Regearing

I see, I guess altitude must make an incredible difference, cuz I'm 16/43 6 over arm and my b!tch will scoot. It will come up quick on a prepped track, and spins like there's no tomorrow on the street.
 
I live at 2700' altitude and the DA gets to the 5-6000' level all the time. I ride up in the Angeles Crest and it goes up to 7000' max. I went 16/42 and I wheelied so bad I could not even get down the strip. But, I am a wimp. Then I went 17/42 and ran my best ET until tonight hitting the rev limiter in 3rd before I got to the end of the 1/4. Next I ordered a 41T rear sprocket and I am running that right now. My SpeedoHealer shows that I hit 134 at the rev limiter with the 41T rear and I go through the 1/4 at a max of just over 132. Using the 134 for the 41T gear, you would be at 130.8 with a 42T rear in 3rd and 123.1 in 3rd with a 16/42 gear. With your trap speeds you should try a 42T rear sprocket first to see how it works. They are relatively cheap and easy to install and the stock chain works great. I hit a personal best tonight and, I am still learning, but the bike is much easier to launch than it was with the 16/42. 16/42 felt like insane gearing and the engine was buzzing on the freeway. The 41T rear gear is a 2.5% change and easy to do. The 42T rear gear is a 5% gear change and easy to do. Of course, if you are lowering your bike and strapping it and putting an extended swing arm on it, disregard all I have said. My bike is stock and set up for corner carving with 37PSI front and rear, even at the strip.
 
Unless I missed it we're still guessing on what sort of bike your riding, year model and other mods...
 
One last observation about these gears. 16/46 gears would do approx:
1st = 65
2nd = 88 (with stock gearing 1st goes over 80)
3rd = 112
4th = 133.5
If you can ride, and you are trapping around 130, this would not be a bad gear ratio to run to use the first four gears in the 1/4.
Top speed would be limited to about 155 and 70 MPH would be 4600 RPM in 6th, 80 would be almost 5300 and 100 would be almost 6600. 16/46 would be geared too short for the street IMHO, but, I live in the wide open spaces.
Post a before and after time slip so we can see the difference in the 1/4.
 
i have 16/42 gearing, i weigh 275, stock except the gearing. If i shift at 11 grand into 3rd gear the front wheel is a minimum of 8 inches off the ground. Sounds like you may have performance issues with your bike.
Happy trails, Dan
 
A busa with only 130 hp you need to go to a dyno and get it tuned at your sea level cause something's wrong sounds like to me?
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I am from Colorado Springs originally and I can tell you he is losing so much due to altitude. I had a camaro that ran like a turd no matter what I did. When I took it to Kansas though man would she fly. In order to get the launch we all know and love he is going to have to do alot more. Timing and fuel are critical in altitude, the timing has to be bumped up a couple degrees and the fuel has to be right. Spend the money and get it tuned properly and then you had better hold on tight.
 
Heres my 2 pennies, If you want to win a race or have faster times, spend the money get the horsepower then hold on. And then depending on what your racing , whether it be an 1/8 or an 8 tenths of a mile , which I prefer, then set it up accordingly with the right gears
 
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