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Author Topic: Just got back from the dyno  (Read 2387 times)

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Offline kmb69

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Re: Just got back from the dyno
« Reply #25 on: September 16, 2018, 02:44:59 pm »
Actually I'm shocked that my "old fella" comment didn't even get a rise out of you.  ::) Guess if the shoe fits. LOL

The old fart probably didn't "hear" it!  LOL  ;D  ;D  ;D

Offline Sam Green Racing

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Re: Just got back from the dyno
« Reply #26 on: September 17, 2018, 03:05:00 am »
Stout numbers Mike, well deserved Bro.

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
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Offline andy750

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Re: Just got back from the dyno
« Reply #27 on: September 17, 2018, 03:19:25 am »
Excellent numbers Mike although I am not too surprised having seen how this bike ran the other weekend. Hoping to join you at the dyno next time!

cheers
Andy
Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico (CB750K4), 2003 - European Tour (CB750K4), 2004 - SOHC Easy Rider Trip (CB750K4), 2008 - Adirondack Tour 2-up (CB750K4) , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild.
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. VStrom DL1000 2003
4. XLR650L 2006

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350

Offline jus4selling

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Re: Just got back from the dyno
« Reply #28 on: September 17, 2018, 10:48:53 pm »
Unreal #s!

Offline PeWe

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Re: Just got back from the dyno
« Reply #29 on: September 18, 2018, 08:52:41 am »
Good numbers Mike !
Bill Bentons Billet engine numbers ? Must be in that range too?

My bike stop rev at around 7600-8000 rpms (dyno and road). Before that similar. I start to think about changing exhaust, from 4-4 to Hindle 4-2-1 and see if it will continue to 9000 rpm.

Leaner jetting and you'll not get the bog around 5000 rpm, right?  Good luck on your journey beyond 110 rwhp!

Billet block work fine on a cruiser. Mine had 1 step  lean pilots causing high oil temp. A little bit cooler after new jets.  If next summer will be hot as this one I'll give it 20W-60.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 stock looking project started 2017

Offline Leino

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Re: Just got back from the dyno
« Reply #30 on: September 19, 2018, 12:24:11 am »
Quoting you Mike... "I can see the RS Mikuni dip..."
Nice results!  ;)

Online MRieck

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Re: Just got back from the dyno
« Reply #31 on: September 19, 2018, 02:37:37 pm »
Quoting you Mike... "I can see the RS Mikuni dip..."
Nice results!  ;)
Yes...it is there Juha BUT not to bad.....i have seen much, much worse. ;D
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Offline Tracksnblades1

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Re: Just got back from the dyno
« Reply #32 on: September 21, 2018, 10:03:47 pm »
Mike,
How close was your on board A/F display, as compared to the dyno print out ?  If you still had it on your bike.
Age Quod Agis

Offline Ilja

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Re: Just got back from the dyno
« Reply #33 on: September 22, 2018, 02:02:08 am »
Very nice!  8)

Perfect street bike like that!

Online MRieck

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Re: Just got back from the dyno
« Reply #34 on: September 22, 2018, 06:20:45 am »
Mike,
How close was your on board A/F display, as compared to the dyno print out ?  If you still had it on your bike.
Idle AF was very close on the WEGO meter. I really didn't look at it during the actual run......doh! I will when I bring it back in a couple of weeks. Fresh oil and going from a 132.5 to a 127.5 should pick up HP nicely.
Owner of the "Million Dollar CB"

Offline PeWe

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Re: Just got back from the dyno
« Reply #35 on: September 22, 2018, 02:51:57 pm »
Mike,
How close was your on board A/F display, as compared to the dyno print out ?  If you still had it on your bike.
Idle AF was very close on the WEGO meter. I really didn't look at it during the actual run......doh! I will when I bring it back in a couple of weeks. Fresh oil and going from a 132.5 to a 127.5 should pick up HP nicely.
No logs to be taken afterwards from the WEGO?
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 stock looking project started 2017

