Suzuki 1997 VZ 800 fueling problems

Hi Guys can you help.
I have bought a 1997 VZ800 marauder and it has problems with the fueling. When I took it out for a run after cleaning the carbs and fitting new air filters it misfires in the mid range, if you hold the throttle open long enough the bike accelerates through the mid range then clears up. The misfire gets worse as the engine gets hotter.
I took the plugs out and found the rear cylinder plug was very white (porcelain) and the electrode was grey, the front cylinder plug was black (porcelain) and the electrode was going grey. I removed the rear carb thinking the misfire was coming from their. I raised the needle on rear carb to its max by moving the C clip and changed the main jet too 107.5 to see if this made any change, took for a run misfire still their but slightly better but when I removed the plugs found them the same. I have left the front carb as standard. I balanced the carbs and checked all cables and both carbs throttles move at the same time. I have checked valve clerances all Ok. Anyone got any ideas.

Front Carb Main 90
                Pilot  40
Mixture Screw 1 3/4 turns out
              Needle Standard

Front Carb Main 107.5
                Pilot  45
Mixture Screw 1 5/8 turns out
              Needle Standard

Help Ian

Hello Ian,
did you get you're fueling problem sorted out? VZ800.  If so, can you tell me what the problem was as I have, what sounds like, the same problem? I also have a VZ800

Thanks .....Bryan

Hi Bryan,

Have another look at your other posting on 'VZ' fueling issues - I've just added a bit more - not sure it will solve the problem - but worth a check.

Yam