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Discussion Starter #1
Hi All:



Myself and another engineer are working on reverse engineering CDI units for our BW200 and BW350

bikes. These have become almost impossible to find, people buy bikes just for the CDI, and when

available they are expensive $300-$500.



We see the TW200 1980s models have almost the same motor and CDI unit. I own a 2003 TW and

a buddy has an 87. As I understand it they change the CDI in 88 and then it remained the same

for a bunch of years.



What I am looking for is any dead TW200 CDIs that anyone may have and are willing to donate

to the project, I can pay for shipping to me as needed.



We are depotting a dead BW200, BW350 CDIs that we are getting from the yahoo Big Wheel group

I am in, similar to this group but on yahoo, check us out.

http://autos.groups.yahoo.com/group/YAMAHABIGWHEELS/



The plan is to redesign the CDI units to use more modern electronics, programmable

spark advance curves and add protection from failure. The old blown units give

us insight into what to protect in the new design and to see whats common among these

very similar bikes.



We have used our x-ray machine to look inside two of my working CDIs, here is an

link to some images, its pretty cool that we can look right through the metal case

on the CDI unit. My next task is to depot the dead ones that are on their way to

me and compare components.



https://picasaweb.google.com/82indypc/CDIProject



The objective is to make units available that are hard to get and expensive, so

we call all have a couple spares to test out when our bikes start acting up, and

replace them when they die.



It kills me to see bikes parted out on ebay just because the CDI died.



I appreciate any help anyone can offer. I will become more active in this

group once I get my TW out of storage and on the road and finish my BW200 restoration

project.





Cheers

Tim
 

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Remains to be seen if he's as operose as Operose..... iz.
 

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For his sake, let's hope not. My bike can't move under its own power (still? again? i don't even know anymore)



plus it is off of the ttr cdi and onto a "proper" setup from a 98 tw200 because i was lazy and let it all get chewed up inside the motor
 

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Discussion Starter #5
ummmmmmmmmmmmmm. WOW!




Check out a couple of my old threads on here, I guess


OK I am new to this site and dont know my way around yet. I take it there have been

discussion by your before on the TW CDI topic. If there is some question as to

my ID or intent you can check out my history on the BW site, there I am pungoclassic.
 

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.....Myself and another engineer are working on reverse engineering CDI units for our BW200 and BW350

bikes....


Isn't there an App for that?




Good Luck with your project. I know a lot of people need help with CDI issues. I'm sure you have a good market for a replacement CDI.
 

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No need to question your intent, we are all friends here. Besides, "I pity da fool" that thinks having busted CDI units shipped to him is a good or profitable scam




Just some guy on the internet that had cdi problems that one time.



You should really dig up the thread(s)
 

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Sure, BW. I have a partially de-potted CDI from a TW200, Jan '89, unless it is not original. Send an appropriate SASE envelope to:

DN

When you succeed, add a "Check Engine Light" dedicated to ignition.

My best, GB
 

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There's not a lot of active components in that! I was originally an EEE many years ago. I honestly don't think there's think that much difference between the AC CDI systems of older bikes - they have a charging coil and a firing coil. If you match the wires up correctly for the coils I suspect they will work on your BW200.
 

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Take a look at this. The best schematic (simplest) I've seen, I reckon that the Bosh coil with built in CDI would be an easy fix for your problems.



Once again - there's only two coils - the charging voltages are not overly critical and there are only 4 wires to sort out.



I'm an old schooler who rewired a PE175 CDI system back in the 80's in a country we couldn't get parts so I'm not talking out my ass.



Do you have a fluke scope meter?



 

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Discussion Starter #11
Sure, BW. I have a partially de-potted CDI from a TW200, Jan '89, unless it is not original.

When you succeed, add a "Check Engine Light" dedicated to ignition.

My best, GB


Thanks, how far along did you get taking it apart?



I spent about 6hrs yesterday de-potting our first BW200 CDI, man that silicone is rough

stuff, have to look into a dissolver for the next one.
 

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Discussion Starter #12
Take a look at this. The best schematic (simplest) I've seen, I reckon that the Bosh coil with built in CDI would be an easy fix for your problems.



Once again - there's only two coils - the charging voltages are not overly critical and there are only 4 wires to sort out.



I'm an old schooler who rewired a PE175 CDI system back in the 80's in a country we couldn't get parts so I'm not talking out my ass.



Do you have a fluke scope meter?





Yep, thats the basic circuit for one but there is more to it than that. Its mostly about the spark advance

curve and at what RPM to advance and how much. The is one IC in the one I x-rayed and depotted. We are

thinking to replace it with a PIC controller so we can program in the advance curve, and change is as desired.



Some CDIs have a stepped pulser magnet to get the timing for the spark advance, others dont and its

done in the electronics. Without the advance the motor will not have power as it goes up the RPM curve,

will also start braking up, its one of the signs of a dead CDI unit also.



