BigBlkYJ Posted March 31, 2010 Posted March 31, 2010 I'm new to this whole vintage bike thing so go easy on me haha! I've got an old 175 Enduro, which by looking online at all the parts look-up sites, says its a DT175A. Anyways, the stator is producing almost 13 volts when revved above idle, and its blowing all my lights. I'm wondering what the fix is for this, if any...? Its a 6 volt system. Everything works well when a battery charger is connected to produce 6 volts to the battery terminals. The headlight is on the stator and will not work unless its running, which is unfortunate since its a sealed beam light, and sorta expensive to keep blowing up. Any insight would be great, its pretty frustrating.
DTGordo Posted March 31, 2010 Posted March 31, 2010 Hi BigBlkYJ, The head, tail and instrument lights are on the AC circuit and the indicators, horn and stop lights are on the DC circuit. As far as I know, a few things can give you too much voltage on the AC cicuit, blowing the bulbs. Check all the connections and for any burned out bulbs in the AC circuit. It needs all the bulbs working to balance the voltage. Could be the lighting coil resistance - I'm not too good on the detail on that one or the 175. If AC bits are good then it could be in the charging circuit - If bad connections, or stuffed battery or rectifier, the voltage will then be too high in the lighting circuit. I had the same problem which was fixed after a new battery and voltage recitifier. No problems since then (nearly 2 years now). Hope that hels. Gordo
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 Hi BigBlkYJ, The head, tail and instrument lights are on the AC circuit and the indicators, horn and stop lights are on the DC circuit. As far as I know, a few things can give you too much voltage on the AC cicuit, blowing the bulbs. Check all the connections and for any burned out bulbs in the AC circuit. It needs all the bulbs working to balance the voltage. Could be the lighting coil resistance - I'm not too good on the detail on that one or the 175. If AC bits are good then it could be in the charging circuit - If bad connections, or stuffed battery or rectifier, the voltage will then be too high in the lighting circuit. I had the same problem which was fixed after a new battery and voltage recitifier. No problems since then (nearly 2 years now). Hope that hels. Gordo Well that might be the problem right there then. There is no battery in it at all right now. When I got it, the battery was trashed completely, so I just figured that I'd test everything with a 6 volt battery charger. Everything works well with the charger there was just problems when I fire it up (without the charger on of course). As far as the DC side goes: I can run the blinkers, tail light, brake light, horn, and the blinker indicator from the 6 volt dc charger. The headlamp, indicator for high beam, and for some reason the neutral safety light work on the AC. Also the neutral light only seemed to work when the headlights were turned on, is this correct?
Speedshop Posted March 31, 2010 Posted March 31, 2010 13 volts is about right, direct off the generator, don't forget you'll lose a fair bit at the rectifier then the voltage regalutor will control to a lower level. If that was the level measured AFTER the rectifier and regulator then you do have a fault.
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 13 volts is about right, direct off the generator, don't forget you'll lose a fair bit at the rectifier then the voltage regalutor will control to a lower level. If that was the level measured AFTER the rectifier and regulator then you do have a fault. Well, this was measured at the headlamp connector. As far as a voltage regulator, i'm not sure there is one...? I know there is a rectifier, but i'm pretty sure there is no regulator.
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 Anyone know what this is? Is plugged into the harness down by the brake pedal. Its not listed on the schematic and i'm not sure if its what's causing the problem. Doesn't look like any resistor or diode i've ever seen.
Moderator Cynic Posted March 31, 2010 Moderator Posted March 31, 2010 That is more than likely the issue. These bikes use a resistance in the ground/earth return line in the charging,lighting circuit. The resistance caps the voltage at a safe(ish) max of around 8 volts. If you check back that should lead back to the lighting circuit ac connections at the headlight. Thing is it can fail, that will allow un capped voltage into the AC lighting circuit and when the lights are off depending on model and markets the same 13 odd volts into your battery. Destroying it in the process by boiling out the fluid. If you post the first half of the frame/engine number we can narrow it down a bit.
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 That is more than likely the issue. These bikes use a resistance in the ground/earth return line in the charging,lighting circuit. The resistance caps the voltage at a safe(ish) max of around 8 volts. If you check back that should lead back to the lighting circuit ac connections at the headlight. Thing is it can fail, that will allow un capped voltage into the AC lighting circuit and when the lights are off depending on model and markets the same 13 odd volts into your battery. Destroying it in the process by boiling out the fluid. If you post the first half of the frame/engine number we can narrow it down a bit. When you say the first half, do you mean before the dash? Anyways, the manual i have for it, and the parts lookup online, both dont show a resistor anywhere that i can see. Also the wiring diagram doesn't show it..?
Moderator Airhead Posted March 31, 2010 Moderator Posted March 31, 2010 Anyone know what this is? Is plugged into the harness down by the brake pedal. Its not listed on the schematic and i'm not sure if its what's causing the problem. Doesn't look like any resistor or diode i've ever seen. Hey thanks for the pic, i've been wondering what these look like. can you give me a more detailed description of where this resistor was connected to, I assume one side was to chassis or negative wire. And the other? Measure the resistance of it to see what it comes out at...let us know.
