Shift Points

slickwill · 02-13-2007, 3:19 PM

I created a graph that shows the mathematically ideal shift points for a 2002 CBR 600 F4i with stock gearing if you are trying to get maximum acceleration. The correct shift points would be the point where the line for 1st crosses the line for 2nd and so on. By shifting at those points you maintian your bike at the highest possible horsepower. You can see that Honda has done the math on these ratios as it is possible to maintain your bike in the proper RPM range to be making over 90hp from 76mph all the way to the listed max speed of 156mph. The graph is limited by the accuracy of the dyno chart from Sportrider that I used but it should be pretty close. I'll repeat it when I get a dyno chart for my own bike. It definately shows that there are different shift points that should be used in each gear. The shift from 1st to 2nd would be at 65mph or 13,500rpm but from 2nd to third it would be at 86mph which gives 12,900rpm then for 2nd to third it comes at 106mph which gives 12,700 rpm. By waiting to get to 110mph which puts you closer to redline you have lost 7hp. Conversely if you were to shift at 60mph in 1st rather than at 65mph your RPMs drop to the point that your bike goes from making 94.8hp to 75hp. You then have to pull for awhile before you are making good power again.

*sinfuldragon* · 02-19-2007, 4:44 PM

Interesting, I'll keep this in mind once I get to ride my bike again

slickwill · 02-19-2007, 8:40 PM

Since you are riding the same bike it should work for you. It would be different for every bike based on the dyno and gearing.

*sinfuldragon* · 02-20-2007, 7:15 AM

Quote:

Originally Posted by slickwill

Since you are riding the same bike it should work for you.

Thats why I found it so interesting

Can't wait to try it out!!

astorino · 02-27-2007, 12:55 PM

damn that looks real good and informative. wanna do one for an 04 600RR

slickwill · 02-27-2007, 2:55 PM

I need the gear ratios for each gear, primary drive ratio, and final drive ratio (Teeth on Rear divided by teeth on front). Then I need a good accurate dyno sheet. I could get first gear started for you and then explain the process to complete it for the other gears.

*sinfuldragon* · 02-27-2007, 4:13 PM

Quote:

Originally Posted by slickwill

I need the gear ratios for each gear, primary drive ratio, and final drive ratio (Teeth on Rear divided by teeth on front). Then I need a good accurate dyno sheet. I could get first gear started for you and then explain the process to complete it for the other gears.

Would that be too much to post here? That would help me out as well since while I have the same bike that you did the paper on I have changed the front and rear sprocket so its not going to be just right for me as is

slickwill · 02-27-2007, 5:35 PM

When I get home I'll see if I can condense the process down. I might have some information already done that I figured out based on going -1 and -1 +1. How are your skills in MS excel. That simplifies things a lot. I have a spreadsheet done that would help you out quite a bit but it is organized in such a way that only I would know what is going on. If I can get it cleaned up I might be able to email it to you.

*sinfuldragon* · 03-02-2007, 7:33 PM

Quote:

Originally Posted by slickwill

When I get home I'll see if I can condense the process down. I might have some information already done that I figured out based on going -1 and -1 +1. How are your skills in MS excel. That simplifies things a lot. I have a spreadsheet done that would help you out quite a bit but it is organized in such a way that only I would know what is going on. If I can get it cleaned up I might be able to email it to you.

I suck at it but my wife is a wiz with it! I would love a copy if you don't mind sharing!!