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Vernjeggies

1978 DT175 Ignition points?

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Hey everyone,

Just picked up this bike and I'm eager to get it running. PO did an engine swap and now the numbers match, but he attempted to change the ignition from CDI-> points... or maybe vice-versa. I have a Clymer manual on the way, but I'm curious if anyone on here has an electrical diagram for this year or at least knows if the 78 was CDI or points? The bike came with a parts box containing both... Any help would be awesome!

Thanks in advance

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Yeah it's a monoshock. I don't know why the PO would have switched it to points.... doesn't make much sense to me

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The 125 had points. Could be the bottom end was changed sometime.

No biggy if it was aside from the ig you only have 1 clutch plate less and a very slightly shallower clutch basket. 

Some feel points would be better for extreem offroad work. Only the mag to drain after deep water. Drowned cdi would be a bitch. Never stopped mine though.

 

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It seems like it was originally a CDI. Everything is there, just need to figure out what colour wire goes where! Anyone holding an electrical diagram?

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48 minutes ago, Vernjeggies said:

It seems like it was originally a CDI. Everything is there, just need to figure out what colour wire goes where! Anyone holding an electrical diagram?

you must bear in mind that this was written for the UK market bikes

 

DT175MX Ignition checks

There were two versions of ignition systems on DT175MX bikes. The mk1 version from the earlier bike had a 7 wire CDI the early bikes had a round section swing arm.

The mk2 version had a 6 wire CDI, the red wire is absent on these. These bikes have a square section swing arm.

 

The HT cap (AKA spark plug cap)

unscrew it off the HT lead, it is supposed to be a resistor cap so should be around 5K Ohms
The ignition coil primary...Orange wire to battery neg should be 1 Ohm +- 10%
The ignition coil secondary...HT lead to battery neg should be 5900 Ohms +- 20%

If the readings are much higher, check the ignition coil has a clean ground connection.

Yes and the ignition coil mounting is a wiring harness ground point too, so check its clean and bright there.

 

Disconnect all the wires from the CDI.
Then using your multimeter on the loom side of the connectors.


Black probe on a clean part of HT coil ground point
Red probe on......



Orange, Meter to 200 Ohms, expect 1 Ohm (HT coil primary)

Brown, Meter to 2k Ohms, expect 420 Ohms for  mk1 and 300 Ohms for mk2 (Magneto charge coil)

White/Red, Meter to 200 Ohms, expect 12.4 Ohms for mk1 and 10 Ohms for mk2 (Magneto pulser coil)

 

Red, Meter to 200 Ohms, expect 13.6 Ohms for  mk1 only. (Source coil 2 or high speed coil)

Black female connector, Meter to 200 Ohms, expect dead short
repeat for black male connector
Any difference in the results for the two black wires may possibly be rectified by cleaning the front engine mounting bolt and a little of the frame behind the bolt head, then tighten to torque spec.

Black/White, Meter to 20K Ohms, with ignition off expect dead short, with key on expect open circuit, with kill operated expect dead short (Engine kill operation)

 


If all these tests are good you would be well advised to try another CDI.

If they are not good...reading higher...disconnect and clean any plugs/sockets you find along the way, if the magneto coils are reading lower, new ones needed if more than 10%...or so the book says
:rolleyes:

 

Finally, if you are working with a box full of mixed parts!

Mk1 1 flywheel is Mitsubishi F3T250, it has two slots in the face of the flywheel

 

Mk2 flywheel is Mitsubishi F3T251, it has four slots in the face of the flywheel

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Wowzer, great info. Does most of this apply to the non-motos? I never knew the caps were resistor types, something I must look at  on the 175E.

