[andy175]

Hello all,my names Andy and just joined the forum.

Ive just acquired a DT175mx in need of much t.l.c.

Its got matching engine and chassis numbers but no v.5/log book.
Before i got it someone decided to take all the electrics off it,leaving a very tatty wiring loom in a bag which i'm sorting out

Anyway,could anyone help me acquire a replacement magneto pulse sensor coil ?
Ive been going through the coils with a multi meter,and it seems the pulse coil has died as there are no ohms being recorded from it !!
I'm still waiting for a haines manual to be delivered, but ive found on the internet that it should be between 10-12 ohms.
But mines got nothing

Ive looked up the part number on cmsnl and they show it as :3m285580-20.

Any help appreciated folks.

[oldgitonabike]

Hi andy, seen you lurking and now youve popped in from the cold...greetings

Ive found one...its the only one left in the world Here ....Yep its expensive and no I wouldnt pay it but it does give you the part number so save it as a search on ebay and see if another comes along, alternatively engines or part engines come along now and again so maybe cou could watch out for them. another alternative is maybe get yours re-wound, I dont have experience with this but i would give west country winding a ring and have a chat about it 01279 731172. www.westcountrywindings.co.uk Have you tried Granby or Fowlers for genuine yamaha spares?

...Paul

[andy175]

Hi Paul,yes been lurking around in here

I hadn't thought about getting it recoiled,its so small it may come under micro surgery !!

Here's another i saw to but not quiete the same part number My link

Ive seen new one's up for 150 euros,thats unreal

As you say i will keep an eye on ebay for now, and if no joy in a few weeks i may have to go down the recoil route, if i can find someone brave enough to tackle it !!

Yes i will give fowlers a call as ive had parts off them before and found them pretty helpfull in the past.


Andy..

[oldgitonabike]

Be careful what you buy though because the two you have posted are not for your bike , need a 2a7 prefix

[oldgitonabike]

Have you got the coil off the bike and tested it? dont forget there is only one wire connected, so the return is through the mounting screws to chassis, may be a bad connection...BTW i found another cheaper one

[andy175]

Oh !!

I thought the part i needed was:3m285580-20

Your saying the part i need should be:2a785580-20 ?

Also am i right in thinking that the pulser coil is energised by the magnets passing over it as the magneto turns ?

Another also,are the slight changes in part numbers stand for differing values in ohms being given off by the coil?

Cheers again,Andy..

[andy175]

Well i have had the coil off as it came in a plastic bag along with the source and lighting coil.

Yes there is just the one red/white wire on it,and its screwed onto what looks like a alloy backing plate.So i can't see how it would earth through that?

Also how would i go about testing it off the bike,as i can take it back out in just a couple minutes now

Without a workshop manual for this model,i'm putting it back together from memory of many years ago !

Andy..

[oldgitonabike]

Yes one side of the coil is connected to the wire and the other side id to a small ring terminal which one of the mounting screws goes through,,,thereby grounding that side of the coil (i think)

like you can see here on the source coils

[andy175]

Ah,well ive screwed it on the right way then

As ive attached it the same way as the other two coils,i can only assume that the pulse coil has had it then

Good job this is a long term project

[oldgitonabike]

andy175, on 20 November 2009 - 11:05 PM, said:

Ah,well ive screwed it on the right way then

As ive attached it the same way as the other two coils,i can only assume that the pulse coil has had it then

Good job this is a long term project

I would assume that the ring terminal is not beneath the screw (where it may twist and break off the coil) but is trapped between the coil assy and the stator backplate...if you see what i mean.

[andy175]

Yes i know what you mean.
I did try that earlier today,to see if it made a difference,sadly not !

I also wondered if the air gap was adjustable like the crank position sensor on a modern car,but no to that also.

Just my luck that the most expensive coil has gone on

Its a shame there is not the yamaha equivalant to David Silver available !!

