Author Topic: Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.  (Read 1245 times)

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Offline Spanner 1

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Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.
« on: September 10, 2009, 05:22:35 PM »
Pulled 7K R.P.M. in 5th. gear today on a 'quiet' piece of highway, but my speedo lags behind at speeds over about 60 according to other riders riding beside me. I read 70 when they read 80 mph. So anyone know what speed on a K1 @ 7, 000 rpm? Standard sprockets, I believe.....
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Offline fergie

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Re: Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.
« Reply #1 on: September 10, 2009, 06:11:52 PM »
I don't know about 7k in 5th. but a healthy cb750 should be good for 125 mph top speed.
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Offline myhondas

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Re: Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.
« Reply #2 on: September 10, 2009, 06:56:02 PM »
Ray,

My original K4 which has less power than your K1 was 120mph @ 8500rpm.....so you were probably doing 110 or so. How's it going anyhow? sounds like you need a new speedo. I am debating on going up to michigan with my tank to have it clearcoated over the signatures by my painter this weekend....want to wait a little cause I will not have a bike while he has the tank.

ray
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1974 CB 750 K4 IN PART-OUT PROCESS (my original bike)
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Offline Kevin D

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Re: Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.
« Reply #3 on: September 10, 2009, 06:59:47 PM »
I'd say about 15mph per 1000 rpm so 7000rpm about 105mph

Not so easy to read this chart on manual page 10, it kinda confirms that, but the grid is in kph.

http://data.sohc4.net/HSMCB750_0.pdf

from the chart:  a little more than 166kph at 7krpm
                       and convert 170kph=105mph
« Last Edit: September 11, 2009, 02:58:07 AM by Kevin D »
71 CB750 K1
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Offline Spanner 1

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Re: Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.
« Reply #4 on: September 10, 2009, 07:32:56 PM »
Thanks, Kevin and thanks Ray.....I think your fab Honda 50 would love to be ridden for a few days until your tank comes back. Life passing by at 25-30 mph is lovely !!
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline bucky katt

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Re: Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.
« Reply #5 on: September 10, 2009, 07:57:04 PM »
i had 95 or so at 9k........with 52 rear sprocket and 17t front one, 18" rear rim.
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Offline ekpent

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Re: Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.
« Reply #6 on: September 10, 2009, 08:30:01 PM »
How was it handling Span-did it feel good. My old girl would take take me there -her engine is purring real good but I shut her down around 85-not ready to do the "TON" yet--- Ride Safe----Eric

Offline Spanner 1

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Re: Could 7,000 R.P.M. in 5th. = 110 mph ?...K1 750.
« Reply #7 on: September 10, 2009, 09:15:06 PM »
Doing the 'TON' on a 40 yr. old bike is scary, but it honestly felt solid and I was sitting up almost in a cruising position too....your bike looks really nice, bet it sounds good with them drag pipes. If I had a video cam I'd post a ' 0 to 100 mph on a K1'  tank- cam video, oh wait, that's an illegal speed, ah well !!
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....