m33

[watcycle mechanical]

Im hopeing like heck there is a bsa single specialist out ther who can shine some much needed light on my problem for the first time in my career as a motor cycle mechanic which spans some 30+ yrs Ive got a motor that Ive rebuilt from the bottom end up new mains rebored new piston about the only things that havent been replaced are the cases barrell & head Ive set the cam timeing with the relavent marks on the intermediate gear & cams corresponding also the ignition timeing has been set at 3/8 B.T.D.C & the best Ive managed to get it to do after much kicking  & rechecking all the specs is to run for a couple of minutes then die & refuse to restart it has plenty of fuel & good spark magy has been rebuilt & new carb with the correct jets fitted & the needle set at the correct hight this ones got me stumped Ive tried all the tricks I know. Yours in anticipation Geoff

[bikerisme]

I THINK IF YOUR VALVE TIMING WAS OUT IT WOULD BACKFIRE THRO THE CARB OR EXHAUST IF ALL THE MARKS LINE UP IT SHOULD BE OK PLUS YOU WOULDNT GET IT TO RUN AT ALL,DO YOU HAVE TO SET THE MAG ON FULL ADVANCE THEN SET THE TIMING? TRY NEW PLUG HAD THE SAME TROUBLE ON A 350 AJS AFTER ENGINE REBUILD WOULD FIRE AND RUN THEN DIE OUT PUT NEW PLUG IN WENT FIRST KICK IS THE PLUG GETTING WET AFTER KICKING THE LIFE OUT OF IT, IS THE BREATHER HOLE IN THE TANK CLEAR? I WOULD TRY A NEW PLUG FIRST THEN SEE WHAT HAPPENS THEN CHECK THE CARB IF IT RUNS THEN DIES IT COULD BE THE FLOAT IGNITION TROUBLE TENDS TO STOP SUDDENLY

[watcycle mechanical]

your right the advance retard does need to be set at full advance which has been done new plugs were installed from the get go & have treid a couple of different heat ranges all new am useing remote tank with adquate ventilation carby is brand new set up as per specs any more ideas. regards Geoff.

[bikerisme]

HAVE YOU CHECKED VALVE CLEARANCES I KNOW YOU HAVE A NEW CARB BUT IF IT RUNS FOR A FEW MINUTES THEN CUTS OUT IT COULD BE A STICKY FLOAT NEEDLE THE CHOKES NOT STUCK ON? IS THE PLUG GETTING WET WHEN YOU TRY TO START IT? I WOULD RECHECK THE CARB AND MAKE SURE THERE IS NO AIR LEAK WHERE IT BOLT TO THE HEAD IS THE MAG OK AND NOT BREAKING DOWN AS IT GETS WARM ALL YOU CAN DO IS RECHECK EVERYTHING CANT BE MUCH WRONG IT I LIKE A CHALLENGE!!