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Offline PeWe

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CB750 porn
« on: January 26, 2013, 09:13:50 AM »
Time to stop being lazy and do my bike.  Plenty of parts are waiting to be assembled.
Videos like this helps to get inspiration.  :o
CB750 HONDA 4 BIG BORE KIT 1050
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CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Greg H

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Re: CB750 porn
« Reply #1 on: January 26, 2013, 12:32:13 PM »
You're not wrong mate . I've watched that clip a few times in the past and it gets the old juices going  ;) .
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Offline Sam Green Racing

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Re: CB750 porn
« Reply #2 on: January 26, 2013, 02:22:28 PM »
Only 95bhp from a 1050, needs a Mike Rieck head. ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

Sam. ::) ;)  nice video though.
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C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline Leino

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Re: CB750 porn
« Reply #3 on: January 27, 2013, 05:27:51 AM »
First set of blue pistons I've ever seen  ::)
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Offline Sam Green Racing

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Re: CB750 porn
« Reply #4 on: January 27, 2013, 05:51:12 AM »
psychedelic Juha, very 70s don't you think. ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D
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C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline Leino

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Re: CB750 porn
« Reply #5 on: January 27, 2013, 06:03:01 AM »
Don't remember much about the 70's put I'm sure you know what you are talking about  ;D
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Online CycleRanger

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Re: CB750 porn
« Reply #6 on: January 27, 2013, 08:30:12 AM »
pods.... ::)
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Do you have a copy of the Honda Shop Manual or Parts List for your bike? Get one here:
https://www.honda4fun.com/materiale/documentazione-tecnica
CB750K5        '79 XL250s     CL350K3
CB750K3        '76 XS650      '76 CJ360T

Offline Leino

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Re: CB750 porn
« Reply #7 on: January 27, 2013, 10:57:37 AM »
Quote from: CycleRanger on January 27, 2013, 08:30:12 AM
pods.... ::)
With RS's why not?
Unless you mean he should be using velocity stacks instead of pods  ::)
« Last Edit: January 27, 2013, 10:59:40 AM by Leino »
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Offline Retro Rocket

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Re: CB750 porn
« Reply #8 on: January 27, 2013, 02:23:22 PM »
Quote from: Leino on January 27, 2013, 10:57:37 AM
Quote from: CycleRanger on January 27, 2013, 08:30:12 AM
pods.... ::)
With RS's why not?
Unless you mean he should be using velocity stacks instead of pods  ::)

Pods are fine with the RS carbs but they look like emgo, which would account for the rolling eye's smiley..... Put some K&N's on it..... ;D
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750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Online CycleRanger

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Re: CB750 porn
« Reply #9 on: January 27, 2013, 04:51:31 PM »
My comment was meant to be tongue-in-cheek. Yes, pods are fine on that bike but those do look cheap.
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Do you have a copy of the Honda Shop Manual or Parts List for your bike? Get one here:
https://www.honda4fun.com/materiale/documentazione-tecnica
CB750K5        '79 XL250s     CL350K3
CB750K3        '76 XS650      '76 CJ360T

Offline Greg H

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Re: CB750 porn
« Reply #10 on: February 10, 2013, 01:04:27 AM »
Quote from: Sam Green Racing on January 26, 2013, 02:22:28 PM
Only 95bhp from a 1050, needs a Mike Rieck head. ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

Sam. ::) ;)  nice video though.
O'K Sam , how much RWHP would you expect from  a full race motor of similar capacity ,fitted with a Mike Rieck head . ;) . And a second question do you know what the RC Cobra motors were producing at the rear wheel back in the day ? .
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Offline Sam Green Racing

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Re: CB750 porn
« Reply #11 on: February 10, 2013, 11:28:44 AM »
Hi  Greg, I don't know what the Cobra motor put out and I don't know what a full race motor would put out with Mikes head work.
As well as I know Mike, (we have visited one another several times) I have never heard him say that he has built a full on race motor.
What I do know is that when I asked him to build my 836 motor, I based it on the specs of a motor that Mike had built for a customer that pushed out 94bhp. Mikes own motor (911cc I think) put out 98bhp at the rear wheel.
Bearing in mind that these motors are only hot street motors and well under 1050cc, I reckon with a race cam and high comp 1050 pistons, you must be looking at well over 100bhp.
Mike's own bike is now out to 1000cc with the use of his own billet block, I'm sure that when it goes on the dyno it will produce over 100bhp and it is still only a hot street motor. ;)

Sam. ;)
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C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline Greg H

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Re: CB750 porn
« Reply #12 on: February 10, 2013, 01:05:06 PM »
I know that it is possible to estimate RWHP fairly accurately using the bikes terminal speed over the quarter , I have the formula somewhere . My 970 used to run 123mph in the quarter, and if my memory serves me right, I estimated a RWHP figure of 85/90 bhp back then. As you know back in the day ,if a bike was running the terminals it was making the power, ie the strip was our dyno . Knowing that some guys ran speeds of over 140mph in the quarter on sohc Hondas in the past, I think that we can assume ( all things being equal) that their motors were making substantialy more than 100 RWHP . 
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Offline jweeks

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Re: CB750 porn
« Reply #13 on: February 10, 2013, 03:04:15 PM »
Greg,
     Check out some of Bear's builds that were over 120 horses. He's pushing cc's where Cycle X is pushing better cylinder heads. Marry the two and what do you get? (please, no answers that include the word "breakage")  ;)

                                                            Jon Weeks
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Offline Sam Green Racing

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Re: CB750 porn
« Reply #14 on: February 10, 2013, 03:07:22 PM »
I agree Greg and there are web sites on the net where you can dial in the figures to get a BHP figure.
I have used them in the past and although they have proved very accurate at times, other times they have been way off when the BHP figure was already known.
To give you an idea how data can vary, the first CB750 I built turned 60bhp at the wheel and did just 92mph across the stripe.
That was with my mate riding it who was nearly 5 stone heavier than me. When I rode it, the speed went up to 105mph but my ET was over a second slower, the power remained just the same.
When the same bike was tuned, the power went up to 86bhp, much like your figure but only had a TS of 116mph, I didn't get to ride the bike in 836 form but could it have reached 123mph with  me on it  :-\ I'don't know but I doubt it.
One thing I really do agree on is the guys turning 140mph plus are making well in excess of 100bhp. 8) 8)
Anyway, just get on with the bike then we will know. ;D ;D ;D ;D ;D ;D with the right cam and pistons, I'm sure you will be joining the 140+ brigade.  ;)

Sam. ;)

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C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline BLUE71TURBO

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Re: CB750 porn
« Reply #15 on: February 10, 2013, 07:24:08 PM »
 So whats my 1000cc turbo engine at 20lbs of boost making ??  Running VP C-16 FUEL.   :o
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Offline Sam Green Racing

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Re: CB750 porn
« Reply #16 on: February 10, 2013, 10:57:44 PM »
are there no dyno's in So Cal ?.... ;D ;D ;D ;D ;D ;D ;D

Sam. ;)
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C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike
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