Carb flooding

Camel, Sahara, Kanguro, Coguaro
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3potjohn
Posts: 1243
Joined: 02 Jun 2007 13:58
Location: Devon

Carb flooding

Post by 3potjohn »

I was investigating a likely source for a small quantity of water in the front carb (PHBH on a Coguaro) Having eliminated the fuel tank as the source I thought it possible that something had gone down one of the pair of fuel breather pipes which run from small ports and terminate on a frame clip.I did wash the bike off the other day. The pathway is essentially downhill all the way back to the carbs.
I tried simply blocking the ends of the tubes. Immediately the front carb just flooded out.
I swapped floats black and white types ,needles and jet The flooding carried on.You could hear it. Fuel was passing direct to the front cylinder. Queue oil change.
What I cannot figure out is why blocking the fuel vent tubes would cause flooding of one carb.Surely fuel level is governed by the float? The only other thing I can think is the float is rubbing on the bowl? Unblocking the pipes stopped the front carb flooding. The rear carb behaved perfectly. Any ideas? After all the carbs on my Sport do not have these fuel vents.
John
'It must be a .....'
Posts: 365
Joined: 12 Sep 2010 12:25

Re: Carb flooding

Post by 'It must be a .....' »

Hi, each of my Coguaro 28mm carbs had two small vent elbows on the bodies just above the float bowls with hoses attached; one up to the frame clip (air vent?) and the other down past the engine (fuel overflow?).

I simply removed all the elbows, hoses etc; as the 500 and early 501 Camels didn't have all this additional breathing tubery

The engine runs fine with the carbs venting straight to atmosphere in all weathers etc

Try removing the pipes first; I only removed all the elbows (tight push fit) after one fell out

Have fun, Ian
3potjohn
Posts: 1243
Joined: 02 Jun 2007 13:58
Location: Devon

Re: Carb flooding

Post by 3potjohn »

There is a lot of tubing what with those and the vacuum tap arrangement. I shall see what I can achieve.
John
'It must be a .....'
Posts: 365
Joined: 12 Sep 2010 12:25

Re: Carb flooding

Post by 'It must be a .....' »

I'm not a fan of the vacuum tap because of fuel starvation when the engine is hot which makes starting problematic and usually needs reserve to initially get enough fuel in the carbs, especially if using the kick start.
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