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Author Topic: Just got back from the dyno  (Read 2242 times)

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Offline MRieck

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Re: Just got back from the dyno
« Reply #50 on: September 25, 2018, 08:05:55 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
Had to use one of the KA tensioners. Has Carrillo's, 71.25 flat top pistons, milled the head a good amount to get the chamber CC's I wanted and increase the squish band. Cam is a Megacycle 125-30. I think there are better cams out there for the 1000 cc's. Maybe a Kenny Harmon Super F.....Rick Stetson thought that would be a good grind. Maybe a CX-10 grind......I have one on the shelf.
 I am already thinking about building another engine with 72mm pistons and a 5mm stroke. Not fond of welded stroker cranks but Marine does a great job and the engine would not see a lot of running time. A bit more compression than the current engine and that CX-10 cam. 125 HP and about 75lbs of torque would be real fun on the street
« Last Edit: September 25, 2018, 08:11:02 am by MRieck »
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Just got back from the dyno
« Reply #51 on: September 25, 2018, 11:42:28 am »
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..

Dennis had (I think) a backed off valve adjuster Frank so he was basically running HP numbers on 3 cylinders.
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Offline PeWe

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Re: Just got back from the dyno
« Reply #52 on: September 25, 2018, 12:09:45 pm »
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
Had to use one of the KA tensioners. Has Carrillo's, 71.25 flat top pistons, milled the head a good amount to get the chamber CC's I wanted and increase the squish band. Cam is a Megacycle 125-30. I think there are better cams out there for the 1000 cc's. Maybe a Kenny Harmon Super F.....Rick Stetson thought that would be a good grind. Maybe a CX-10 grind......I have one on the shelf.
 I am already thinking about building another engine with 72mm pistons and a 5mm stroke. Not fond of welded stroker cranks but Marine does a great job and the engine would not see a lot of running time. A bit more compression than the current engine and that CX-10 cam. 125 HP and about 75lbs of torque would be real fun on the street
Name of cam do not sound hot..but.. it has good lift.
125-35  .407    266   105     Especially for '78 F2 models.      28/58    .005
(125-30).407    268   106     Great mid-range and top-end. Must  60/28    .005
                              use modified pistons and springs
                              Check carefully in CB K models

Mike, your dyno encouraged me to finally mount my Hindle 4-2-1.  Really nice deep sound  and roar loudly when twisting.
You have your Hindle 4-2-1 on now?
« Last Edit: September 25, 2018, 12:17:06 pm by PeWe »
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Online gschuld

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Re: Just got back from the dyno
« Reply #53 on: September 25, 2018, 01:53:14 pm »
Good info Mike.  What did you end up with regarding static compression? 

I’m also curious of your reasoning behind the 125-30 Megacycle cam over your generally preferred 125-75.  It’s an honest “want t learn” question, not a criticism of course.  We briefly discussed big displacement steeet gas motors in the not too distant past, and the 125-75 cam was brought up as a likely good choice.

Hmm, a Marine Crankshaft welded stroker crank, street gas compatibile compression, 72mm bore pavement pounder.  What a great idea... ;)

So Mike, what would you do with a second and bigger engine?  Do you have another cb750 chassis to put it in?

George

« Last Edit: September 25, 2018, 05:05:26 pm by gschuld »

Offline dragracer

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Re: Just got back from the dyno
« Reply #54 on: September 25, 2018, 07:56:23 pm »
I know where to find a fresh,  marine stroker crank.

Online gschuld

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Re: Just got back from the dyno
« Reply #55 on: September 25, 2018, 08:31:46 pm »
I know where to find a fresh,  marine stroker crank.

 ;D ;D.... ???...... :o

George

Offline PeWe

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Re: Just got back from the dyno
« Reply #56 on: September 27, 2018, 02:59:31 am »
Mike, 104.2 rwhp. How many crank hp is that?
How many hp are lost in transmission to wheel?

I have read about -15% but nothing absolute.
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Offline MRieck

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Re: Just got back from the dyno
« Reply #57 on: September 27, 2018, 06:34:14 am »
Mike, 104.2 rwhp. How many crank hp is that?
How many hp are lost in transmission to wheel?

