Author Topic: re: CB750: Finally, some decent DYNO Charts (Read 4969 times)

MCRider · « **on:** June 04, 2016, 01:10:36 PM »

Following are the 3 DYNO Charts I got for Phaedrus, my Project for which the link is in my signature:
Engine: 888cc, Arias Pistons probably 10.5:1 or higher; Mike Rieck head and cyl work, 1.5mm OS Intake valves; WebCam 41 cam aka puny; Mikuni VM29 Smoothbores; OEM points with HondaMan transistors; MARSHALL Deep Tone exhaust (very quiet aka restrictive.
Non-perf items include APE crank, Crower Rods, HD chains, APE extra plate clutch; APE valve springs; APE titanium retainers and nuts, HD cyl and main bearing studs:

Engine has 165 hard miles on it, 3 runs down the drag strip, many trips to the Dyno. It doesn't smoke or leak. I say this to support the "hard break in" approach.

Dbl clicking may make the pictures larger. Max HP is 78.63; Max Tork is 55.29. The cam and pipe are limiting factors, but it pulls with authority.

ekpent · « **Reply #1 on:** June 04, 2016, 04:45:05 PM »

Any idea as to what a bone stock 750 may dyno at as a comparison ? Looks like your making some good power.

MCRider · « **Reply #2 on:** June 04, 2016, 04:58:29 PM »

Quote from: ekpent on June 04, 2016, 04:45:05 PM

Any idea as to what a bone stock 750 may dyno at as a comparison ? Looks like your making some good power.

The average consensus is about 55hp and about 40lb ft tork.

I'm happy with what I've done thanks to Mike. A simple pipe and cam change would make a bigger difference.

I haven't admitted it till now. I set the timing with feeler gauges 2 years ago and it still has the breakin spark plugs. I did recheck the valve lash once, they were all OK. And I need to recheck the cam chain lash.

drumstyx · « **Reply #3 on:** June 04, 2016, 05:14:14 PM »

That is one hell of an improvement. Is that primarily the displacement, or was there significant porting?

MCRider · « **Reply #4 on:** June 04, 2016, 05:35:41 PM »

Quote from: drumstyx on June 04, 2016, 05:14:14 PM

That is one hell of an improvement. Is that primarily the displacement, or was there significant porting?

Well, "there's no replacement for displacement", as they say.

But the head was routed out by our own Mike Reick, and 1.5mm OS intake valves installed. The real weak link is the pipe which is similar to a potato up your butt. But, it is quiet with a nice tone, which I wanted. And the Mikuni Smoothbores get it started.

Old Scrambler · « **Reply #5 on:** June 05, 2016, 06:00:41 PM »

Very Nice..........so far

An open exhaust may help on the dyno............I found 5 or 6 HP on my C.B.R. motor by advancing the timing a few degrees. The domes on the pistons require time for the flame to travel.

brewsky · « **Reply #6 on:** June 05, 2016, 06:34:36 PM »

Quite an improvement!

I'm a little confused by the shape of the curve....shouldn't hp and torque cross at 5252 rpm?

scottly · « **Reply #7 on:** June 05, 2016, 07:43:28 PM »

Quote from: brewsky on June 05, 2016, 06:34:36 PM

I'm a little confused by the shape of the curve....shouldn't hp and torque cross at 5252 rpm?

Normally the hp and torque will cross at 5252, but the graph was plotted with different scales for hp and torque. It had me wondering too.

brewsky · « **Reply #8 on:** June 06, 2016, 02:06:47 AM »

Quote from: scottly on June 05, 2016, 07:43:28 PM

Quote from: brewsky on June 05, 2016, 06:34:36 PM

I'm a little confused by the shape of the curve....shouldn't hp and torque cross at 5252 rpm?
Normally the hp and torque will cross at 5252, but the graph was plotted with different scales for hp and torque. It had me wondering too.

HELLO!

MCRider · « **Reply #9 on:** June 06, 2016, 05:59:40 AM »

Quote from: scottly on June 05, 2016, 07:43:28 PM

Quote from: brewsky on June 05, 2016, 06:34:36 PM

I'm a little confused by the shape of the curve....shouldn't hp and torque cross at 5252 rpm?
Normally the hp and torque will cross at 5252, but the graph was plotted with different scales for hp and torque. It had me wondering too.

