Typhoon 125cc racking sound at accelerating

Im new here, and i ask your help far away from Estonia. Well i bought a 125cc typhoon with white contra spring and littlebit lighter rollers.. and noticed, that the acceleration is not the best.. It makes like a little racking sound, when i start to accelerate from dead stop. It is until 7-10 mph and then sound stops and it starts to accelerate normally..
I bought a donor machine also.. and fitted it's variator, rear pulley, front pulley and clutch, and the variator bunt, what was on the second scoot 1.5mm longer. then the racking sound eased down littlebit.. But stil it is in and it does not rev up properly in start.. I know it is not in the carb..
It has something to do with belt not going up or it is going up to fast.. what do you guys reckon?
also, i but on green springs, but there is huge clutch slip.. is it pointless for stock engine?
i havent found time to bolt on the 172cc and 24mm carb yet..

I hope ya guys understand my problem and know the answer for it.
Thx=)

 

Well clutch is like new, and also the belt. I have stock clutch springs on. But with white contra spring it moves littlebit better, throttle response is better..
But biggest problem is with the accelaration from start.. it even doesnt do burnout, cause engine does not rev up, at start..maybe some spacing issues like alot of guys here have??