Got a problem with my bike

i just bought a yamaha r6 and sometimes i will be cruising down the street and it says im going 45 mph, i look up then look down at the speedometer then it will show 0mph while im still cruising, then i stop at a light and go and it will be working again. The guy i bought it from told me about it and said that it has been happening ever since he change the tires and brakes. Also on the left side of the bike it has a fuel clear thing you could see how much fuel you have, it looks like its full but then the fuel light is on, i go pump gas and it stops at like 1 dollar and i go riding around a bit and the gas light is on again, any one know what the problem could be?

i know its not an r1 but maybe someone will know

I think the R6 has the speedo pick up on the countershaft cover. So, either the pick up could be bad, or the thingie that trips the pick, which is on the countershaft sprocket, is a problem. Probably worth looking at...

As for the fuel thing, why not look in the tank to see ho much fuel you've put in?

other than the pick up sensor check the plug on the back of the speedo assembly it's self. It may not be plugged in securly making an intermediate problem.

You may want to check the R6 forum also

http://pub114.ezboard.com/byamahar6messagenet