Just analyzing my data collections I made over the weekend trying to dial in my VE's and realized that my front cylinder seems consistently about 10% lower than my rear in the same cells. I checked some basics but not really sure what a consistent reason for this would be.

On the plus side, the bike is running decent and a bit cooler. I'm getting around 50mpg with canned AFR and timing tables, etc. Some decel pop around 1750rpm but not really any other weird conditions. And even though they show a difference like that between cylinders, the adjustments at each between runs are minimal (so in the low rpm and cruising range anyway I think I have my VE's as close as I can get them on my own). Any explanation whats going on? I notice a block I could check to "link changes between front and rear cyl's." But haven't tried it yet, or looked it up to learn about it. Perhaps this weekend when I get back at it.

103- stock cam, heads, pistons
S&S Stealth air cleaner with cover installed
Thunderheader
SE Super Tuner

This engine is never gonna be a wild setup, its a travel bike. This winter might yield a little more work but nothing crazy.

Explanations appreciated!

 

It's not unusual to have different VE's on the front and rear cylinders. The rear cylinder runs hotter so there will be some differences. I wouldn't worry about it.


I wouldn't bother with linking the changes, as autotune max.s the VE's for you and each cylinder has it's own O2 sensor.


Decel pop can probably be tuned out using Decel Enleanment in that range.

 

FWIW, one reason some/most canned maps do not seem to be very close to targets is due to variances in production injector output (+/-10%) and other variables such as exhaust and cams, etc.
Bob

 

I didn't think of that. I should know better about that kind of stuff actually. I'm not uninformed... heh... put in and setup so many 6 packs of injectors in trucks I could puke. Thought being a wrench for a living was a great idea... before I was a wrench
Anyway, I was wondering if it was an airflow issue. I didn't notice this kind of thing before when I only changed the headpipe and was running stock aircleaner. Then again, it was my first time doing any kind of flash tuning on a bike so maybe I just didn't notice. My other thoughts were possibly a weaker 02 on the front (didn't swap sensors yet to see if that proves out) and I had thought about the heat issue btwn cylinders, but thought that would make the rear run not as good as the front.
And last, as I sit here typing I realized that I still have the old plugs in so I didn't foul brand new ones. My tables aren't changing that much, maybe its time to get the new ones in and see what happens.

 

Shared intake, not tree same airflow in each cylinder