Topic: Post your Dyno Graphs here.

[PeWe]

Dyno day today!

Whp: 104.29 DIN
Torque: 91.47 Nm/67.46 ft-lb
New setup, new Dyno run
- 970cc  (now a little  higher compression, 206-209 PSI, before 197.5-202.5 PSI with a cheap tester )
No pinging!
- Ported 392 head with kibblewhite valves 33.5/28.5mm
-125-75 cam
(smooth power from low to top, no sudden wake up after 7000rpm)
-Dyna-S , Dyna 5 ohm coils.
-APE Ultra crank.

Result:
- A few horses more than before
Dyno last year with 1005cc, same cam, different head with F2 in -34/ kibblewhite 28mm valves:
Whp: 101.06
Torque: 91.35Nm (67.38 ft-lb)


To do next:
- Pilots need to be smaller.

Dyno operator verified what I have noticed when cruising on low rpms, ~2000-3600 when slowly increase throttle and reduce just a little that ends up in "bbbbbbrrrrllll" (rich sound )
- Acc pump need to be adjusted for more fuel when twisting.

[Old Scrambler]

This looks to be an ideal STREET motor..............and could be a LANDSPEED competitor 

How did you get from 1005 to 970cc ?

[PeWe]

I did not tighten the head gasket enough last winter on the 1005cc setup.
Only 25Nm, the MLS did not compress as it should which ended up in heavy oil consumption after some time.

Head and pistons really dirty. I took it all apart for cleaning and inspection if something has happened inside.  Bores OK, roundness checked, only the MLS that I did not tighten as hard as before and must be tightened.

At the same time a friend had a setup of new JE 70 mm CR12.5:1 pistons I could buy for a good price. (Some years old used in a build but never started)
CycleX 74.5/69mm sleeves bought earlier when they had sale. Perfect for 70mm bore.

My friend has some CB750 parts so a good looking cylinder with small oil return holes to be used

My nearby shop got the Billet block with pistons to compare with to find a good verified compression.
The 70mm pistons are 0.5 mm lower on the outer edge than the JE 71.25mm from Dynoman. Billet block 84.5mm high, stock cylinder 85 mm
So the new cylinder had to be shaved 1mm down. The holes for sleeves flanges cut deeper so the machining of cylinder did not make the sleeves thinner. Holes for 2 o-rings to head also adjusted to stock depth.

The pistons crown volumes compared, the 70mm pistons shaved to similar volume. I think 3mm was cut off.
The result exact as planned!

Healthy higher compression.
The Billet block setup used a thick RCS  base gasket on dyno last year.
The thinner as used now should crank it up some.

I had to test now while the guy in the shop 2km away from my home is still working and if further adjustments should be needed. He is on overtime, 70 years old.

Shaving cylinder another 0.25 mm further should make the (squish)  pistons outer area 1mm to head with thin MLS and thin RCD. But this might need adjustments on the crowns.
It work fine anyway.

I have rejetted the carbs, ready for another dyno if I can get time this week.

It ran rich on idle and up into needle area. A little lean on top. So I have reduced pilots 2 steps, increased main jets 1 size.

Fuel screws need to be adjusted to the smaller pilots. I might do that tomorrow if not raining. A ride with screw driver and adjust. I have done this some times now I have increased 1/4 turn, maybe max 1/4 more.

So, hopefully a little bit more to squeeze out.

[MRieck]

 Thanks for sharing Per. That 125-75 cam belongs in the CB750 Hall of Fame.

[Jerry Rxman Griffin aka MuthaF'er]

What do you think those 12.5:1 pistons increased your HP over a 10.25/10.5:1

[Old Scrambler]

Sounds like a reasonable build guide

Not for long-distance touring.........needs more than pump-gas.

[gschuld]

PEWE,

Great results.

I’m a little confused about where you ended up regarding static compression.  Milling the domes down 3mm likely brought you to around 11:1 or so? A little less?

Are you running 94 octane or lower pump gas with success?

