the same thing happened to me, i think it might have to do with the spark plug. Some snow blower plugs can interfer with tv signals so maybe the same goes for your cycle computer. Try a new plug, i think they make ones with out rf interferance, i dont know. It could also be that your computer wires are too close to the ignition wires?
Are you talking about using "fuel magnet" on the spark plug wire?
I searched for "clip on RF Filter" and got these, which look exactly like the "MIT designed magnetic fuel activators" I got from a catalog for $10 each
I don't know if they increase fuel mileage, but I suspect they would stop any metal flakes before they reached the filter or engine.
I used to have no problems with my cyclo computer, but lately its reset every ride. I tried a new battery but it still happens, so I am thinking that the new wire routing (the traditional spiral around the handlebar and brake cable to the sensor) is exposing it to more to the spark wire radio interference.
I'm going to try unspiralling it and wrapping the wire in electrical tape.
Then if I have to, I 'll try putting a "fuel magnet" on the spark plug wire.
it's r.f. interference from the ignition on the motor.
there is nothing you can do about it exept get a better speedometer.
you can try to shield the computer (speedo) by isolating it from touching anything metal by putting a peice of ruber between it and where it's mounted.
you can try using a sheilded spark plug wire (or a resistor plug wire)...but seriously i went through all of the suggestions and nothing worked.
go to wal mart, and buy yourself a $10.00 schwinn compter/speedometer...it'll work just fine.
you should replace the stock spark plug wire anyway, because it isn't a real spark plug wire...it's just a peice of thin wire wrapped in rubber sheath.
I have the red $10 Schwinn Walmart computer. I used electrical tape instead of rubber to keep it from turning on the bars. I put the magnet on the sensor wire, right next to the computer, with one wrap to keep it from moving. So far so good. It didn't reset today.