Several years ago, my friend had an FZ1 with a Dale Walker of Yoshi can, I can't remember which. He didn't rejet the bike. He and I did several roll-ons, me with my Sato/PC-ed 919 vs his noisey unjetted FZ. Both stock gearing. The 919 walked away. Posted that on the FZ1 site. Shit storm of biblical proportions. If my dumbass friend would have rejetted his FZ, it'd have left the 919 for dead, but he didn't.
The above pink 919 was made up by one of the FZ gang.
Boy that was fun.