At a trial yesterday, my 2010 Evo 300 4T was overheating and when I checked the fan, it was running very slowly with the bike at idle and when I revved it, the fan stopped completely. When the bike cooled down, the fan didn't start to run, which implies to me that the thermostat is OK. The fan can also be turned freely and there is no noise coming from it.

Before the trial, I had removed the small covers on the frame to polish it, but I checked again and the wires don't seem to be trapped or damaged.

Any suggestions on how to diagnose it or do I just need to buy a new fan assembly?

Thanks

Hi i have a Beta Evo 4t and I had the same/similar problem last year, when I revved the engine it did not pick up properly and the fan stopped. It turned out to be the capacitor which is wrapped in the tape in the wiring harness just under the frame left hand side near the carb top. Its a pain to get too but if this capacitor has blown like mine had, its 60p fix. PS this capactor is effectively the battery for the bike.

Just had the exact same problem with our 2010 evo 4t, Fan and electronic fuel tap wouldn't work, Discovered that it was down to the capacitor in the wiring loom, They cost about £1.00! You can get them from Maplin or eBay the one you need is a 4700uf 25V, Or you can use a higher voltage. As said above it is basically a battery

Edited April 28, 201412 yr by benbeta23

Thanks for the feedback. Capacitors are on order!

Mike

On 4/28/2014 at 2:45 PM, keithns said:

Hi i have a Beta Evo 4t and I had the same/similar problem last year, when I revved the engine it did not pick up properly and the fan stopped. It turned out to be the capacitor which is wrapped in the tape in the wiring harness just under the frame left hand side near the carb top. Its a pain to get too but if this capacitor has blown like mine had, its 60p fix. PS this capactor is effectively the battery for the bike.

hello,can you test this capacitor, and wher to buy it? grtz

There are many ways to test a capacitor, but if you don't already know how, you probably don't have the proper instruments.  In that case, substitution of a know-good part is the best method.

eBay is probably the easiest (not necessary best) place to buy capacitors.   A prior post said, 4700uF @ 25VDC.  But I have no idea if that is correct.  Whatever the value is,  it should be rated for 105 degrees C.  Look for a capacitor specified as having  "low ESR", or better yet one that specifically says it's capable of withstanding high ripple current.

Some capacitors made in China are okay, but unless you have experience with a particular manufacturer/vendor, I would suggest buying a capacitor made in Japan.  If you buy Chinese, buy several to have as spares.

Mine had this issue years ago, I disconnected the fuel solenoid and it worked fine… solenoid was shorting out internally. .. I just fitted a normal petcock rather than the solenoid