I've posted these charts in two or 3 places. On one I asked about the non-crossing. Then I saw what you saw, comparing it to a chart from last year, that the vfertical scales, left and right were not synched, and supposed that might be the deal. Thanks for the confirm.

Next time, I'll point that out to the Dyno guy.

Stev-o · « **Reply #10 on:** June 06, 2016, 07:08:14 AM »

Hey Ron....why do you want a quiet exhaust? Why not buy another for when you are running dyno, the strip or The Mile?

chewbacca5000 · « **Reply #11 on:** June 06, 2016, 07:11:42 AM »

Hey Ron,

Let me know when you want to have a track day.

MCRider · « **Reply #12 on:** June 06, 2016, 08:40:21 AM »

Quote from: Stev-o on June 06, 2016, 07:08:14 AM

Hey Ron....why do you want a quiet exhaust? Why not buy another for when you are running dyno, the strip or The Mile?

Its a build criteria left over from when I was building this for me to ride on long trips. For health reasons I can no longer ride, but I wanted to finish it as though the original build plans were intact. Purely a personal thing. I want to see how strong a really friendly street motor could be. My days of loud exhausts are behind me. But...

I am piecing together a Kerker. I have the front header part left over from years ago, and just bot a megaphone from edwardmorris, which needs work, but should come around.

So the testing work will continue on.

MCRider · « **Reply #13 on:** June 06, 2016, 08:45:03 AM »

Quote from: chewbacca5000 on June 06, 2016, 07:11:42 AM

Hey Ron,

Let me know when you want to have a track day.

I used to roadrace this same chassis, before I put it back on the street in 1980. I've been to several track days with my 88 HawkGT, but those days are over.

Phaedrus has been lowered to the point it wouldn't be much fun on a left right track. Even at that, I can't get my leg over the seat.

I hope to scab together another chassis I have, a 1975F, and it will be track worthy, for fun, probably not competitive.

chewbacca5000 · « **Reply #14 on:** June 06, 2016, 03:15:51 PM »

I have 4 or 5 k frame laying around if you want to go that route. If need someone to put some miles on Phaedrus I would be happy to help you break her in.

PeWe · « **Reply #15 on:** June 14, 2016, 08:48:10 AM »

Frame kit on this bike?
If you have, try the DP315 cam. (Or an RC315 if you have one on the shelf) My bike is very streetable with DP315.

MCRider · « **Reply #16 on:** June 14, 2016, 09:00:38 AM »

Quote from: PeWe on June 14, 2016, 08:48:10 AM

Frame kit on this bike?
If you have, try the DP315 cam. (Or an RC315 if you have one on the shelf) My bike is very streetable with DP315.

YEs, I have one of the original; APE frame kits, circus 1980. I want to see how my original configuration performs. Then I'll either mothball it and go on to something else. Or, try a different cam and pipe.

PS: Getting ready for the OHIO Mile speed trials this weekend. WooHoo!

Stev-o · « **Reply #17 on:** June 14, 2016, 07:17:50 PM »

Quote from: MCRider on June 14, 2016, 09:00:38 AM

Quote from: PeWe on June 14, 2016, 08:48:10 AM
Frame kit on this bike?
If you have, try the DP315 cam. (Or an RC315 if you have one on the shelf) My bike is very streetable with DP315.
YEs, I have one of the original; APE frame kits, circus 1980. I want to see how my original configuration performs. Then I'll either mothball it and go on to something else. Or, try a different cam and pipe.

PS: Getting ready for the OHIO Mile speed trials this weekend. WooHoo!

WooHoo. Looking forward to reading a full report. Good luck!

brewsky · « **Reply #18 on:** June 15, 2016, 04:33:12 AM »

Quote from: MCRider on June 14, 2016, 09:00:38 AM

PS: Getting ready for the OHIO Mile speed trials this weekend. WooHoo!

Good luck!

A friend usually goes with a turbo Busa sidecar rig, but I think he may be ready to sell it.

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Author Topic: re: CB750: Finally, some decent DYNO Charts (Read 4969 times)