my speedfight wont start ???

Hi a have a speedfight r-cup 07 reg and i cnt get it to start of the electric this problem is on and off all the time.
1. the kickstart always works after a few trys
2. the engine always needs to warm up before it will move eg if i rev it full as soon as i have started it the bike will just stop running and on the roads it is just so slow until it starts to warm up (it never used to be like this)
3. i just put new roller bearings in but it worked fine for about a day and then went back to normal
4. the bike used to du 53 and now does 45 at a push and then starts to lose power back down to 30 why???
5. it has a viper racin exhast if you need to know
6. i find that if i clen the plug of the electric start problem is fixed but i have to do it all the time :s

please help me im loosing my marbles here lol