Topic: Post your Dyno Graphs here.

[dragracer]

Scottly,  I also have a K model with Dyna S that I rode on the streets for many miles. I installed it in 1984. It never failed. I have not ridden the bike in several years now but I would not hesitant to take this bike on a cross country trip with the Dyna S. Yes, I've read about the failures of Dyna S but only through a few members of this forum.  Not certain how or why they stopped working.  If Gerald has an ignition package on hand, I do agree he should use it instead of buying something new. Nevertheless,  I still have confidence in a basic Dyna S and good coils. We all have opinions and this is one I'll stick with until I personally determine otherwise.

[PeWe]

Dyna failures might have been a bad batch from year x to y.

Single components can suddenly be out of spec, especially when made in China. Temperature related like capacitors, transistors etc.

[bear]

My experience is similar to Frank's.
I still have the three originalI DynaS units I purchased so many years ago I can't remember when.
Used with later Honda 3ohm coils and never had a failure.
It would appear that the later units are a different story.

Cheers,
Brian

[Jerry Rxman Griffin aka MuthaF'er]

Thanks for the input guys. Needless to say I am skeptical about todays Dyna in general now. I have a Dyna III from mid 80's on my other 750.

[paul_cb836]

Have two Dyna 2000s. One on 836 road bike and one on 915 race bike. Been on both bikes for quite a few years and never had a problem.

[Jerry Rxman Griffin aka MuthaF'er]

Have two Dyna 2000s. One on 836 road bike and one on 915 race bike. Been on both bikes for quite a few years and never had a problem.

Which curve do you use?

[johno]

Well Jerry, some more tuning will get it right, for me Im a noise man, it sounds horny ! 
cheers Johno

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         

[Jerry Rxman Griffin aka MuthaF'er]

Thanks Johno.

Blue and I both have that same condition 

[scottly]

Scottly,  I also have a K model with Dyna S that I rode on the streets for many miles. I installed it in 1984. It never failed.

Frank, you and Bear don't spend much time on the main bikes forum. The Dyna S failure plague was at it's peak 10 or so years ago. Every spring, there were multiple cases, usually with symptoms like "My bike ran fine when I left this morning, but started losing power, like it was only running on two cylinders." It became automatic to ask if they had a Dyna S. In the last couple of years the failures have slowed to a trickle, but they still do pop up. Near as I can guess, the bad units were made starting around 2005-2009, and Dyna came out with a new design pick-up around 2015. So far, I've never heard of a failure with the new version. The new version is easy to tell visually from the old; the old pick-ups had a more block-like shape, and the new have a more contoured shape. As far as the 2000, I seem to recall that it may have used the same pick-ups as the Dyna S? If so, the 2000 box itself *may* still be good?   

[PeWe]

Is this the newer or the failer?
Purchased 2014.

[scottly]

Yes Per, you have the newer version.

[PeWe]

Yes Per, you have the newer version.

Thanks for the knowledge!
I had to adjust 2-3 just a little to get that side to line up as 1-4, marked before moving it. Took me 5 minutes extra

[paul_cb836]

Re which curve I use on Dyna, would have to check on 836 road bike (not home at moment, maybe curve 4) but on race bike we use curve 3 with total advance of 35 degrees).

[PeWe]

Another Dyno today.
JMR Billet block,
JE 71.25mm CR11:1 pistons (w std 22.5cc chambers)
Head w 23.7cc chambers.
Valves 6.5mm stems:
In- F2 34mm with lash caps,
Ex- KPMI 28mm
Cam 125-75
Dyna-S

Lower values in red: Old head w issues and RC295 cam profile.




New dyno next year with hopefully a few more

How hard can it be to add 5-7 more??
They are in there, just let them out!!!

[Jerry Rxman Griffin aka MuthaF'er]

Looks fantastic. Carbs dialed in too. Gotta love that A/F line.

Elevation?
Carbs?

Is this 2 separate runs with different configurations showing on the same graph??

How do you compare the 2 cams?

[PeWe]

Yes, 2 different runs not really comparable. Today in blue, the red over a month ago.
Different heads and cams.
The progress good to see anyway.
Elevation 30-50m over sea level.

The RC295 profile will most likely produce better with the better working head.
My old head had leaking valves on 2-3 due to cracked carb boots and more lower compression when nuts sank into the alu, mostly on ex side.

The "new" head has smaller chambers to crank up the compression. 23.7/23.8cc vs 24.4cc, therefore CR11:1 pistons.

