i have a derbi 50 and sometimes the thermostat looks like its on red and the light comes on. I have checked oil water and recently changed the sparkplug. Any ideas why this might happen? it isnt happening all the time and the bike doesnt feel hot

Pel, February 2013

it could be the gauge, sender unit or the wiring, if your gauge reads hot too soon after starting from cold remove the wire from the sender unit,(sorry do not know exactly where it is on this bike, probably near the thermostat) if the temperature drops then renew the sender unit, if the temp stays high it could be a faulty gauge or the wire to it is damaged and is shorting to earth, good luck.

Perry, February 2013