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'87 CDI Repair

24K views 39 replies 23 participants last post by  admiral 
#1 · (Edited)
Long story really short, did "EVERYTHING" to include putting the cdi in the freezer(which helped).
Cut cdi case in half with a hack saw and pealed the potting compound off the circuit board.
Using a magnifying glass I found 4 bad solder joints and 7 more needing touched up inside the cdi.
Lets see if i make it home from work today.

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I can explain more later. If anyone is interested.

Here is my full story.

Three years ago my TW200 started to spit and sputter at any throttle position above idle. I got frustrated to the point where I parked it and let life with 4 kids and a wife take over.

I decided that I would spend my birthday this year getting the beast back on the road. For the past three weeks I have been tinkering with it and learning a few things along the way about TWs. I started by doing a few things to it before I tried cranking her over.
Cleaned tank
Cleaned Carb and replaced float needle valve
Cleaned black soot off spark plug DR8ES
Cleaned and oil air filter
Change oil
Replaced battery
Washed it
Change air in the tires

The little beast fired right up and I was able to ride it around the neighborhood. I was happy for the moment. I noticed that at around 50 mph there was a pulsation and only got worse if I tried to go any faster. I wasn’t too worried about it and I figured it would get me to work Monday morning. WRONG!
Started it in the morning and let it idle for 3-5 minutes, jumped on and bumped the throttle and she fell flat on her face, spitting and sputtering with any throttle input. &$#%@$(@)^#!. Parked it and drove the truck to work. When I go home after work I jumped on the bike and it fired right up with no issues other than the 50 mph mentioned earlier. I rode it around like this for about a week tinkering with different spark plug heat ranges and gaps, timing light on plug wire checking firing consistency.

With no issues raising their ugly head I attempted to ride it to work once again. Started her up, let it warm up, jumped on and took off from the driveway, when I was 100 yards from home, !*&^^%#%!($^@!#. Back home it goes. Let the real troubleshooting begin.

These are the things that I checked or double checked.
Cleaned Carb bowl, nothing found
Main jet 114, No shims under needle, Idle/Air 2 ¼, should be lean
Float level, 1/16 below bowl rim
Spark plug (still black soot) replaced with new D7ES
Inspected all ignition electrical connections, no issues found
Removed air filter element (to see if this clears running rich)
Put CDI in freezer for 2 hours, then reinstalled
Started the bike (no choke still)
Throttle response is good

Test ride = Hold on to the bars! Noticeable more power and goes 65 mph before she starts to flutter, but now has a small midrange surge (lean condition?).

One more time to try and let this thing get me to work. Started in the morning, great throttle response, jumped on and away I went. It felt good to finally be riding it in the morning commute, up until I was 300 yards from my work place. ^$@&(*)($^@). It would not do anything but idle AGAIN!

I proceed to remove the CDI and determined to fix this problem.

I took a hacksaw and cut, just barely, though the plastic case around the outside edge centered between the top and bottom.
Using a Leatherman and an Exacto Knife I was able to cut the potting compound and pry the lower side of the case off. This was very simple and the only fear I had was pushing the Leatherman knife blade down the sides of the lower half. The case half came off with a little prying but not much, a lot of the potting compound with the case half. I then inspected the back of the circuit board and bingo. I soldered up the cold joints, used silicone and a little duct tape to seal things up and hold it together and off to the races (Home that is) I went. Still no air filter installed.

I would highly recommend performing surgery on your CDI, especially if you intend on buying a new one anyway. On a scale of 1-10 this was an easy 4.

The bike ran great all the way up to 65 mph before it started to flutter a little bit. When I got home I checked the spark plug and it was no longer black and sooty but rather a nice tan color. I put the filter back in and waited till the next morning to go to work. It ran great until 50 mph where it started surging. I pulled over removed the air filter and she came alive again, 65+ mph with a slight midrange surge.

I got the CDI fixed and now I need help with my air filter issue.

I believe that I am jetted as lean as it can go, but runs rich if I install the foam element. The element has be washed/oiled, then washed and even run in the bike dry with the same results. There are no blockages in the intake ducting. I am able to breathe though the foam element, so it seems clear.

****************************************************************************************************************

Well, The CDI lasted for two tanks of gas and then started flaking out again. I took it back apart to find that the silicone that I had used really tarnished all of the solder joints that it came in contact with. There were also more bad solder joints on the small circuit board on the opposite side of the CDI. this time I am not going to seal it up with silicone but just duct tape it together in case I have to rip it apart again.

I am temped to get one of those $16, 12 volt CDIs of of ebay and see if it works at all and have it for an emergency backup.

It is running very good now, but I suspect it is still rich, as it starts right up with no choke. i am going to run it another tank and then check the spark plug.
I am crossing my fingers but this time feels right to me.
 