The 125-75 has a very nice and even power curve. It work fine with bigger bore.
I had CX-7 on 836cc before,  not much, suddenly woke up as a 2-stroker at 6500-7000 rpm

The carbs are really fine now.
They were way too lean up to 3000 rpm. Idle way too rich. This is not visible on the graphs.

I have tried 1 step bigger mains which ends up in really rich at high speed, reduce a little and a little bit more again.
Same if going up a little on needles, now 3rd notch from top with an M3 washer under making 3.5.
4  cause too rich.
3 less power at acceleration compared to 3.5.

Needle jet the trickiest to find. Pilot for idle and the first 2mm lift followed by needle jet.
Fuel screws must not be opened too much. Mine are now 1 1/8 minus 1/16. If they must be richet for 2000-3500 area something else is lean, like pilot and/or needle jet. Much fuel screws will cause too rich idle.
I know the hard way!!

I'm satisfied to finally have found the carbs to be OK!
Jerky behaviour at low lifts can be unsynched carbs that must follow from idle-3000 rpm and up.

Flat slides react quick but seems to show the flaws much better too
Not as forgiving as old stock carbs.

125-75 idles fine at 1200 rpm.

[Jerry Rxman Griffin aka MuthaF'er]

I did some adjusting and returned. On my way to pickup new mains at Honda it started popping badly. Much worse than as witnessed by the "burbles" on the printout and as heard on the dyno. It died and left me stranded on I-25. Turned out the 4 pin connector on my Dyna2000 had 1 side and the ground pins loose coming from the pickups going to the module. Now the numbers look better as far as HP and A/F but more jetting required. On my first set of runs it was "fat" on top. Easy adjustment. It had 120's so I dropped to 110's. Normally I'd just do one size each time but it was way rich below 10/1. The A/F between 2000 and 3000 was lean but it went fat at 4000. My assumption was that the needles need to be raised so I raised them 1 clip. I found out I should have left them as is for this run because it starting going fat around 4000+ and that was on the needles. The 110's seem to be very close starting around 7000. This round James ran on run up to 9200. He was skeptical since the tach redline starts at 8400. You can hear which run that was. It was just starting to drop off as far as HP goes. So anyway this round got me up to 82.07HP and 55.27 lb ft at 6000' elevation. One thing to note: as I was working on the ignition I reset the timing to 35* and previously it was set to 40*. Possibly more numbers when I take it back to 40*? Not major improvements this round but positive improvements. More to come.

https://www.youtube.com/watch?v=GIENqmCR9xI

As you watch the video you will see James struggling with the throttle. The grip slips a little and the stock pull cable needs an inch or two due to tightness. Things to work on when I return in the spring. Along with that I will drop the needles 1 notch. I'm obviously expecting that to get the A/F in the mid-range closer and improve the mid-range responsiveness and power.

[PeWe]

You need to verify all jets on dyno with A/F meter and slowly increase throttle while looking at the A/F ratio with knowledge of the throttle lift.

I had too rich needle jet causing too rich around 3mm throttle lift.
I made needles leaner which improved that problem, but I lost 5hp on next dyno since it was too lean at the needle working area.

Later recommendation by a carb guy to decrease needle jet. 1 step leaner fixed it. From P-1 to P-0. But I tried even leaner O-8 and O-6 too
Hesitations over idle to 3000 rpm (the first 1-2 mm throttle lift) fixed by pilot jet, 32.5 is OK on my carbs (will test 35). Smaller must have much more fuel screws causing way too rich idle. Fuel screws now  1 turn out, maybe 1/16 more is OK. (Less wirh bigger pilots)

Too lean pilots needed over 2 turns out to run OK to 3000 rpm, but idle was stinking.

My jetting took very long time since I tried all kind of combinations before final dyno.
High speed butt dyno has risks.

My too rich needle jets + needles caused very rich at 4000- 6000 rpm on my first dyno at WOT.

[PeWe]

Another dyno today after adjustments of carbs.
Too rich idle before.  Now fixed by 1 step richer pilot (32.5-35) so fuel screws could be reduced from 1  1/8 to 3/4 turn out
Earlier AF graph showed a rich snake around 4000-6000 rpm. Needles earlier 3.5, washer removed now 3:rd notch from top.

Today bad whether reducing over 1 hp. Drive chain really bad, too stretched for dyno or hard throttling. But did risky ride with a chain that can snap.