I have read about -15% but nothing absolute.
No idea what power is at the crank Per.....I'd guess loss is more like 10%
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Offline dragracer

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Re: Just got back from the dyno
« Reply #58 on: September 27, 2018, 06:43:13 am »
Mike, this is a great example of your work. Glad to see the outcome on one of your own bikes. Looking forward to the next step with this project.

Online gschuld

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Re: Just got back from the dyno
« Reply #59 on: September 27, 2018, 09:10:52 am »
I agree.  Those are really impressive numbers for any cb750 Sohc engine, but even more so for an engine that is meant to be run on a street legal bike drinking non ethanol street level octane fuel.

Mike, I certainly hope you reach your 110 RWHP expectations.

Waiting impatiently for the second round of dyno testing...😎

George


Offline PeWe

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Re: Just got back from the dyno
« Reply #60 on: September 27, 2018, 09:59:44 am »
Then offer a " 110rwhp Mike package" with everything needed except a stock engine ;) Carbs jetted and ready for the street.
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Offline simon#42

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Re: Just got back from the dyno
« Reply #61 on: September 27, 2018, 10:08:18 am »
Mike, 104.2 rwhp. How many crank hp is that?
How many hp are lost in transmission to wheel?

I have read about -15% but nothing absolute.
No idea what power is at the crank Per.....I'd guess loss is more like 10%

might be closer to 15 , that extra change of direction will cost a bit

Online gschuld

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Re: Just got back from the dyno
« Reply #62 on: September 27, 2018, 11:31:48 am »
Then offer a " 110rwhp Mike package" with everything needed except a stock engine ;) Carbs jetted and ready for the street.

There is an idea.  It’s agood way to avoid rediculously stubborn customers wanting you to build a clearly less that optimal engine with outdated parts.  Not that I speak from experience(on both sides of the customer/contractor basis) or anything.🙄

I’ll offer to build you a very presentable engine shipping crate expressly for the purpose for your first customer on one of those, for free including shipping..

George
« Last Edit: October 08, 2018, 06:48:47 pm by gschuld »

Offline Sam Green Racing

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Re: Just got back from the dyno
« Reply #63 on: September 29, 2018, 11:00:45 am »
Mike, 104.2 rwhp. How many crank hp is that?
How many hp are lost in transmission to wheel?

I have read about -15% but nothing absolute.
No idea what power is at the crank Per.....I'd guess loss is more like 10%

Most bikes with 67 at the crank are lucky to see 50 to 53 at the wheel and it's the same loss for everyone unless you're running ceramic wheel bearings.
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Offline PeWe

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Re: Just got back from the dyno
« Reply #64 on: September 29, 2018, 11:38:59 am »
Mike, 104.2 rwhp. How many crank hp is that?
How many hp are lost in transmission to wheel?

I have read about -15% but nothing absolute.
No idea what power is at the crank Per.....I'd guess loss is more like 10%

Most bikes with 67 at the crank are lucky to see 50 to 53 at the wheel and it's the same loss for everyone unless you're running ceramic wheel bearings.
67 is the early CB750 stock bhp? The later got only 63 as my K6
This point to more than +20% to add dyno whp, 25%.
104 rwhp is around 125-130bhp, probably the latter. 110whp almost 140 bhp. Good to know when compare to other bikes.

I read a thread where they compared HD's on dyno with stock bhp, around 20% loss or a little bit less. 25% to add the other way.
http://xlforum.net/forums/archive/index.php/t-52498.html
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Offline MRieck

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Re: Just got back from the dyno
« Reply #65 on: October 10, 2018, 04:00:13 pm »
Back from the dyno again....not that thrilled. Bike eventually pulled 106.4 HP and 66.2 lbs of torque. Problem is going leaner on the main exacerbated real lean condition at 3,500 to 5,000RPM. Peak power went up it was killing power in that RPM area. On the road the lean condition wasn't that noticeable in higher gears but in that area cruising in first or second it kinda sucked.We (Rick Stetson and I) believe it's the cam.....I'll be changing to one of my all time favorites the 125-70 Megacycle cam. And remember.....a cam like the 125-70 (75) is ONLY good IF you time it correctly. ::) ;D ;D
 I'll post a dyno sheet with a 3 run overlay later. ;)
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Offline PeWe

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Re: Just got back from the dyno
« Reply #66 on: October 10, 2018, 09:32:50 pm »
"real lean condition at 3,500 to 5,000RPM"
Needles to be set richer?
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Offline bwaller

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Re: Just got back from the dyno
« Reply #67 on: October 11, 2018, 04:20:25 am »
It's no good riding with that condition. It will be interesting to see what the other cam produces. I don't remember reading about what your thoughts were on the "30", it seems to me it isn't as popular, what's the story on this cam?

