Topic: Post your Dyno Graphs here.

[PeWe]

Mike, that rich area on your last dyno reminds me about my dyno some years ago. (836cc Megacycle 125-20 cam).

I changed cam and the very rich bump at WOT disappeared.  Maybe the less overlap? (To Action Fours SS-1)
It was still rich on later dynos with 71.25mm pistons and same carbs TMR32, lowered the needles 2 steps and it disappeared.
The low throttle lift was not perfect though.
I was determined to find out last year and tried various combinations needle jets and needle heights. I have before that tried pilots + fuel screws all over the area.

Needle jet, the jet I should have changed from the very beginning!
P-1 to start with. I leaned out to O-6, O-8 too lean despite high needles. Now P-0, only one size smaller than delivered with my TMR carbs. Needle heights hopefully right. Too lean needles remove the freight train feeling at WOT, huge difference.

I initially compensated with wrong jet (needles) and got other issues affecting pilot area in need to be richer and finally got too rich sooting idle, still jerky take offs.

I'll add a new dyno here later in April if possible with the dyno guy and weather is OK.

[Old Scrambler]

Nice work, Mike Too bad your over 1000cc or I could run your motor in my chassis to give it a try on the BIG WHITE DYNO

Pewe......very informative as I run a TMR 29 on my Triumph Cub with snowmobile 'emulsifier & needle' that gets the fuel a little higher into the venturi.

[PeWe]

" snowmobile 'emulsifier & needle' "...
Is that optional parts to order?
My TMR has small needle jets, 12 mm long sitting on top of the main jet holder that is a pipe, like a shorter emulsifier. The venturi has a brass pipe sticking up around 5mm.

Here more photos when I did rhe needle jet replacement for the first time a few months ago.
http://forums.sohc4.net/index.php/topic,179479.msg2081757.html#msg2081757

[MRieck]

Nice work, Mike Too bad your over 1000cc or I could run your motor in my chassis to give it a try on the BIG WHITE DYNO

Pewe......very informative as I run a TMR 29 on my Triumph Cub with snowmobile 'emulsifier & needle' that gets the fuel a little higher into the venturi.

Thanks Dennis....changing the cam will hopefully straighten out the fuel curve. And big thanks to Per for his TMR work. I'll be using them on my next engine which should be 1140cc's if everything goes right.

[Old Scrambler]

Pewe.........that looks a lot like mine............Used to be lot of 3 or 4-carb sets on ebay under snowmobile carb searches......cheap

[CBJoe]

Never Did post this...but heres my last Dyno Run....going to do some minor tuning and take it back for one more go, but I doubt I'll get much more HP/Torque out of it on my setup.  Basically going to tune the carbs a bit Richer for mid-WOT.

- 836cc
- Megacycle 125-75 Cam
- Mikuni RS34 Carbs

[PeWe]

........ I'll be using them on my next engine which should be 1140cc's if everything goes right.

You'll replace the 106whp engine?
1140cc ... stroked crank, right?
Billet crank?

Dennis, thanks for the carbs hint.

I'll add new dyno chart later this year and ride report about the jetting.
/Per

[frodef2]

just back from the dyno. 

Logged over 100 on my MRieck monster ..

Frode j

Update:
The engine contains:
MRieck stage 4 head with 5 mm valvestems. I do not remember every mod that goes into the stage4 job
71,25mm flat top pistons
Billet block
Carrillo rods
Lightened crank
R6 generator
125-75 cam
RS34 carbs

I might add that the jetting on the carbs was spot on for the main jet. The dyno operator tried 1 fatter and one leaner, but reinstalled the original size.

The only work done by the tech was synchronizing and idle/mix adjusting.

I would like to thank mr. Rieck again for expert advice. All i did was to do it as i was told.

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[turboguzzi]

very nice!

[gschuld]

FrodeF2

Nice result 👍

Would you mind adding to your previous post the basic details of your engine as it gives reference.

I recall you using one of Mike’s awesome billet cylinders and 71.25 piston sets.

I’m curious about which ones(JE I’m guessing: dome wise/flat) and the static compression you ended up with.

Megacycle 125-75 cam I think

RS34 carbs

Lightened crank.

Rods?

Head details?  JMR state 4 perhaps?

These details are very helpful for those of us comparing different big bore engine set ups.

Thanks you and congratulations 😉

George

[MCRider]

SUBSCRIBE

[PeWe]

FrodeF2 means F2 head with 34/31 valves right?

Compression test with a cheap tester is interesting too. It show CR and cam overlap combo.

Mike has shown what to beat with his cool billet block (+1000cc) and matching parts ! If not, tweak it more!
Power at low rpm is also a winner for a street bike.

[MRieck]

 The only problem with a 100 HP CB750 is you get used to it quickly and want more.

[MRieck]

I had to go back to see Frode's build. Nice parts (R6 charging system, Carrillo's, 5mm valve conversion etc etc). Bike is beautiful. Great combination of good looks and good power......Mr Honda would approve.

[PeWe]

Mike, you can offer a 105whp package for CB750 owners on street gas, right?
It will be very interesting to see what a turbo can do with a billet block CB750 which is an ongoing build on this forum!

Tweaking the bike is the fun part with a CB750! Always ready for a test ride.

