On a 2007 SportsterLow running 93 octane fuel running in 95 degree weather, my totally stock bike wants to detonate when at 1/2 throttle or more. If the stock bikes have Ion sensing, why are these bikes so prone to detonation. At this point in the fuel map, it appears the bike is open loop and fairly fat. The thing that is throwing me is why is the stock code allowing the bike to ever get to this point.

I may ellect to not blow away the stock maps untill I canrecord this on the data loggers later this summer.

AW

 

The ion sensor takes about three revolutions of abnormal combustion before it changes any timing to correct the problem....that's what your probably hearing.

 

What I am really starting to question is if these things are that sensitive to IAC and/or cylinder cooling, can they be dyno tuned an anything less than hot days?

I have noticed insane IAT temps of like 50 degrees above ambient even on cool days when the bike is on the road. It will be interesting to look on a 100 degree day.

In this case I always notice it on a section of road that I have to accelerated for a stop sign uphill ona entrance ramp that I have to get up to 65 MPH or so to merge into traffic. I have to feather the throttle all the way up to speed to keep the bike out of dead detonation. It was the primary reason I justified the SERT to figure out what the motor was doing. I removerd the Rinehart 2-1 with quiet insert as I was concerned I would not be able to catch the detonation with the loud exhaust.

AW

 

Try changing out the plugs? When I was in Sturgis I ran Autolite 4163's as opposed to 4164's (6R12 equivalent) worked better for me.

 

No ION sense in the Sportster ECM.

 

If running platnum plugs, dump them and go back to stock plugs. On a hot day, the platnum plugs retain enough heat to ignite the fuel without sparking (pre-combustion). I run platnums in the winter and stock plugs in the summer.