Mixture?

[ukzknos]

Having just got the bike out of winter mothballs and tinkered with it to ensure it will sail through the UK MOT (Ministry of Transport) test I have a frustrating problem, symptoms:

Bike starts very easily on choke.
Once up to temp it idles perfectly and rides great but only once the RPM passes 2500.
Below 2500 it is not free revving and tends to splutter a bit.
If I engage the choke by the slightest amount it now runs OK below 2500 RPM but worse above it.

Carbs balanced to perfection
Air/mixture screw (new) set to handbook specification.
All jets, etc. new last year.

Is this a simple case of getting the mixture right?
or, other suggestions please?

Steve

[Barry]

Sounds to me like the usual gunge around the needle jet emulsion tubes. Try checking the float bowls for any signs of water and drop the main jet, needle jets and emulsion tubes out to check for any blockage in there.
May as well check the pilot jets and the tiny bypass ports at the same time.

A few drops of oily water from the engine breather had mine behaving the same way after the winter break.

[nhmaf]

+1 it is likely partially clogged jet/tube/ or gummed up needle.

[the_admiral]

have you the same amount of free play in your throttle cables at the carbs? if not it will be very lumpy at lower revs