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 Hey thanks for the pic, i've been wondering what these look like. can you give me a more detailed description of where this resistor was connected to, I assume one side was to chassis or negative wire. And the other? Measure the resistance of it to see what it comes out at...let us know. The resistance was 166K ohms which seems pretty high to me. Also I don't know that this is actually a resistor. It acts like a diode when placed in diode check mode on a meter. Also its connected to the harness that comes out of the engine stator assembly's black wire (which has a double connector on the end, but only this is connected to it) The other end plugs into the harness that heads up into the main harness with the rear brake pedal switch.
Moderator Airhead Posted March 31, 2010 Moderator Posted March 31, 2010 The resistance was 166K ohms which seems pretty high to me. Also I don't know that this is actually a resistor. It acts like a diode when placed in diode check mode on a meter. Also its connected to the harness that comes out of the engine stator assembly's black wire (which has a double connector on the end, but only this is connected to it) The other end plugs into the harness that heads up into the main harness with the rear brake pedal switch. 166k is not going to reduce any voltage at all youre right. Acts as a diode though...lets prove that theory, hook it up in series with a light bulb across the battery terminals, then reverse it. if it is a diode and is working the bulb will light one way only,
Moderator Cynic Posted March 31, 2010 Moderator Posted March 31, 2010 When you say the first half, do you mean before the dash? Anyways, the manual i have for it, and the parts lookup online, both dont show a resistor anywhere that i can see. Also the wiring diagram doesn't show it..? Depends on the model, there are a couple of names for it. Its location is also a little hit and miss. The really early ones are in the loom under the tank. The engine number is always the best way to identify the age and model.
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 166k is not going to reduce any voltage at all youre right. Acts as a diode though...lets prove that theory, hook it up in series with a light bulb across the battery terminals, then reverse it. if it is a diode and is working the bulb will light one way only, Well i have a diode check on my meter and it only works in one direction with this thing. One way the forward voltage drop shows up as .53 volts. But just to be sure I did check it with a 6volt lamp, and it will only light in 1 direction.
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 The engine # is 443-010XXX (do you need the entire #?)
Moderator Airhead Posted March 31, 2010 Moderator Posted March 31, 2010 Well i have a diode check on my meter and it only works in one direction with this thing. One way the forward voltage drop shows up as .53 volts. But just to be sure I did check it with a 6volt lamp, and it will only light in 1 direction. That is without question a doide then, and furthermore a fully functioning one. I wonder about this resistor, i'm beginning to doubt it exists. That diode is in your case a rectifier, is there another more familiar one on that bike or is this the bike's rectifier? this topic is bearing a lot of similarity to the other one on here at the moment(DT360)
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 That is without question a doide then, and furthermore a fully functioning one. I wonder about this resistor, i'm beginning to doubt it exists. That dido is in your case a rectifier, is there another more familiar one on that bike or is this the bike's rectifier? this topic is bearing a lot of similarity to the other one on here at the moment(DT360) No there is definitely a rectifier. Its mounted under the tank, and has an integrated heat-sink. What i found odd about that was the book said that the electricity should flow when connected from the pos. lead on my meter to the red lead on the rectifier. However its opposite. I would think though that this being from the factory would be correct. The leads are soldered onto it, not push on.
Moderator Airhead Posted March 31, 2010 Moderator Posted March 31, 2010 No there is definitely a rectifier. Its mounted under the tank, and has an integrated heat-sink. What i found odd about that was the book said that the electricity should flow when connected from the pos. lead on my meter to the red lead on the rectifier. However its opposite. I would think though that this being from the factory would be correct. The leads are soldered onto it, not push on. Now youve got me wondering, there is no heat produced by a rectifier unless it is being used as a current shunt to ground, thereby acting as a regulator (a zenor diode) so is this the regulator then?
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 Now youve got me wondering, there is no heat produced by a rectifier unless it is being used as a current shunt to ground, thereby acting as a regulator (a zenor diode) so is this the regulator then? Well there's definitely no heat here, since the entire thing was cased in a poured rubber of sorts (i'm going to just shrink tube it back). I guess its working normal though since it functions. I'm still wondering if my not having a battery in place is causing this issue. However I'd hate to fry a brand new battery if it's not.
Moderator Airhead Posted March 31, 2010 Moderator Posted March 31, 2010 Well there's definitely no heat here, since the entire thing was cased in a poured rubber of sorts (i'm going to just shrink tube it back). I guess its working normal though since it functions. I'm still wondering if my not having a battery in place is causing this issue. However I'd hate to fry a brand new battery if it's not. Any chance of a photo before you cover it up again? so did you check this with your diode test too?
BigBlkYJ Posted March 31, 2010 Author Posted March 31, 2010 Any chance of a photo before you cover it up again? so did you check this with your diode test too? You want a picture of the rectifier under the tank? I checked it with my meter but not the lamp test. I guess i could try that also. I just got off the phone with Yamaha customer support, and they confirmed the bike is a 74 DT175
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