Tracking down AFR problem w/ WEGOIII

[FLTRI]

And then...  Bam!, I whack the throttle open. You see a big shot of accel pump make it go rich, and then...   uh oh, I opened the Mikuni slide too much! Too big of a hole = no velocity = no fuel getting sucked out of the needle. I am lean, until the revs start building, velocity is picking up, fuel is starting to flow, and the AF starts returning to normal. That's all that was.

That all sounds logical until you apply the same exact senario to the dyno, which is SOP; steady state - 2000rpms then the whack the throttle open. I will see momentary rich, if there is way too big of pump and/or it lasts too long, but at no time do I see it go lean, really lean, like I see in your run. Basically what you are saying is that you squirt way too much fuel in for way too short of time period. May be, but you must have something really different going on there, OR the data is not correct.
AND...IMO you should feel a gross hessitation to accellerate from being too rich to too lean.

What really stumps me is how and why the O2 sensor sees so much air (phoney lean) @ high RPM/WOT when we know the exhaust is most reliable with out air (reversion, etc) getting into the mix.

Everytime I see that leanness for real the rpms flatten right out and the rider can feel the engine stop accellerating because the power goes away big time.

Me too!!! I wish there was a dyno chart with AF of the same "build", just a crate 124 with a Mik48. I can't be the only one...

I have done plenty crate 124 with Miks and Gs and never have seen them making power with AFR that looks like yours. I just can't trust the data.

[ederdelyi]

>>Ed- I noticed between my runs and the dyno, different points where the afr goes lean. The dyno one had a 28" long front primary, it's 40" now. More wave tuning effects?<<

Posssibly. I admit i don't know exactly what is happening here ... EGT readings or a 5 gas analyzer could help pin this down. Since it's carbed I guess the good news is that there isn't a whole lot you could do to trim the AFR on the cyls. anyway :>)

>>Burn patterns? I had these heads off, the pistons looked exactly the same. Didn't see any indication of burning lean or detonation.<<

That's a good sign. If the burn patterns and the fire ring on the plugs look good that further points to the anomaly existing in the header and not in the combustion chamber. I'd still be tempted to try a 2:2 setup just to see WTF is going on in that front pipe ... or just ride the F'ing thing and enjoy :>)

[fuzznut5197]

Bob, now I understand what you're getting at. Yes, this wego III was designed at a price point, and it shows. There is no smoothing, averaging, integrating, etc so what the thing samples is what you get, even if that one sample point is not representative of the data surrounding it. I admit I'm trying to use in a way it wasn't designed for, as in a Dyno sniffer. 10th second sample rate is not good enough. I never thought it would completely replace a dyno, but it's pretty useful for its price. Anyway, tomorrow morning is dyno day, and we shall see what its really doing. Call the tuner and tell him I'm a pain in the neck. 

Ed, I think the only people that have multi-gas analyzer around here is the department of motor vehicles. 
Yeah carb! And only one timing curve! Simple stuff for the dinosaur engine.

I am going to ride it and enjoy. But I will try the 2-2, just to see. Later than sooner.

[fuzznut5197]

Anyway, tomorrow morning is dyno day, and we shall see what its really doing.

Back from the dyno! We will never know what that front pipes doing, he saw that I had O2 bungs and wanted to use them. I told him to put it on the rear pipe, just because I didn't want to waste time if the front afr was all screwy. I got a whole bunch of graphs to assemble, and you will see from the curves that the front wego afr is BS. I'm still in disbelief of how much power this engine is putting out!   

[ederdelyi]

Cool :>) It would be kinda fun to see if the "problem" could be identified using some other methods, but I'm sure you'd rather ride it than turn it into a "WTF is happening here" test mule ... Enjoy.

[fuzznut5197]

Hey the WEGO recorded 29 dyno pulls. All useless data. 

[ederdelyi]

>>All useless data<<

Not at all, I'd bet that you learned a thing or two along the way. Having been involved with test and measurement for a good portion of my life, not taking test results as the gospel just comes naturally to me. "Suspect everything and believe nothing" :>)

[fuzznut5197]

That's so true Ed! 
Yeah I learned a whole heck of a lot. There is always something of value, good data or bad.

[Sonny S.]

Anyway, tomorrow morning is dyno day, and we shall see what its really doing.

Back from the dyno! We will never know what that front pipes doing, he saw that I had O2 bungs and wanted to use them. I told him to put it on the rear pipe, just because I didn't want to waste time if the front afr was all screwy. I got a whole bunch of graphs to assemble, and you will see from the curves that the front wego afr is BS. I'm still in disbelief of how much power this engine is putting out!   

