Hello.

I am a new owner of a xt660x from 2004.

I have read alot in this forum and want to get some clarification regarding the fuel mod.

My model does not have the o2 sensor but does it have open and closed loop? If the engine cant read the oxygen levels of the exhaust it should not be able to correct it either. Right? So my ecu is therefor open loop all the time?

The fuel mod, from what I have read, adds resistance in serial of the tempsensor in the airbox? Fooling the ecu to richen the mixture compensating for colder temp.

My bike runs great when engine cold and running on choke. When engine gets warm it gets more uneven when cruising and not as alert on throttle.

Would a fuel mod act similar as the when the engine is cold?