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Discussion Starter #1 (Edited)
for a wide view, here is a good summary of the various types of "powersport" ignition systems.
Powersports Ignition Evolution

"making spark is easy- making it at the right time is difficult"

overheard on the internet.

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hi

This thread is to provide and build baseline information about the tw ignition system,
so that testing, replacement, and substitution becomes easier. not to mention possible.

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my bike is a 1990, so some of this initial information is specific to the 1988-97 tw's.

lets keep general cdi troubleshooting - "help my bike won't start !" , "hey friend have you checked that sidestand switch?" off this thread please.

corrections, updates, overlooked resources, independent verification (with a real oscilloscope!?), data for other years, special skills, and confirmed sightings of successful tw cdi swaps with part #'s are all very welcome!

thanks,
slowmod

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once upon a time,

my bike ran erratically, yada yada, ended up being a bad cdi, yada yada. oem = $430 cdn plus tax. no.

after months of combing the internet, it seems that cdi substitution attempts seem to fall into 3 catagories: 1) the many who tried valiently but eventually had to give up, 2) those rumoured few who lucked out, hacked something in and it worked, but it's not easily replicate-able on the tw for some reason, and 3), those who bought expensive programmable ignition units to squeeze out max performance, or went to truly great lengths to build their own, or swapped entire systems from similar bikes.

good tw reference data at that last link, by the way; cdi #s, years, previous attempts, links, etc.

however, none of these outcomes is of much use to those of us who just want something resembling a reliable stock working bike for cheaper, before the summer ends, ideally.

so i set out to find what the tw offers up to a perspective substitute cdi. i am really hoping not to end up in catagory 1.

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this first round deals with trigger and power; finding a cdi that also has a similar-to-stock timing curve- starting near 10deg btdc advancing up to 30, (a straight line, a rise then rolloff, or?) is the next layer.

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scalpel please

if one pulls out a dead tw cdi, what's left? (ignoring the interlocks and all that crap for the moment).

upstream; the spark coil, plug wire, cap, and spark plug.
downstream; the cdi power/source/charge coil/stator/magneto, and the pulser/pickup/trigger coil/stator.

finding out exactly what those coils are putting out, and when, is kinda key to matching in a substitute cdi.

as well, the possibility of powering a new cdi with 12v exists, although the older tw charging systems don't have much/any headroom for power consumption. swapping out the headlight with a new led type might free up enough power to run a modern 12v cdi.

focussing on the pulser: different cdi's look for different types of triggers, (separate from when the cdi's should have them, and how long they delay once they have the trigger signal..).

some cdi's look for a rising-plus-voltage-when-it-hits-1v (ie the briggs and stratton magnatron which also provides some timing advance, as the 1v occurs earlier with more rpm/energy); some cdi's look for the plus, or minus peak; square wave, sine wave...

some cdi's look for a rising-minus-at-zero, and some look for a falling-plus-at-zero.

(the gy6 cdi's, for example, according to the good folks at buggymart), who offer plug-and-play retrofit cdi service, though they haven't done tw's yet. i am in contact with them and will report back if we figure it out for the tw.

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cdi/pwr/pulse schematic
tw_cdi diagram_v1.0.JPG

stators
tw_coils1_web.JPG

magnets
tw_magnets_web.jpg


testing, testing

all tests done at cranking speed.

first, i determined and marked actual physical tdc.

led-as-timing-light is powered directly by the coils (with resistors as needed to drop voltage).

shows the signal peaks.

pulser coil

grn+
tw_grplus_wneg+web.JPG

w+
tw_wplus_grneg_web.JPG

there is also wasted spark trigger occurring directly opposite, but the led is not pointed there so not visable.

(continued in next posts, only 5x images allowed per post...)
 

