Corbstar Posted October 26, 2013 Share Posted October 26, 2013 Hi all. I'm new to site so sorry if I'm in the wrong end but thought I'd start with my electrical dt 400 woes and let someone guide my through! This bike runs, lights, horn all work, no blowing bulbs etc. 2nd battery now and both seem to of chucked the fluid out through vent pipe. Having to top up regularly but I am only just re commissioning with short road blasts. I'm a novice but can say charge looks good with lights on and revs up but no charge in daytime no lights? Something obvious to look for? Corbstar uk. Hi all. I'm new to site so sorry if I'm in the wrong end but thought I'd start with my electrical dt 400 woes and let someone guide my through! This bike runs, lights, horn all work, no blowing bulbs etc. 2nd battery now and both seem to of chucked the fluid out through vent pipe. Having to top up regularly but I am only just re commissioning with short road blasts. I'm a novice but can say charge looks good with lights on and revs up but no charge in daytime lights out. Something obvious to look for? Corbstar uk. Link to comment Share on other sites More sharing options...
Corbstar Posted October 26, 2013 Author Share Posted October 26, 2013 Hi all, finally found the DT area! My 1975 dt 400 b seems to charge ok with lights on but nothing when in day time-lights off? I'm on the second battery and both have lost, gassed fluid and needed topping up regularly. It's getting a few short blasts on road as re commissioning but all runs well. Lights, horn fine with good battery. Rectifier seems ok with tester, any thing obvious to check? I really can't understand how this system should work. Corbstar uk. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 26, 2013 Moderator Share Posted October 26, 2013 Not sure about the 400 but most 2 strokes of this era run the lights from one coil and the other electrics run from the battery. What is the volts at the battery with the bike running and running with the lights on? If the battery is boiling then it sounds like too many volts to the battery which will kill it very quickly. Rectifier/regulator issues are normally what cause this. Link to comment Share on other sites More sharing options...
Corbstar Posted October 26, 2013 Author Share Posted October 26, 2013 I'm getting nothing with lights off and about 8v at 6-7000 rpm with lights on. I've put a new regulator on the light side of loom but it never had one anywhere else. The workshop manual I've got claims if all correct then it shouldn't need regulator? I've done the basic test on rectifier and it seems ok, only reading one way round? Brake lights, horn all on battery, front beam and dials on engine. Corbstar. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 26, 2013 Moderator Share Posted October 26, 2013 Threads merged into one. Link to comment Share on other sites More sharing options...
blackhat250 Posted October 26, 2013 Share Posted October 26, 2013 The charging system is Flywheel; charging/lighting coil; Rectifier; Battery. Alterating current flow fromcharging/lightn coil to headlight / meter lights,-to the rectifier [ where its converted to D/C] to charge battery If all are installed and working, there is no need for a regulator ,,.its done by impedance [ resistance] as revs increase at lighting/charging coils./ Day time volts should be same ,as nightime volts 7volts @2000rpm...and 8.5volts at 8000 rpm.[ daytime] 8 volt [ night] Link to comment Share on other sites More sharing options...
blackhat250 Posted October 26, 2013 Share Posted October 26, 2013 If the measuered voltage is too High or Too low, - check the connections / if the bulbs capacity is too high, through -out the lighting system, .. when checking silicon rectifier, mind to reverse check, Link to comment Share on other sites More sharing options...
Corbstar Posted October 27, 2013 Author Share Posted October 27, 2013 Ok that makes sense. Connections! It is original loom and I thought I'd cleaned all but now understand just how one little bad one will play up. I've tested rectifier both ways and its showing .538 and reversed 1 on digital tester, I've actually got two rectifiers, the original and a new one, both about the same? Do I need fully charged battery for real accurate readings? The one on right now is only about 4.9 volts and I think cooked as again I think the middle cell got low. I guess that means something must be charging? Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 27, 2013 Moderator Share Posted October 27, 2013 I'm getting nothing with lights off and about 8v at 6-7000 rpm with lights on. 2 things spring to mind. Nothing with the lights off would mean a bad feed or the charging coil is shot. But 8v with the lights on makes it sound like there is an earth in the switchgear which is stopping the battery charging when the lights are switched off. It can be one of those problems that frustrates the life out of you. ...................... If all are installed and working, there is no need for a regulator ,,.its done by impedance [ resistance] as revs increase at lighting/charging coils.............. You might not need one but you can buy one. This is the same issue as my TS250, it just cooks batteries. I fitted a generic 6v rectifier for a DT to it and it is fine now. This is what I brought LINKY Same as this? LINKY Link to comment Share on other sites More sharing options...
