Why can I only reach 180mph

[Vbooosa]

The bike is a 2001 model and is stock, except for being lowered and having a 42 tooth rear sprocket.  I also have a TRE.  I weigh 162 in street clothing and I'm considered a good rider.  I tuck low enough to look through the screen, so why can I only go 180mph?  As mentioned on my previous post, our altitude is 360ft.
Last year with stock gearing I also only hit 180.
Oh ya, that tack reads approximatly 11,200.
I use a GPS.
Is this just the norm?

[JorNic Motorsports]

42 tooth rear sprocket

 

try your stock 40 and try again. maybe even a 39.

[Vbooosa]

42 tooth rear sprocket

 

try your stock 40 and try again. maybe even a 39.

As mentioned above, last year with stock gearing I also only hit 180.

I can't see how a 39 would help if I don't have the power to reach the limiter any way.

[Bergie]

tuck  

[pooh]

That's about all stock busas do.   You might get 184/185 if you practice your tuck and body position a lot.

Put your bike on a rear paddock stand facing a smooth blank wall, then place a light behind the bike and look at your shadow on the wall.  You'll see from the image what bits of you are sticking out.

[VincentHill]

You might want to "Raise" your skinny behind to allow the air to attach  

[Busashot]

It's amazing how body position can make a difference. Raising your arse a little up and against the hump will prevent from being trapped. Tightly squeeze your legs against the tank.

Tucking your arms against the tank and literally having your head below the windscreen but actually touching your chin on the tank can yield some good results. Your helmet can trap a lot of air so when under the screen you should barely be able to see the the road as your chin also should be against your chest.  Make your leathers as tight as you can stand it. Make sure your jacket doesn't fill up with air behind your neck(Duck Tape?). Your gloves should be tucked over your sleeves. Don't have lazy feet, in other words, make your feet point the same direction as the bike, not straight down.....air drag.

The more you limit air getting trapped between you and the bike the faster you will go.

I have reached 173mph(radar verified) on my 01 Busa. It has Yosh cams, BDE pipe, BMC race, small airbox mod, no pair valve, crankacase breather, 16/41. I weigh 245lbs suited @ 6'0" and I am wide at the shoulders. At 5300' altitude, I got 169mph @10,800rpms before proper techniques. When adjusting my body a few times I got to 173mph @11,200rpms(rev limiter kicking in). It also seemed like I got there faster.

Removing the mirrors may help a little. I've seen 4mph gain from a 2000 ZX12R when the mirrors were removed going from 192mph to 196mph. The Busa may pick up half that.....worth trying if you are looking for a #.

And for the sake of the bike, run a little higher octane fuel so you have no sudden lean out problems.

Steve

[joea]

decent advice, except ........octane has nothing
to do with leaness, or richness

Joe

[Busashot]

What I was saying about octane rating is that not everyone has a good state of tune and a higher octane rating is just insurance against detonation whatever the reason. When you live in a state that uses oxygenated fuels for the winter, you'd be surprise how lean a bike can get from that alone. Higher octane rating can help keep your engine alive when doing long Top Speed challenges.

Nutec 5 and VP MR9 are oxygenated and can give upwards of 6-8% increase of HP but amazingly enough, we have seen a 4-6hp increase from just ordinary pump gas without tuning.

Don't mean to get off the subject....................anyhow.......have fun and be careful.