I've used it. Worked well for me, no difficulty hitting the button with the throttle pegged open on the front straight. Normal length thumbs, as far as I know.

 

I've never actually used the lap timer function on my bike.

It was, back in the mists of antiquity, say 6 or 7 years ago, quite a cute idea. Then mobile phone makers started adding GPS to their phones, and then a once a year track day rider suddenly had access to data logging, that race teams 10 or 12 years ago used to spend squillions to get.

Personally, I used RaceChrono on a Nokia phone, but I am sure that there are similar apps for iPhones available.

If you add a blue tooth dongle thingy to the OBDII port, you can also gather all sorts of interesting data from the bike, as you ride round the track.

regards,CrazyCam

 

Looks like you're riding with your elbows out a fair bit, making your hands sit an an angle to the grips. If you tuck your elbows in a bit (as you would if you were "faningin' it down the straight') it'll naturally bring your thumb closer to the button.

Its all a personal grip thing - I know on my old Suzi GSR600 - I used to ride with my hands in a similar position.

I've used my lap timer on the track, and the hardest part I found was remembering to push the button each time I crossed the line!

 

It's a bit annoying to have to press a button to click off laps, and it's just not as accurate as a beacon- or GPS-based system, as you'll never hit it at exactly the same time every lap. M'boy has a similar built-in lap timer on his 848, and found it annoying; he got the IR plug-in instead.

I have a MyChron Light TG, and it is fantastic. Huge numbers, easy to read, good range, and you can set a 'minimum laptime' so if a bunch of goobers put their beacons all up and down the straight, you still only get one read per lap.

http://www.aimsports.com/products/tg/index.html

 

It is a "little" cumbersome since you have to use your right thumb on the starter button while you have the throttle pegged. I just pick a reference point, like the end of a rumble strip, at the same point each lap.

It's never going to be perfect, but once you get yourself trained, you can at least tell the difference between full seconds so you can measure your consistency and progress during the day. It's no use trying to split tenths though, it's unlikely it'll be that repeatable.