Fuel/Air Mixture Screw problem
 

Hello all,

Just an enquiry as to whether this is a known problem.

I was trying to adjust the fuel/air mixture as the bike is running a bit rough at idle and very rich (reduced fuel consumption) but the screws (on both carbs) dont move either way.
Is this a common problem with them seizing up?

Re: Fuel/Air Mixture Screw problem
 

Yeah they do sieze in.
If an adjustment hasn't caused the problem, it probably won't fix it. I would suspect the choke plungers.

Re: Fuel/Air Mixture Screw problem
 

Thanks, it was setup for a different exhaust and that was changed so needed to adjust the fuel/air mixture on the carbs, choke plungers seem to all be ok.

Im going with the 'may require another pair of float bowls' then, with moving screws I hope

Re: Fuel/Air Mixture Screw problem
 

The screws aren't in the float bowls, they're in the body.

Re: Fuel/Air Mixture Screw problem
 

What exhaust was on it? Even a full system doesn't generally need the screws adjusting much differently to stock.

What mains is it on? Stock is 137.5 if they've had a full pipe and a decent air filter on they'll probably be 150+ mikunis or dynojet 170+ size. Stock pilot jet is 17.5 but again this is generally OK with a pipe and filter so no need to change it.

Whip the choke plungers out and have a look at them as this is really common that they don't return properly and make it run rich. Also the carbs being a yard out of balance will affect economy as one cylinder will run rich, the other one will run hot.