Surely there is an alien civilisation four or five light-years away marvelling at the brilliant minds on this site and wondering how best to get in touch. Y'all smart!:wacko:

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Wow Airhead that's amazing information! I knew there were some knowledgable people on here but that was next level. I have the 175E... does that fit in to either of those categories? It's got the round swing arm. Unfortunately, not only am I working with a box of random parts, half of the connectors have been amputated. The stator I'm working with is a 5 wire with no connector and the CDI is a 6 wire with no connector and no red wire. I'm starting to think these parts not belong on this wiring harness?

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Paul is the Biz. with electrics ,:rolleyes:

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2 hours ago, Airhead said:

is there a Red wire in your harness at the Stator location?

The biggest problem I'm having is that I don't even know where the stator would plug in to. There's a random red wire off my wiring harness, but it's not grouped with anything. The stator that goes with the CDI doesn't have a red wire, no.

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So I finally found a wiring diagram on google, but none of the components are labelled. It looks like the CDI and stator that I have are definitely not for this bike. Potentially for a 79? Anyway, I guess that puts me in the terrible position of looking for electrical parts for this old machine. Any suggestions?

IMG_0008.JPG

Also, it looks like this diagram shows what could be a battery (#9)? I didn't know it had one. My wiring harness definitely doesn't have any battery connections.

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horn, indicators, tail light / brake light, dashboard lights....these all work from the battery. The engine does not need the battery as it has a magneto ignition

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I"l give you colour,[ Abait dt400] , most yams  of this age were similar,  Brown wires are feeds from battery[ Via the ignition], brown/white [ flasher unit] Pink horn] black/whites [ kill switch] ,Yellow A/C lighting,

img024.jpg

No7  is C,D,I.   18 iggy switch,, 12 Light switch,   that's the main items , the rest are visable

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On ‎07‎/‎02‎/‎2017 at 10:47 PM, Vernjeggies said:

Hey everyone,

Just picked up this bike and I'm eager to get it running. PO did an engine swap and now the numbers match, but he attempted to change the ignition from CDI-> points... or maybe vice-versa. I have a Clymer manual on the way, but I'm curious if anyone on here has an electrical diagram for this year or at least knows if the 78 was CDI or points? The bike came with a parts box containing both... Any help would be awesome!

Thanks in advance

Ok, when you say the numbers match.

What does the engine and frame numbers start with, i think its going to be 2A6 but could be others.

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4 hours ago, blackhat250 said:

I"l give you colour,[ Abait dt400] , most yams  of this age were similar,  Brown wires are feeds from battery[ Via the ignition], brown/white [ flasher unit] Pink horn] black/whites [ kill switch] ,Yellow A/C lighting,

Hopefully my clymer manual shows up soon. I'm not sure what out of this box of parts even goes on this bike anymore. Haha

3 hours ago, Cynic said:

Ok, when you say the numbers match.

What does the engine and frame numbers start with, i think its going to be 2A6 but could be others.

Both frame and engine numbers start with 2A7 however I have parts motors with 559 and 3V5 prefixes. From what I can find, the one in the bike is stock and a 78. The parts motors are 76 and 80.

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2A7 then that diagram is the one, be careful though. These diagrams are not cast in stone and colours and connections can vary, not to mention some of the smaller links and such are not shown either.

When i remade my loom i found this. There are several connectors buried within the harness, also the companies that made the looms have used some licence as to using wire that isn't long enough and joining 2 pieces together again within the loom. That red wire for the cdi being a good example, earlier bikes its no surprise to find it a separate wire outside of the main harness. Mine was.

Waste not want not, their efficient but not German.

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There may be a number on the harness which identifies it, near the steering head I think. If you find one it would tell you if the harness is the correct one or something a po fitted for whatever reason.

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21 hours ago, flyday58 said:

There may be a number on the harness which identifies it, near the steering head I think. If you find one it would tell you if the harness is the correct one or something a po fitted for whatever reason.

There is! Thanks for pointing that out. It never would've occurred to me, but the harness is actually off the 76...pre CDI.

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Um...dang, I actually helped for once. At least you know what you got now. Not why but hey, it's a start! :thumb:

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