Are ya done yet ?   

[fuzznut5197]

Are ya done yet ?

I was!   

[Sonny S.]

Are ya done yet ?

I was!   

just remember....we are never done ...lol

[fuzznut5197]

just remember....we are never done ...lol

True!...   right now I'm happy just riding in the nice warm weather, so this stuff is on the back burner. But I have next week off, and will stick the wego back on there for a comparison against the dyno AFRs. Fortunately, the dyno operator noticed the O2 bungs and, telling me that it would be more accurate if we use them instead of the sniffer, put the O2 sensor on the rear pipe (at my request).
So I will put the O2 on the rear pipe and see exactly how the wego and dyno afrs match up. But I learned something with all those dynp pulls, that a carbed bike can be "all over the place" with the afr, and it doesn't correlate well with power output. Take a look at this graph, 7 back to back full throttle runs. If you look at the afr at 5,800rpm (HP peak), run #1 and run#7 are the furthest apart in afr, but it didn't make any difference as far as power.




Here is a closeup, with cursor values.




Here it is with no smoothing. Even with 0 smoothing on the chart, the dyno afr isn't nearly as rough as the WEGO...

[fuzznut5197]

So I will put the O2 on the rear pipe and see exactly how the wego and dyno afrs match up.

OK, here's a wego run of the rear pipe. It never got anywhere near the 11s afr on the dyno, so the data is kind of useless. The graph below that is the front, same bs.

[Sonny S.]

IMHO it's going to act different on the dyno when you whack the throttle.

To me the data log makes sense.
On the street...whack the throttle and as the bike launches forward more fuel goes to the rear cylinder and it goes rich...front goes lean...just like your charts.
On the dyno you don't have the same scenario. Bike is sitting still.

You were having a lean spike even off the rear...that appears to be gone.
Log interval of .1 sec might show that

[FLTRI]

Interesting.....I would have guessed the top graph was the front and bottom was the rear???

[Sonny S.]

Interesting.....I would have guessed the top graph was the front and bottom was the rear???

bet it would on the dyno   

[fuzznut5197]

What do you mean? The dyno afrs I posted (Posted on: April 27, 2009, 11:42 PM) of the rear cyl, and the wego rear cyl I just  posted, both show a tendency of the afr to go richer as the revs go up. The wego one is showing consistently richer than the dyno afrs. The wego front cylinder shows the same lean bs that has been plaguing me since the beginning of time.

[se]

when the weather gets warmer and JD's empties out you and i will take a ride to pa and throw the bike on the dyno and let Dave take a look at it.
Maybe TXCHOP will also tag along for a day at Daves.......

[Sonny S.]

the charts in your first post look different than your last...to me

[fuzznut5197]

when the weather gets warmer and JD's empties out you and i will take a ride to pa and throw the bike on the dyno and let Dave take a look at it.
Maybe TXCHOP will also tag along for a day at Daves.......

Sounds great! I never did get front cyl dyno data with the new build. I'm curious...

[fuzznut5197]

the charts in your first post look different than your last...to me

Yeah, like you said the interval is .5 instead of .1. But .1sec is only 10 minutes of logging time, and I have to travel a bit to get to a suitable road to do the above 4th gear runs (I forgot to mention that), and needed more logging time.

[Sonny S.]

sorry 

I still don't think seeing the front go lean WOT ( or rear go rich ) on the street is uncommon. I think it would level off if you stayed in the throttle for a longer distance.....although a ticket might take the fun out of it...lol
Years ago I saw a thermal imaging scan done on carbed drag bikes, and as the bikes launched the front cylinder went lean....it has to.
Not going to do that on the dyno.

[se]

Sonny you mentioned the same thing on the old Site if i remember .. now would it be the same with an EFI bike compared to a Carb?
the fuel is more routed and a better shot to the frontt and real cylinder with efi then carb. so i would guess it might not go as lean as a carb bike would. base upon guess here since the injector is pointed more towards each ctlinder.
G

[Sonny S.]

SE,

I'm thinking along the same lines as you in regards to EFI.
One more reason it is superior to carbs....right Bob ?   

[FLTRI]

sorry 

I still don't think seeing the front go lean WOT ( or rear go rich ) on the street is uncommon. I think it would level off if you stayed in the throttle for a longer distance.....although a ticket might take the fun out of it...lol
Years ago I saw a thermal imaging scan done on carbed drag bikes, and as the bikes launched the front cylinder went lean....it has to.
Not going to do that on the dyno.