When to shift?

So I have this 1976 KZ900 LTD and the other night I "raced" it next to a friend's vintange Honda CB750 (I think). He had been working on it to get it ready to race this weekend at Gingerman raceway in Michigan and needed to take it out to test his handywork.
So we gun it at the start of an freeway onramp and the next thing I know he's slowly pulling past me around 3rd gear.
I didn't think too much of it as his bike is pretty well tuned up for some racing and I'm still working out a few maintenance kinks, but the question stuck in my head:

What is the most optimum RPM that I should change gears at to get from 0 to (insert ungodly MPH here) in the shortest amount of time?

I think I saw a doc in the filebase that shows the specs on a stock KZ900(I understand that my bike is now 30 years old and that it may not perform to the stock numbers):

torque tops off at 7500RPM
horsepower tops at 8500RPM


Would I shift at top torque, or top horsepower to get the most out of it?

It's not that I'm planning on riding my KZ into the ground (or some other vehicle), but I'd just like to know the optimum operating range.

got pods, got 4-1 exhaust if that makes any diff.
Tim

I checked out your photo in the Gallery. Very sharp!
I always thought that 8500 was the best shift point for max acceleration. The bike spools up so fast that it's kind of tricky, what with that and my jumpy tach. Do you have the stock 15/35 sproket setup?

I'll check the sprockets tonight. So far everything seems to be fairly stock except for the pods, exhaust and Dyna-S ignition. Most other changes are cosmetic.

If the bike is stock,8500,9000 with a pipe.

To work it out accurately you'd need a dyno chart but basically you should shift just past peak power so that the motor stays as close as possible to peak power when it drops into the next gear.

i dont think there is really a number set in stone,every bike is gonna be a little differant.take it out and ride the wheels off of it,it will tell you when its time to shift.if a 750 honda is whipping up on ya it definately needs some help i saw some hard running gs750 suzukis when i was younger that could hold there own with a stock 900,but ya cant have a 750 honda doing it!

ltdrider had a good point... you more than likely got out sprocketed. Not to take anything away from those ol' CB750s. They will defiantly run a hole in the wind.

Back in the day when I cared about hole shots and such I ran the police sprocket. Which were 15/41s if I remember correctly.

If you can get a bead on the RPM that wants to take the front tire off the ground in the lower gears. That should be the RPM that pulls the best in the higher gears.

I have ridden both the 900 and the 1000. There IS a distinct difference. The 900 wraps up quicker. It's kind of like comparing a 283 Chevy small block to a 350 or 400.

mrbreeze wrote:

ltdrider had a good point... you more than likely got out sprocketed. Not to take anything away from those ol' CB750s. They will defiantly run a hole in the wind.

Back in the day when I cared about hole shots and such I ran the police sprocket. Which were 15/41s if I remember correctly.

If you can get a bead on the RPM that wants to take the front tire off the ground in the lower gears. That should be the RPM that pulls the best in the higher gears.

I have ridden both the 900 and the 1000. There IS a distinct difference. The 900 wraps up quicker. It's kind of like comparing a 283 Chevy small block to a 350 or 400.

its the lighter crank in the 900;)

Is the CB750 a SOHC or a DOHC motor?
The 79-80 4 valve Hondas were alot faster
than the older ones.

I think I would be doing some tuning on the bike, then go open up a can of whoop ass on the honda

BSKZ650 wrote:

I think I would be doing some tuning on the bike, then go open up a can of whoop ass on the honda

just do what i used to do,tell em its just an old 900.its stock,honest!:whistle:

Yes I have the stock sprockets.