Here's someone i will call :My link

[oldgitonabike]

Well worth atry with their sensible prices, thats the place i got my source coils from, did you notice the logo on the picture i posted? The thing is...they only list source coils for our bike so i hope youre lucky...although that one in the link does kinda look right...keep us posted

...Paul

[andy175]

Hi Paul,This is the responce i got back today regarding the pulser coil :
.....................................
Hi Andy



Sorry, I can’t give you a definite reply about this because we don’t have a listing for the DT175/P30. Generally speaking if it looks identical it should be the correct part.



Regards

Lesley Houghton

Electrex World Limited

Tel: **44 (0)1491 682369

Fax: **44(0)1491 682286

www.electrexworld.co.uk

............................................

Now i'm in agreement with them over this,as its dimensions are the same and its just a switch over trigger at the end of the day !!

If we ever get a dry day again,then i will go outside and check the earth and a few other things

And if that doesn't work i may well order a new one from them

[andy175]

Well i had a change in direction to over come the pulser coil problem.

I have changed the whole ignition system and wiring loom to that of another bike that runs a 12 volt system

I have only just fitted the loom today,and got a spark from the plug resting on the head so all looking good so far

Have had to do some major work to adapt the stator and magneto to fit some of the yamaha parts,but all done at home with some alternative tooling

Still have to set the final timing exactly,but hoping to have it running very soon.

[oldgitonabike]

andy175, on 13 December 2009 - 08:51 PM, said:

I have changed the whole ignition system and wiring loom to that of another bike that runs a 12 volt system

Have had to do some major work to adapt the stator and magneto to fit some of the yamaha parts,but all done at home with some alternative tooling

Still have to set the final timing exactly,but hoping to have it running very soon.

But your bike will still be 6v will it, whats the plan for the bike...road use?

[andy175]

Quote

But your bike will still be 6v will it, whats the plan for the bike...road use?

Well today i got the DT up and running properly.

The bike now runs a full 12 volt system, that is lights,ignition and indicators e.t.c.

The bike now owes me about 120 quid,so if i can find some road legal parts cheap enough then i will get it back on the road.

I'm after a headlight with brackets,speedo/rev counter with bracket and a rear mudguard.
Oh, and a later type kickstart lever,as mine has the twin shock style one at the moment

Back to watching ebay for bits now !!

[oldgitonabike]

andy175, on 17 December 2009 - 11:49 PM, said:

The bike now runs a full 12 volt system, that is lights,ignition and indicators e.t.c.

Well done on getting tho old DT going again ..Now C'mon Andy, tell is some detail then. The CDI...did you replace that? and how about the battery, must have been difficult to get a 12v battery in that small space ? and the voltage regulator that has the purpose of keeping the AC voltage to suit the standard 6v bulb...what did you do there?...12v horn now?
You sure went to a lot of trouble for that pulser coil

[andy175]

Well Paul,all the electrics are now from the 12volt donor bike

From the stator plate,coils,pulser coil,magneto,cdi,ign coil,reg,relays and of course the whole wiring loom

Once i got it into my head that i could modify a 12 volt system to fit,i was just determined to make it work !

I can post some pics of the magneto/stator conversion if interested ?

[oldgitonabike]

Yeah please do, what was the donor bike then and what about the battery....I have always believed this to prevent a 12v conversion, wrongly it seems

[andy175]

Right then, the donor bike i used was a Honda c90.
Although the c70 or c50 will do as long as its the later non points model.
They all use the same electrics according to part numbers ive seen.

Here is the remains of my original dt175mx stator plate in situ:



And here is the c90 stator before i fixed it in place:



And here is the two magneto's,the one on the left being the c90 part.
Now purely because the woodruf key was about 1mm different between the two,i drilled out the rivets of the centre sleeve's to swap them over.
Now i had to turn down one of the sleeves slightly to fit inside the other magneto,then i had to reset the timing before drilling new holes to bolt back together the sleeve to magneto.
I used nut and bolts as i didnt have any blind rivets left, to give it the factory type look



For some reason my camera phone pics of the finished article didnt come out,so i will take some more if the rain ever stops down here on the south coast
Will add some more with new photo's soon.