Hi all,

I've got a 2010 2 stroke Beta Evo 290 and it's having electrical problems. The bike starts easily and runs smoothly but it's got no light and the fan doesn't work.

I bypassed the thermostat but it still won't turn. Thus plus the fact that the lights won't work makes me think that the rectifier (?) is damaged.

I've been looking for information if there is a way to measure any values in or out of the rectifier without success.

Any ideas about:

a-) Am i correct thinking that the problem is with the rectifier?

b-) Any way to find out if the rectfier is damaged?

c-) Could it be something else? Any hints/ideas of what to verify?

TIA

I think I found out where the problem is.

As soon as I get it fixed I will post the solution

Regards

I remember on my '08 the lights came directly off the coil and only the fan went through the rectifier/regulator. I'd have to look at the schematic for your bike to see if that is the same.

Thabks Dan. Yes, this is the case with the Evo 2010: only the fan goes through the regulator

I checked all (most of) the wiring and the light switch, checked and cleaned all the connections and now both lights and fan work.

Still I'm not quite happy with the solution, mainly because I didn't clearly found where the fault is.

Regards

I know the fan takes a fairly robust supply to start. I had one in the lab once and had to set the current limit of the supply I was using to test the fan at 10A to get it to start. Running current was much less but the initial draw is quite large so a resistive ground can be problematic.

I've been riding this morning troublefree.

Thanks Dan for your reply. Yet I don't quite get what you mean by "so a resistive ground can be problematic".

Regards

Sorry, I spend all day with other engineers and forget to be clear. If you have a bad connection it looks like a resistor so anything that doesn't draw a lot of current, like a voltmeter, will be relatively unaffected but something like the fan that needs a big pulse of current at startup might not operate. Ohm's law says E=IxR Voltage = Current x Resistance so if the resistance is low like a proper ground connection a lot of current can flow without a voltage drop. With something like a loose connection where an oxide layer builds up the resistance of the connection causes a voltage drop as more current is drawn. The same effect you see when your lights dim when the ac comes on. The high current draw of the ac causes a voltage drop because of the resistance of the wires.

Does that help or did I just make it worse?

Thanks Dan. You made it very clear!