Corbstar Posted October 27, 2013 Author Share Posted October 27, 2013 Yes real frustrating. Where about in loom did you hook it up, mine is on the yellow feed to front lamp. Well I think it is, just spliced in. Now I'm wondering if that's part of the problem? Also noticed when any load on ie brake, horn, lights the voltage drops to 0 with bike running. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 27, 2013 Moderator Share Posted October 27, 2013 The TS, like the DT's, have the separate charging and lighting coils. The USA version of the TS has a regulator but the UK one doesn't - there is a wire in the harness to fit it though. After a couple of attempts I fitted it to the coil feed wire of the rectifier (the side NOT connected to the battery). This then sucks any additional power before it hits the rectifier and leaves the correct voltage to be pushed through the rectifier to the battery. As the rectifier is a diode (only allows current one way), it doesn't allow any power from the battery back to earth. I have had no problems since. It is just a piggy back connection so the feed into the rectifier has 2 wires (the feed in and the regulator) both connected to it and the "out" wire goes to the battery. As Blackhat says, it shouldn't need one but I couldn't get to the bottom of the TS issues straight away so did this as a temporary fix - it is still in place. Link to comment Share on other sites More sharing options...
Corbstar Posted October 27, 2013 Author Share Posted October 27, 2013 Thanks, really appreciate the info. I'm going through it all. Link to comment Share on other sites More sharing options...
Corbstar Posted October 27, 2013 Author Share Posted October 27, 2013 Ahhhh. Still no joy, nothing really at tick over but up to 8 v at 8k rpm with lights on. Also cleaning tank today, trying the spirit of salts method. Works pretty well, sleep on the electrics for now. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 27, 2013 Moderator Share Posted October 27, 2013 Ahhhh. Still no joy, nothing really at tick over but up to 8 v at 8k rpm with lights on. Also cleaning tank today, trying the spirit of salts method. Works pretty well, sleep on the electrics for now. what do you mean "nothing really at tick over" what and where are you measuring, or do you mean 6v at tickover and 8v when revs are 8k ? Link to comment Share on other sites More sharing options...
Corbstar Posted October 28, 2013 Author Share Posted October 28, 2013 Yes that's it, just the battery level at tick over and then when lights on it goes up to 8v with revs but only slight change with lights off, i thought it should read more than 6 on tick over but thinking about it i am testing at battery?? Putting new battery on next, I don't think I've been very methodical with this- could you give me the best plan of order to test and give you guys the most accurate info? Cheers. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 28, 2013 Moderator Share Posted October 28, 2013 My plan would be:Disconnect the battery and check the voltageConnect the battery and check the voltage - lights offCheck the battery side light on only voltageCheck the battery main light on voltage.A new battery would stop some possible mis reading. After that it would be checking the volts coming from the charging and lighting coils at the wires from the coils. Normally the best place to do this is where the wires feed into the harness. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 28, 2013 Moderator Share Posted October 28, 2013 Clearly the battery is over charging, I'd try this Check the regulator is functioning Back in the distant past I had overcharging problems, in my case it turned out to be the yellow / white wire had broken away from the regulator, I also had blowing headlight bulb at the time though and I note you said that you dont have this other problem. At some time I've thought a way of testing the regulator is actually doing it's job, though I have never needed to do this in anger. The test is simply to verify that current is passing through the regulator If it is, then to me It's working, It's disposing of excess voltage by passing current back to chassis. Disconnect the regulator yell/whi Set your multimeter to ac current (20A), not 100% sure on the ac setting though...try dc too put the meter leads in series with the loom socket and the regulator plug Start the engine and try different rpm's, you should see varying amounts of current passing through the regulator, if so...then it's doing a job and can be deemed OK All this can be done without any further expense because you do have a meter. Like I said, I've thought it but never done it so look forwars to seeing how you get on with this test. Link to comment Share on other sites More sharing options...
Corbstar Posted October 31, 2013 Author Share Posted October 31, 2013 Ok will do, my regulator is new one and purely on the headlamp feed yellow. Really not sure if it needs to be back in the loom somewhere? Link to comment Share on other sites More sharing options...
Corbstar Posted November 10, 2013 Author Share Posted November 10, 2013 Hi all again. Just want to check out the wireing I seem to have, I'm getting confused with the various diagrams out there. This is the Dt 400 b with cdi. I've got 6 wires coming from the flywheel and they are yellow, green red and both conect to the same colour at junction but there is also the green white from loom that just stops there? Then it's white green, white red, black - all on another moulded black conector so you can't plug in the wrong way round, last cable is brown on its own conector. That all looks correct with main cdi flywheel diagrams and they clearly show the two wires, yellow and green red on one four way connector but I can't make out the green white running through the loom from light switch all the way back to that connector but then no connection?? It just stops there. The green white in question seems to be on the light circuit for day time while green red is night time running. Help! Link to comment Share on other sites More sharing options...
blackhat250 Posted November 18, 2013 Share Posted November 18, 2013 heres the diagram ittinery Link to comment Share on other sites More sharing options...
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