difficult is an understatement.. when the engine is cold the only way I can get it going is to remove the plug and squirt some fuel into the bore the when I kick it over it will fire a couple of times then die, I have to repeat this process about 3 or 4 times before it stays running. Once it is going it goes well and it will start easily up to a few hours after I turn it off. Any suggestions as to what I should be looking at? I put a new piston and rings in it a while back and had it re-jetted(larger jet) at the bike shop cause the old piston had a hole burned in it from running too lean. so the carby was cleaned and rejetted by a "professional".