Help knocking noise when accelerating

I am getting this knocking sound when i accelerate from still, only at slow speeds 10mps and lower. i don't know how to describe the sound but it's something like khat, khat , khat , khat, gets faster with higher RPM. I don't hear it when it's in neutral and i Press the gas.

Let me know guys what's going on before i take it to a Mechanic and get @#$$

thanks

... i take it to a Mechanic and get @#$$ ...

Mechanic has unfair edge: he sees your bike, may guess details u dont tell...

Wheel fallin off?

U putting the expen$ive gas in? Water in the gas? (try .80c can of drygas)