Topic: Phaedrus: CB750 RestoMod - Update: 09/23/21 w/ new video

[MRieck]

DYNO Results: Peak HP = 78.63 @ 8200rpm; range above 75 from 7500rpm to 9000rpm.

Peak torque = 55.29 @ 6200rpm; range above 54 from 6000 to 7500.

Nice street bike numbers, I bet a 4th gear roll on would be fun.

Color commentary and graphs after work tonight or tomorrow. Finally, very happy with the Dyno shop.

Sounds good Ron and I'm glad you are happy with the shop. Good dyno people can be hard to find.

[MCRider]

DYNO Results: Peak HP = 78.63 @ 8200rpm; range above 75 from 7500rpm to 9000rpm.

Peak torque = 55.29 @ 6200rpm; range above 54 from 6000 to 7500.

Nice street bike numbers, I bet a 4th gear roll on would be fun.

Color commentary and graphs after work tonight or tomorrow. Finally, very happy with the Dyno shop.

Sounds good Ron and I'm glad you are happy with the shop. Good dyno people can be hard to find.

Yeah. Numbers are on the low side of expectations. but my desire for a quiet pipe is a handicap. I'm putting together a Kerker for later on. And the pitiful state of tune... mostly ignition timing,  more on that later.

Hope you can make some comments on AFR once I get it posted. Skosh lean above 7k, maybe OK. Way lean below 3K. Right on 13 most of the way.

The shop is heavy VTwin oriented, but me and the owner are getting along. He's got the nicest Dyno room so far. He has a waiting area with a monitor so customers can see what he sees on his monitor.

[MCRider]

DYNO Results: Peak HP = 78.63 @ 8200rpm; range above 75 from 7500rpm to 9000rpm.

Peak torque = 55.29 @ 6200rpm; range above 54 from 6000 to 7500.

Nice street bike numbers, I bet a 4th gear roll on would be fun.

Color commentary and graphs after work tonight or tomorrow. Finally, very happy with the Dyno shop.

Wow! 78.63 hp at the rear wheel!  That's pretty outstanding.

Thanks! A more open pipe and better ignition timing would probably get it to 85. My choice of the milk toast 41 cam (not even 41a) cam is holding us back. But rideability was my priority. Since I'm not riding anymore, maybe a hotter cam and pipe is in the future.

[MRieck]

I forgot it was a 41 cam.....those #'s are good for that. Put in a 125-60 cam in, med comp baffle Kerker and put some timing in it and you will be at 85 no problem.

[Jerry Rxman Griffin aka MuthaF'er]

Now you have an idea for jetting then a return trip. OR.... a real cam THEN a return trip. Keep at it Ron.

[MCRider]

I forgot it was a 41 cam.....those #'s are good for that. Put in a 125-60 cam in, med comp baffle Kerker and put some timing in it and you will be at 85 no problem.

Oh yeah, I forgot to say, besides starting on a tap of the button, revving like crazy, and so smooth all the way, (thanks to JMR head), it didn't smoke a whiff!

It only has about 165 miles on it, so I'm a testament to the "break it in hard" school.

[MCRider]

Vicious watchdog:


May have already posted this. Deadman switch for Ohio Mile:

[MCRider]

Period fuses found on EBay:

[MCRider]

1st Graph: HP & Torque:

2nd Graph: HP & Torque; AFR and Speed:

3rd Graph: Same HP & Torque; AFR w/ rpm


Questions: How can the DYNO know what the speed is without tire dia, gearing etc?  My speed calculator says with my set up, should be able to hit 130 at 8500rpm, DYNO says about 115mph.

The AFR is too lean down low, drifts rich in mid; then is lean (14.03) up high. Worth trying to richen it up? FYI: The AFR line is at 13, my Mikuni VM29 manual says to shoot for 12-13. And if poor cooling, should shoot for 10-12!

Drag Race launches should occur at 6 to 7K rpm? Shifts at 8-8.5K?

[scottly]

Questions: How can the DYNO know what the speed is without tire dia, gearing etc?  My speed calculator says with my set up, should be able to hit 130 at 8500rpm, DYNO says about 115mph.

The dyno drum has a known diameter and weight, as well as a sensor that records each revolution of the drum. Did the operator use 4th gear for the run? This is the standard procedure.
I was expecting to see more HP; comparing this latest run to the one last fall, you are down on both HP and torque at about 6800 RPM, where that earlier run was ended. What has changed since then? It does appear that the curves drop off just when the AF goes lean?   

[MCRider]

Questions: How can the DYNO know what the speed is without tire dia, gearing etc?  My speed calculator says with my set up, should be able to hit 130 at 8500rpm, DYNO says about 115mph.

The dyno drum has a known diameter and weight, as well as a sensor that records each revolution of the drum. Did the operator use 4th gear for the run? This is the standard procedure.
I was expecting to see more HP; comparing this latest run to the one last fall, you are down on both HP and torque at about 6800 RPM, where that earlier run was ended. What has changed since then? It does appear that the curves drop off just when the AF goes lean?

I think he said 5th gear. I didn't know to ask. But 4th would make it come much closer to my Internet max speed calculator.

Yeah I looked at last year's too, it had an optimistic trajectory for sure. All  I've done was drop the final drive sprckt from an 18 to a 17. Would that make a difference?

[scottly]

No, the sprocket change shouldn't have had any effect on the dyno readings. You might want to richen up the mixture a bit; shoot for 12.8-13.2 in the power band, and don't worry if it's a little too rich below 6k RPM.

[MCRider]

No, the sprocket change shouldn't have had any effect on the dyno readings. You might want to richen up the mixture a bit; shoot for 12.8-13.2 in the power band, and don't worry if it's a little too rich below 6k RPM.

Yup, will do. It has 122.5 in now. Going to 125.