BUT, the streetable area improved! 4000-6000 rpm better which was obvious on butt dyno. It runs smoother and better plug color.
Even ride around 120-130 kmh a little rich. Possible to reduce to 2nd notch + washer. I'll check if I can reduce 1/3. M3 washer is 1/2 notch. Need 2X3.5mm washers. (1 notch on needle is 1mm)

Blue graphs today (last run)
EDIT:
Torque in Nm.
Here are the ft lb numbers to compare with others Dyno runs where torque is in ft lb.
Last run: 99.33 whp, 67.848 ft lb
Before:  101.06 whp, 67.376 ft lb

https://www.unitconverters.net/energy/nm-to-ft-lb.htm

[Old Scrambler]

Hmmmmm.....100-RWHP in a Liter Bike that weighs about 440-lbs..........most manufacturers would be envious

[PeWe]

Hmmmmm.....100-RWHP in a Liter Bike that weighs about 440-lbs..........most manufacturers would be envious

When comparing with newer japanese 4 cyl bikes with lots of power. I feel better to compare the 3500- 8500 rpm range. They are not that much better there!!

Even if I should add a fairing with air inlets pressing air into carb filter area at higher speeds, dyno will not show that.

A really light rear wheel and higher tire pressure to get higher values. Butt dyno will not indicate...

[scottly]

Another dyno today after adjustments of carbs.
Too rich idle before.  Now fixed by 1 step richer pilot (32.5-35) so fuel screws could be reduced from 1  1/8 to 3/4 turn out
Earlier AF graph showed a rich snake around 4000-6000 rpm. Needles earlier 3.5, washer removed now 3:rd notch from top.

Today bad whether reducing over 1 hp. Drive chain really bad, too stretched for dyno or hard throttling. But did risky ride with a chain that can snap.

BUT, the streetable area improved! 4000-6000 rpm better which was obvious on butt dyno. It runs smoother and better plug color.
Even ride around 120-130 kmh a little rich. Possible to reduce to 2nd notch + washer. I'll check if I can reduce 1/3. M3 washer is 1/2 notch. Need 2X3.5mm washers. (1 notch on needle is 1mm)

Blue graphs today

Per, the way the A/F is graphed is hard to read. As the sensor can read no lower than 10:1, having the graph set for 0 to 20:1 compresses the usable data. Your operator can change the settings to display the graph from your previous runs, and print new ones. Show him this as an example:

[PeWe]

Thanks for the comments.

A graph showing a very slow increase of throttle should show more.

I got  information told to me.
The fuel ratio is now really fine at idle and all the way up to just before 5000 where it become a little rich until ca: 6000rpm as also seen on the graph.

This is a common cruising speed  so decrease needles just a little is more important than ev throttle response from that area. Dirty plugs will not help during acceleration either.
Lubrication might suffer and carbonized ex valves not good.

This graph is during WOT so first rich must be the acc pump.

*** Last run is blue graph. ***



I have ridden the bike on 5th gear from 2000rpm and slowly increased throttle just a little, maybe to 3000rpm, slowly reduced back to 2000, increased a little bit more , reduced again. Repeated this to full speed.
It has no hesitations at increase nor too rich bubble at throttle decrease.

A little rich will be visible when reducing throttle with no load.

Hesitation at increasing throttle,  and OK when reducing throttle is too lean.

Way too rich will cause issues during acceleration and decelerations. Black smoke when rev slowly when parked, sooting plugs at idle demanding revving it up before take off at green light after red.

I have ridden so many test rides this year so this has become my way of riding. >10.000km and 2 rear tires this year.

I also watch the voltmeter, follow how the voltage change.
I listen to the bike constantly

Next step is to find 0.75mm thick M3 washers. Decrease needles 1 notch (1mm), add the washer of 0.75mm under.

Update:
I found 0.8mm washers on eBay from China. I'll know next year if that will help. I need to measure on a needle if it really will lower by 0.2mm.
2nd notch with washer under compared to 3rd notch.

After lifting the head, I noticed how carbonized the pistons and chambers were after not much use.
I changed my mind about needles. I'll set a little bit lower with thinner washer to reach 2 1/2 notch. 
If compression will increase, actual jetting will be richer.

[HondaMan]

Thanks for the input guys. Needless to say I am skeptical about todays Dyna in general now. I have a Dyna III from mid 80's on my other 750.

You have a working Dyna III? Mine both died in less than 1 season (one in 1 month).

[newday777]

Yes Per, you have the newer version.

I saw an ad for NOS set of Dyna S, coils and plug wires for $300 and wondering if it is one of the failing models?? Price seams high too??