I have a 2001 Hayabusa and I'm experiencing a slight problem. The bike has tremendous power and torque, but when I'm cruising down the road in sixth gear around 60-70 mph, the bike feels like it's missing and almost like it's choking itself out. I roll on the throttle and there's instant response, and I have no other problems with the motor at all. Have you heard of this problem? I have Yoshimura RS-3 race slip-ons, with a BMC air filter. Thanks for any inputs you can make.
The slip-ons and air filter you've installed on your Hayabusa have most likely caused it to run lean at that cruising speed, resulting in the missing and choking feeling you're experiencing. Your bike would certainly benefit with some fuel injection help to richen up that part of the rpm range. A Power Commander (www.powercommander.com) or Techlusion TFI (www.techlusion.com) add-on box piggybacks the stock ECU and modifies the injection signal, or you can tweak the stock map with a Factory Pro Teka SFI (www.factorypro.com). The Hayabusa has been around for a few years now, so there should be lots of knowledge and known setups that work with your modifications.
A Slipper Clutch That Doesn't Quite Slip
I have an '06 R1 LE, and the slipper clutch seems to be, well, not quite up to par. The clutch doesn't want to fully disengage at times. You really notice it at slow speed, like coming to a stop, and more so when the engine is not up to temp. It seems to take the torque of the engine to actually break the contact of the plates and fully disengage, not the actual pull of the clutch lever. It can be a problem, as you might guess, as the engine wants to keep pulling even with the lever to the bar. Have you guys heard about this from anyone else, or know where I can get info about it? I love the bike, but the clutch has me concerned.
Our test bike's clutch works properly and fully disengages when the lever is pulled in. First check your bike's oil level and clutch-lever free play, making sure your oil level is in the window with the bike level, and the clutch has 10-15 mm of free play. If you can't set the adjuster at the lever for that amount of free play, follow your owner's manual and adjust the cable near where it enters the clutch cover. If you still can't set the lever for the right amount of play, you'll have to adjust the set screw on the clutch actuation rod, which is under the clutch cover-refer to a service manual for the right procedure. If the set screw isn't adjusted properly, no amount of fiddling with the outer adjusters will make the clutch work properly.
Another explanation is that the clutch may have been put together with insufficient oil, or there is an oiling problem and the plates are too dry and sticking together. Your dealer should be willing to check that under warranty.
Did We Mention We Get A Lot Of Tire Questions?
I was re-reading the December '05 issue on tires and have a question about the cupping/rippling effect on front tires. My R1 has Dunlop D208s with several thousand miles left in them, but the cupping/rippling is to the wear bar in places. Most of this appears to be off-center, at about a 30- to 40-degree angle on both sides. I always make sure inflation is to recommended pressures. For the cost, it seems somewhat unacceptable. I have tried different brands, and as a motorcycle mechanic I have seen it to be a common problem on different bikes. Is there a reason/solution, or do we have to live with it as normal?
Dale M. Cole
Tire cupping, especially on front tires, is natural, and you should expect it to some extent. Deformation of the tread blocks, especially under braking, causes uneven wear on the face of each block, leading to cupping or scalloping over time. That said, you should still check your bike's steering head and wheel bearings for wear, as well as the front fork for any sloppiness. Cupping that is uneven around the circumference of the tire is a sign of improper balancing. Both overinflation and underinflation can cause excessive cupping; on our R1 test units with D208 and D218 tires, we generally see little cupping after a couple of thousand miles using 32 psi in the front tire.