GPz 500S Fuel tap problem

[Chris45]

Got the fuel tap off and stripped down to replace perished rubbers, however I notice there is meant to be a small spring mounted behind the diaphragm and mine didn't have it! Can I replace the diaphragm and put the fuel tap back together without the spring, or is it essential to the working?

[Kickstart]

Hi

Yes it pretty much is essential if you want it to work as a vacuum fuel tap. The vacuum pulls the piston to allow fuel to flow, and the spring returns the piston when the engine is switched off, cutting the fuel flow off

All the best

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

[Rogerborg]

Aside, what's the big deal about vacuum taps? Thinking back, I've had three manual taps, none of which I ever turned/turn to off, and none of which have resulted in flooded carbs.

I mean, if the theory is that carb floats can stick and flood, then a vacuum tap can break too - i.e. you might take yours apart and find that the spring was already missing...
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Chris45]

[RhynoCZ]

When I had the GPz550 (vacuum tap), I was specifically told to turn it to the OFF position anyway, as many members of the GPz550forum had flooded engines in the past. There was no fuel filter, but the metal mesh in the tank. If you tried to fit a fuel filter into your line, you pretty much soon enough found out it was too restrictive and the engine had fueling issues at high speed.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Kickstart]

[Rogerborg]

[davebike]

GPZ500 is well know in the trade for flooding It's carbs don not cope well with constant fuel pressure and no usage when engine not running
If you cannot get the vacume tap to work properly fit an in line tap on the feed to the carbs and use it
____________________
Dave
NC750Xdct + others at work !
davebike1@gmail.com

[Chris45]

Thanks for the replies everyone. Agreed, I have to persist with the vacuum kit. Apparently ScrewFix supply boxes of extension springs, assorted sizes, so hopefully I can get a correct match and tension for the diaphragm.

Chris
Inverness

[Kickstart]