Breaking 100 RWHP is no easy feat..👍. Especially for a streetable engine with a nice strong even power curve.

George

[MRieck]

PEWE,

Great results.

I’m a little confused about where you ended up regarding static compression.  Milling the domes down 3mm likely brought you to around 11:1 or so? A little less?

Are you running 94 octane or lower pump gas with success?

Breaking 100 RWHP is no easy feat..👍. Especially for a streetable engine with a nice strong even power curve.

George

The compression is the thing. Engines love compression until they blow up. The torque etc is also a result. Good gasoline and no problems. I have a very hard time getting my billet block up to 200 F  oil temp....I mean it is hard to do.

[PeWe]

Yes, the cam, (125-75 billet)    behaves very well. A very even power all over. 
I fully understand why Mike always have recommended it
Good idle at 1200rpm. Easier to ride with not too low idle.

I guess the pistons are in the CR 11:1 area. The 71.25mm pistons for Billet block was ordered for 24cc chambers. They look as Dynomans DP1000 11:1 pistons they started to sell, like shaved 12.5 pistons.

The heads chambers are around 23.6-23.8 cc.
Piston CR numbers  usuallly  for 22.5cc chambers, right?

Cut piston 70mm at left vs 71.25mm piston.


Piston vs cyl block, no base gasket.


Head that is used.


The piston before cutting it. The guy that my friend bought it from could not get it right and gave up. Very hard to crank engine
Drilled space for plugs.


It runs fine so I doubt I'll open the engine again soon.

My other engine case I have was planned for 890cc and super rods.
I wonder if super rods can handle 1005cc +100whp?

I already miss that tough look that is a spectator magnet

I have a CB750 -75 frame that need to be painted, most of the other parts all over the garage

I hope for a new Dyno time. Road test now is dangerous with more animals running around. Testing main jets have had scary moments before.

EDIT:
Fuel is Shell V-power as both my bikes get.
My car like it too.

[johno]

Nice work Per, your a cool dude

[PeWe]

Thanks!
You are cool too!
If weather should be better I should call for a new Dyno time. I hope I have cured the slightly lean main jet.  Hopefully more ....

[PeWe]

Time for an update, keeping this thread higher in the flow!
Still 970cc, 125-75, ported 392 head with 33.5/28.5mm valves, Hindle 4-2-1.
APE crank and Carillo rods for stability. Mikuni TMR32 carbs.

Dyno day today. Got a few more than before
Fuel: Shell V-Power gasoline for street.

DIN: 107.59whp / 67.59 ft lbs (91.64 Nm)

STD: 107.63whp / 67.62 ft lbs (91.68 Nm)





Last week 104 whp, as earlier dyno runs in May 2022 and October 2021.

Changes before this run today:
Reduced main jet from 145 to 142.5, cleaned and oiled the K&N pods.

[gschuld]

Excellent results.

I’m curious, did you intentionally cut the end of the run at +/- 9200 rpm?  The power peak
appeared to still be rising(albeit slowly).  I’d LOVE to see a run where you kept on it until 10,500 or so.  Just to see how the engine reacts.  Whether the power peak floats a bit or drops off more abruptly.

For example in road racing, the typical shift point is around 10% past peak HP.  So knowing how well the power hangs in there past peak HP is really useful.

Of course you aren’t racing.  But my selfish mind would love to know.

George

[PeWe]

Hi George,
I think I have agreed about 9200 rpm earlier when we also saw where the peak was.
It really look like still increasing. Last dyno ran up to 9400 rpm.
Another 500 rpm and reaching 108whp?

Cam is timed slightly different than the first session last year.
A little bit more advanced. I have marked cam and sprocket with punch marks. Now sit side by side to more advanced.
I measured IN to open around 27* with 0 lash, earlier 26*.
But this is not that exact. I have tried 29.5 almost 30* which was a loss of several hp.
Same with retarded, less power.

I need to fix the cruising area when riding 100-120kmh in 5th. Too rich, AFR 12.2-12.5.

