Hi all, a friend of me bought a 2010 TE 250 with mikuni EFI. we can't find the problem : The cold start don't work (no answer). the idle screw don't work (no answer). i change the i-beat value and the only i find is 85 102 100 !! . if i-beat is 100 102 100, the engine don't want start with kick or electric starter. i changed all parts with my 2011 TE310, EFI, temp sensor, the problem is the same. i removed the lambda sensor. the engine start with difficult cold or hot. the only part i haven't changed is the ECU with e010r306 number. Do you think it's the ecu ? have you a solution. Thanks
The cold start knob is nothing but a fast idle circuit, it bypasses a small amount of air around the throttle plate to help during warmup. It does not directly add any fuel. The engine temperature sensor is the main factor that affects fuel trim during warmup. It a simple mathematical algorithm that multiplies the value in the main fuel map based on temperature. The cold start valve bottoms out on the idle screw when pushed in. Therefore, turing the idle screw simply moves the cold start valve which changes the amount of bypassed air with the cold start knob pushed in. That's why turning the screw in (clockwise) increases bypass air and out (counterclockwise) decreases idle air. I've found that the idle screw has more affect on idle mixture (air fuel ratio) than idle speed. The more clockwise the leaner the mixture and vise versa. I use a wideband 02 sensor to adjust my idle mixture (after I've set the TP sensor and tuned the low speed fuel map via Ibeat). However, these is a reasonable range from which to start, for example 2 to 3 turns from bottom out. There are several threads on this subject you can search on to find the initial setting for your bike. Unless the idle screw is wildly off, neither it or the cold start valve should significatly affect your bike from starting. In fact, my 450 starts easier without using the cold start knob.
well , i have this : TPS : 0% 100.2 1030mv CO : 75(idle) 110(to test) 112(to test) if i make 100 (for idle) have not enough air
If you have compression, spark and fuel it should start. Compression and spark are easy to verify. Fuel is another story. However, if you have proper fuel pressure and set your CO at 100, 100, 100 and it still doesn't start something is definitely wrong. Do you have a Power Up kit installed?
i think your TPS is off. At full throttle it should be 102.3% At 100.2 your idle will me very high and the screw may not change it.
hunh. I've been looking for a description of how the cold start works. thanks. I'm gonna hafta digest this a bit though, to get my head wrapped around it- assuming it's the same for Kehin TBs. ...and I'll keep an eye open for those (old?) threads
It should reduce the idle speed a lot. I set my TPS to that (old) spec a while back and the idle went way up and the idle mixture was richer too. Just like you have.
