I would start by checking your primary. I have heard other guys having a problem with something hanging up on the primary and knocking. Never had this prob my self.

May be try a search, I know i have seen it before

 

what is the primary

 

Your primary clutch on the right side of the motor under the big black cover.

May want to get a service manual or bring it to a dealer.

 

Get a puller to remove the primary clutch. Remove the clutch and the belt,then run the engine,if the noise goes away,you know it's a clutch problem if it doesn't you have a bad crank bearing.

 

where can i purchase puller and how much is it?
or even could it be made and how?

 

bump up

 

you can purchase a primary puller from epi.. EPI: Technology to Move You.