I hope I can add a dyno result here in April.  Well lubricated and correctly tightened drive chain to not loose a hp or 2.

[frodef2]

I updated the original post with the specs of the engine.

Late update as I had a long drive back to where i live. (250miles)
The local dynos have all closed, or wouldn’t touch a carbed bike with a 10 foot pole.

Pewe: the head is a 392 head supplied by Mrieck.


Frode j



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[MRieck]

I updated the original post with the specs of the engine.

Late update as I had a long drive back to where i live. (250miles)
The local dynos have all closed, or wouldn’t touch a carbed bike with a 10 foot pole.

Pewe: the head is a 392 head supplied by Mrieck.


Frode j



Sent from my iPhone using Tapatalk

Wow.....I admire your tenacity Frode.

[scottly]

Late update as I had a long drive back to where i live. (250miles)
The local dynos have all closed, or wouldn’t touch a carbed bike with a 10 foot pole.

I can understand that they wouldn't want to tune the carbs, but at least they might do a dyno run to give you the data to re-jet yourself, then re-test?

[PeWe]

It must be possible to get the dyno runs done with A/F ratio and get the graphs emailed as pdf files.

When I got my dynos done I could see on the graph where wrong and hopefully what. One slow dyno run slowly increase throttle to see how needle area was. And the area just before, emulsifier (needle jet).
I did all changes home when I knew what the uneven running engine was. Sometimes difficult to feel difference between too rich or too lean.

I have learnt where the needle jet area start and not mix it up with needles which ends up in an endless series of adjustments.
My next dyno to verify correct needle jets and needle heights. Main jet too.
A better flowing exhaust reveal those problems much more.

[Jerry Rxman Griffin aka MuthaF'er]

Finally after 2 unsuccessful engines it has happened. AND this is just the start to dial it in.

CycleX 915 kit and crank, JMR Stage 4 head, Megacycle 125/75, Carrillo rods, FBG undercut gears, 17/48, Kerker with competition baffle. Keihin CR31's 120 mains, needle in 3rd or 4th slot(?) 6000' elevation, 78 degrees, 19% humidity, 4000' air density.

First dyno attempt for me and the bike. 4 pulls with the first aborted. Really fat on the top end.

The advice was to go down 2 sizes on the mains and hold off on the needles. I thought I had 125's in it so when I returned home to drop them 2 sizes I found I had 120's and not 125's. I only have 115's on hand so I put them in. These CR31's are a dream to jet!!! Looks like I'll make a trip to the 2 Honda dealers in search of a couple more sets of mains to give me a more complete set - 110's and 105's. Who'da thought that small of a jet?! Hoping the next dyno visit will get me dialed in.

James at American Bike Tailor is great to work with. I surprised him with the results. He thinks with proper jetting we can get another 10 to 12 HP. Factor in the altitude and that should get me in the ball park of 100 HP +/or -. I'm good with that.
     

[scottly]

110's and 105's. Who'da thought that small of a jet?! Hoping the next dyno visit will get me dialed in.
   

I ended up with 105's with Webers, and that was still a bit on the rich side. With the original 125's, my A/F was pig-rich, just like yours, flat-lining at 10:1.   

[Jerry Rxman Griffin aka MuthaF'er]

Here's my dyno pulls:

https://youtu.be/uLX7b71I0xA

As I was heading to Honda to get the jets my fukn Dyna2000 took a #$%* on me on I-25 with 4 lanes of fast busy traffic running 75 - 80. Started slightly bucking and popping. I turned around and headed back. It progressively got worse. I made it to within 3 miles of home. Terrible feeling sitting on the side of the road!! Thank goodness for my AMA membership and the road service. At least that's what my initial prognosis is considering the first Dyna200 lasted me about 35 miles and it's replacement got a little over 300 miles. The dyno pulls have some minor popping you will hear. We kinda blew that off to the overlap in jetting with it's rich nature even though I hadn't noticed that when riding previously. Anyway fingers crossed on the ignition. Simple fix.

I just can not win BUT I WILL PREVAIL haha         

[scottly]

Fer cryin out loud, will you finally install the new-in-the-box Gerex ignition you've been hoarding!!??
Also, the "red line" for gas on the A/F chart on my dyno is at 13:1, not 13.5:1, which is considered lean. For max power, the A/F should be in the range of 12.8-13.2:1.
You asked the dyno operator what the HP would be at sea level, and he responded 15% more. The chart shows an SAE correction of 23%, meaning the HP on the chart is what you would expect at sea level. Here at 4500 feet, I usually see a correction of 15-18%.

[dragracer]

Just add a simple Dyna S with 3ohm coils and ditch the 2000. Add a basic dyna high side limiter for safety and never look back. I ran a dyna s system with 3ohm coils for years on a dragbike without failure. Bike ran 8.80s in the 1/4 mile at over 145mph. The only reason I took it off was to upgrade to a Dyna 4000 super pro with an add on shift counter set up for a 1-2 auto tyranny that I installed afterwards. K-I-S-S. Keep it simple, stupid.  Lol

[scottly]

Certain vintage Dyna s as well as Dyna 2000s have been notorious for #$%*ting the bed while on the road; your bike only had to run for 9 seconds at a time, Frank.
My Gerex multi-spark came on my bike when I bought it in 1979, and has never given me any problems.