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Discussion Starter #2 (Edited)
continued

these are the source coil outputs, timewise. (peaks)

brn+
tw_brnplus_grndneg_web.JPG

brn - 3172
tw_brnneg_grndplus_web.JPG

(red is very similar, as is brn to red. see waveforms)


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waveforms:

these pulser/stator signals are recorded as audio then "looked at" in audio mix program (details at end).

voltage levels are not to scale, ie the pulser puts out ~5v peak, and the red wire is ~100v+ peak.
the signal strength levels have each been adjusted while recording so they "fit".
time (ie peak to peak, zero to zero, etc should not change).

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for a tdc reference signal, i hooked up a mechanical wiper switch contacting at tdc,
electrically isolated from the bike,
switching a 1.5v bat to the audio.

ref wiper bench
tw_ref_wiper1_web.jpg
the the two wires at the left are bridged by the contact point at the right when it comes around on the guitar, er, camsprocket.

ref wiper installed
tw_ref_wiper2_web.jpg
the reference switch contacting (in this case, switching 12v to directly power the led) (w/450ohm inline).
at cranking speed, ~350rpm, so that's ~10x individual contacts/light pulses we're seeing! pretty consistent.
the image would be a little sharper but the camera lens is focussed past the switch.

ref check @start
tw_tdc_reftest1_web.JPG
rechecked at end of session, had not strayed.
(switching 12v to power the led).


(continued next post)
 

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Discussion Starter #3 (Edited)
continued

these may not be the actual polarity of any or all of the waves- if we figure out it's a different configuration i can generate new views.

tw_statortest2.1_wideall_web.jpg

tw_statortest2.1_wavetiming1_web.jpg

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for a cdi looking for a falling-plus-at-zero, or a rising-minus-at-zero trigger, the tw pulser will serve up either ~63 deg btdc or ~2 deg btdc.

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analysis/ thinking out loud

we don't know what the stock tw cdi was looking for polarity-wise for signal or power.

focussing on the source coil-

keeping in mind that "ground" is not really ground, it's just a big wire with lots of different ac and dc electrical potentials with different polarizations passing thru it concurrently and, mostly, independently..

12vdc; unregulated/unrectified 15-18vac, 30,000vdc (spark "return" to coil), at least 30vac (brn "return"), and at least 150vac (red "return").
_that's why the little but important 5vac pulsar signal is not referenced to ground, it has a wire on each end going right into the cdi.

in terms of talking about polarity, ground/frame and the ac output of the source coil, the frame of course would have alternating polarity.
however, the peaks would occur at different times as the load "sees it" depending on how it is hooked to the coil output.

the cdi would probably be looking for certain polarity or particular chunk of the wave at certain times; getting a blast/peak of source juice _just before or during spark output to optimize the cap discharge is the one i've seen mentioned a fair bit, makes sense.

because electricity flows from neg to pos, spark plugs apparently fire better if the tip is neg; the energy bottlenecks there in a focussed jumping-off point.
not sure how much that is practised, but i am thinking that the tw cdi may treat the frame as plus, and harvest (only?) the neg half of the stator wave from the brown and/or red wire to charge the cap. or not.

the cdi may draw (ac) power from the both ground to brown, and ground to red. maybe as low and high speed, maybe also using brown for some sort of timing advance reference, maybe..

or, perhaps the cdi's main power draw is from between brown and red, as a form of isolation, and the windings between brown and ground just drains off interference or such? are they "floating" the whole cdi power supply except for that winding/shunt to ground?

interestingly, the factory manual only says to test brn to red, it is not concerned with ground...

the newer tw's have an extra wire from the source coils, i wonder if it is an independent "ground"/common back to the cdi?

some discussion of tw waveforms here.
Another CDI question... - Yamaha TW200 Trailway Discussion Forum

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because i had recorded the source coil signals via a transformer, i couldn't be sure or the "polarity" of those signals.
that's where the led timing marks off of the brown wire come in - the polarity of the diode is a known; one can see, timewise, where those peaks happen, and cross reference that back to the waveforms.

