asimo Posted August 18, 2014 Report Share Posted August 18, 2014 hi my Sherco 2004 200cc 2stroke fan doesn't work.. I tested the fan on its own and it works how do I test the thermostat? I had to have the motor rebuilt and I may have wired up the thermostat wrong... anyone know which wires go where? can I remove the thermostat and wire up the fan for manual use? what do you think? any help would be appreciated. the bike goes great, starts first go every time, it had been seized before I bought it but after a rebuild its unreal. I have never seen the fan go, I ride it for half an hour every day but it gets hot so I turn it off. thanks for the help last time regards asimo . Quote Link to comment Share on other sites More sharing options...
dadof2 Posted August 18, 2014 Report Share Posted August 18, 2014 Put it in a pan of water with a resistance meter (or bulb and battery) connected across the terminals. Heat the pan with thermometer in it ans see at what temperature the thermostat conducts electricity at. I don't know what it should be for a sherco 200, it may be stamped on the thermostat but it should be between 65 and 88 degrees celsius. Quote Link to comment Share on other sites More sharing options...
copemech Posted August 19, 2014 Report Share Posted August 19, 2014 You should normally be able to connect the yellow and red wires at the thermo switch together for the fan to run. If it still does not run then you have other issues. 12V source is yellow, red goes to rectifier to achieve the DC voltage the fan motor requires from the AC source. Fan will not run if rectifier is faulty. Quote Link to comment Share on other sites More sharing options...
tony27 Posted August 19, 2014 Report Share Posted August 19, 2014 Thermoswitch doesn't care which way round the wires are, it's just a normal switch that happens to be heat activated When trailriding it's most of the guys I ride with have a short piece wire with terminals both ends to bypass the switch if needed, as long as the motor is turning over the fan will run Quote Link to comment Share on other sites More sharing options...
asimo Posted August 19, 2014 Author Report Share Posted August 19, 2014 Many thanks I will try that tomorrow. are the yellow wires the earth as it is on my bike. which is the rectifier? is it the little box under the fuel tank? which way should the fan run? I still cannot get over how I can get help from people all over the world, it pretty amazing. I race go karts and nobody helps you, totally different cheers asimo Quote Link to comment Share on other sites More sharing options...
copemech Posted August 20, 2014 Report Share Posted August 20, 2014 (edited) Many thanks I will try that tomorrow. are the yellow wires the earth as it is on my bike. which is the rectifier? is it the little box under the fuel tank? which way should the fan run? I still cannot get over how I can get help from people all over the world, it pretty amazing. I race go karts and nobody helps you, totally different cheers asimo The rectifier should be square box mounted by the CDI as I recall, the regulator is rectangular. if memory serves. Link to site with pics. http://www.shercousa.com/pdfs/ryp_wiring_installation.pdf Fan should blow air rearward. Seems they call out the rectifier as a DIODE in the assy. Actually it is a diode assembly which shunts the bad AC vibes to earth and leaves the positive DC pulses of the waveform created my the magneto. The regulator just simply t's in as well shunting off excess voltage to earth. Simples! I suppose a shorted regulator could reduce available voltage as well, causing a fan not to run properly. As these bits must work together to supply proper voltage and current to the 12V DC fan motor. Edited August 20, 2014 by copemech Quote Link to comment Share on other sites More sharing options...
asimo Posted August 20, 2014 Author Report Share Posted August 20, 2014 Thanks guys, I found the rectifier was not wired up correctly, I soldiered another wire to it and the fan worked so I reconnected the thermostat to see if it would work. after a half hour ride the thermostat opened and the fan came on for 2 minutes then off so I rode longer and the fan operated for a longer period of time. I will go for a ride on the weekend and give it a full test I have also made up a bridging wire to connect the thermostat wires together in case it stops working. thanks again for your help regards asimo Quote Link to comment Share on other sites More sharing options...
copemech Posted August 21, 2014 Report Share Posted August 21, 2014 Thanks guys, I found the rectifier was not wired up correctly, I soldiered another wire to it and the fan worked so I reconnected the thermostat to see if it would work. after a half hour ride the thermostat opened and the fan came on for 2 minutes then off so I rode longer and the fan operated for a longer period of time. I will go for a ride on the weekend and give it a full test I have also made up a bridging wire to connect the thermostat wires together in case it stops working. thanks again for your help regards asimo Well you have it working at least. Understand the thermostat as you call it is nothing but a bi-metal electrical switch that kicks in if coolant temp rises above a given point, activating the fan. It does not control coolant flow, as if the pump is pumping the coolant flows continuously and if you are moving fast enough to provide airflow through the rad the fan may never come on on a cool day. Lower speeds or sitting still the fans will kick in normally in 5-10 min after startup, yet a 125-200 bike will take a bit longer as I recall. Simply not producing as many BTU. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.