[Jerry Rxman Griffin aka MuthaF'er]

Ron, are you going to drop the needles a notch? WFO is what you need but the needles get you to the upper rpms and affect part of the upper rpms.

[MCRider]

Ron, are you going to drop the needles a notch? WFO is what you need but the needles get you to the upper rpms and affect part of the upper rpms.

I was hoping to avoid that. A complexity of the VMs I'm not ready to tackle now, maybe in the winter. But it seems I am rich where the needles work, and not even very rich at that, per what the manual says (12 to 13). I'm going richer on the pilots as I have some, and on the mains. That should get me through the Ohio Mile. And some drag racing.

Then Dyno it again, see what for the needles, and try to get it closer.

[MCRider]

Prep begins in earnest for Ohio Mile LSR, June 18 and 19. Got a room minutes from the track and my wife will come over for Saturday day and night. I'll go on Friday afternoon so I can be rested for Saturday and Sunday. Rider Rick and his crew will arrive under separate cover, with a few bikes of their own.

I don't really expect to be competitive for an LSR, I just want to see how fast she'll go.

So we pulled the carbs for rejetting, fiddled with the centerstand bracket which doesn't seem to want to cooperate. Switch out the final drive sprocket from a 17 to an 18, adjust and lube the chain, see if the MotionPro throttle tube I bot will replace the fitted quickthrottle we have now. Make a list of things to forget...   Maybe its due for some new sparkplugs, since it still has the startup plugs in it that went to the drags... 

Dropped the oil for the umpteenth time. I probably have a record for the most oil changes is 165 miles. Both magnet plugs were clear of debris. The filter cover was clear of debris also, as was the filter. Very happy about that. I've been checking the tank level periodically and it will go for weeks between starting with no change. The oil pump fix kit from Elan really worked, no more wet sump.

Have to put in some extra shop hours to make sure its all ready.

[Tintop]

Looking forward to hearing how this goes Ron.  Also please remember we love photos.

[scottly]

No, the sprocket change shouldn't have had any effect on the dyno readings. You might want to richen up the mixture a bit; shoot for 12.8-13.2 in the power band, and don't worry if it's a little too rich below 6k RPM.

Yup, will do. It has 122.5 in now. Going to 125.

Sounds like a plan. I wouldn't mess with needles or pilots yet, as the AF readings above 6000 RPM were at WFO, so they wouldn't be in play. The rich readings below 6000 RPM are most likely caused from over-scavenging where the resonance of the intake, exhaust, and cam timing is out of sync.   

[MCRider]

No, the sprocket change shouldn't have had any effect on the dyno readings. You might want to richen up the mixture a bit; shoot for 12.8-13.2 in the power band, and don't worry if it's a little too rich below 6k RPM.

Yup, will do. It has 122.5 in now. Going to 125.

Sounds like a plan. I wouldn't mess with needles or pilots yet, as the AF readings above 6000 RPM were at WFO, so they wouldn't be in play. The rich readings below 6000 RPM are most likely caused from over-scavenging where the resonance of the intake, exhaust, and cam timing is out of sync.

Thanks Scottly, your input has been much appreciated.    8 days to the Ohio Mile!

[Jerry Rxman Griffin aka MuthaF'er]

Yeah Ron, don't use you mid-range at the mile............

[MCRider]

Yeah Ron, don't use you mid-range at the mile............

Right-o!

[MCRider]

Seems like the more I do, the more to be done. Swapped 17 F for an 18. Calculated Top Speed 137 @ 8500rpm. Timing was on the Ts,    advanced it to the Fs. Should help. Valve lashes all good. Various other stuff.

Broke 3 bits trying to drill nuts for safety wire, even with a $35 jig. Went rooting around in my drawers and found 4 8mm nuts that were drilled from previous escapades YEARS ago. Good to go on front fork axle caps.

I'm so slow with the PD, I was slow enough when healthy. 

But I've still got time.   

[grcamna2]

Seems like the more I do, the more to be done. Swapped 17 F for an 18. Calculated Top Speed 137 @ 8500rpm. Timing was on the Ts,    advanced it to the Fs. Should help. Valve lashes all good. Various other stuff.

Broke 3 bits trying to drill nuts for safety wire, even with a $35 jig. Went rooting around in my drawers and found 4 8mm nuts that were drilled from previous escapades YEARS ago. Good to go on front fork axle caps.

I'm so slow with the PD, I was slow enough when healthy. 

But I've still got time.   

What type of fuel are you running Ron? I know she'll perform better w/ the timing on the 'F'

[MCRider]

Seems like the more I do, the more to be done. Swapped 17 F for an 18. Calculated Top Speed 137 @ 8500rpm. Timing was on the Ts,    advanced it to the Fs. Should help. Valve lashes all good. Various other stuff.

Broke 3 bits trying to drill nuts for safety wire, even with a $35 jig. Went rooting around in my drawers and found 4 8mm nuts that were drilled from previous escapades YEARS ago. Good to go on front fork axle caps.

I'm so slow with the PD, I was slow enough when healthy. 

But I've still got time.   

What type of fuel are you running Ron? I know she'll perform better w/ the timing on the 'F'

They sell it at the track. Its $45 for 5 gallons. That's the cheapest of about 10 varieties they have. Closest to street gas I imagine, though better.

[MCRider]

Rotating the point plate to time it, turned the condensers into the screw boss of my Frankenscycle clear point cover. Its going to require some hogging out with the Dremel.

But build buddy Bruce came over and got me over the hump. Reinstalled the APE frame kit, bike started, checked over, oiled up, loaded on the trailer.

Point plate cover and number plate mods all that's left.  Nap time, then hit it again.

I had ordered a "750/Four" café seat for it, but it hasn't come in time.    ,