(the led (light emitting diode) blocks current flow in one direction, and makes light when it lets it flow thru in the other direction. that's it's polarity. essentially one is seeing half the ac signal: above or below zero). if one hooked up another led (oowh, a different colour..) oposite to led #1, one would see both neg an positive spikes at once on the camsprocket.


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how these tests were done.

i cleaned the surface around the cam hole and used water soluble kids glue-stick to attach a small piece of bond paper. then i found tdc with a wire in the plug hole and turning the crank with a socket wrench. made a mark. checked again. and again. and again. and again. good. and dead on at the crank T line. ok. lined up the paper degree-wheel cut-out with the tdc mark and glued it on.
here's a printable cam degree-wheel pdf. kinda hacky, i mistakenly deleted my first one.
tw_cam_degreewheelv1.0_web.jpg

the cam wheel timing marks were lit by a ~4.5v led hooked directly to the green and white pulser outputs; or brown to ground(frame) for the stator test (with 500ohms added inline to protect the led).

time exposures of 3-10 seconds while cranking. tired starter, no plug.

the waveform signals were recorded onto a computer as several .wave files, via a small audio mixing board for level control and isolation. i used extra inline resistance (up to 200kohm as needed), and also used a small transformer from a 6v "brick" power supply (which gave 7.7vac from 115vac house power for example) to further isolate and drop the outputs from the brown and red stator leads.

audio equipment is looking for levels that are nominally ~.5vac mic level and 1.5vac line/headphone level.

the mechanical tdc switch was hooked up to a 1.5v battery and into one of the mixboard channels. it shows as a 1-2deg spike (or dip), depending on polarity. a lot of filing and fiddling to get it thin and narrow and accurate. pretty happy with the result, but "if i had to do it again" i would probably go for something bumping a microswitch, or ign points or such.

i only have one mono channel into my computer, so i mixed signal (ie pulser) and the reference pulse into mono, and recorded that.
the next signal i again mixed in with the reference pulse to mono and recorded that.

then i imported the audio files into an audio edit program, lined up the reference marks, and looked at the waveforms.
then i did screengrabs and added notation in "photoshop".

i arrived at the waveform btdc values by measuring 360 deg worth of pixels, then the other points, then doing the math.
they matched pretty good with the cam timing marks.

this whole timing thing has maybe a plus/minus 2deg overall accuracy, which, if true, is not too shabby for a bubble gum-pantyhose-and solder type job.

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that's what i got so far. thoughts?

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Thank you,slowmod. I'm trying to understand all of this,with the intent to make some sort of successful substitution using another system(or parts of) to provide my TW with just a functioning ignition system. As you mentioned ,there have been(allegedly) successful substitutions ,but either the author failed to properly explain the procedure in enough detail,or the components used weren't sufficiently identified as to allow anyone else to know exactly what to source......yes,it(may) have worked for them,but replicating the substitution is still difficult because of that lacking details.....
 

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this has to be the most 'technical' post I've seen….i think it will take a few reads to take it all in..certainly more than a browse i just did…good info
 

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Slowmod - let's try to find info on the other years cdis we go through this process.

Mine is an '87. I bought the bike recently not knowing TWs and thought it was a carb problem. Did the "The '87 Dance" as lizrdbrth calls it. Timing light showed a bad cdi, tried to solder any cold joints with no success. Need to find an inexpensive solution as you mentioned above.

Thanks for your work so far.
 

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Discussion Starter #7 (Edited)
Slowmod - let's try to find info on the other years cdis we go through this process.

