GreatWill Posted April 20, 2010 Share Posted April 20, 2010 I have a Dt Mx 125 2A8 engine that is connected to a buggy, but I'm not sure of the wiring and any help would be appreciated. I just need to know what connects to what. There are no lights ect, I just need to create the spark. I have looked at a wiring Diagram but not having much luck. Many Thanks ~ Will Link to comment Share on other sites More sharing options...
Moderator Airhead Posted April 20, 2010 Moderator Share Posted April 20, 2010 Magneto Black (Chassis) to CDI Black Magneto White/Red to CDI White/Red Magneto Brown to CDI Brown For the engine stop CDI Black/White to a switch and then back to chassis CDI Black to chassis CDI Orange to HT coil Other HT coil wire to chassis Link to comment Share on other sites More sharing options...
Speedshop Posted April 20, 2010 Share Posted April 20, 2010 Is that a CDi generator? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted April 21, 2010 Moderator Share Posted April 21, 2010 Is that a CDi generator? Thats a good point and posting a picure from the back of it isnt very revealing. Here's mine for DT175MX Link to comment Share on other sites More sharing options...
GreatWill Posted April 25, 2010 Author Share Posted April 25, 2010 Does this photos help any more? The wires do not seem the original colours which is the main reason I have no clue what goes where... Im still rather stuck! Many Thanks for your help ~Will Link to comment Share on other sites More sharing options...
Moderator Airhead Posted April 25, 2010 Moderator Share Posted April 25, 2010 Link to comment Share on other sites More sharing options...
GreatWill Posted May 23, 2010 Author Share Posted May 23, 2010 Thank you for all your help, but Im still having trouble to get a spark (I did about 3 years ago before I took it off the buggy so know it should work) I have tried to create a paint masterpiece to help me explain what I have got so far: And here are some actual pictures if they help (It was hard to get a suitable angle) Any advice would be greatly received Many Thanks ~Will Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 23, 2010 Moderator Share Posted May 23, 2010 what have you done with the CDI Bk / We ? EDIT It looks to me that you connected it to a black Disconnect it from that black, connect the black to chassis with the other black Connect the Bk/We throgh a switch to chassis, this will then be your engine kill switch. When the switch is open you have spark, when closed...no spark. Link to comment Share on other sites More sharing options...
GreatWill Posted May 23, 2010 Author Share Posted May 23, 2010 Right, I have now changed that and this is what I have: Mag White / Red -> CDI White / Red Mag Brown -> CDI Brown Mag Black -. CDI Black -> Chassis? (Not sure about that part) Mag Lighting / Charge -> Just dangling CDI Black -> Chassis CDI White/Black -> Just dangling as I have no switch at the moment. CDI Orange -> HT Lead I'm still not getting a spark, and I have tested the spark plug on a lawnmower and it worked. Can I use a multimeter somewhere to test it? Thanks once again for all your help! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 23, 2010 Moderator Share Posted May 23, 2010 Right, I have now changed that and this is what I have: Mag White / Red -> CDI White / Red Mag Brown -> CDI Brown Mag Black -. CDI Black Socket-> Chassis? (Not sure about that part)This one not to chassis Mag Lighting / Charge -> Just dangling CDI Black Plug -> Chassis CDI White/Black -> Just dangling as I have no switch at the moment. CDI Orange -> HT Lead I'm still not getting a spark, and I have tested the spark plug on a lawnmower and it worked. Can I use a multimeter somewhere to test it? Thanks once again for all your help! This is as the wiring diagram, If that does not work we need to check coil resistances next. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 23, 2010 Moderator Share Posted May 23, 2010 Make sure the HT coil mounting bolt is clean and has a wire to the same chassis common point. Link to comment Share on other sites More sharing options...
