18/40 sprockets

[GLIDEMAN]

I have an '06 busa. With PCIII, Yosh slip-on. TRE, small air box mod and 40 shot dry nitrous that I would use on some runs. Are 18/40 sprockets a reasonable starting point for the Texas Mile? I have read all the posts on sprockets. I now have 16/42 and never was that interested in top speed runs, until now.

[Texanzone]

18\40 may be a Little much you would probably do better with 17\41 or 17\40 ,the weather you and your bike weight and power all figure in

[GLIDEMAN]

18\40 may be a Little much you would probably do better with 17\41 or 17\40 ,the weather you and your bike weight and power all figure in

BASICALLY, I SHOULD GO BACK TO STOCK SPROCKETS? Thanks.....Is there a combination that allows me to keep my current length ZZZ chain which I replaced with these second set of sprockets recently and and keep the 42 rear sprocket??

[Texanzone]

you could try a17\42 ,do you know how much power you have and how much do you weigh ,we have a head wind at the mile ,Oct is not as bad most of the time and sometimes not at all---------- a 18\43 is close to a 17\40

[GLIDEMAN]

you could try a17\42 ,do you know how much power you have and how much do you weigh ,we have a head wind at the mile ,Oct is not as bad most of the time and sometimes not at all---------- a 18\43 is close to a 17\40

Thanks again--- Out of curiosity--is it lack power on a stock bike or the NOS, etc. that makes 18/40 a bad combination?? I weigh 230 with leathers.

[Texanzone]

I don't know where your at with power but I can not pull 18\40 to red line and I weigh alot less than you ,I made 200 hp on the dino

[GLIDEMAN]

I don't know where your at with power but I can not pull 18\40 to red line and I weigh alot less than you ,I made 200 hp on the dino

Thanks for the information..............

[RansomT]

I did my best speed ~204 MPH with a similiar set up to yours using a 18/40.  Nitrous is different than N/A becuase you will make more torque lower in the RPM range. You will drop TQ off more rapidly above 10K RPM, percentage wise, than N/A.  I would suggest either a 17/39 or a 18/40.  However, the problem you will encounter is loss of bottle pressure.  IIRC, I was spraying only 5th and 6th gear and my bottle pressure (2.5#) would drop from 1200 psi to 750 psi.  I had it regulated to 800 psi.

[GLIDEMAN]

I did my best speed ~204 MPH with a similiar set up to yours using a 18/40.  Nitrous is different than N/A becuase you will make more torque lower in the RPM range. You will drop TQ off more rapidly above 10K RPM, percentage wise, than N/A.  I would suggest either a 17/39 or a 18/40.  However, the problem you will encounter is loss of bottle pressure.  IIRC, I was spraying only 5th and 6th gear and my bottle pressure (2.5#) would drop from 1200 psi to 750 psi.  I had it regulated to 800 psi.

I also thank you for the comments---You are talking about being on the nitrous for the 204 MPH with 18/40??

[Texanzone]

I did my best speed ~204 MPH with a similiar set up to yours using a 18/40.  Nitrous is different than N/A becuase you will make more torque lower in the RPM range. You will drop TQ off more rapidly above 10K RPM, percentage wise, than N/A.  I would suggest either a 17/39 or a 18/40.  However, the problem you will encounter is loss of bottle pressure.  IIRC, I was spraying only 5th and 6th gear and my bottle pressure (2.5#) would drop from 1200 psi to 750 psi.  I had it regulated to 800 psi.

your right ,i went back and look at my power graft and my tq starts droping at 9000 and by 11000 its down to 92 or 3, I ran some pretty speed with the 18\40 but I was leaveing quite a few rpms on the table

[GLIDEMAN]

Well, I think that I am going to like the 18/40 sprockets. I put it on the dyno. The dyno gives an error message if the speed is higher than 185 MPH. We first corrected the bike speedometer with the speed-o-healer. The bike without the nitrous in fifth gear shut the dyno down and pegged the speedometer. But, I am not sure if that actually means it would be over 200 MPH in sixth gear with or without nitrous since I would be on it and having to deal with the tuck position, wind and my own fears of going at that speed.

[FASBUS]

Another good thing about using an 18 up front is every tooth you change on rear will be less drastic........

[Texanzone]

Well, I think that I am going to like the 18/40 sprockets. I put it on the dyno. The dyno gives an error message if the speed is higher than 185 MPH. We first corrected the bike speedometer with the speed-o-healer. The bike without the nitrous in fifth gear shut the dyno down and pegged the speedometer. But, I am not sure if that actually means it would be over 200 MPH in sixth gear with or without nitrous since I would be on it and having to deal with the tuck position, wind and my own fears of going at that speed.

you can do it