Mine is an '87. .
that's perfect! you can check yours and then we'll know for the '87's! :)

the led timing tests are really easy, you don't need to photograph (though that's not hard either).
for either eyeballing or photos, you'll want a somewhat dark space, it's not bright like a full up timing light.

any electronics type places can sell you led's and resistors, or you can find a cheapy led flashlight that takes 3x1.5v batteries (=4.5v), bypass any logic switch (one push on/bright, two push dim, etc), note the polarity the bulbs are getting from the batteries, and there's your tester for the pulser.

adding 400-500 ohms resistance should let you test the cdi source coil output timing (lowvolt/brown wire, if there is one) as well, and also the resistors let you hook the led directly to 12v should you like.
i am not sure of the wiring config on the '87, so meter it first. worst that will happen is the led stops working. don't lick the stator output wires while cranking.

i seem to recall the 87 pulser wires are also green, and white. i think all the tw's are.

if the pulsar timing is the same across the years, then we know that a 12v cdi, anyways, which works on one tw would work on all tw's.

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Discussion Starter #8 (Edited)
here's a new "view" of the waveforms.

tw_cdi_stators_v2.21.jpg

in thinking about this some more, i realized that the tw source coil is grounded at one end, so thus it can only "present" to a cdi in that polarity, or phase i guess in ac terms. the new view reflects this.

the fact that the tw pulser is not referenced to ground is good, it runs a cleaner signal, and polarity and thus trigger point can be swapped. many of the newer/cheaper bikes and cdi's seem to tag one end of the pulser to ground to save on a wire, and the cdi's have only one terminal for the pulser. with the tw pulser, one can choose which end of the pulser to tie to ground.

timing of the source coils may not be important. the cdi may just store up what it needs powerwise whenever, it's getting 2x pulses per spark.

question: how do "they" get twice as many pulses out of the source as the pulser? both coils look to be sitting similarily next to 4 spinning magnets.

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I was recently given a pile of TW because the previous owner just gave up on it. I reassembled the bike, rebuilt the carb, cleaned the tank, changed oil, and finally got the bike to fire. Barely. After following a bunch of threads on the subject, testing the pulse and source coils, testing all safety switches, I was fairly certain it was a CDI issue. In fact, after knocking the CDI around a bit, the bike actually ran well enough to zip it around the block a few times. But after the bike cooled down, it went back to its old ways. In desperation, I poured over the schematics for the 87 and subsequent models to see why the 87 CDI system is fabled to be so different from its later iterations. The biggest difference I noticed was that the later pulse coil white wire was bonded to chassis ground somewhere in the harness, whereas the 87 remained isolated. This means that universal AC cdi boxes that require a single-wire pulse signal seemed to be out of the question. With nothing left to lose, and a cheap $10 universal CDI in hand, I bonded the white wire to ground and was able to measure voltage between the green pulse coil wire and chassis ground while cranking. I wired in the universal CDI and the bike fired up and I was able to rev it through the entire RPM range with no stumbles or hesitation. I have been starting the bike and taking quick rides around the block for the past two days. It fires quickly and idles perfect every time (87-90 degrees F ambient temp). With only one previous ride on an "OK at the time" CDI to compare it to, the bike seems to run about the same. Perhaps I got lucky. Perhaps this may be a viable stop gap for those who want to keep riding while they save up for a pricey OEM unit. For sure it was a good option for someone who got a non running TW for free and had nothing to lose by trying it. It does come with concerns though:
1) Non model specific timing curve. These cheap units are clones sold to fit anything from 50-250cc Chinese knock-off ATVs scooters and motorcycles. This may mean a loss of performance or perhaps even too much timing resulting in spark knock or predetonation (I have not noticed any spark knock or detonation and I don't have much of a comparison point performance-wise).
2) Possible damage to pulse coil. I am no electrical engineer, so I have no idea what the long term ramifications of bonding the neutral(?) side of the pulse coil to chassis ground are. From what I can tell from schematics, the 88+ systems came like this from the factory with no ill effects. Only time will tell.
3) Component longevity. Who knows how long this CDI will last, but at $10 shipped to your door, keeping a spare around isn't gonna break the bank.
 

