Hello there,

does anybody have some idea what can I do? I had so much problem with the fuel cock in the past months.
I checked and cleaned everything, but later ended up to buy the Tourmax FCK-24 kit.
After I exchanged all the parts from the kit, I started to play with it (making vacuum with my mouth) and realized that doesn't seem to work so well.
I know how should it work and the fundamentals of the tap. So the auto fuel cock function is not working at all, even I try to jogging the tap. The only way of course if I open the screws on the chamber and the vacuum goes away. So this might be a silly question:
May I do so much pressure which couldn't handle by the small spring?
What could be the rough amount vacuum which can I measure in the 4th cylinder when the engine is running?



Thank you

That kit isn't for the 400. I'd buy a 2nd hand 400 unit, or a short manual RH 8mm tap with 35mm spacing, which work better than the auto units. Just remember to shut it off every time if you get one.

hmmm seems like it is, look at the URL below:
https://hu.fowlersparts.co.uk/parts/596 ... /fuel-cock

at least mine was equipped with this one.

The only listing for that tourmax kit is for the 1100. If it all fits well it should work. Check that the valve is free to move in the tap body. You could polish the bore with metal polish to try and make it easier to open.

Best way to clean these fuel taps is to completely strip them, which includes removing the press fit collared washer.
I didn't do this before because I was afraid of damaging the washer and the seal, but it's the only way to properly clean the internals.
I also had both fuel taps vapour blasted which caused a large amount of the glass grit to get stuck inside.
Used a blind bearing puller and some heat to get it out, no problems.
Much smoother turning now!

I think I'll have another try without touch the tap again and hopefully it won't leak anymore.
The bore and the plastic plug don't look so bad, and I already changed the outer seal on the tap.

Thank you guys, I'll make a feedback soon