Any bike/motorcycle experts please help me:

I building a sports bike and it was almost completed and.I am experiencing some issues related to throttle when I give full throttle it slides leftward i checked each and everything but I found nothing.I tried all my knowledge to resolve this but unsucessful.So if there are any experienced ones please download this bike and fix this and make it perform better like real ones and send it to me.I had planned it to release on 4th May of this year and I have so many other things to do and I have no time to think about this and resolve this.I will give credit to you on the headlines in description when it will be released.
Please Help me I am so much upset while building this.

Link
Here is the bike