Another carb question or 3

[Gavin]

Took the Mk2 out yesterday, it is running very rich black plugs B7ES tends to run better when opening the throttle, but very sluggish at low revs, suggesting the problem is on the pilot side also there is spitting back sounds ( best description I have come up with) which I thought meant lean
How can it run very rich when the symptoms point to a lean mixture.
It is running VM 28 pumper carbs with 117.5 and 107.5 jets
Hopefully some carb guru can point me in the right direction.

Gavin

[Gavin]

Just had a thought, when I owned this bike in the late 90’s I had o put an inline fuel filter on because the tank had a coating of old dried out petrol
lining it, so when I put petrol in it all partially dissolved but enough to clog up jets etc, from what I can remember from 20 yrs ago the symptoms are very similar,
This tank has sat with petrol in the bottom for 12yrs no idea how much it started with but there was about 1/2 a gallon left. Going to take the carbs off clean out the passageway and jets and stick a filter on to see what happens

[zed1015]

Gonna have to recommend having the choke plunger seals replaced.
Depending on how bad they are they will contribute to the over rich symptoms and poor running.

[Gavin]

Could be right Rob, the carbs have been dry for 12 years.