PWKs leaking fuel out of overflow

ashman · Jan 20, 2013

Hi All

I have a set of Jim's PWKs carbies on my Norton today went for a ride and the left carbe is pissing out fuel out of the overflow and is running like shit, it got me home but not running good when over reving it as well only idaling on the right side cylinder, when I turn the fuel tap on and open the throttle its starts to flow out of the overflow, have just pulled the left carbie off, what could be causing this to happen there was no crap in the float bowl and the float is lifting ok, I am no carbie expert so any advise would be welcome, these carbies have been on for about 1 1/2 years now without any problems at all.

Ashley

rpatton · Jan 20, 2013

Put a piece of tubing on the fuel inlet. Turn the carb upside down and blow some air into the tube. The valve should be shut and sealed. If that works then the valve is good so the float may be sticking or really setup wrong. Can they hang up on the gasket on a PWK? Check the valve for crud?

FastFred · Jan 20, 2013

I've had that little joy as well as another myriad of problems with my carbs. It was crap on the needle jet on that occasion. Pull the float bowl off and have a really good look at the needle tip and clean the needle seat.

ashman · Jan 20, 2013

Thanks for that I will give it a go and have a look at the needle jet, these cabs have been set up right as they have been working fine till today the carbies have over 12,000 miles on them so far and haven't had any problems with them till now, have pulled the bowl off but have to wait till day light to check to see if they are ok.

Thanks Ashley

pete.v · Jan 20, 2013

You may have a piece of debris stuck in the neelde and seat. Should be a simple clean out. Check your strainers in the tank.

1up3down · Jan 20, 2013

sent you a PM on this

ashman · Jan 20, 2013

Hi all

Thank for all your help will look at it all today, have the carbie pulled apart and give it a good clean today, the fuel bowl was clean no crude in it but will check every thing else, I say the float was sticking open, easy fix.

Ashley

xbacksideslider · Jan 25, 2013

Sometimes there's a piece of crud that gets between the float needle and its seat, or between the float needle and its bore, or between the top of the float needle and the float. Then, you take it apart and that tiny piece of crud escapes your eye . . . . it may remain there to bounce and float around to bother you again, or fall away and disappear . . . .

Tim_S · Jan 25, 2013

I had this same issue on one of my other bikes. My plastic float pivot a swallon up from the gas and was hanging up on the float pin. I trimmed the ends off to allow more room. While everything looked Ok at first it wasn't until the float was exposed to the gas it would hangup. The float can give you impression it moves on the pin but in fact it's the pin that is moving because the float is tuck on it. That was my case..........

Tim_S

ashman · Jan 26, 2013

Thanks all, I pulled the float bowl off, was clean inside, the float needle was also clean, couldn't fine no crude at all but gave everthing inside a good clean and all is well now, no more leaking and the bike is running as nomal, I also drained the fuel tank and cleaned the fuel taps but every thing was clear and clean, so all good for now.

Ashley

Brooking 850 · Jan 26, 2013

Hey Ash, when I had taken my float bowls off for a thorough clean and check, had issues with the bowl gaskets having swollen with the fuel here in NZ and they were too big to get back on their groove. Raised the issue with Jim, he sent me a couple of spares. Jim suggested warming them to get them back to size.
How did your fair?
Regards Mike

pete.v · Jan 26, 2013

Brooking 850 said:
Hey Ash, when I had taken my float bowls off for a thorough clean and check, had issues with the bowl gaskets having swollen with the fuel here in NZ and they were too big to get back on their groove. Raised the issue with Jim, he sent me a coup,le of spares. Jim suggested wrming them to get them back to size.
How did your fair?
Regards Mike

I experienced this. I used a small screw driver and worked them in place as I snugged the screws down. Another instance of, although they work, not a good quality product.

ashman · Jan 26, 2013

Hi All

Yes the gasket was a bit swollen but lucky wasn't to bad and went back in the groove as nomal, but if I have to take it apart again I think I will need to get some new ones, but with any luck I should be right for now, another small problem is getting the float bowl in place takes a bit of jiggling around, but other than that all is good, other than that Jim was spot on with his jetting and needles size for my carbies as when I brought them I told him what cam I was running and what other work was done to the motor, he went up a size in the jets and the Norton performs pretty good with these carbies.

I have just brought a new Triumph Thruxton, picked it up yesturday so now my Norton is going to be semiretired and will be ridden only on the weekends and runs, or when I want to take it out for a bit of a flogging :roll:

Ashley

1up3down · Jan 26, 2013

Guys, I have had my PWKs from Jim Schmidt since he first offered them.

The tolerances are a close fit inside those carbs, as you know from carefully fitting them together.

I carry in my tank bad a socket wrench that fits the big bowl nut on the very bottom of the carbs.

Don't know why but my left carb will occasionally start overflowing, and when it does i use the wrench to remove the bottom nut and let it pour gas out of there for a little while into a cup, this seems to flush out whatever was holding the float up, no need to dismantle or take the lower carb off.

I just picked up a cheap inline gas filter to put in the line as the petcock filter must still be letting some stuff in.

xbacksideslider · Mar 12, 2013

The ethanol, added to our gas at the insistence of the Greenies and the farm lobby, will crud up any carb, not just the PWKs. I'm running every carbureted engine dry - the weedwacker, the lawnmower, all my bikes. The higher fuel pressure of the fuel injected cars seems to enable them to tolerate the ethanol's corrosion and gunk better.

If you let your bike sit for a month or three, the ethanol is almost guaranteed to cause problems, so if you are going to put her up for a while, turn the gas off and idle the bike dry, then hope that your petcocks don't leak.

madass140 · Mar 12, 2013

the fuel here in the Philippines is full of ethanol, on the carb of my Yamaha SR500 the needle jet holes all 16 of them and the pilot jet which has an extremely small hole were all blocked up after sitting for a while.
never had that problem pre ethanol days, its shit stuff in my opinion.

bluto · Mar 12, 2013

Definitely carry a fire extinguisher until you get that squared away. When I bought my bike the PO had installed new floats and bowls on the Amals and they did not have enough clearance so the float would stick sometimes and the carbs would overflow...he also put split loom on the alternator wires so on one occasion while I was kickstarting it the carbs overflowed, filled up the split loom, and evidently a spark from the alternator connectors started a fire. I was very fortunate to be able to beat the fire out with my gloves but easily could have lost my bike. (FWIW the fix was as simple as filing the float pivots down a little so there was adequate clearance between them and the bowl)

PWKs leaking fuel out of overflow

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