I've got a VFR800 with F/I and find it difficult to get good (trailing) throttle response in corners. The throttle seems more like an on/off switch. It sometimes gets a bit hairy when I'm mid-corner and let off the throttle a bit too much and the bike tries to stand up. Anybody got a fix? I did find that if I adjust all the play out of the throttle cable that I have given myself a little more control over this situation. I think it's the nature of F/I, or at least this bike. Maybe a map change is in order, but I've grown to expect it so it's not so much of an issue as it once was. Can anyone explain why a bike wants to stand up mid-corner if you brake or chop the throttle. It's hard to explain to a new rider that to spite your instincts sometimes you just have to drive out (under power) of some bad situations. It is the hardest thing for me to do, and believe it's the most difficult trick to being an accomplished rider. In most day to day situations you just don't encounter the need to have it in your bag of "survival tricks". When you need it, you really need it!!! In most cases coming into a corner hot and hitting the brake hard, or chopping the throttle is a quick way to learn the hard way what a "highside" is.

 

Sorry, I can't help. I don't have fuel injection and I clearly do not ride as hard as you. For the record, the VFR is what I would like for my next bike, I'm looking for a '98. I figure with 49,000 miles on my '85 Nighthawk 650 it is time to upgrade. Good luck getting this issue of yours sorted out.

 

I have FI on my bike and have no such issues. I ride hard and corner equally as hard but have never noticed this. Could just be the bike. I've ridden several other FI bikes and have not seen this.

 

Triple-H; I think you will love the VFR. The bike does have a couple of issues. Some owners have had problems with the rectifier going bad. In most cases it after high mileage +- 20K, but I know of others with a lot less. It's a $30. part, but when it goes the bike won't start and can be a pain in the butt. A number of new owners have reported tranny issues when the bike is new that go away after a few thousand miles. My bike will still rejects a soft shift into sixth gear sometimes.

 

Most fuel injected bikes have the throttle lag - it is most noticible on sportbikes when driven hard. The late 90's Suzuki's (TL, GSXR's) had such dramatic on/off throttle response than they had to recall them for remapping. This lag is caused by the delay in processing info from the throttle postion sensors. The new '02 VFR/ CBR954 have 12 hole injectors and a faster processor to minimize this condition. Early reports have the new R1 with best fuel injection system available on a sportbike. It's so good you'd swear it was carbureted!

 

I've noticed the same issue with all older FI bikes (and newer ones w/shaft drive) but I just believe the FI requires a steadier throttle hand. Can't say about recent sport models like the VFR800, which should probably be the S2K's official motorcycle companion...

 

Many of the fuel injected bikes I've seen have less sophisticated "throttle position sensor" technology, rather than some sort of air mass flow sensor. Basicly, just measuring how far open the throttle is cranked and dumping in a pre-calibrated amount of fuel. Much cruder than what our S2000 has.

When coupled with advanced emissions (02 sensors and the like) on bikes like the BMW Oilhead R series (R1100, R1150, R1200), this can create "surging" if the throttle cables are not balanced *perfectly*.

Perhaps the lack of smoothness you are describing is also related? What type of throttle/air sensor does the VFR use?

On the "no chop/no brake in corners" rule. Do it in an S2000 and you might slide the rear or spin. Do it on a bike and you'll likely run head-on into the car/truck coming around the corner the other way. Very dangerous, and critical to teach new riders to fight the instinct. Far better to lay the bike down because you gave it too much lean angle then chicken out in a corner, grab a handful of brake, and go head-first into a car. In general, though, bikes can corner at much more aggressive lean angles than new riders would imagine...

 

Two points.
First, not all FI bikes are overly sensitive to throttel. I owned the first FI bike on the road over 20 years ago - a GPZ1100 Kawasaki. I can honestly say that bike had the best throttle response of any bike I have ever owned bar NONE - FI or carby. However, as PFB correctly points out that bike used a MAF rather than a TPS - I am sure this helped.

Second, as for bikes standing up mid corner, it has nothing to do with FI. I have noticed many later generation bikes (i.e. post 1990) have this trait. My Bandit B12 (non FI) is particularly bad in this regard if you touch the brakes. I'm sure it has something to do with the frame geometrys / tyre shapes we are seeing on bikes now as I never experienced it to anywhere near the same degree on older bikes.

 

Thanks for the heads-up about the rectifier. I agree, I think I will love the VFR!

 

Chipster,

You need a Power Commander, which enables you to re-map your fuel curves via a laptop. They really work well!

http://www.powercommander.com/