July 21, 20242 yr Hey guys Just bought my second trials bike, old used one. Wanted to try the 300cc. Anyways after some suspension fix, greasing the linkage, changing all the fluids and all that good stuff I wanted to take it for a spinn. Rode for let's say 10 minutes or so. Got back to my driveway and let it idle for 30 sec to a minute. It boiled over and I believe that the fan did not come on. Took the fan and the radiator of the bike, hooked the fan to a battery charger with some wires and the fan worked. So took a look at the electrical system to see if I could see any broken connectors or wires. All seems good to me. I have the Ducati system and I believe the "Fun Module" is missing, it's stated in the parts manual as number 2. Can't find a wiring diagram for my bike, just the 2003 with the Ducati system and that does not show a fun module I believe. Will show you guys some pictures from my bike with what I got as far as electrical parts Third pictures shows everything and the wires in the middle is where the fan goes and no alternator is to be found. As far as electrical system my knowledge is pretty much zero. I did have a look at the water pump to see that nothing was seized or so. I found oil behind the water pump cover but no water in the gearbox oil when i changed it. But is it supposed to be oil next to the water pump? picture below Would be thankful for any replays and insights If your having a hard time reading this it's probably because i'm not a native English speaker. Best regards Adam Edited July 21, 20242 yr by AVikman
July 21, 20242 yr You can test the fan itself by applying 12 VDC directly to it from a battery. Fan motors often fail if the bike gets pressure washed carelessly.
July 21, 20242 yr Author 26 minutes ago, konrad said: You can test the fan itself by applying 12 VDC directly to it from a battery. Fan motors often fail if the bike gets pressure washed carelessly. I got the fan to spinn with the 12V battery charger.
July 21, 20242 yr Substitute the thermostat (switch that is in the radiator) with a piece of wire while the engine is running. The fan should run. You can test for DC voltage between the wire leading into the thermostat and chassis ground with a multimeter or a 12V light bulb. BTW, the alternator comprises the flywheel and stator plate behind the flywheel. The yellow wire from the stator provides power for the fan. The stator emits AC and the regulator changes it to DC and and limits the voltage.
July 21, 20242 yr 3 hours ago, AVikman said: Square black box, looks to be your rectifier/regulator and that will be the part that turns AC (Alternating Current) from the alternator (stator coils) into 12 volts DC (Direct Current) required by the fan motor. Conversion to DC from AC uses diodes and diodes are one of the more likely components to fry.
July 21, 20242 yr 1 hour ago, lemur said: Square black box, looks to be your rectifier/regulator... Nope. That's an unusual combination CDI and high-tension coil. Silver box is the rectifier/regulator.
July 21, 20242 yr Author 4 hours ago, konrad said: Substitute the thermostat (switch that is in the radiator) with a piece of wire while the engine is running. The fan should run. How is that done? Thought that I needed (see picture) this to convert from DC to AC? manuals states (fun module) which I don't seem to have. Just the Bobina, big black box with curved edge on one side and the silver box. I've tried to use the multimeter to see if I can get a reading from the thermostat without any luck. just reads 0 on all settings of the multimeter. Edited July 21, 20242 yr by AVikman
July 21, 20242 yr What you have circled is for an older model bike. Fun Module is a misprint. It should say Fan Module. The thermostat should actually be called a thermo-switch. It is electrically open when the engine is cool. It closes to turn the fan on when the engine requires cooling. Connect a jumper wire between the two terminals in the photo I have cropped. At this point you may need to enlist someone locally who has some electrical knowledge to help.
July 21, 20242 yr 4 minutes ago, konrad said: Fun Module is a misprint. It should say Fan Module. I'm so disappointed. I was thinking that every bike should be fitted with a fun module. 😆
July 21, 20242 yr Author 12 minutes ago, konrad said: Connect a jumper wire between the two terminals in the photo I have cropped. At this point you may need to enlist someone locally who has some electrical knowledge to help I did just try that, the fan did not come on, and yes. I will be calling my local bikeshop tomorrow, I'm in way over my head. Okey, so the part that I circled earlier I don't actually need? Btw, when the fan didn't come on when I connected a wire between the two. What does that tell me except that the fan did not work? Edited July 21, 20242 yr by AVikman
July 21, 20242 yr Your circled part is the old version of the silver part in your photo. Had the jumper wire caused the fan to run, it would have showed that the thermos-switch (thermostat) was defective. Time to take it to the bikes shop. Konrad out.
July 22, 20242 yr Author 8 hours ago, konrad said: Your circled part is the old version of the silver part in your photo. Had the jumper wire caused the fan to run, it would have showed that the thermos-switch (thermostat) was defective. Time to take it to the bikes shop. Konrad out. Thank you Konrad, I will give them a call and see what they says. Will report back if I find out what the problem was.
July 22, 20242 yr Author Well I had another go this morning with the bike, I tried to jump the thermos-switch again and the fan came on. I think I'd messed up last night when i tried it, the wire wasn't secured enough. Just so I get this straight, if the fan comes on when used with a jumper wire it tells me that the thermo-switch is kaput yes? Best regards Edited July 22, 20242 yr by AVikman
July 22, 20242 yr If the fan works by by-passing the thermostat switch then yes 👍 you found the problem. Replace the switch or by-pass it with a little toggle switch and operate the fan manually.
July 22, 20242 yr Author 7 hours ago, lemur said: If the fan works by by-passing the thermostat switch then yes 👍 you found the problem. Replace the switch or by-pass it with a little toggle switch and operate the fan manually. Great, just ordered a new thermo switch. Will let you all know how it all went. Hopefully this was it and everything will work as it should.
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