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To build on my previous post, and to add to the discussion regarding CDI substitutions:

IMG_0227.JPG

What I used is GY6 CDI clone sold online as a "New Racing CDI". It is the AC version and for some reason it fit snugly in the TWs factory CDI holder. As you can see I used Weatherpack connectors to make a Yamaha to Weatherpack adapter harness in hopes that I could make a quick swappable CDI harness so I can Weatherpack and easily swap in and test other CDI units without having to damage my TWs harness. I can post a wiring diagram upon request if anyone wants to try this setup on their 87. I am timid about doing so without a direct request because as previously stated, I am still beta testing this setup myself. I don't want to be responsible if this ends up negatively affecting anyone's rig. If anyone else is willing to beta test as well and accept all liability, I have no qualms about detailing exactly how I went about swapping in this CDI (it's really straight forward, actually) I just don't want to offer this up as a magic bullet for the 87 just yet (as far as I've researched, no one else has documented a GY6 clone swap on an 87, could be wrong though).
 

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Discussion Starter #12 (Edited)
To build on my previous post, and to add to the discussion regarding CDI substitutions:


What I used is GY6 CDI clone sold online as a "New Racing CDI". It is the AC version and for some reason it fit snugly in the TWs factory CDI holder. As you can see I used Weatherpack connectors to make a Yamaha to Weatherpack adapter harness in hopes that I could make a quick swappable CDI harness so I can Weatherpack and easily swap in and test other CDI units without having to damage my TWs harness. I can post a wiring diagram upon request if anyone wants to try this setup on their 87. I am timid about doing so without a direct request because as previously stated, I am still beta testing this setup myself. I don't want to be responsible if this ends up negatively affecting anyone's rig. If anyone else is willing to beta test as well and accept all liability, I have no qualms about detailing exactly how I went about swapping in this CDI (it's really straight forward, actually) I just don't want to offer this up as a magic bullet for the 87 just yet (as far as I've researched, no one else has documented a GY6 clone swap on an 87, could be wrong though).
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now we're getting somewhere. a confirmed sighting ! woo-hoo! i suspect there have been many swaps to cy6 cdi's if they work, and you are saying it does. it is such a comman engine people would try the swap. there is a ton of aftermarket cdi's for the cy6's, in different casings and different timing curves, or at least some without rev limiters, which is not an issue the tw anyway.

i still have not heard back from buggymart, so maybe i will go ahead an get a cy6 cdi anyway.

PB, can you be persuaded to do that led pulser timing test mentioned upthread? that would be great, even just a visual, it would cross reference a working cy6-on-a-87 forward to other years.

in regards the pulser grounding, my '90 is not bonded to the frame, both green and white wires are only hooked to each end of the pulser coil. the main manual clearly shows that as well. i looked at the 2007 suplement and can't tell as they only show a wiring not circut diagram - the wires just enter a box.

a unbonded pulser can be grounded to frame at either end no problem. i suppose if a crappy cdi breaks down it might bleed some hv source juice into the pulser, but really i doubt it. the bigger possible issue with substitution is if the new cdi draws too much (presents not enough resistance) from the coils, but again that's probably unlikely as the newer cdi's may just generally use less power and be "in range" anyway. a resistor could be added inline to limit the current flow somewhat but still let enough through so the cdi functions. i don't have values for ya.

in regards timing issues, it seems to be somewhat more critical than i thought, there are good threads on here about that by people more knowledgable than myself. it ties into carberation/airbox/exhaust/altitute. once you are more operational i think you can monitor engine health somewhat by pulling and looking at your spark plug.

anyway, thanks for the info. you got a part # for that cdi?

i'd be interested in seeing your wiring diagram. just right "beta" across it. i think that's pretty well assumed on here anyway or should be!

