Hitchcocks Forum

Hi,
I have recently bought a 1943 WD/CO which was running a little rough I have since rebuilt the carb (276) using new jets/needle and gaskets, but now I have the following problem.
She starts and ticks over but when I open the throttle its spits in the carb and refuses to rev cleanly sometimes I can get to rev past this point then it runs ok annoying being as I can't ride it in town without revving the nuts of of it.
Any pointers would be greatly appreciated

Cheers

Rob

I'd lift the needle one notch. Spitting is a sign of leanness.

Hi guys-------- This is an extract from our hosts "Technical Notes -- Mk 1 Concentric Carb "-------------------- but they apply generally across the board.}-------Throttle position is,  closed to 1/8 open: idle system: controlled by the pilot jet and fine tuned with the pilot air screw and throttle stop screw
 1/8 -1/4: the cut-away portion of the throttle valve
 1/4 - 3/4: the needle and needle jet
 3/4 to full throttle: the main jet ................... A further check on plug type/ gap and points gap wouldn't go amiss either.............

Cheers Gents
i will give the needle a try
if that does not work i will get hold of a concentric/monobloc and give that a try

Cheer

Rob

Hi Rob - what you describe is typical of a slide with a cutaway that is too large and so gives a weak mixture as you open the throttle.
It may require only a cutaway with a lower ref number to fix the problem.

I agree with Presto, you are near to solving this, don't open another can of worms by fitting a different carb!
REgards, Mark

Cheers Gents
I will give the slide a go

Rob

Hi guys----------- ditto that re}--- not changing the carb..My extract was relating to throttle position in regards to jetting etc..."One thing at a time" is the best way to get meaningful results....