disabling petcock auto "on"

hi all,
i am in the process of "cafe-ing" my xj 600. i wish to disable the automatic "on" feature of the petrol tap, or petcock as most of you refer to it.
i've been through most of the threads, but ca'nt find the answer to this,
if i disable the intake air line, and use the "petcock" to be on or off, do i lose the reserve facillity.
or is there a way of blocking off one of the internal ports, to retain reserve.
replacement "manual" taps are a bit pricey to ship to uk.
cheers
stu.

 

"Reserve" is the same as "PRI" except it's vacuum operated and PRI isn't.

"ON" is only "main" because it's standpipe in the tank is taller, so it runs out before it can draw from the last couple of inches of fuel in the tank.

So unless whatever mod you make to it still allows the use of the two positions, ON and RES/PRI you'll lose the "reserve" feature.

 

Just remove the rubber diaphram inside, make a new gasket so it doesn't leak without the rubber, and plug vaccuum hole. You keep all function except off.

 

And .. if you want OFF add an inline tap like on a lawnmower or such to what streetbrawler said and get used to using it.

 

Take your petcock apart an study how gas flows thru it. I was able to return mine to on-off-reserve normal operation (prime now being off) by flipping the lever and label plate upside down on my XJ700. The valve must remain closed or you can block off the hole with something.

 

cheers all,
so it seems there may be a way of retaining all features, i'll take the thing apart then and have a look. :lol:
cheers
stu.

 

yaaaay, managed to dissable the auto on feature with your help especially the suggestion by "osprey" to flip the moving part over.

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stripped the petcock and filed off the stop tab on the moving part to enable it to spin all the way round

 

blocked off the auto on valve with epoxy putty

 

this is the I.D plate "before"

 

covered I.D. plate with body filler

 

sprayed the plate with silver spray can and re-lettered the plate using" rub on" letter sheets.

 

made thick rubber gasket and dicarded auto valve plate, and replaced rear cover.sorry for poor pictures

 

clear coated the I.D plate, and re-asembled.
so now there are two "off's" top and bottom
"on"pointing forward
"res"pointing backwards

 

put dab of red paint on end of lever and clearcoated over, need to get an extra intake air hose blank to seal off the air inlet.
job done, i hope
cheers, stu.