Cleaned the carburettors. Changed the spark and charged the battery (now it works for 10 tries maybe more).

The mixture screw is 3 turns out now and it fires up almost each time but dies. After 2-3 attempts it picks up rpm and it's ok.

Engine seems to be running good but I still don't like something ...

If I stab the throttle (neutral) it bogs a little and died once (maybe it wasn't completely warmed up ...)

The weather is really cold now going bellow freezing most of the time. Should I try 4-5-6 turns out on the mixture screw ? The needles (both) are in middle position clip and the transition between carbs is running nicely.

I suspect the engine is not revving as high as it should (I have to test this - I've mounted a rpm/hours gauge and it recorded 4800 rpm and I did quite a strong acceleration) I think this engine should go towards 6000-6500 rpm will have to test ...

The signs is giving me it could still be leanish running since it takes 2-3 minutes to run on choke when started from cold and it has those start and die symptoms ...

Quite hard for me to tune it since I have to wait for it too cool down completly so I can try again ...

When its warm is really a pain in the ass to tune that mixture screw since I keep burning my fingers most of the time ... I've made a small tool to adjust it !

I don't know if I should try buy a second hand pair of carbs just to test it ... I can't figure out if the choke is busted or not ... but the tests that I've made tell me its working, for example if the mixture screw is 3 - 3.5 turns out and engine is warm and I pull the choke it almost dies from rich mixture ... is this normal ? I believed it could run on choke but at higher rpm ...

I don't know how much popping on the exhaust is normal on this bike. I can try go leaner and try to see if it starts better ...

Will have to test further and try to see if I can make it work. I just want it to start on 1st or 2nd attempt and keep running ... the engine fires up like I said but it dies and it doesn't pick up rpm ...

I've set my idle rpm higher like I've been told here ... now is at 1450-1500 rpm (when hot).

I just can't seem to figure out the dying at startup is from lean or rich but I don't think a rich running engine can die at startup it can only die if its lean or the compression is low or the spark is weak ... please advice here

Also the spark when I've looked at it it was yellowish not blue ...