Author Topic: Fuel tap assembly  (Read 179 times)

robel

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  • Location: Maidenhead UK
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  • Putting a stock TZR250 1KT back on the road.
Fuel tap assembly
« on: February 26, 2018, 02:11:09 PM »
Bought a reconditioning kit from Yambits and rebuilt the fuel tap carefully reinserting the plastic spacer.  The problem is before I assembled it all the bits got moved so I am not sure if the plastic spacer is up the right way. When I put fuel in the tank none came out the feed until I sucked on the vacuum pipe, then I flowed but would not stop.

The spacer has a small recess between the fine air feed hole and the centre fuel hole.  I have assembled the tap so this side is on the big flat disc washer side.  I do not want to change it round until I know that it is wrong as it is very delicate.

robel

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  • Location: Maidenhead UK
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  • Putting a stock TZR250 1KT back on the road.
Re: Fuel tap assembly
« Reply #1 on: February 26, 2018, 06:17:29 PM »
Talked to NRP and they confirmed the orientation of the plastic piece.  I think the leaking when the vacuum is removed maybe due to the small o ring part in the centre not seating properly.  Think I need to polish the seat.

boomerangpom

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Re: Fuel tap assembly
« Reply #2 on: March 06, 2018, 12:35:12 AM »
I recently spent hours studying how & why these fuel taps leak, technical answer = the vacuum design is utter shite.....They can, and probably will, leak even after a rebuild kit.
 Answer is to reassemble 'incorrectly' so that the metal plunger with O ring bit is rammed really tight into the hole in the casting, also you need to remove then refit tap rotated 180 degrees, after all this you will have a tap with OFF, ON, RESERVE position. VERY IMPORTANT You must blank off the vacuum stub on the carb.
I did the above then tested by putting fuel in the tank, hanging the petrol hose over an empty jar for 48 hours, result= OFF position does not leak at all.
Just so you all know, petrol leaking into your engine can cause serious problems, I had my engine rebuilt recently, it appears the engine filling with petrol had washed oil out of crankshaft main bearing causing failure !!!  YOU HAVE BEEN WARNED............MODIFY + THEN CHECK YOUR FUEL TAP IS NOT LEAKING