I just bought an 07 R6 and found an issue I need help with from the Yamaha guru's out there. The bike has 8k miles and doesn't seem to have been abused. The issue is when the bike is under full throttle in third, fourth or fifth, @12k rpm...it raps the redline until the throttle is chopped and allowed to recover back to 12k and then steadily roll on throttle until redline. One problem may be my size( 6'3" @ 230lbs). I was wondering if stronger springs were needed as well as the weight loss....Thanks for any insight!
(hardly a guru but i have had and have a bunch of these bikes) clutch plates are likely worn. Stonger springs could help, but not at this point i fear. 1st order of business is to pull the clutch cover off, remove the pressure plate, and measure the stack height of the clutch pack. If it is below minimum speck that is likely your issue. Measure the individual fiber plates too but realize there are potentially 2 outer metal plates different thicknesses from the rest. These come in diff. sizes to make up the correct stack height when putting a new clutch together. More slip.. more wear. It is only gonna get worse. Measure the height of the clutch springs and see if they cut away 1 or more of the 3 prong basket springs too. Even my superbike r6 motor that makes 10+hp more than my ss motor wont' slip with a good stock clutch. I have never used aftermarket springs, plates, baskets, slippers , etc.
Street R6's very often have worn clutches. The squids rev the tar out of them and slip the clutch for a mile! Melk is correct pull the clutch and repair. Stock parts work the best. Also pull the oil pan an clean the residue, pay close attention the the oil pick screen. There have been oil starvation issues when the clutch gets cooked.
