my CBR: 1/4 miles times and speedo woes

[yamablaster24]

Well i took my bike to the track for the first time today and they say the bike should run a 11.28 bone stock from the factory. I have a vance n hines exhaust and jetted and the best i could get was a 11.9. Either way i want to make this better. How do you guys launch your bikes? I got it up to about 5-6,000 rpm and let clutch out fast but didnt pop it and i took off immediately doing a controlled 1 foot high wheelie until i hit 2nd gear. I raced a hyabusa and just flat out smoked his tire even into 3rd gear. Do i just need something faster or should i be burning my tire instead of wheelying. Also me and a couple of friends ( including a girl i like ) are on our way back from the race and they are all in a mustang and they speed up to about 120 when i pass them doing maybe 150 according to my speedo then i top the bike out at about 176 ish. Now i know for a fact my 600 doesnt not do anything over 155 so what up with my speedo. It is also off 10 at about 45 mph. Any way to fix it? Is it connected with front wheel?

[GPracer2500]

Speedos on bikes are never (well, almost never) accurate and read high as you've discovered. Not sure if there's a way to change that--probably there's a way but you'll have to research to fine out how. On many modern bikes the speedo is driven from a sensor on the countershaft and sent electronically to the speedo's display.

As far as the quarter mile time, there's no "rule" that your bike should run a certain time. Track surface conditions, track elevation, air temperature, gearing, rider weight, manufacturing tolerances between bikes, etc. etc. all impact 1/4 mile times. For example, I remember a few years ago when SportRider magazine broke 10 seconds on a ZX-10. The bike was ridden by Kent Kunitsugu who is a pro-level rider and he weighs about 130lbs (I'm guessing--he's a pretty small dude). He made umpteen passes before finally breaking 10sec and ruined the clutch in the process. Does that mean that on a different day, on a different track, with a different ZX-10 you or I could break 10 seconds? No.

If you've seen some published figure from a magazine or something that says your bike year/model can run a 11.28 and you ran an 11.9 then I'd say you did pretty damn good. I use to ride a CBR900RR that was "suppose" to run in the low to mid 10s. I don't think I ever broke 11 seconds. Also, I had seen 180mph on the speedo of that bike when I know my bike could only touch 170 on a good day. Probably not even that fast...

[suck my pipe]

is it a cbr 600? I havent been to the track yet but mines supposed to run 10.3. "750"

[z400roosteR]

For your speedo question look into the "speedo Healer" on google. It's a very popular mod for street bikers that want an accurate speedo.

As for your 1/4mile time what kind of bike are you riding? From my opinion i would say slip the clutch that is the best way to take off for racing.

[JLanphear]

Originally posted by GPracer2500
........................................

Finally a post I agree with 100%! Well put man.

So far I have had my Gixxer 750 speedo reading 186 with more to go, but they are supposed to really top out around 170 +/-.

Originally posted by yamablaster24
Well i took my bike to the track for the first time today and they say the bike should run a 11.28 bone stock from the factory. I have a vance n hines exhaust and jetted and the best i could get was a 11.9. Either way i want to make this better. How do you guys launch your bikes? I got it up to about 5-6,000 rpm and let clutch out fast but didnt pop it and i took off immediately doing a controlled 1 foot high wheelie until i hit 2nd gear. I raced a hyabusa and just flat out smoked his tire even into 3rd gear. Do i just need something faster or should i be burning my tire instead of wheelying. Also me and a couple of friends ( including a girl i like ) are on our way back from the race and they are all in a mustang and they speed up to about 120 when i pass them doing maybe 150 according to my speedo then i top the bike out at about 176 ish. Now i know for a fact my 600 doesnt not do anything over 155 so what up with my speedo. It is also off 10 at about 45 mph. Any way to fix it? Is it connected with front wheel?

Too many more 176 MPH runs down the interstate and you won't be worrying about 1/4 mile times!!

[yamablaster24]

yeah thats what i was thinking, it was 95 degrees out, my rear tire is completely bald,very very humid out also. I mean my motor is 11 years old i know it isnt going to run like brand new lol. So i guess im happy with the 11.9. Maybe some nos?Also i could have shaved .5 seconds off of my reaction time ( had a .505 ) so i guess ill work on it next time at the track i only got 4 runs in and i still learned a lot each time.

[duke416ex]

The speedo is probably off because of gearing. Do you know if it has ever been changed on teh bike, my 600 was -2 in the front and it was off like 10 for every 50 it read. So if it said 50 I was only running 40 and 80 instead of 100. The launching is just a person to person thing. I do my launch similar to yours, some people slip the clutch, very few do I see spin the tire on perpose, and if they are they probably aren't getting the time they could. Another thing to remember is posted times for bikes are usually done by pro racers and then adjusted to altitude, you will rarely ever see a completely stock bike get very close to what they say it will.

[Blue250X]

Originally posted by yamablaster24
yeah thats what i was thinking, it was 95 degrees out, my rear tire is completely bald,very very humid out also. I mean my motor is 11 years old i know it isnt going to run like brand new lol. So i guess im happy with the 11.9. Maybe some nos?Also i could have shaved .5 seconds off of my reaction time ( had a .505 ) so i guess ill work on it next time at the track i only got 4 runs in and i still learned a lot each time.

haha, id edit "nos" to be nitrous, lol, ive seen ppl catch hell for that one

[yamablaster24]

lol ever since i saw fast n furious ive called every nitrous oxide system Nos and so does everyone i talk to.. excuse me nitrous lol. I think NX makes a kit for my bike for like 300 dollars hehe

[Blue250X]

Originally posted by yamablaster24
lol ever since i saw fast n furious ive called every nitrous oxide system Nos and so does everyone i talk to.. excuse me nitrous lol. I think NX makes a kit for my bike for like 300 dollars hehe

haha, i call it nos too....i feel stupid after i do. but wat can ya do

[z400roosteR]

Originally posted by JLanphear
Finally a post I agree with 100%! Well put man.

So far I have had my Gixxer 750 speedo reading 186 with more to go, but they are supposed to really top out around 170 +/-.

How old is this bike your talking about? Cause i don't think a 750 tops out at the set margin. And if it's within like the last 3-4years it did NOT have more to go cause there is a global agreement for motorcycles to be goverend at 186mph or 300kph.

[GPracer2500]

Originally posted by z400roosteR
How old is this bike your talking about? Cause i don't think a 750 tops out at the set margin. And if it's within like the last 3-4years it did NOT have more to go cause there is a global agreement for motorcycles to be goverend at 186mph or 300kph.

The 300kph "limit" is for actual speed, not what the speedo says. Anyway, he said 170+/- is what it might actually do, not 186mph.

[yamablaster24]

here is my 12 second run, after this i got my reaction time better and got in the high 11's

http://media.putfile.com/matt-lance-goin-down-norealk-on-the-bike

[z400roosteR]

Originally posted by GPracer2500
The 300kph "limit" is for actual speed, not what the speedo says. Anyway, he said 170+/- is what it might actually do, not 186mph.
On the newer bikes the speedo will not READ past 186mph...go get one and top it out and see for yourself.