Online MRieck

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Re: Just got back from the dyno
« Reply #36 on: September 22, 2018, 04:26:47 pm »
Mike,
How close was your on board A/F display, as compared to the dyno print out ?  If you still had it on your bike.
Idle AF was very close on the WEGO meter. I really didn't look at it during the actual run......doh! I will when I bring it back in a couple of weeks. Fresh oil and going from a 132.5 to a 127.5 should pick up HP nicely.
No logs to be taken afterwards from the WEGO?
I guess I could Per but when I got the unit it was Windows and I have Mac now. I do have an old Windows computer but I'd need my son to help me......I just hate F'ing around with that stuff when I have so many other things to do. You are right though.....I am sure it is in the unit. ;)
Owner of the "Million Dollar CB"

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Re: Just got back from the dyno
« Reply #37 on: September 22, 2018, 05:03:43 pm »
 Also.....I just went through some old RC catalogs George Schuld was gracious enough to give me and RC advertised the Cobra motors at 130 RWHP. Astonishing. Despite my best efforts and modern parts I am still left in the dust from RC Engineer's work of 40 years ago. God do I feel embarrassed and I bow to the kings.....no .....the Gods .... of CB750's. Russ Jr would laugh his a$$ off at that.
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Offline Tracksnblades1

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Re: Just got back from the dyno
« Reply #38 on: September 22, 2018, 06:50:31 pm »
Also.....I just went through some old RC catalogs George Schuld was gracious enough to give me and RC advertised the Cobra motors at 130 RWHP. Astonishing. Despite my best efforts and modern parts I am still left in the dust from RC Engineer's work of 40 years ago. God do I feel embarrassed and I bow to the kings.....no .....the Gods .... of CB750's. Russ Jr would laugh his a$$ off at that.

They had Tetraethyl Lead,  you don't.
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Online gschuld

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Re: Just got back from the dyno
« Reply #39 on: September 22, 2018, 08:24:49 pm »
Come on Mike, it was the 70s.  It was the time of Disco music, polyester bell bottomed leisure suits, and a mild dose of exaggeration in the days of salesmanship.

Perhaps you can chalk ...some ...of it up to flywheel hp compared to RWHP🤔

Regardless of the big claims, it’s hard to argue that with regard to cb750s they did basically dominate the record books for drag racing during that time period.  From the Pro Stock to Top Gas to Top Fuel they broke more records(usually their own) than anyone else in the engine type.

The standard cobra motor advertised at RC certainly didn’t put out 130 RWHP, not even at the crank.  But I still have a healthy amount of respect for their innovation and successes.  And boy did they break s#!t along the way...😉

George

« Last Edit: October 08, 2018, 06:42:44 pm by gschuld »

Offline Ilja

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Re: Just got back from the dyno
« Reply #40 on: September 23, 2018, 04:46:15 am »
Also.....I just went through some old RC catalogs George Schuld was gracious enough to give me and RC advertised the Cobra motors at 130 RWHP. Astonishing. Despite my best efforts and modern parts I am still left in the dust from RC Engineer's work of 40 years ago. God do I feel embarrassed and I bow to the kings.....no .....the Gods .... of CB750's. Russ Jr would laugh his a$$ off at that.

I think they slightly exagerated that with about 30-40hp.  ;D

Offline PeWe

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Re: Just got back from the dyno
« Reply #41 on: September 23, 2018, 08:48:20 am »
Also.....I just went through some old RC catalogs George Schuld was gracious enough to give me and RC advertised the Cobra motors at 130 RWHP. Astonishing. Despite my best efforts and modern parts I am still left in the dust from RC Engineer's work of 40 years ago. God do I feel embarrassed and I bow to the kings.....no .....the Gods .... of CB750's. Russ Jr would laugh his a$$ off at that.

I think they slightly exagerated that with about 30-40hp.  ;D
100 rwhp seems to be a reachable number for a streetable bike. Pistons 71-72mm CR10.5:1
I do not know what higher CR and race fuel will give together with an RC327 cam. 
How much does RPE Racing in Australia squeeze out from their Hulk 1200?
« Last Edit: September 23, 2018, 08:51:25 am by PeWe »
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 stock looking project started 2017

Online gschuld

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Re: Just got back from the dyno
« Reply #42 on: September 23, 2018, 11:05:35 am »
Bill Benton ran what I recall was a vintage RC built Cobra motor for a short time.  He could offer some  off the cuff comparisons to that motor compared to engines he built and dyno tested.  There are also ET times to compare.

It should give a reasonable power number toward that particular engine for those interested.  Id guess a shade over 100 for the high compression 73mm Cobra in worn condition.

