poor starting after long periods

[extonyg]

hello, i have recently been having problems with starting my bike if its left for long periods of time like over night. its an L1. starts up fine when hot or short periods.
when i start it i have to have no choke and full throttle and it will start and 'splutter' maybe 10 seconds or longer as if its not running on all cylinders and the just rev up and be fine after that idle a little low but ok as its cold. i have had the carbs apart and not found anything as i am still in the process of setting the carbs up as the plugs are still coming out a little dark rather than a nice brown colour.
the other day i took the plugs out before i started it once it was left for a few days and the plugs were 'wet' with fuel. so i suspect the carbs are draining out into the cylinders when left for long periods. causing the poor starting as it is having to fill the bowls and empty the chambers at the same time.
the float valve tips look ok and not ridged and the guide part that the float valves seat in the 'o' rings on them arent split and seem ok.
just wondering if anyone else has had this problem or know of something i can check.
ive got dynojet needles and also the carb filters have been removed.
any help would be great thanks

[extonyg]

just thought i would give you an update. finally got round to checking valve clearances and found all of them to be too tight a couple had no gaps at all. upon looking further found that a couple of the rocker arms are heavily worn/damaged because of the incorrect clearances. the right hand one in the picture is the damaged one its hard to see in the pic once ive got them out i will get a better picture.
so its engine out time now..........once ive stripped the engine down i will decide wether im better off doing a full overhaul on the engine or buy another..........
i also found this little black plastic part near the cam chain when i took the cam cover off does anyone no what it is??

[RedexRobB]

refresing the engine yourself will be far cheaper then buying another running engine. To change the HG, cam chain, cam chain blades your looking at less than 100 quid, and you only need to replace whatever followers are damaged. You also have the added benefit of it being your own work and knowing the engine is going to be ok for a good while before anything goes wrong again.

No idea what that black piece is, reminds me of the rubber bits just above the cam chain that stick out.

Clearances like the ones you measure are definatelynot going to help starting. Alot of mine were tight and the bike could be a bit of a pig to start but nce i did them it fires up straight off the button!

[extonyg]

ye ill get it all apart and see what the bores etc are like and see.i would like to do it all myself so i no its all up together.
thanks for your help i keep you all posted on progress

[jackdim]

Do a compression test before you strip it

[extonyg]

i have done they were low, i think because the clearances were so tight with no gap it was partly holding the valve open.ill be taking head off anyways.