Will try smaller needle jets and raise needles a notch. This will hopefully fix it or at least move fuel to where needed better.

So another dyno will hopefully be done. Then run to 9500 rpm to see.

I have thoughts to reduce valve lash on exhaust. From 0.15mm (0.006") to 0.10mm (0.004") as inlet.
A very little increase in lift and duration might change something. Maybe not better.

I remember my DP315 cam that lost power with half lash than its recommended double/triple lash than other cams

//Per

[bear]

I'm very impressed with the torque figures.
They are about the same as my stroker engines.   

[PeWe]

Brian, you mean the torque curve in general, right?
You had higher top value than
67.62 ft lbs (91.68 Nm)?
And much more hp, in the +120 range.

My engine has stock stroke, 70mm pistons.
Megacycle 125-75 cam has a nice power curve.

Might be right match of displacement, compression and cam timing.
Normal fuel from Shell gas station.

It work too well to fiddle with it further. I have a new 125-70 on the shelf. It might have another horse lurking... or not...

I wonder how much the lighter APE crank affect the power.
Next build has stock crank ...

[MRieck]

Brian, you mean the torque curve in general, right?
You had higher top value than
67.62 ft lbs (91.68 Nm)?
And much more hp, in the +120 range.

My engine has stock stroke, 70mm pistons.
Megacycle 125-75 cam has a nice power curve.

Might be right match of displacement, compression and cam timing.
Normal fuel from Shell gas station.

It work too well to fiddle with it further. I have a new 125-70 on the shelf. It might have another horse lurking... or not...

I wonder how much the lighter APE crank affect the power.
Next build has stock crank ...

The lightened crank won't unleash more power Per. I'd stick with a stock crank with balancing especially as you increase displacement.

[PeWe]

Brian, you mean the torque curve in general, right?
You had higher top value than
67.62 ft lbs (91.68 Nm)?
And much more hp, in the +120 range.

My engine has stock stroke, 70mm pistons.
Megacycle 125-75 cam has a nice power curve.

Might be right match of displacement, compression and cam timing.
Normal fuel from Shell gas station.

It work too well to fiddle with it further. I have a new 125-70 on the shelf. It might have another horse lurking... or not...

I wonder how much the lighter APE crank affect the power.
Next build has stock crank ...

The lightened crank won't unleash more power Per. I'd stick with a stock crank with balancing especially as you increase displacement.

Thanks Mike.
I have ideas for my slow going engine build with stock crank and have CycleX super rods for it. I have VM29 carbs to be used. But can I build it with known limitation from the very beginning?
Best to accept the last dyno as a top result. Next can be less, another day with maybe less oxygen.

[bear]

Brian, you mean the torque curve in general, right?
You had higher top value than
67.62 ft lbs (91.68 Nm)?
And much more hp, in the +120 range.

Yep your right Per.
When I looked at your sheet I assumed the toque figures where in ft lbs not Nm's.

[PeWe]

Brian, you mean the torque curve in general, right?
You had higher top value than
67.62 ft lbs (91.68 Nm)?
And much more hp, in the +120 range.

Yep your right Per.
When I looked at your sheet I assumed the toque figures where in ft lbs not Nm's.

I guessed that.
That's why I translated Nm to ft lbs in the text.
My clutch is working today More torque might cause issues.

[PeWe]

Another run today which verified the old needle issue I have tried to avoid.
But it will only move the rich issue, too lean somewhere else.
Needle taper need to be different after a few mm lift.

Thicker needle in that lift that make 4000-5000rpm on 5th gear something. Before and after OK.

A little higher rpm, ~9500. Did not dare to enter the green area after the red, 10.000
The power reduce slowly.

The Dyno filter made bigger difference between DIN and STD.
Power as last time, +107whp. Bike feel fine with that

Note! Torque in Nm.

EDIT:
I have after this dyno finally  found correct needles so middle range is better, at least the AFR.
Before too rich needles.