Since they have been making the TW for so long perhaps there is not a CDI issue for your guys.



Parts available with no problem?



Perhaps they do not fail that often?



Hopefully they have become more reliable over the years and less need for replacement.
 

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I got into it enough to find no obvious fried spots and to know that it wasn't recreation. I think I was using naphtha as a solvent. Maybe acetone, but it was something I had on hand. I quit when I realized I would remove the lettering of the components if I wasn't careful. GB
 

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I've got two dead 1987 TW200 CDI units. I bought new ones at around $200 each. I'll happily donate them to research, shipping reimbursement appreciated. Both still ran the bike, but not well.



Operose, do you still have any interest in this? I could send one to each of you.



John
 

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Yep, thats the basic circuit for one but there is more to it than that. Its mostly about the spark advance

curve and at what RPM to advance and how much. The is one IC in the one I x-rayed and depotted. We are

thinking to replace it with a PIC controller so we can program in the advance curve, and change is as desired.



Some CDIs have a stepped pulser magnet to get the timing for the spark advance, others dont and its

done in the electronics. Without the advance the motor will not have power as it goes up the RPM curve,

will also start braking up, its one of the signs of a dead CDI unit also.



Since they have been making the TW for so long perhaps there is not a CDI issue for your guys.



Parts available with no problem?



Perhaps they do not fail that often?



Hopefully they have become more reliable over the years and less need for replacement.


I saw that IC and quickly googled it - it didn't come up (not good) but I suspect it's just packaged discreets like an SCR / Thyristor or something. I highly doubt that it is a uP or similar. As for the PIC that's a good idea - many years ago I was involved in a project to build a CDI for cars that ran on NG and we used an 8051 for the spark advance control. I'd almost prefer an analog computer (i.e. RC circuit) with a pot to adjust the advance tho. Less to go wrong.
 

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I've got two dead 1987 TW200 CDI units. I bought new ones at around $200 each. I'll happily donate them to research, shipping reimbursement appreciated. Both still ran the bike, but not well.



Operose, do you still have any interest in this? I could send one to each of you.



John


Another member shipped me a dead and partially de-potted 87 CDI already. Thanks though!
 

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Discussion Starter #17
I've got two dead 1987 TW200 CDI units. I bought new ones at around $200 each. I'll happily donate them to research, shipping reimbursement appreciated. Both still ran the bike, but not well.



Operose, do you still have any interest in this? I could send one to each of you.



Excellent, the more the better, trying to determine failure mode as well as understand the components in each.



After the 87 CDI Yamaha changed the part number in 88, it remained the same until 98.



Would like to get one of this vintage as well to see what they changed. I suspect they

just tweaked the hardware after model year introduction.



Please send to



Tim Spires

111 Brandywine Terr

Rochester, NY 14623



Parcel Post snail mail is find. email me your paypal account and the amount

for postage and I will pay your the shipping cost.



John
 

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Discussion Starter #18
I saw that IC and quickly googled it - it didn't come up (not good) but I suspect it's just packaged discreets like an SCR / Thyristor or something. I highly doubt that it is a uP or similar. As for the PIC that's a good idea - many years ago I was involved in a project to build a CDI for cars that ran on NG and we used an 8051 for the spark advance control. I'd almost prefer an analog computer (i.e. RC circuit) with a pot to adjust the advance tho. Less to go wrong.


The IC is a quad op-amp, all analog stuff. We are working on the input power section now, see how turn we need to

get enough power to start running. Not sure if its a 8051 we are planning on using, I have heard of that one

before, seems real popular and rock solid tool chain.
 

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There was some component ID already done in the cdi thread I started a while back, may help speed things along. Cannot get the link for you because I work primarily from my cellphone.



Also tons of compiled research from other forums members, past members, and myself. Truly a group effort and a wealth of knowledge, even if it is hardly organized and sort of incomplete...





Xray machines??? You gotta be kidding!



"Back in my day, we drank a case of beer and manually depotted with a knife and screwdriver to find out what was inside and it was uphill both ways!"
 

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Discussion Starter #20
I've got two dead 1987 TW200 CDI units. I bought new ones at around $200 each. I'll happily donate them to research, shipping reimbursement appreciated. Both still ran the bike, but not well.



Operose, do you still have any interest in this? I could send one to each of you.



John


Think I screws up the last reply to this post, still getting use to this forum UI. Anyway here was the reply

--

Excellent, the more the better, trying to determine failure mode as well as understand the components in each.



After the 87 CDI Yamaha changed the part number in 88, it remained the same until 98.



Would like to get one of this vintage as well to see what they changed. I suspect they

just tweaked the hardware after model year introduction.



Please send to



Tim Spires

111 Brandywine Terr

Rochester, NY 14623



Parcel Post snail mail is find. email me your paypal account and the amount

for postage and I will pay your the shipping cost.



Cheers

tjs
 
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