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Discussion Starter #1 (Edited)
Hi everyone,

My first post here. I initially put this up on AdvRider, but haven't heard back: ht---tp://advrider(dot)com/index.php?threads/1990-yamaha-tw-200-bad-cdi-box-looking-for-advice.1191668/ (I can't post links)

I'll quote my posts here:

Hi everyone,

We traced my TW-200's ignition woes to the CDI box. They go for about $200 online, on the lower end. Haven't seen any used ones.

We managed to get a Honda TLR-200 CDI to work in its place, but it's stuck at full advance. Seems a little picky about starting, but the timing is pretty stable aside from that. Those boxes are much cheaper, in the $60 range. I'm setting this bike up as kickstart only, so getting rid of the side stand switch, clutch switch, and other don't-start gizmos is ideal.

Is there a cheaper CDI that will work properly on it? Is there an open source alternative somewhere? I imagine CDI boxes are pretty tough to make.

There are some threads online specifically about the TW-200 CDI, but I'm not sure if they came up with any great solutions. I sure miss battery ignited points. Seems silly to pay so much for a black box.

Thanks!
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We worked further on this. Seems that the Honda units may expect a lower voltage from the generator coil. Thought about inlineing a resistor to drop the voltage and using a higher gain spark coil, but finding a TW-200 CDI may be best.

Also used a Honda Rebel 250 CDI box. Same thing, no real advance, even though it worked on the Rebel. Probably again because of the generator coil voltage being too high for it to work with.

Did find that depending on the polarity of the trigger, we can make it fully advanced or fully retarded. Both seems to run rather poorly at the wrong end of the spectrum.

I did have an idea that we could add a switch to change the polarity, whether I want full advance for high RPM running, or full retard for starting and idling. It would be cludgey, of course.

We've got some ideas for building a CDI, but I may just wait and see if one pops up for cheap.
Thinking about this a bit more, what is a normal voltage to see at the trigger coil? I read one post that said 24V. I think the resistance is in range, but voltage is definitely lower than 24V. I would have to check again, but I think it's in the 12V range or maybe a bit less.

Has a good CDI box alternative been found? Is anyone making custom igniters for these? (CDI or not)

Thank you!

Edit: Here's a link to the best in-depth CDI thread I've found: ht-tp://tw200forum(dot)com/forum/technical-help/11545-cdi-baseline-info-wires-waveforms-timings-substitution.html

Still, nothing working with advance. I am getting tempted to freeze/bake my CDI and see if I can resurrect it.
 

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Discussion Starter #2
Welp, stuck the CDI in the freezer, but found that we probably just had it wired up wrong. At one point I had disabled the side stand switch and I must have ran ground to the blue and yellow wire. That may have come off at some point.

These bikes are sure strange. Relays for ignition and sidestand cut offs?

Happy to be done with those. Also happy to have the bike running with advance. Pretty peppy for a 200.
 

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...... Pretty peppy for a 200.
:D Those of us who started riding Honda 90 Trails back in the day, then went to Bultaco 250's, then something 500's, then 650's, etc. have finally learned that a mere 197 cc's can do some pretty amazing things, as long as you don't want to go 80 mph. :p

But that is what I have a BMW R1200GS for. :icon_thumbright:
 
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