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Slowmod, thanks for your thoughts on the matter. You are certainly right about the abundance of GY6 gear available. I, myself, would have thought that there would be plenty of write-ups regarding the GY6 CDI swap. It HAS to have been done before, but I have not stumbled across it documented in my many hasty and frustrated Google searches. As far as my assumption on the white side of the pulse coil being bonded to ground, I pulled a diagram from another thread on this site while working on the bike in the woods with one bar of 3G coverage. Here is a link to that thread and a repost of the image pgilles originally provided to the OP.

http://tw200forum.com/forum/technical-help/3444-no-spark.html

TW200 Wiring Diagram with Labels.jpg

worksite.jpg
This was my CDI swap station.

I will attempt the LED timing light test this weekend. Any info I can add to this discussion will just be paying forward for all the info I have been able to gather from the site as a lurker. I will post up a diagram this afternoon when I get home from work. In regards to the part number, I don't think there was one, but I'll check. It is one of the blue anodized boxes with a sticker that says "New Racing CDI" available on auction sites when searching AC GY6 CDI.
 

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Discussion Starter #14 (Edited)
hey PB that's a hardcore workstation, at least i am inside with a bench. looks like nice country tho (anything with trees!).

i hear you on paying it forward/returning the favour, i also have gotten tons of help and info off this forum, and others when i was rebuilding my truck. plus it's fun.

that wiring diagram is off a newer bike, '97 or '07 forward, i'm a little unclear on the exact wiring/year changes. anyway you can tell by the yellow wire and the 3phase 12v stators.

regarding the pulser grounding, the diagram you posted indicates that the white is bonded _inside the original cdi, so the pulser polarity _could be easily flipped if needed (unlike if it was bonded inside the sidecover, ie the red wire/source coil in that diagram and generally).

your new cdi probably only has one wire in for pulser so you would have to ground the other end anyway?

white=ground, and green =plus should be giving the pretty blue cdi a trigger point of around 2-0 deg btdc, and an led flash of ~6deg btdc.

so it appears that the cy6 looks for a trigger around there. but it could be easily 5-10 deg "off" , and start/run ok in nice warm weather, so it's still important to figure out the base timing for the cy6. if anyone has a cy6 to test....

if you are also able to do a spark timing test at the cam pulley hole, we'll know how much that cdi advances from trigger at different rpm's.

at crank/idle it should be, i have heard, 10 deg btc, although the "fire" marks on the flywheel are 5-8 deg btc i think.

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UPDATE ON THE GY6 "New Racing CDI":

After hooking up a digital timing light, it appears that at idle, the unit runs base timing at around 15 degrees BTDC. The main agenda of today was to try to see what, if any, advance curve the cheap CDI has. Survey says? ...................... NONE. I had my wife rev the bike up while I watched the timing marks with my light and the timing never advanced past 15 degrees. I was afraid of that. My friend rode it and said that the bike felt a bit "flat" to him, even being a 200cc. Having no advance curve would explain that. I had read that some of the cheap CDI boxes had no timing advance, even when advertised as having one. So, although the bike starts great, idles great, and gets me around, I am not getting the most out of the bike. I can say that the blue anodized "New Racing CDI" is probably off the table. I will search more reputable stateside vendors who may have a "higher-end" $25-$50 CDI that they can verify has an actual timing advance.

edit: found this online at buggypartsnw.com
"The stock spark timing on most GY6 125cc and 150cc vehicles is ~12° before TDC. This CDI advances the base timign to 15° before TDC and allows you to adjust the timing between 15° and 20° before TDC. Simply turn the dial on the face of the CDI to make the adjustments."

It appears that the GY6 runs base at 12 degrees and the "racing cdi's" bump it to 15. This site sells an adjustable unit that bumps to 20 degrees at 3000+RPM, but that is still ~10 degrees shy of what we need to see at full timing advance.
 

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Discussion Starter #16 (Edited)
nice.

so, no built in advance on the stock cy6. a friend of mine had suspected that.
still, it runs not bad, a great back-up cdi to have in one's kit, to get out of the woods with if nothing else.

