Injected WR 450, lean idle, rich on throttle. Cold weather problems.

Hi all.

New owner to an injected WR450 -12. I have a kind of chicken-egg problem...

I bought the bike with GYTR Competition kit installed (mainly header and slipon). Europe spec. No throttle stop screw.

When riding in temps below freezing (0 deg Celsius), it won't start without pulling the cold start knob, or first crank it for a few seconds at fully open throttle. And I don't mean at first cold start, but after a while of riding, stopping for a minute, and then trying to start it. Won't start without cold start knob.

When cold starting it, I must of course use the cold start knob. But after afte about 20 secs of idling, the header gets red hot. So, my first thoughts was it was running way lean. But when running, it pulls strong. When engine braking it pops. So I guess it's way lean, at least at closed throttle.

I suspected that O2-sensor that was removed with the stock header made the mixture wrong... So I tested to install stock header and stock slipon. Same result; the bike ran strong but was popping at engine braking and wouldn't warm start without the cold start knob. 

But the interesting thing was the competition kit header... It was all sooty, as if it was running way rich!

I bought an injected bike to NOT have these problems!


All these tests were made in freezing temps and with airflow blocked to the left radiator.


One thing I can't explain is, that when using kick-starter, it warm started everytime at first kick.


My suspicion is that the coolant temp is the culprit... The damn thing just don't get up to normal working temp! I'm thinking of installing a KTM thermostat to get rid of the rich on-throttle and a re-map to enrichen the idle. Or just sell it and buy a KTM...


Any suggestions?


Does anyone have installed a thermostat with success on a WR450?


Looks like the CO setting is too low.   Most that have this bike have had to increase the CO setting to enrichen the low RPM part of the circuit.  This is done with the fuel diagnostic tool. from a factory setting of 0 to 12.  It is the part of the fuel mapping that is not controlled by the power tuner (do you have the tuner ?  That also has to be mapped into the ECU to set to higher RPM part of the curve).  After increasing the CO setting (the dealer could do this for you too), you should notice great improvement in the idle and your manifold won't  glow anymore. 

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