Just curious...

I'm bringing the bike back in for pinging under load from 2,000 - 3,000 RPM after my cams and dyno tune. Pings under load with 93 octane, but only up to 3,000 RPM, then it runs like a raped ape. As it turns out, that's where the dip in the dyno is - from 2,000 - 3,000 RPM.

I haven't seen my AFR yet - it wasn't included on the original dyno. So I'm curious; what AFR and timing advance should there be set at the lower end of the spectrum? I'm thinking those two things need adjusting to get rid of the low RPM ping.

Sindenote - I'm really not looking for opinions about where the engine RPM's should be under load, so please - save it.

 

Timing is more important than AFR. Typically many guys that dyno tune bikes fail to optimize timing thay only get the AFR right. Find someone that knows to set the timing on the next dyno tune.

 

Max is on the right track, you can have an acceptable AFR and still have ping if the timing is not set up correctly. there are lots of variables involved here. at my place I always road test the bike after the dyno, just to confirm that there are no additional issues that need to be addressed, if so back on it goes till it's right.
m

 

Agreed timing is more important, but I have a feeling it's still set a little lean also. Part of the price of having the dealer do the tune, I think.

I will impress upon the service tech (with the service manager sitting next to me) not to simply retard it a couple degrees and call it a day. I head for Sturgis on Thursday, so no time to be guessing.

 

What tuner are you using? do you have the ability to log data?

Looking at whats going on just before the knock event may give you some insight.

 

I have the power vision. And that's a good idea, now that I'm home.

 

I would feel real lonesome without my AR gauge to stare at.
I don't have to guess.
You guys just keep doing it.

 

You do know that everone that has a PowerVision has an AFR guagd built into that u it dont you KG? You harp on it like its the end all be all.
If the tune was built well it is not a necessary guage to have especially without the specialized knowledge to know how to interpret the info it gives you.
It is invaluable during the tuning process, but once the bike is tuned properly,,,it should be a set it and forget it deal untill more modifactions or changes are made.
m

 

If you cant see your own AFR then you are relying on all other things staying as they should.
That is a pretty big Russian roulette game to play, and, I would NOT.
Next lots of tunners will let you go to lean, once you hit the street all nuances are not accounted for.
Again It is your money.
If It was mine, I would want to see how it is spent and what it is doing.
Next, not all dyno shops are stocked with people that actually know what they are doing.
How so you ask?
I had a kid argue with me about the benefits of twinn plugging my engine!
I did not pursue the stupidity too much, I just asked a few more questions and realized he knew a lot less about engine and tunes then I do.
I dismissed my self and moved on.
This is not hard to imagine .Look at all the HD shops with a dyno!
How many of these guys actually have done a high-performance engine with their hands?
They know what HD demands on the new bikes, now, does that transcribe to modded engine that is brought to them?
Hell NO<!
These "kids" dont own a dyno, maybe never see a real set of ported heads, or could even CC a combustion chamber.
But they sat through a class somewhere on running a dyno.
There is crisis right there a freekin in emergency!
Dont presume too much.

 

As a shop owner, a tech, an engine builder, a tuner and a former dealer tech, I presume nothing! That is why I own a dyno, have been trained how to use it, and still accept the fact thatI DONT know everthing and there is always more to learn/apply.
While i actually do not disagree with kost of your last post, there are diamonds in the rough everywhere. When i worked at the dealer they tried to get me to train those 'kids'. But i also got to meet and be trained by 2 guys that were a couple of the best teachers that I ever had, so not ALL dealer techs are worthless.
one of the main points that i was trying to get across was that ifan injected bike is correctly and properly tuned, the afr guage while nice, just becomes clutter becuase there are other symptoms that will show up tio let the avareage rider know something is up. The tune does not change unless a component fails. It is just IMPERATIVE that it was a well built tune to start with.
If you have a power vision unit, mount it up on your bars, set up guages and watch yor front and rear afrs while riding down the road. I use a wide band pro kit, so after i am done on the dyno, i take the bike out on the road and watch t/p, map, et and fornt and rear afr, all on one screen andmsee if there are any issues. On another screen i watch timing advance and knock events just to confirm that while on the road, the will not have isssue.
marco