Carburetor woes.

crawsue · Post by **crawsue** » Sun Dec 09, 2007 4:47 pm

Decided whiff of petrol in the garage when I entered today,fuel taps off on G80 but definate dampness at base of main jet holder.Removed and fitted new fibre washer,still damp,wasn't sure if it was tracking across base of float chamber,removed cover checked float valve...OK, replaced float cover gasket....still damp.Is it possible for a hair-line crack at the base of the carb' or is there a better way of curing leaks.I think this might be my carburation issue as discussed in "H/wt head repair" any clues?

itma · Post by **itma** » Sun Dec 09, 2007 4:54 pm

If the fuel taps are off, its still likey that they let fuel through.
first things first, suggest you turn taps on too fill carb without ticling it, turn off and disconnect fuel lines.
You will then have eliminated at least on e problem.
As a rule monobloc carbs are quite good re not leaking.
My bet is on the taps.

Don Madden · Post by **Don Madden** » Sun Dec 09, 2007 5:03 pm

I have had cracked bodies where the jet block screws in & damage at the joint. The latter unlikely on yours as it did not leak before.

More common is distortion of the bowl cover which the paper gasket can't seal. Attach the cover without a gasket check & check for even gap, especially between the screws.

Minor distortion can be sealed with a carefully cut thin cork gasket.

Cheers, Don.

itma · Post by **itma** » Sun Dec 09, 2007 6:16 pm

another little thought, do you have a fibre washer under the pilot jet cover plug?
A sure cure for distorted float bowl covers is one of those finned extensions

Biscuit · Post by **Biscuit** » Sun Dec 09, 2007 9:31 pm

Sod the cure, just use care when tightening the screws.

crawsue · Post by **crawsue** » Sun Dec 09, 2007 11:00 pm

Alan,trouble is it's dificult to say if the petrol is coming from the float chamber or tracking across from the base of the main jet.With some better light I'll have another go on Monday.Thanks all for your input,bl**dy annoying........but I'll get there.

paul knapp · Post by **paul knapp** » Mon Dec 10, 2007 4:10 am

Ensure that there is NO washer/gasket under the float needle housing (where it screws into the top of the chamber). This can, if fitted, cause the fuel level to be just high enough in the bowl to seep along the air mixture screw thread and down the side to the jet cover.
Also, ensure that the float needle seat doesn't have a fine, blond hair trapped going through it.

Paul

itma · Post by **itma** » Mon Dec 10, 2007 8:29 am

Blond hair? is there something you are not letting us in on?

Biscuit · Post by **Biscuit** » Mon Dec 10, 2007 9:51 am

Blue tack - stick a sausage of this halfway around the float chamber between the cover and the jet block screw, this will show whether it is tracking across or not.

Bet it's coming from the tapered seating of the main jet cover.

crawsue · Post by **crawsue** » Mon Dec 10, 2007 11:23 am

Had a quick look before going to work this AM and still leaking.Tank was off for 3 weeks during head refit and didn't seem to leak,so I don't think it's that.Will try the blue tac trick,Alan,will also check for blondes,Paul,but might get distracted from task in hand! I have some thin latex sheeting so I will make up a float side gasket and try to eliminate that.The standard new fibre washer for the main jet block is very hard,any simple ways of "softening "them up to try for a better joint?NO washer under the banjo.Thanks all.