Luka,
First off,
check valve clearance and adjust as necessary. The better the valves are adjusted, the easier it is to get a good result with the carbs.
Time the ignition at
full advance, regardless of which ignition system you're using. Idle timing isn't important at this stage, set the ignition to the 40?BTDC mark "A" with the engine at around 3000rpm. Check and adjust
both cylinders if they are timed individually! Idle timing should then end up somewhere between 5-10?BTDC. If the engine has been assembled from bits of unknown origin, it would pay off to check the "A" marking is indeed at 40?BTDC. If timing at idle ends up close to TDC or later, check the advance unit if you're still using it. Late idle timing will not allow a steady and reliable idle.
Check and adjust float levels. Make sure your chokes are closing fully and the choke cables have a bit of play.
Absolutely no point in continuing from here if the choke plungers do not seat properly.
Begin with the idle mixture screws 1.5 turns from fully home. Connect your vacuum guages and start the engine. Adjust the throttle stop screws (those with the springs) so you have an equal reading on both guages with the idle speed around 1000-1200rpm. Now slowly adjust first one, then the other mixture screw so that idle speed rises to the fastest speed,
disregarding the vacuum guages! Once you've found that, back off the throttle stop screws to an idle speed 800-1000rpm, checking the vacuum guages show equal for both carbs again. Slowly open the throttle to around 3000rpm and check the guages for equal readings. This is achieved at the cable adjusters on the carb tops. Check also at higher revs. If vacuum differs dramatically between cylinders at different throttle openings, most likely the carb bodies and/or slides are unevenly/severely worn.
Once you have that, re-check vacuum readings at idle and watch the guages as you blip the throttle. Ideally, both guages will rise and fall in parallel. Tighten up the cable adjusters with the lock nut checking the cable outers still have a little play, fit the cable dust covers, set the throttle cable clearance at the twistgrip to your liking if using a cable splitter, but always retain a little slack in the cables, and re-check the guages. If all is well, disconnect them and re-fit the hose between the vacuum take-offs. Replace tank and seat and go for a ride.
piet
