TOPIC:

I've searched here and seen that the standard on/off/reserve fuel tap on my A1/A2 can be replaced with a vacuum tap from a GPZ900 which will prevent leaks when not running.

ebay item 202748477164, cheaply available from the USA

Seems to be some with 34mm hole centres and others with 44mm, these are pattern taps. Is this the best one to use, are they any good?

Also the vacuum pipe, I guess any of the inlets is ok to take a vacuum pipe off of?

Thanks for any help with this.

The GPZ900R petrol tap is a direct fit onto the 1300 tank.
As you say, you do need a vacuum pipe from one of the inlet manifolds to give it the "suck" it needs.
This pipe needs to be minimum 4mm internal and I found it best to come from cylinder 2 so the length of the pipe is as short as possible.
You can also turn the rear square diaphram plate on the rear of the tap so the vac pipe is in a better position to fit.
I would also advise you put a 4mm thick washer at the inside REAR tank mounting, so the tank sits 4mm further BACK on the bike to allow the tap to reach the RES position, as its a bit close to the cam cover in the normal position (see photo below).

I would also cut the inner feed pipe down to 60mm high so its the same height inside the tank as the standard 1300 tap, so reserve comes in at the same level.

I fitted this tap to my own bike a couple of months ago.

Pete F
UK

Baz...................

Just looking at the tap on Ebay USA you have listed in your message above.................Its definitley NOT a GPZ900R tap.
The outlet is in the wrong place and it looks nothing like the correct one, as seen in the link below
www.z-power.co.uk/fuel-tap-gpz900r

Pete F
UK

Thanks Pete, at £75 may as well go for the genuine article.

I read on your other post that you cut the spring, is that still necessary, or is it a try it and see?

Baz,

I found out soon after cutting the spring, that the spring in the rebuild kit I bought was actually longer than the original spring, hence cutting it to the same size.
I have since fitted the original spring and it works a treat !
I have also since tried the tap with 4mm vac pipe from 2 inlets with an inline Y Piece and with only 1 direct pipe and it made no difference at all.

You may need to put it in the PRI position when starting from cold just to fill the float bowls quickly, then onto the ON position once the engines running.
DONT leave it in the PRI position with the engine stopped (especially on the side stand), as your float valves can allow petrol to pass through as the heat from the engine below the carbs decreases, no matter how new your float valves and seats are.!!

Its a very worthwhile mod to do as the standard tap is of prehistoric design and often allows petrol past even in the OFF position. This can result in a tank full of fuel slowly draining itself into your air box and past the pistons into the engine...............so you then have an engine full of oil and petrol the next morning which obviously needs to be replaced.

Pete F
UK

Does anybody know if a genuine new tap is available in the USA today and where?