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Spit back on first weber carb nearest to bulkhead - one of three carbs!!


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Some thoughts please as to why this may have started to happen. I have checked the jets and settings on the carb but to no avail. Is running rich, a little, so any thoughts there would be good also

Look forward to any help and replies

Peter

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Peter

I think you need to tell us a bit more about your setup

Has the engine been rebuilt,?

Is this first time running with these carbs?

Was it running fine before, what's been done since?

John

 

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^ + 1

Also are you running an air box, socks or open trumpets.

Mick Richards

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Also... are you using an electric fuel pump and a pressure regulator and at what pressure. Is this the first or last carb to get fuel. Did you check the float height by removing the main jet, should be 25mm from the jet housing or 41mm from the top cover

Cameron
 

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So why is it just affecting the nearest to bulkhead carb ? Is that the last or first fed.?

Mick Richards

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23 minutes ago, Motorsport Mickey said:

So why is it just affecting the nearest to bulkhead carb ? Is that the last or first fed.?

Mick Richards

Good question Mick just been helping someone with this I await the answer as that may help have you checked for **** in the tank and filters 

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Could be one of the 2 idle jets with a bit of blockage, or some water in that carb.

I wouldn't touch any settings until you have given it an Italian tune up.

John

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I second the Italian tuneup suggestion. I've never had this problem in 24 years and 135,000 miles with triple DCOEs on my '250s. They never really hibernate, though, getting exercised year round provided the roads are neither wet nor salty. So at most 3-4 weeks. I use a highly acclaimed fuel additive too: Seafoam.

As for clogging the jets, nothing small enough to pass the screens in the fuel inlets can possibly do so. Not sure how water would get in there, but appreciate how it corrodes aluminium - and nuggets of this crud would be past the screens. I've never done it, but pulling the idle jets and running a tiny wire through them might bear fruit.

Great suggestion by Cameron; the height is like a closely guarded secret ( though really, who out there cares except us afflicted? ). For what it's worth, both of mine are lower than 25mm by 2mm in one case and 3mm in the other. 25mm may be the highest practicable setting; there the main jet system will come in the soonest possible. Sameness between the carbs is sublime!

Finally, as most carburetor problems trace back to the ignition ^_^ I wouldn't be surprised if it applies here. I'm not a fan of the electronic types, as mine don't miss a beat with points and the reliability is excellent. I did have a fling with a Crane / Allison setup that lasted for a few years, then when a chronic low speed miss was cured by fitting a worn out points distributor I had on the shelf I saw the light.

 

Tom

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  • 2 weeks later...

Just had another "go" at the spitting! Discovered that the distributor clamp was not tightened and as a consequence had caused the timing to go off!! Have done a quick "tune" and already the spit seems to have gone - going to do a "concentrated" tune tomorrow to see if I can eliminate it once and for all

Thanks to everyone for their inputs and ideas

Peter

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