Please help! i am in a similar situation... I just purchased what I thought was a CRF100F, however, the frame says CRF80F. Looks like someone changed the plastic... When I contacted the seller, he informed me that it is a 100cc engine on the 80 frame....?? Here are the numbers off of the block. HE03E-6515676 If anyone can help, I would greatloy appreciate it!