Carb-incontinence

[rustyrotor]

This just defines the love affair for me. Fix something, create another problem. i freakin do it every time.
How DO the folks who are good at this do it?

Eliminated the fuel crossover. Changed the hoses and fuel filters. All snazzy crap from the nearest speed shop.
Ditto plugs, plug cables. K&N's.

Bike runs great! Very gratifying. All I need now is a sixth gear.

But now gas will occasionally dribble out of carb mouths at stop lights.
Not good.

So. Sticking floats/valves right?

If so why didn't it do it before?

Tips, tricks, decision trees, six sigma, whatever, welcome.

'78 Le Mans, 40 mm Dell'Orto PHM (SC)

 

[contractor20]

Maybe tiny bits of stuff from fitting up the new wizz bang lines etc have got under the float valves?:unsure: :unsure: I guess you'll just have to drop the bowls and have a look (check the levels while ya there) and keep a sharp eye out for gremlins.

PS. Its probably just Murphy's Law B) B)

 

[Christofero]

Your not running velocity stacks are you? I know that the Lemon1 came with them but they are a bad move - fit the oval K&Ns.

Racers figured out a while ago that the small performance loss caused by reduced airflow is more than offset by the long term BMEP loss as your bike eats dust! After all it is just a big vacuum cleaner. The velocity stacks look trick but really are not.

As suggested the float level could be high causing the dribble - Malossi used to make clear float bowls that fit on the PHM which were excellent for checking the level. The pivot pins can be graunchy.

You can get carb standoff (quite spectacular to see on the dyno) due to cam overlap but seeing as this is occurring at idle with the stock cam I don't think so.

If it is really spitting then you might look into cam timing - did you change something.

Also do fit hoses to the carb bowl overflows and direct them away from the starter! I have seen one bike go up like that.

Don't sweat it, you will sort it out.

Ta,

ChrisR

 

[Shane]

How do you see gas dribbling out of the carb mouth when it is wearing K&Ns?

Seriously, you need to fix this. The air cleaners become saturated with gas, and all it takes is one backfire and you can have a spectacular air cleaner fire. Ask Weber DCOE owners about fires with air cleaners; they always carry fire extinguishers.

As said before, it is likely float height. Check the gas taps while you are at it.

You might want to get rid of the 40mm carbs. They are way too much for a Guzzi except a built motor on the track at WOT. All they give you is terrible throttle response, lousy gas mileage, and dodgy accel. pump operation. 36mm seem sweet and accurate by comparison, but they too are arguably too much for the LM.