Ok so I just picked up a 99 F4 with 14,000 miles. The guy I bought it from put a full yoshi pipe on it, knn air filter, Race Jet kit from Factory Pro 1 down 2 up 520 vortex sprockets, And thats all he told me. He had it for about 8 months then lost his job and sold it to me for $1500. When I bought the bike from him he told me that the guy that had owned it before him had a bunch of engine work done to before he sold it.

So I was out riding the other day with my buddy (who has an 05 cbr1000rr all stock except for a two bro's slip on) we got out on a nise long straight away in the middle of nowhere and decided to open them up (55mph 2nd gear for both of us) my buddy was only inching away from me then next thing I know I'm slowly pulling on whim and pass him when I looked down at my speedo it was reading about 15 mph over the 185 mark I figure hey no big deal I know my speedo is off cause of the gear change figure we took it up to around 160 mph and my buddy backed off. When we got to our next stop I asked him how fast we where going he said "when I passed him he was hitting his speed limiter at 185mph"

So my question is what the F^&* could be done to my bike or could his speedo be off by allot?

 

In my experience a stock bike will show up to 20mph faster topped out than your actually going. I use my usb gps and my laptop and record my trip. Then I just go back and read the data for accuracy. Is your buddies bike sprockets changed? yours being geared like it is should accelerate faster but lose topend. It doesnt matter what you do to the motor, the transmission can only top out at its max.

 

Nope his is stock gearing just the slip on I will have to mount my gps on my bike it will record highest top speed and average moving speed.

You have a very good point about the transmission not allowing it to go any faster. I will post up some pics of the gps indicated speed if it is still around that speed.

Thanks for the knowledgeable answer.

 

He must have not been topped out because his top end is going to be higher than yours.

 

Thats what I thought to, thats the whole reason I asked.