View Full Version : Throttle Sensor

04-24-2003, 04:12 AM
There is one sensor at the throttle pulley inside the RS250, it's a potentiometer ( variable resistor ) indicate ohm

what going to happen if i try to modify the position of the
sensor by change the preset value

maybe the powerjet open earlier or advanced ignition
start earlier who's know

any expert here can help me


colin skillicorn
04-24-2003, 06:07 AM
if you disconect the plug to it it stops the ignition retarding at high rpm with race pipes it will rev to 13000 without flatening off

micah apriliaforum com
04-24-2003, 09:41 AM
I have only seen problems on cup bikes with sensor "mods". Carefully mark the exact location with a metal pick so you can go back if you need...to EXACTLY the same place.

04-24-2003, 03:00 PM
The timing is many affected by engine RPM, which is detected by the two magnetos in the flywheel generator. The ECU maps RPM and throttle position to get ignition timing and power-valve opening. Ignition is advanced as the RPM increases, and as the throttle is opened. The ECU effectively limits revs by retarding the ignition at very high RPM (above 10,500 say). To go fast you have the throttle open, so the sensor will already be selecting the maximum advance for the engine RPM. By adjusting the throttle sensor, all you can do is retard the ignition. You could move the magnetos however - the RGV kit alternator cover allows up the magnetos to be rotated a few degrees either way to advance or retard the timing. This however will not be very good as it doesn't change the shape of the ignition curve. What is better is to modify the ECU map itself - but this requires an expert, BDK (www.bdkraceeng.com/bike2.html) (http://www.bdkraceeng.com/bike2.html)) claim to be able to mod RGV's (same engine) but having had no dealings with them I don't know how good their work is nor how reliable their service... If the ignition is advanced to much there can be detonation, and this like compression is related to the octane of the fuel. Infact with even a small advance over standard you will find you have to use 98RON fuel (super unleaded).