Poor economy

[Kenny]

I measured my reserve today and its 2.5 litres not the 4 litres as in the manual

[hjp1968]

I am having a horrible time with the fuel tap on my TDR two repair kits and a replacement and it still dribbles like a 90 year old, making it manual would be the best thing, so the million dollar question.....
How did you do it?
Thanks

[Kenny]

Hi Its actually very simple I removed the spring from the vaccum diaphram and replaced it with washers to make sure the o-ring seal sealed the back part of the tap then reassembled the vaccum side. I then removed the tap side retainer ring with the ON-PRIME-RES and simply rotated it 90 degrees clockwise so now ON is forward OFF is down and RES is backwards JOB done it really is that simple.

[Thom]

have you blocked off the vacuum feed from the inlet stub?

Have you got to turn the tank to "off" when you leave the bike, as surely leaving it on will still allow fuel to flow, flooding the carbs and cylinders?

any other points i should know?

[Mincehead]

You must block of any inelt stub vacuum stubs or hoses because if it`s open to atmosphere your bike won`t run, or if it does it`ll only run on the cylinder with a covered / completed vacuum circuit.
Obviously if you are retaining the vacuum operated fuel pump you`ll still need an inlet stub to pump hose plumbed in.

[Thom]

excellent cheers, i had a thought on this remembering the fuel pump. so the fuel pump and tap are vaccuum operated - if i make the tap manual i have to block off that vacuum circuit, however the pump will still require one. Yes?

So simply cap the fuel taps stub at the inlet.

Next, fuel will still be able to flow from the fuel tap when on or reserve however i wont need to turn it off when the bike is not in use as fuel cant flow beyond the fuel pump without the engine turning over and creating the vacuum neccesary for fuel to flow, so the tap can remain on at all times when not in use, theory correct?

Cheers

[Mincehead]

Yes you`ve got it.
A small piece of silicon tube and a stainless set screw small enough to fit snugly with a little silicon sealer on it easily blocks off the unused inlet stub, especially if you keep the silicon very short, just long enough that the screw doesn`t chatter against the brass stub inside the tubing.
You can watch the tubing and screw being pulled repeatedly and released again towards the stub as the engine takes `breaths`, so it must be allowed some movement but not be long enought to fall over and become flattened which will lead to it splitting eventually along the line of the flattened section in it.

Edit:

Me personally, I wouldn`t rely on the vacuum fuel pump to not allow any fuel past, it`ll make its way into the left hand (IIRC when sitting on the bike) inlet stub. Then fuel will sit against the inlet valves and if you`ve got valves that are not seating efficiently, which is very likely between top end rebuilds, creep past the valves and seats to `wash` the bore of lubrication. NOT GOOD especially on initial start up!
I always turn my fuel taps to off, but being brought up on British iron it`s habitual with me.

[Thom]

if this was facebook i would like your post

Thanks!

I shall give this a try in my efforts to finally right all the wrongs with this damn yamaha.

[Thom]

just another thought for kenny - are you sure you rotated the on/prime/res thing through 90degrees? if so how did you mount it, or do you mean 180 or is there some other fabrication i should know about?

Thom

[Mincehead]

You`re welcome Thom.

[Kenny]

No I turned it through 90 degrees and I had to file a small amount off the plate that says on res etc so the retaining screws could hold the plate in place. Next time I have a chance I will take a pic for you. I do also turn the fuel off everytime I stop the egine its a habit I have anyway so no hardship there. I also left the vac pipes all connected as per normal even though they do nothing for the fuel tap as it as easier.

[Thom]

cheers kenny, ive got washers in the tap now and its nice and tight, i cant blow through the fuel outlet at all so i can only assume there is no air getting in or out!

now i just need to modify the plate to work as an on off tap, i will have a look at this now!

Thom

[alextrx850]

any chance of a step by step procedure with some good photos so we can have a good handle on this mod..i am thinking that with the onset of age on these machines, this procedure would have a great help in saving both headaches and motors..i wouldnt mind knowing that out in the garage, sooty isnt leaking..and the amount of reports lately, its giving me a complex..

[Thom]

If the OP doesnt pop one up i'll take one as soon as i figure out this "90degree clockwise" plate thing!

The other piece is simple and could perhaps be improved by cutting a very short length of metal or plastic tubing the right diametre and putting this in place of the spring/washers.

It's quite crude, but hey, it works - it would seem!

Can i just ask, before pictures become available, when the face has been rotated 90degrees, there is not enough material for a screw to go through, have you simply used the screw heads to pinch down the plate?

[Mincehead]

Did any members ever work out if any `other` fuel taps fit the TRX tank with correct screw hole spacings etc?
There was someone talking of a Divvy fuel tap looking like it would fit, non vacuum type.