For you Newbie and Low Time Intermediates, I discovered this interesting "issue" of Lean Fuel Injection Mapping, almost the hard way.
If you're following the "Maps Only" thread, I'm the guys attempting to program my 2013 WR450F with an FI map that will yield a greater range distance.
I'm also a Low Saddle Time type (a "new guy", less than 100 hrs) for this cycle, but I own (and have owned) many different Fuel Injected cycles.
I'm decades into my motorcycling career, and I have no analogy / similarity for this particular issue. I think it's unique to high torque dirt cycles, and *possibly* to only those that are fuel injected. I'll explain why I believe that in a moment, but on to the issue.
So, I'm playing around with the GYTR Programmer, and I'm riding with a FI Map that "leans out" the fuel, and "retards" the ignition, over a broad range of the FI map (the map array of digits). Here' I want to focus on the Low Throttle / Low Power end of the maps (the lower left hand corner of the array).
While I'm riding one of these "lean" and "retarded" maps, I notice the cycle engine's throttle response is very abrupt, on / off switch like. Twist a little, and it's *there*, lots of grunt, torque being put down. Roll that little bit off, and the motor is *off* like a light bulb gone dark.
Call it "hit", "snap", whatever.
For me, it became very difficult to ride it well.
Here's what happened. I'm heading through a rock wash, in canyon country. I'm down one wall, through the wash, and heading up the other side. While heading uphill, I hit some bump, some rock. The throttle "blips" in my hand. Power comes up, abruptly, and the front wheel lifts. I'm heading off the back of the cycle, from the force of the torque being applied. I manage to not roll on any more throttle, and I'm gripping everything in fear, waiting for the cycle to finish coming up, over, and land on top of me...
It does not. The front wheel comes back down, and on I go. I've had two of these, now (I was ready for it, the second time).
I'm told many things about that experience, from others more experienced, who I relate this story to.
I think you see my point. "New Guys" can get in over their heads with this FI Map programming business.
Just be aware that some FI Maps have "UnIntended Consequences" if you choose to ride them. The one's with lots of (-X) numbers, negative numbers, you want to look at / consider with care.
I was developing the "lean" map with an eye towards extending the cycle range, because I have some "range anxiety" for the smallish 2 gal tank where I ride.
This is not the best solution for a "new guy". A better solution, and one that I'm rolling with, is to buy and mount a bigger tank (IMS 3.0 gal for 33% more fuel), and a "softer" FI map that softens the motors throttle response at low throttle / low power settings.
I'm also looking at throttle cams (highly recommended), rear sprocket with more teeth, heavier flywheel (this idea now discarded), and Training More Training.
My hope is, this writeup will help someone avoid a potentially very bad situation.
Why I believe it may be related to a small sub-set of cycles (High power, high displacement, programmable FI dirt bikes).
So, I've ridden other 450 dirt bikes, carburated, pumper ones, set up by a knowledgable mechanic, for the general altitude where it be operating. I've had the "wow, that front wheel come up easy" moments. I know what that is.
I also have a stable of other street bikes with FI, bone stock from OEM, and so they run lean. They all actually run really well, and they "sip" gas pretty sparingly.
I know what lean, anemic cars and cycles ride like. Low power, low joy. Pretty good range...
None of those are like this. This is unique in my experiences. I might start calling that lower left corner of the FI map "coffin corner", referring to a term every aircraft pilot is familiar with.
That initial "hit", or "snap", and that it's programmable to be violent (very "snappy") or not. *Thats* unique, I think.