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#3 ·
1987 tw

Electrical wiring Wire Auto part Electrical supply Bumper
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Wow, good job! I half heartedly tried to milk a few more miles out of my old one this year by putting some force on the harness with duct tape and zip ties. It didn't work. Ended up popping for a new one. My old 87 is back on the road and trails with a new CDI. There are some good threads about aftermarket DC CDI's, wish I knew more about them.
 
#4 ·
Interesting. Let us know if it works. I have a buddy who does a lot of circuit board repair on automotive items that dealerships will tell you are unrepairable. He does it on the side out of his home. He may be a option for somebody without the capability to do this themselves. PM me if you have a non-functioning cdi you would like to have looked at. I could put you in touch.
 
#5 ·
The CDI is working good. That was quite an easy fix. Wish I would have done it along time ago. It was easier and quicker than rebuilding the carb.
But I am still running rich. I just drilled about 16, 1/2" holes in the breather box which help a little. New foam filter is on order.
 
#6 ·
Great job on the CDI. It certainly sounds like you've covered the bases. You didn't mention doing the valves, but I don't think that's the problem here. It sounds to me that you've eliminated too little air as the problem. It has to be too much fuel. Any chance the hole in the jet got enlarged while cleaning? It's been done before, and not that hard to do. You might try a new stock size jet. That's worked for a few others. It's also possible you could still be having a timing issue with the CDI. Stick with it and you'll get it figured out. Let us know what you find out.
 
#7 ·
Thank you very much for sharing your experience. Things like this really help and save $$$$$.

As B-Dub stated, a new stock jet can work wonders. I replaced my #114 jet with a new one and my overly rich running condition went away. The hole in the center corrodes and though it looks normal it is to big and runs rich.
 
#8 ·
i'm about to put mine under the knife in the next few minutes. spent the last 3 days trying to get my bike running again after a couple years. went thru everything else, had to be the cdi. did the freezer trick and the bike purred. nice sound.

i've fixed an intermitttant wiper module with cold solder joints. nice to find this thread with someone who actually did this module and it worked! i'll be looking into an aftermarket cdi as backup, or firstup depending on how tonight goes.
 
#9 · (Edited)
well, i did not find any bad solder joints, they all looked top notch, which is reassuring,

but... 4 x transistors got ripped from the boards when pealing off the very aggressive anti-vibe rubber layer they are overlaid with.

so, it's decisive, anyway. i guess i am about to enter the wonderfull world of aftermarket cdi units, and compatability theroff. i will price a new stock unit but i am assuming they are dear.

i guess the trick with aftermarket compatability is
a) it's a non-12v system (one could use a 12v and just use the hall sender for the trigger, but naw..), and thus
b) finding a unit that will work off the charge coil plus the hall sender.

i found the cdi case disassembly hard; the case is tapered so it doesn't hold in the vice well, and the plastics were bonded really strong. it was difficult not to apply force in the wrong place when bracing against cuts and prys, especially once one side was exposed. i used a hacksaw, boxcutter, vice, and a thin pry bar. i would avise to cut the hard plastic shell into many sections first, then start peeling. on mine, as soon as one cut past the shell the rubber gave blue chips.

my bike is a '90.

maybe if i had boiled it in gasoline it would have dissolved the rubber and left the electronics intact....

here is a photo of a couple of the transistor pulls.

Electronics Electronic component Electronic engineering Technology Circuit component


both the transistors were embedded flush into the rubber at left. i just pried one out.

the symptoms of the cdi being bad were very carburator-ish. wouldn't take the throttle, surging, backfiring ("lean condition"), start then peter out (fuel supply, vacume issues..), idle barely but with a weird putputput. needed lots of choke.

some usefull outcomes of this is that i understand the carb and wiring way better now!, i found and fixed the leaking carb-engine flange.

also, i installed little disconnects on the blue/yellow and blue wires at the cdi connector.
now, when troubleshooting, disconnect both, and the blk/w connector.
connect the blue/yellow to ground (i dropped a connector nearby) and the ignition is "on" and totally stand-alone.

to stop the engine you have to stall or starve or choke it, (or, with one hand, reconnect the blk/w so the kill switch works, while holding the vibrating bike upright). so best to leave that one hooked up maybe. but yeah, now it's easy to just drop out all that interlock shit to help isolate where an issue is.
 
#15 ·
I got one for my 91 from a Yamaha dealer.I had the same problems and took the carb apart at least 4 times before finding if I smacked the CDI it would suddenly run fine for a while.The new one was well over $300 but now I don't ride in fear that it's going to leave me stranded.
 