I may try to get to Rick's after we are finished here. It should not take long but I feel we need to know what our work accomplished. Will let you know.

Offline Tracksnblades1

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Re: Just got back from the dyno
« Reply #68 on: October 11, 2018, 06:06:39 am »

I'll be changing to one of my all time favorites the 125-70 Megacycle cam.

Don't know your true compression ratio... But since your Genia Pigging for all...Really  curious how that 125-x12 or that CX10 you have would fair @ 10.5-10.8:1. X12 looks like it would do it quicker and a little lower in the rev range than the CX10. Patiently watching for the 125-75(70) pull, with that good exhaust port.
🎯
« Last Edit: October 11, 2018, 06:10:56 am by Tracksnblades1 »
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Just got back from the dyno
« Reply #69 on: October 11, 2018, 08:42:17 am »
Well #$%* Michael, quit dogging it and just keep the R's up  ;D
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline scottly

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Re: Just got back from the dyno
« Reply #70 on: October 12, 2018, 07:39:56 pm »

 I'll post a dyno sheet with a 3 run overlay later. ;)
Is it later yet? ;D
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Offline PeWe

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Re: Just got back from the dyno
« Reply #71 on: October 13, 2018, 12:55:59 am »
Mike, your lean condition seems to be similar as my bike had before but opposite. I had too rich where you have too lean.
http://forums.sohc4.net/index.php/topic,147350.msg1677539.html#msg1677539
It really bogged down at WOT, cleared out around 6500 rpm with 4-1. Comments about needles were correct which was verified later on another dyno with 4-4 2 years later.
In the first scenario I changed cam and the problem disappeared without changing the carb jetting (TMR32). The Megacycle cam was more sensitive with too rich needles. Action Fours SS-1, RC295 profile and DP315, all ran OK at WOT with same needle settings. Another thing when cruising on low lifts from 2000-5500 rpm. A/F ratio was around 11. See attached pic. These thin blue a/f lines cruising 2000-5500 with too rich needles (that bogged down completely with Megacycle 125-20 and 836cc earlier)

I changed needles 2 steps leaner (1 step each time + road tests) and next dyno showed correct values this was with 4-4. I tested the same Megacycle cam earlier this year and it did not bog down as before when needles were OK.It did not rev out with 4-4 though.

Now 4-2-1 and it runs better than ever (RC295 profile). Needles feels OK too. Only fuel screws that are not perfected and main jets not verified on Dyno yet (or full speed on a remote road). (Water drops in carbs after cleaning the bike had messed up the fuel screw adjustments which took a while to get verified. Carbs had to be blown free since water did not want to leave.)

You might try to lift the needles 1 step and try the same cam once more.
Edit: I had a fuel screw road test today with small adjustments.

I guess that adjusting needles on RS34 is as easy as the TMR32 without affecting synch.
« Last Edit: October 13, 2018, 07:46:39 am by PeWe »
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Offline MRieck

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Re: Just got back from the dyno
« Reply #72 on: October 13, 2018, 07:10:30 am »

 I'll post a dyno sheet with a 3 run overlay later. ;)
Is it later yet? ;D
You made me laugh scottly with that. ;D I'll post tomorrow as my wife and I are on a short holiday. ;)
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Offline MRieck

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Re: Just got back from the dyno
« Reply #73 on: October 15, 2018, 03:07:38 pm »
Finally....
« Last Edit: October 15, 2018, 03:09:10 pm by MRieck »
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Offline Old Scrambler

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Re: Just got back from the dyno
« Reply #74 on: October 15, 2018, 03:34:38 pm »
120/117............is that a mixture of jets?  Interesting.......My CBR shows same lean and runs best with 120 jets.....getting 122.5s for next year ;D
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