Offline 754

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Re: Just got back from the dyno
« Reply #43 on: September 23, 2018, 01:33:26 pm »
 That was 70,s horsepower  you had to search for a dyno to check it, if you could find one.
Not the first or last guys to fib about engine output..
 I don't care what they had for hp, till we exceed  their old records, we have not moved forward..
Nice numbers there Mike.. strong for street.
 I am waiting for the stories about bikes you ran up against..
« Last Edit: September 24, 2018, 09:37:02 pm by 754 »
Maker of the WELDLESS 750 Frame Kit
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My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline bear

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Re: Just got back from the dyno
« Reply #44 on: September 24, 2018, 08:32:46 pm »
I don't care what they had for jp, till we exceed  their old records, we have not moved forward..

Very true Frank, very true.
( Mike's numbers aside, his being a road bike & a laudable example of thoughtful engineering)
In my world " If it dosn't make you faster it doesn't matter".
I learnt long ago that big numbers and ontrack performance do not necessarily go hand in hand.

The older I get the faster I was.

Offline 754

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Re: Just got back from the dyno
« Reply #45 on: September 24, 2018, 09:40:11 pm »
You know I thought Old Scramblers dyno output sounded a bit weak  but the proof was on the track.
 Both he and his nearest competitorl, did not have high dyno numbers..
 The above not directed at Mike, i have no doubt his will be brilliant on the street..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline PeWe

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Re: Just got back from the dyno
« Reply #46 on: September 25, 2018, 01:56:49 am »
The torque curve improve the feeling. If its is flat, almost horisontal the engine will feel dull and boring without any kick, hp increase by rpm.
(my car was like that before a program update that allow higher boost increasing the torque a lot, top hp not as much)

My bike has more fun torque from lower rpm  with 1000cc  than earlier.

This might be what you mean?  Good 45 degree torque curve instead of a flat where hp will be seen at higher rpms.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 stock looking project started 2017

Online gschuld

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Re: Just got back from the dyno
« Reply #47 on: September 25, 2018, 03:43:32 am »
Well this thread is about Mike's killer STREET motor.  So on that subject

I'm going to take my best stab at the combination(most details taken from old post from Mike) 

72mm pistons and JMR billet cylinder to match.  JE  pistons  around 10:1 compression?
Head with heavy porting/modified chambers.  Kibblewhite 5 mm stem conversion kit. 
Cam chain tensioner?
Mega cycle 125-75 cam
Falcon rods
Lightened crank
Undercut transmission 
later model clutch setup
RS-34 carbs
Dyna 2000 ignition /3 coils
Earls oil cooler
Terry Pentergast's  spin on filter

Is this close Mike?  I'll correct anything missing or wrong.

George


Offline bwaller

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Re: Just got back from the dyno
« Reply #48 on: September 25, 2018, 04:48:22 am »
George, pretty sure Mike is using a Setrab cooler. He beat me over the head long enough to see that light.  ;)

Now for your information, the 70's was more about a continuation of great music. Whatever happened to allow disco to get a foot hold in that decade... disappeared, nough said.  ;D

All I can say about Mike's engine is that we can count on it being strong, streetable and easy & fun to ride fast. He knows what it takes to produce a race engine, believe me. Not the case here.

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Re: Just got back from the dyno
« Reply #49 on: September 25, 2018, 07:37:45 am »
George, pretty sure Mike is using a Setrab cooler. He beat me over the head long enough to see that light.  ;)

Now for your information, the 70's was more about a continuation of great music. Whatever happened to allow disco to get a foot hold in that decade... disappeared, nough said.  ;D

All I can say about Mike's engine is that we can count on it being strong, streetable and easy & fun to ride fast. He knows what it takes to produce a race engine, believe me. Not the case here.
Actually it's an Earl's unit. I do have a Setrab setting on the shelf ready to install when the Earl's unit starts leaking (and eventually it will). Setrab is just a better unit.
 I am hoping to get about 110Hp out of it. The 65lbs of torque is fun too.
 And Brent.....you do yourself a disservice brother.....coming up with a 6 speed transmission takes more than luck. Also.....I can supply a couple of parts but you got to build it and we all know there is a big difference between assembling an engine and BUILDING an engine. ;)
Owner of the "Million Dollar CB"

 

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