#19 ·
so just installed the new cdi and cant seem to get engine to turn over. carb is fully cleaned, even went back to the old cdi, trying to get this thing started and go back to new cdi. i see spark when i hold the plug next to block, is it maybe the voltage is too low open to any ideas? thx working thru maintenance manual on ignition
 
#21 ·
thx will give a a try tomorrow when its light out. also per the manual i cant get a spark to jump the quarter inch to block. if i hold it almost directly on no issue a quarter inch away (.24) no joy. frustrating since i'm pretty sure my rough running was the cdi.
 
#22 ·
yes, what elime said. prime it.

sparkwise, i suggest wrapping a wire around the removed spark plug, then vice-grip the wire to a good ground.
this is a good way to observe the "actual" spark. 1/4" inch of spark shouldn't be nessessary.

i have a theory that the aftermarket cdi's may not "power up" as quickly as the oem cdi's. i think that's what the extra (brown) power wire is about, that stator is designed to generate power at low rpm. so the aftermarket units may need a few revolutions before they are charged up.

*note* the pulser/pickup wires must not be reversed. green goes to the cdi, white gets grounded (many aftermarket cdi's have "one wire" pickup inputs)
if they are reversed it fires at the entirely wrong time. so ya would see spark, but ...

anyway, if you are seeing spark you're close.
 
#23 ·
Elime and Slowmod you guy were dead on thx! primed it a couple of times (probably too little gas the first time or two) started weak then finally started pumping on its own. Was able to head out for a ride with the new cdi. no hiccups so hope this solves the problem. Set just a little low on idle but losing daylight so that will wait til next weekend. thx so much... as always folks here on the forum came thru.
 
#24 ·
87 CDI issues

First of all, I am a newbie. I have an '87, serial number 3255. I bought it from my uncle, he lives in Bullhead City Az. He had replaced all the cables, battery, chain, sprockets, tires, installed DG exhaust, petcock and internal filter, cleaned tank, re-built carb, replaced plug, replaced missing headlight parts and repainted the bike. He is very talented and 77 years old. He mentioned selling it and I jumped on the chance, I have been wanting one for years. I live in Shreveport Louisiana. I went to pick it up about three weeks ago.

The bike looked great, it was as nice as he said it was. It had 5200 miles on it. He had not cranked it for at least three months. We checked the gas and it smelled OK. We cranked on it to no avail. We pulled the plug and gave it a shot of either. When I hit the starter, she cranked instantly. At this time he told me it was very cold natured and he had taken it to the local bike shop to have it checked out. The mechanic had played with the carb and jetting. He told Unk to let it warm up for at least 5 min. before trying to give it any throttle. It warmed up, and I gave it a spin around the block. It sputtered, back fired, puked and struggled, but managed to run on. I figured it was just bad gas. i loaded her up and went to meet my friends for a desert ride on my new TW. We never made it there. When I unloaded it from the rack it ran horrible. My friend is a mechanic, he works on Jet skis and motorcycles for two of the rental places in town. He said lets pull the carb and make sure all is clean and good. We pulled the carb and he tore into it. I drained the gas from both tanks and replaced it. Everything looked good inside the carb, he went through everything. When we cranked it, it ran perfect. After letting it warm up I ran the piss out of it in the neighborhood. It ran great.

The next morning it didn't want to start and when it did finally it ran like crap. I took my Rhino out and left the TW. When we got back it was dark. That is when I found this forum. I must have read every page. There was so much great info I had to soak it up. The next morning we checked every wire, every connection, the kill switch, everything looked good. I poured the seafoam in it and we went out to run the crap out of it. For the most part it cleaned up and ran good for the first 8 miles. Then it started missing and lost all power. I coasted to a stop after it died. When I hit the starter it fired right up and we were off again. To make a long story short, it did this every 20 min. or so. On the way back I had to coast down the hill for a couple of miles, it would only idle. I turned it off, turned it back on, hit the starter, she cranked up and ran perfect for the last 10 miles to the trailer. We knew at this point it wasn't the carb. We tore into it the next day, trying to make the CDI misfire. The bike was running perfect but when Jimbo started tweaking the wires on the CDI it would stumble, and miss. It wasn't one wire that made it miss there was no rhyme or reason. Wiggle this one, it would miss, wiggle that one it would miss and it got worse. It finally quit running at all.

A push had come to a shove. I was leaving the next day to return home. We decided to do the DR. RADBUGGY surgery to the CDI. We cut the top of the plastic container off and spent the next hour or so digging out the potting material to look for bad spots. We didn't have to dig it out completely. We found a wire that felt weird so we tweaked it, pulled on it, jacked with it and decided to try it. We plugged that sucker in and it ran good. We taped the cover on it and loaded it on the trailer. I stopped in Seligman Az. for a few days.
the elevation there is 5800'. The little TW ran fine but it would miss a little here and there and really didn't have much power. I rode it for 75 miles or so, its a fun little bike. When i got home I ordered a new CDI. The day it came in I warmed up the bike and drove it around for a while just to set a baseline. I changed the CDI. It cranked instantly. When I started out it felt as if I was on a different bike. I was amazed. Problem solved. I rode it today on the freeway. She ran steady at 65 to 70 for 15 miles or so. Again I was amazed. These are the little bikes that could.

