Yamaha TRX850 Enthusiasts Forum

This is becoming more of a problem as time goes by.
The TRX fuel tap was never good, not even from new.
Now it is becoming not only a problem but in some cases a very expensive one.
I was very lucky that my cylinder full of fuel only caused a compression lock and didn't end up in disaster like Dave's.
I've made what I consider to be a temporary fix by replacing the tap internals, but as these are all crap anyway I'll not be trusting this long term.
The fuel pump and float valve needles may also come into play during a leak situation, but any problems with these become moot if the fuel tap does not leak in the first place.

What is the general consensus for a replacement fuel tap that does not leak when in the no vacuum position, or a complete On/Off/Res type replacement.

I replaced mine with an on/off/reserve one, and I leave it set to on or reserve all the time without issue. As you say though the float valves come into play.

I replaced it because the old vacuum one didn't work so any time I wanted to take the tank off I had to drain it. They are available on e-bay pretty cheap. The fitting to the tank is a common size across loads of Yamahas, you just need to make sure get one with the outlet on the left and with the same size outlet diametre. Also try to get one with a decent reserve (about 3cm difference between the on and reserve

This is NOT a definitive list but I believe that these bikes all use the same base and tap assembly as they all have the same part number for the internal diaphragm.
The complete tap assembly may have different length Pri/Res assembly but the rest of the parts seems to be the same.
The complete fuel tap assembly is ridiculously expensive, far cheaper (and better) alternatives are available on eBay.

YAMAHA YZF600R 1996
YAMAHA YZF600R 1997
YAMAHA YZF600R 1998

YAMAHA YZF-R6 1999
YAMAHA YZF-R6 2000
YAMAHA YZF-R6 2001
YAMAHA YZF-R6 2002

YAMAHA TRX850 1996
YAMAHA TRX850 1997
YAMAHA TRX850 1999

YAMAHA XJR1200 1996
YAMAHA XJR1200 1998

YAMAHA XJR1300 1999
YAMAHA XJR1300 2000
YAMAHA XJR1300SP 2000
YAMAHA XJR1300 2001
YAMAHA XJR1300SP 2001
YAMAHA XJR1300P (BLACK/BLUE 2002
YAMAHA XJR1300P (SILVER 2002
YAMAHA XJR1300R (YELLOW 2003
YAMAHA XJR1300R (BLACK/BLUE 2003
YAMAHA XJR1300 2004
YAMAHA XJR1300 2005
YAMAHA XJR1300 2006

My tap leaked, so I bought a second-hand one off ebay and rebuilt it with a kit, only to find that it leaked too. Is there a tap available that really works or one that has an off position that fits ?

http://www.ebay.com.au/itm/YAMAHA-XJ750 ... SwrklVZnDS

this should do the job, I replaced mine with one like this without issue

Con Rod wrote:http://www.ebay.com.au/itm/YAMAHA-XJ750 ... SwrklVZnDS

this should do the job, I replaced mine with one like this without issue

Firstly, lads..there is in the origional trx fuel tap, a small O ring that is pulled down by the vacume operated diaphragm inside the tap itself....from the tube that runs from the left inlet manifold.
There will be some fuel in the tap and or tube which might seem like it is leaking,..and might well be leaking if there is grit around the small O ring seal..ive serviced mine a couple of times and found a dust like material that is fine enough to pass the gauze pre filter sock.
Personally, I would be in favour to the base style tap that Con Rod has linked ,..as it would not have the pesky lower tap elbow problem some have had ,..and as long as the vacume line is plugged all,is sweet.
The only down side will be that the bike legally should have an auto shut off fuel system for in case of accident.
Stops fuel flowing over the hot engine.

There is no O-ring in the junction of the spigot to the main tap body.
There never was.
It is a very tight fit and glued into place.
If you put enough pressure on the spigot you can make it turn.
You will then have a fuel leak as you have broken the adhesive that hold the spigot in place.
Either JB weld or similar to glue it back together, or buy a better fuel tap.

dicky wrote:This is NOT a definitive list but I believe that these bikes all use the same base and tap assembly as they all have the same part number for the internal diaphragm.
The complete tap assembly may have different length Pri/Res assembly but the rest of the parts seems to be the same.
The complete fuel tap assembly is ridiculously expensive, far cheaper (and better) alternatives are available on eBay.

YAMAHA YZF600R 1996
YAMAHA YZF600R 1997
YAMAHA YZF600R 1998

YAMAHA YZF-R6 1999
YAMAHA YZF-R6 2000
YAMAHA YZF-R6 2001
YAMAHA YZF-R6 2002

YAMAHA TRX850 1996
YAMAHA TRX850 1997
YAMAHA TRX850 1999

YAMAHA XJR1200 1996
YAMAHA XJR1200 1998

YAMAHA XJR1300 1999
YAMAHA XJR1300 2000
YAMAHA XJR1300SP 2000
YAMAHA XJR1300 2001
YAMAHA XJR1300SP 2001
YAMAHA XJR1300P (BLACK/BLUE 2002
YAMAHA XJR1300P (SILVER 2002
YAMAHA XJR1300R (YELLOW 2003
YAMAHA XJR1300R (BLACK/BLUE 2003
YAMAHA XJR1300 2004
YAMAHA XJR1300 2005
YAMAHA XJR1300 2006

YAMAHA XTZ 750( left side) is an advice from the german Forum.just shorten the reserve thing. The YZF 750 fuel tap is often used For racing purposes.
It's true that is a real problem. Many members from the German forum have the same struggle at the moment including me. If you are going to replace the fuel tap, make sure the lines are long enough, so you can lift up the tank without plugging out the fuel lines.

I've heard that an 2000-2001 YZF-R1 (5JJ) fuel tap is a direct bolt on fit with only on/off positions.

it is. I fitted one to my dads trx last month.

its about a quarter of the size also.

So to clarify, if I remove the original petcock and install one with just on/off.
1.) You then remove all the vaccum lines that would have been on the original?
2.) block off vaccum ports on the carby?

1. Yes. The remove the vacuum hose.
2. Yes. Block the port on the inlet manifold.

Double check to make sure you remove and block the correct hose.

I put a thunderace on/off tap on mine with an electric fuel pump, works well.

Hate to be a pain, but which one is the inlet manifold hose?
Appreciate the quick responses to

02Gsxr1000 wrote:Hate to be a pain, but which one is the inlet manifold hose?
Appreciate the quick responses to

The smallest hose on the fuel tap. Should be on one of the manifolds.
The other vacuum hose one goes from the manifold to the fuelpump, which you still need so leave it (unless you are using an electric fuelpump or somehting).