've never dealt with a vacuum tap before, so does anyone have any ideas what could be up with it?
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Past: 55 Sym Jet, 91 ZZR250, 03 NSR125R. Present: 97 ER-5.
https://www.nsr125.co.uk - NSR Owners forum.

[Kickstart]

Hi

First guess would be that there is some water in the petrol tank. Water is heavier than petrol so sinks to the bottom of the tank, and only gets drawn in when you switch to reserve.

Last GPZ500 we had was a pain for getting water in the tank.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[ncrn]

I guess that's something that I'll only see if I can get the tank off and the fuel out?
____________________
Past: 55 Sym Jet, 91 ZZR250, 03 NSR125R. Present: 97 ER-5.
https://www.nsr125.co.uk - NSR Owners forum.

[Kickstart]

Hi

Afraid so. And it doesn't take much water to cause a problem.

This is what came out of the GPZ500. Had decanted most of the petrol by the time I took this. The orange stuff at the bottom is water.

https://www.alfa-pages.co.uk/TempPicture/GPZFuel.JPG

If the tank is empty you might be able to just disconnected the fuel pipe, connect a spare length to the tap, stick the other end in a suitable container and turn the petrol onto prime.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[ncrn]

Will give that a go this evening, cheers .
____________________
Past: 55 Sym Jet, 91 ZZR250, 03 NSR125R. Present: 97 ER-5.
https://www.nsr125.co.uk - NSR Owners forum.

[Stelmer]

I just stripped the vaccum fuel tap on my ER5 as it was doing the same as yours.

I found rusty watery residue on the vaccum side of the tap. Cleaned it all out, ensured the wafer thin diaphrams are not ripped and put it all back together. Works like a charm now.

Engine also works better as the vaccum tube is not sucking in extra fuel or air as it now keeps it's vaccum.

[ncrn]

May be a silly question, but are you supposed to remove the fuel line from the tank first or the vacuum line first?
____________________
Past: 55 Sym Jet, 91 ZZR250, 03 NSR125R. Present: 97 ER-5.
https://www.nsr125.co.uk - NSR Owners forum.

[Kickstart]

Hi

With a vacuum tap on the tank it will not matter when the engine isn't running. No running engine means no vacuum, which means no fuel will flow (except on prime).

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[ncrn]

Good news, took the tap off and turns out the filter was just dirty, cleaned it out and its running well. There was a good 5 litres left in there so I wasn't out of fuel.

I need to take it for a ride tomorrow to check if its sorted, will report back when I know.
____________________
Past: 55 Sym Jet, 91 ZZR250, 03 NSR125R. Present: 97 ER-5.
https://www.nsr125.co.uk - NSR Owners forum.