I really enjoy the forum. You guys are amazing. Thank you all for helping me. I really enjoy the forum.
 
#25 ·
First of all, I am a newbie. I have an '87, serial number 3255. I bought it from my uncle, he lives in Bullhead City Az. He had replaced all the cables, battery, chain, sprockets, tires, installed DG exhaust, petcock and internal filter, cleaned tank, re-built carb, replaced plug, replaced missing headlight parts and repainted the bike. He is very talented and 77 years old. He mentioned selling it and I jumped on the chance, I have been wanting one for years. I live in Shreveport Louisiana. I went to pick it up about three weeks ago.

The bike looked great, it was as nice as he said it was. It had 5200 miles on it. He had not cranked it for at least three months. We checked the gas and it smelled OK. We cranked on it to no avail. We pulled the plug and gave it a shot of either. When I hit the starter, she cranked instantly. At this time he told me it was very cold natured and he had taken it to the local bike shop to have it checked out. The mechanic had played with the carb and jetting. He told Unk to let it warm up for at least 5 min. before trying to give it any throttle. It warmed up, and I gave it a spin around the block. It sputtered, back fired, puked and struggled, but managed to run on. I figured it was just bad gas. i loaded her up and went to meet my friends for a desert ride on my new TW. We never made it there. When I unloaded it from the rack it ran horrible. My friend is a mechanic, he works on Jet skis and motorcycles for two of the rental places in town. He said lets pull the carb and make sure all is clean and good. We pulled the carb and he tore into it. I drained the gas from both tanks and replaced it. Everything looked good inside the carb, he went through everything. When we cranked it, it ran perfect. After letting it warm up I ran the piss out of it in the neighborhood. It ran great.

The next morning it didn't want to start and when it did finally it ran like crap. I took my Rhino out and left the TW. When we got back it was dark. That is when I found this forum. I must have read every page. There was so much great info I had to soak it up. The next morning we checked every wire, every connection, the kill switch, everything looked good. I poured the seafoam in it and we went out to run the crap out of it. For the most part it cleaned up and ran good for the first 8 miles. Then it started missing and lost all power. I coasted to a stop after it died. When I hit the starter it fired right up and we were off again. To make a long story short, it did this every 20 min. or so. On the way back I had to coast down the hill for a couple of miles, it would only idle. I turned it off, turned it back on, hit the starter, she cranked up and ran perfect for the last 10 miles to the trailer. We knew at this point it wasn't the carb. We tore into it the next day, trying to make the CDI misfire. The bike was running perfect but when Jimbo started tweaking the wires on the CDI it would stumble, and miss. It wasn't one wire that made it miss there was no rhyme or reason. Wiggle this one, it would miss, wiggle that one it would miss and it got worse. It finally quit running at all.

A push had come to a shove. I was leaving the next day to return home. We decided to do the DR. RADBUGGY surgery to the CDI. We cut the top of the plastic container off and spent the next hour or so digging out the potting material to look for bad spots. We didn't have to dig it out completely. We found a wire that felt weird so we tweaked it, pulled on it, jacked with it and decided to try it. We plugged that sucker in and it ran good. We taped the cover on it and loaded it on the trailer. I stopped in Seligman Az. for a few days.
the elevation there is 5800'. The little TW ran fine but it would miss a little here and there and really didn't have much power. I rode it for 75 miles or so, its a fun little bike. When i got home I ordered a new CDI. The day it came in I warmed up the bike and drove it around for a while just to set a baseline. I changed the CDI. It cranked instantly. When I started out it felt as if I was on a different bike. I was amazed. Problem solved. I rode it today on the freeway. She ran steady at 65 to 70 for 15 miles or so. Again I was amazed. These are the little bikes that could.

I really enjoy the forum. You guys are amazing. Thank you all for helping me. I really enjoy the forum.
Welcome to the forum bro!! :D
 
#26 ·
Sounds like what I went through with mine but I kept pulling the carb hoping that was it.Every time I got it running really great I took it out only to have it leave me stuck.I left the rack in my truck and would only ride if my wife was home to come get me.A new CDI fixed it.
 
#27 ·
I better join the 87 CDI club. bike runs great after sitting in the cold all night, but I guess when the box heats up it starts backfiring. I've been selling crap on ebay to try and justify spending two hundred plus dollars.. Made 150 just this week selling ipods and scooter parts. Also am parting out a B15 Nissan Sentra if you guys need any parts....
 
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