Q. I have a 2003 Suzuki GSX-R750 and when it gets to its max temperature (107 degrees) it overheats and cuts out in traffic, I have to wait until it cools down before it starts again.
It was fully serviced a month ago so all fluid levels are fine. It also happened before the service, I’ve been told that it may be one of the ten sensors on the bike that maybe causing the problem.
Scumdeth, MCN forums
A. 105 to 110 degrees is the normal range for the fan to cut in, so I doubt it’s overheating. To properly check that there is enough coolant in the bike you need to start with a cold engine.
Undo the radiator cap and check the coolant level, if it’s very low, top it up, this will be the problem. If it’s just a bit low run the engine with the cap off with a bowl underneath to catch any coolant. Let the temperature rise and let the coolant overflow from the radiator.
Rev the engine quite hard about three times (about 7000rpm), stop the engine, top up to full. Run the engine up again until the fan comes on, if the temperature drops with the fan on everything is OK. If not there is a bleed screw on the back of the thermostat housing to let air trapped in the water jacket out.
This can be found if you follow the top hose by the radiator next to the filler cap to the back of the block. You will need to lift the front seat and fuel tank to get at it.
Another possible cause could be the throttle position sensor, if it cuts out when you blip the throttle, but if you blip the throttle with the engine off after a cut-out, and it restarts while still too hot, then that could be a faulty TPS.