BACKGROUND:Just finished the rebuild on my twin (basket case so was not running previously) and have fuel problems (I think). I have no previous experience of Concentrics Mk1's so don't know if they have any foibles or age problems! Have used 276's, Monoblocs, TT's and GP's and have NEVER had the problem below. Bought the Concentrics from a club member several years ago and have dismantled and cleaned them prior to fitting but have not renewed anything.
SYMPTOMS: Turned on the juice and did the usual carb tickle (3-4 pushes) and started kicking - nothing. This went on for a while with nothing happening - not even a cough! Tickled the carbs some more (actually until petrol started to drip from the float bowls) and it fired up, ran for a bit on one and a half cylinders and then settled down to life as a 500 single! If I blipped the throttle it seemed that both cut in. Felt the pipes and No2 was hot and No1 was cool. Tickled the carbs again and found the float bowl for No1 was empty (ie the tickler did not make contact with the float bowl until I tapped it quite hard up and down against the stops). Fired it up again, ran as a twin for a while and then went back to being a 500 - But with lots of spitting and coughing from No1. If I tickled No1 whilst it was running, this stopped and it chimed in. Occasionally, No1 would be the hot pipe and No2 the cool one! So it seems to me that petrol is not flowing easily into the float bowls, somehow - any thoughts other than I wouldn't use Mk1's!
OTHER INFO: I have fitted new Spares Co fuel lines and taps and the mag has been rebuilt and retested ok (I originally thought I had an intermittent spark causing the problem but I don't) - so I think I am left with a petrol feed problem which should be so simple to fix it's driving me round the bend!
SYMPTOMS: Turned on the juice and did the usual carb tickle (3-4 pushes) and started kicking - nothing. This went on for a while with nothing happening - not even a cough! Tickled the carbs some more (actually until petrol started to drip from the float bowls) and it fired up, ran for a bit on one and a half cylinders and then settled down to life as a 500 single! If I blipped the throttle it seemed that both cut in. Felt the pipes and No2 was hot and No1 was cool. Tickled the carbs again and found the float bowl for No1 was empty (ie the tickler did not make contact with the float bowl until I tapped it quite hard up and down against the stops). Fired it up again, ran as a twin for a while and then went back to being a 500 - But with lots of spitting and coughing from No1. If I tickled No1 whilst it was running, this stopped and it chimed in. Occasionally, No1 would be the hot pipe and No2 the cool one! So it seems to me that petrol is not flowing easily into the float bowls, somehow - any thoughts other than I wouldn't use Mk1's!
OTHER INFO: I have fitted new Spares Co fuel lines and taps and the mag has been rebuilt and retested ok (I originally thought I had an intermittent spark causing the problem but I don't) - so I think I am left with a petrol feed problem which should be so simple to fix it's driving me round the bend!