View Full Version : Looking for experience with TMax

11-20-2007, 07:52 AM
I did a loaded run the other day and was able to record 20 minutes of normal riding. During playback, I had 3 instances of Front AFR reach 14.50 and 2 instances of Rear AFR reach 19.30. On both occasions, the target AFR never exceeded 13.85. These figures don't make sense when the ambient temp is 65 degrees and I use Syn in all three holes. I never went above 260 head temp but was very surprised to see playback at cruising at 2600 and the Rear AFR hit 19.30. Any experienced opinions with regards to this?


11-20-2007, 08:00 AM
And any interpretters to explain it? ;)

11-20-2007, 08:15 AM
As you wick off the throttle while cruising engine load diminishes and so does the amount of fuel vs full throttle which takes it to the full rich mixture. The engine only takes what it needs at a given time.

Hope this helps

11-20-2007, 08:22 AM
As you wick off the throttle . . . .

We are talking about a motorcycle, right? pns

11-20-2007, 10:13 AM
Did it hold at 19.30 AFR or just run thru it for a second, like it was 'searching'? How long have you been running your current map? It takes a several miles (& several run/stop cycles) for the AT to fully adjust to various conditions & 'settle in'. Even then (like Wide said) I don't think any engines ever run at a CONSTANT AFR tho.


11-21-2007, 10:06 AM
I've been running the map they programmed at Zippers for the last 5K miles. The 19+ doesn't last very long and during playback, I watch it climb 3 separate times over a 15 minute period. The Tgt AFR hovers around 13.85 when this occurs and the rear AFR goes through the spectrum. I could understand it getting lean if I closed the throttle but anything above 14.00 seems beyond lean. The super lean spikes are contributing to my I-95 stop and go engine temps too. (I've got recorded temps on numerous occasions of over 320. I'm running 20w-50 syn in engine and primary and 75w-140 in the tranny.) I haven't rode in the last week as I am concerned about doing serious damage to the engine at this point.
What would the symptoms be for a bad WB O2 sensor? This is the only thing I could think of at this point as I wait for Zippers to respond to my problem.
Rehash of current symptoms
1- Head Temps reaching 320+ when ambient temps are 70 degrees or more in stop and go traffic for periods lasting >20 minutes.
2- Super lean rear cylinder AFR spikes during normal operation.
3- Closed throttle at speeds above 75mph produce shotgun blast acoustics and flame out of R side pipe. (I scared the shit outta my buddies during a road trip and nearly gave one of them a heart attack.)

11-21-2007, 10:10 AM
Pardon the interruption, but what is "AFR?"

11-21-2007, 10:31 AM
Rear cyl AFR varies more than the front w/mine too w/an occaisional 'flash' of 14.'something'. I believe the rear cyl generally always runs leaner tho, & I'm not worried since the bikes come at 14.7 or so from the factory. The good ole EPA, dont'cha know..Yep, 320* is warm, is it a Sporty?

AFR = Air Fuel Ratio.


11-21-2007, 12:22 PM
Thanks for the definition, Vic. How is it that one cylinder can run leaner or richer than the other? Are after-market ECMs capable of making the distinction between cylinders? How can the cylinders be differentiated in the map?

11-22-2007, 05:41 AM
The TMAT only allows one AFR setting between the two cyls, & a programmable rear cyl offset of the ign timing. I believe the DTT TCFI allows more complete individual cyl tuning, but not 100% on that. The PCIII usb allows individual cyl AFR & timing, & I'm pretty sure that the SERT does too. I donno about any of the others...


11-22-2007, 08:15 AM
I'm not rolling on a Sporty, it's a FLHR. You think the temps are acceptable? I definitely want to figure out this rear AFR deal. Any suggestions on what to try first?

11-22-2007, 08:36 AM
I have my engine temp alarm set at 300.17* & it hasn't set a fault. I don't do much stop/go riding, but don't think I'd be comfortable w/320* on a TC. As for your rear AFR, have you checked for an intake leak? Noticed any drop in performance or MPG?

Maybe you should consider calling Zippers about your issue. They're good guys; courteous & very helpful.