TOPIC:

What Rpm is you kz1000 doing at 70?
What size rear wheel?
What gearing? Front and rear sprocket

My at 70......Around 4300
Rear wheel....16"
Gearing ...front n/a....rear think 33 or 45

Would like to get it down to 2500 for long hauls

I'm running 16 -30 sprockets

At 80 mph I'm at about 3,800 rpm

Rear rim is 18"

Tire is 150 x 70 x 18

With a 16 and a 33 you should be at 3500 at 55 and 4000 at 70.
15 is stock.
Steve

I think 2500 rpm @ 70 mph might be a little unrealistic, I believe if you actually achieved that (through really tall gearing) you would have no usable power to get you out of trouble, overtake etc etc and your motor would be lugging at that speed combination.

bluezbike wrote: I think 2500 rpm @ 70 mph might be a little unrealistic, I believe if you actually achieved that (through really tall gearing) you would have no usable power to get you out of trouble, overtake etc etc and your motor would be lugging at that speed combination.

Yeah you would have to slip the crap out of the clutch to get going from a stop as well. I know it seems like you are over-reving at speed, but these engines were designed to spin. Consider this; what RPM does your car have at 70mph? my tacoma is at 3000 at 70mph and redlines at 5500 so Im at over half of my sustained RPM range to keep that speed. The tacoma has overdrive to get it into that range, so taking that into consideration 4500 at 70 seems fine to me, you are at about the same ratio of cruising RPM to sustained RPM range as most inline 4 cylinder cars.

It would have been nice if these bikes had six speeds.

For 2500 rpm at 70 mph I think you need a v twin.These sporty, short stroke high revving zed motors have a lot of valve overlap that makes them inefficient at low rpms.

Even if you could get it geared like that, with a 140 mph top speed you'll be a 5000rpm - impossible..or spin it to 10 000rpm for a 280 mph top speed, also impossible.

Gearing should be based around the tourque curve, adding or losing a tooth on the front maybe but 2500 rpm at 70mph would be badly overdone.

Trying to run at 2500 rpm at 70 mph is asking a lot from that engine. Keep in mind that air resistance (drag) increases at the square of the velocity (speed of the bike), so at 70 mph there a lot of air resistance. At 2500 rpm the KZ1000 is only making (at most) 20 hp, so I believe you will need more revs or the engine will be laboring to keep up that speed. Ed

My figures are with a 18" rim. I went to the 16 tooth years ago when the limit was 55. Dropped it down to 3500 from 4000. It does lug and I have to drop down 2 gears to get into my power band to pass. On take off I have to use the clutch more. Tempted to go back to the 15 and if I still lived in the city, I would. The 1X cams are for low end but didn't make much difference on take off. That's how it is.
Steve

If you have a 16, you can go with the 16 counter shaft but I'd keep the 35 rear. You'll lose too much low end if you go smaller.

Will check sprockets this evening. Must be getting a little old

You could boost tourque by tweaking your valve timing by retarding and reducing overalp, but as 650ed made the point, these motors are don't have much power at low rpm. Drag co-efficient on a bike is higher than that of a car, even when fully faired,

Shorter duration milder cams timed right would also bring the tourque down lower.

Try to use the biggest front sprocket you can to reduce chain wear.

spdygon wrote: What Rpm is you kz1000 doing at 70?
What size rear wheel?
What gearing? Front and rear sprocket

My at 70......Around 4300
Rear wheel....16"
Gearing ...front n/a....rear think 33 or 45

Would like to get it down to 2500 for long hauls

My 750 turns 5k at 70 mph with stock gears. I lowered the rear sprocket to get it down a chunk, but nowhere near 2500. Mine used to spin about 4200 at 70 mph running the small rear cog.