Author Topic: DT 360 A. Pulser coil fix.  (Read 16054 times)

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mainline

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Re: DT 360 A. Pulser coil fix.
« Reply #30 on: July 24, 2012, 07:45:07 pm »
I haven't opened one up but i've been trying to seal one up that was leaking black ooze with some Sikaflex. Didn't work.
« Last Edit: July 26, 2012, 06:38:32 pm by mainline »

Offline mitch75

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Re: DT 360 A. Pulser coil fix.
« Reply #31 on: July 24, 2012, 08:16:40 pm »
Thank you for your excellent information on what not to use to seal a CDI mainline.
Yamaha DT360a DT250b DT100c YZ400D WR250ZG.

mainline

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Re: DT 360 A. Pulser coil fix.
« Reply #32 on: July 24, 2012, 08:47:48 pm »
No worries, i'll let you know how the Nugget shoe polish holds up

mainline

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Re: DT 360 A. Pulser coil fix.
« Reply #33 on: July 24, 2012, 09:24:13 pm »
Actually, a mate of mine who's into electronics mentioned araldite? Might be worth a try.

Montynut

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Re: DT 360 A. Pulser coil fix.
« Reply #34 on: July 24, 2012, 10:29:07 pm »
5min Arildite is fine but be careful of mixing and potting a large quantity in one go as it generates a large amount of heat and expands slightly.

casting resin is good but use minimum hardener so that internal heating is kept down.

Offline mitch75

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Re: DT 360 A. Pulser coil fix.
« Reply #35 on: July 25, 2012, 02:20:08 pm »
Is the DT 360a a stepped type pulser?.
Yamaha DT360a DT250b DT100c YZ400D WR250ZG.

Offline mitch75

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Re: DT 360 A. Pulser coil fix.
« Reply #36 on: July 25, 2012, 03:09:47 pm »
I think this is how the spark advance system works on these bikes.
High tech stuff for the seventies.
Yamaha DT360a DT250b DT100c YZ400D WR250ZG.

Montynut

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Re: DT 360 A. Pulser coil fix.
« Reply #37 on: July 25, 2012, 03:43:47 pm »
most 2st of the '70 and even '80s had static timing with maybe one step change at low rpm

Offline mitch75

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Re: DT 360 A. Pulser coil fix.
« Reply #38 on: July 25, 2012, 04:26:22 pm »
Do you read silicon chip magazine Montynut.
The May 2008. Issue has a section on building CDI module.
Yamaha DT360a DT250b DT100c YZ400D WR250ZG.

Offline Mike52

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Re: DT 360 A. Pulser coil fix.
« Reply #39 on: July 25, 2012, 05:19:56 pm »
I like your give it a go attitude Overthehill.
By what i understand as engine speed increases so does the voltage in coil this rise in voltage is used to advance the timing.
A over voltage pulser would cause to much advance at starting.
Putting a resistor inline would bring down the voltage going to the CDI retarding it making it easy to start.
How does it trigger there are four magnets in there? Sealed box magic?
According to my suzuki book  mitch75 that's exactly how they get the setup to advance.
The scr triggers at a set voltage and the system reaches the trigger voltage earlier as the revs rise.
Seeing as how two strokes don't need any advance the only reason I can see for the advance setup is easier starting , less kickback.
I have a DT 175 flywheel here [ 4 magnets and 2 bigger gaps ] and it fires twice per rev , 1 TDC and 1 BDC.
Not a problem firing at BDC as nothing happens.
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Offline mitch75

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Re: DT 360 A. Pulser coil fix.
« Reply #40 on: July 25, 2012, 06:17:38 pm »
They use the AC wave form and get it to trigger at low voltage 1.5v.
As speed increases so does the wave form reaching the 1.5v quicker.
Yamaha DT360a DT250b DT100c YZ400D WR250ZG.

Offline OverTheHill

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Re: DT 360 A. Pulser coil fix.
« Reply #41 on: July 25, 2012, 08:01:08 pm »
your right about firing twice per revolution, accidentally found that when strobing by old AG100 [cdi ignition], had me head scratching for a while but thought in the end--nothing to stop it doing that!!. Had an MX250b new in"75 'with the two step' trigger [retard & advance]--same type set up as the DT360A except for the full flywheel. Anyway the MX went strong right out of the box then next year"76 YZ250C mine was a slug compared to year before. Took me frustrating ages to find an answer as mechanically identical motor. But found the ignition was [too trick for me] so strobed it & found it advanced to [i dunno] lots, say 36 degrees then retarded off gradually to bloody near tdc at full revs so though bugger it & just over-advanced it on the backplate which fixed it, didn't ever give any problems. BUT--asked the Yam factory mechanics that came to our work with the importer [they were doing the rounds & we were to line up a few problem jobs--was fun watching their methodology for working it. They were on to anything we could throw at them--damn. Anyway, asked them [why] re-ignition & they said we do that to stop you blowing it up by over-revving. Bugger that i thought [in those days] give me power. Cheers.