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apparently tho, there are other cy6 units that do advance -though perhaps more than we want - the buggymart tech emailed me this a couple weeks ago in regards to their cdi's: (i emailed again today but haven't heard back).

CDI Power:
Minimum 16vAC for stable spark. Typical 80v - 140vAC.
I don't know of an upper limit to the power voltage for the CDI, but I assume it is more than 250v.

Timing
I haven't had the opportunity to bench test the CDI timing myself. But according to a GY6 community veteran the AC CDI has 22 degrees advance at 1500 to 2300 rpm. Then it advances rapidly until 52 degrees at 3200 rpm. There is no rev limiter - our 150cc engines routinely see 10k - 11k RPM.

If the GY6 CDI isn't directly compatible, we have access to a number of CDIs for other models that can potentially be used. We also have the 12v DC version of this CDI, trigger specs are the same but I'm unsure of the timing characteristics.


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apparently delayed timing can cause partial, and late, ignition, resulting in less power but also burnt valves and detonation in the exhaust system.
the higher the revs/ the more fuel being delivered at those higher revs, the more this would be an issue i would think.

the fixed 15 deg might be pretty close to stock tw spark timing at around 2000rpm?


tw_duraspark_web.JPG
i hooked up a duraspark cdi out of an early '80's ford ranger to my tw. it had no advance (the stock application is all mech and vac advance). the bike would start with dificulty, and idle low, but would not spin any faster no way, as it was firing @ the pulser signal, on or real near tdc.

tw_timing_dura_web.JPG
i also tried a suzuki rm80 cdi i bought blind for $25, so who knows if it was good. but some of those rm80's and such apparently take their trigger off the source coil - and in this case that's how they were firing (4x). the 45/90 timing lines are kinda wonky, early version.

congratulations, pushingboulders, you have the first documented working substitute tw cdi swap! you win... a (sortof) working tw!

sortof...

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Slowmod, I actually read that thread about the Duraspark when the guy that gave me this TW was having problems. It was a cool idea. I have used duraspark in the past to rid older Ford small blocks of their points ignition systems. Cheap and easy. But, like you discovered, all timing advance is either vacuum or centrifugally accomplished within the dizzy. At this point, I am seriously debating just biting the bullet on a factory CDI unit. But for what it's worth, I still see the GY6 as a cheap, viable tool in diagnosing tricky CDI issues on our TWs. It is like having a "known-good" component you can swap in. Even if the timing curve doesn't move, at 15 degrees, the bike will fire. If nothing else, if you are riding an older TW with the original cdi, you could keep it in your kit as something that will get you off the trail if your CDI bites the dust. So that being said, here is how I hooked mine up.

twcdi.png
 

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Discussion Starter #20 (Edited)
slowmod and PB....are you my brother in disguise !....... LOL
hey, it's possible i suppose, my folks did a lot of traveling in the states, back in the day. half brothers anyway...

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emboldened by pushingboulder's success i've got a fixed-timing cdi on order, should get it by the end of the week. supposedly it cross-references to the tw to some degree. (not a timing joke).

it should get me going, but i can't see how fixed timing will be satisfactory for much time or distance.

tw_subarudizzy1_web.jpg
i pulled a dizzy from an early 90's subaru loyale, which interestingly has an optical sensor.

so the idea is to replace the tw cam-sprocket bolt with a longer bolt, w/nut-as-bolthead, cut off the real bolthead - there's the protruding shaft. flat plate with a shaft seal replaces the camsprocket-cover.

onto all that goes the optic sensor and a new one-hole disk onto the shaft. or points, or a mag/pickup...

at the very least i can adjust the fixed timing (on the go?) and eventually add in a centrifical advance on the disc. the optic interests me because it's so lightweight. needs power (5v? 12v?). could easily switch back to stock pulser for dead battery situations.

the deluxe version, i'm sure, will have integrated full-time led timing lights firing on the sprocket, visible thru the clear viewing panel. by 2018 for sure.

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