GreatWill Posted May 23, 2010 Author Share Posted May 23, 2010 Right, So i have all the connections as above. I have been playing with the multimeter and I am getting slight volts from most the wires. Red / White & Brown are showing the most but they are all so varied from each kick (From 0.10 to around 1.5 max) The only wires I am not getting a reading from is the Black MAG & the HT Lead. The Orange CDI is around 0.30 each kick. Every reading seems so inconsistent Does this mean anything? When you say it should have a wire to the "same chassis common point", There are no places on the HT Coil for another wire to be attached to? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 23, 2010 Moderator Share Posted May 23, 2010 When you say it should have a wire to the "same chassis common point", There are no places on the HT Coil for another wire to be attached to? When on a standard bike, there is a ring terminal under the HT coil mounting bolt, with Bk wire to chassis. Link to comment Share on other sites More sharing options...
GreatWill Posted May 23, 2010 Author Share Posted May 23, 2010 But as the Ht Coil is already mounted on the chassis via the bolt ( Creating an earth) Is it needed? I'm starting to think maybe one (If not multiple) wires could be making a bad connection or something, there are multiple joins on most the wires. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 23, 2010 Moderator Share Posted May 23, 2010 But as the Ht Coil is already mounted on the chassis via the bolt ( Creating an earth) Is it needed? Thats how it is on the bike, the bolt alone isnt trusted and a wire is placed under it. I do understand your scepticism but you are not in a position to cast doubt. Link to comment Share on other sites More sharing options...
GreatWill Posted May 23, 2010 Author Share Posted May 23, 2010 You are right, I will give it a go tomorrow. Fingers Crossed Thanks once again for you so quick responses! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 23, 2010 Moderator Share Posted May 23, 2010 I'm starting to think maybe one (If not multiple) wires could be making a bad connection or something, there are multiple joins on most the wires. If your'e not happy with the connections, neither am I. It goes without saying the all need to be clean and sound, as in no oily wires twisted together. More things to check Check the resistance values of your magneto source coil = 420 ohms +- 10%............Brown to chassis Check the resistance of the magneto pulse coil = 12.4 ohms +- 10%...........White / Red to chassis Check the resistance values of the ignition coil, Primary = 1.0 ohm =- 15%, secondary = 5900 ohms +- 20% But sort the wiring first. Link to comment Share on other sites More sharing options...
GreatWill Posted May 24, 2010 Author Share Posted May 24, 2010 Just been looking at the wiring, at the base of the Ignition Coil where the HT lead comes out the wire was completely broken. I'm not sure If its worth me paying to get a new Ignition Coil in a hope that it was the only fault. I am thinking I am now just going to have to Sell the whole buggy and engine on ebay. Thanks for all your help ~ Will Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 24, 2010 Moderator Share Posted May 24, 2010 Just been looking at the wiring, at the base of the Ignition Coil where the HT lead comes out the wire was completely broken. I'm not sure If its worth me paying to get a new Ignition Coil in a hope that it was the only fault. I am thinking I am now just going to have to Sell the whole buggy and engine on ebay. Thanks for all your help ~ Will Pattern coils are not all that expensive Just do a search for one, I guess you are American, here in the uk for example http://www.wemoto.com/bikes/Yamaha/DT_175_MX/78-79/picture/Ignition_Coil/'>http://www.wemoto.com/bikes/Yamaha/DT_175_MX/78-79/picture/Ignition_Coil/ http://www.wemoto.com/bikes/Yamaha/DT_175_MX/78-79/ £16.45 You will also probably fetch a better price for a runner If the coil is scrap as it stands now...why not have a go at digging out the lead from it and replacing that with some new lead...nothing to loose there just check you get the 5900 ohms or whatever before you buy new lead. Link to comment Share on other sites More sharing options...
GreatWill Posted May 24, 2010 Author Share Posted May 24, 2010 Me again... , Just given it another test with the Multi Meter and tbh with you I am not entirely sure what settings it should be on, here are my results. Wire Going In -> Ignition Coil Ground = 0.12 On 200 ohm Scale (It sometimes moves much higher at the start but seems to settle on this number and this is the only setting I can get a reasonable / registering number on) Ht Coil Wire -> Ignition Coil Ground = 6.20 ish on 20k ohm Scale What would this suggest? (I am in the Uk) Link to comment Share on other sites More sharing options...
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