TW200 Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
77 Posts
Discussion Starter #1
I believe I've figured out my TW's problem, but I want to find out if it is something that has happened to other TW owners. I took my bike to the local, well-respected Yamaha mechanic and explained my situation (acts like its "missing" above 45mph, not much top end power, idles great and runs fine at lower speeds/rpms). I fired the bike up and it idles perfect, but as soon as I got to around 1/2 throttle it starts to cut out and run terrible. It only took him about 3 seconds to say "its your CDI". He said that normally a CDI will just go out completely, but that he's worked on several TW's with my same issue and it has been the CDI unit. He wasn't sure why, but apparently TW's can have the CDI go out partially.



So when I got home I started searching on this forum and the old one about CDI testing. I haven't done any of the testing yet, but will over the weekend. I just wanted to know if anyone on here has had the same issue and if it truly is possible for a TW to "partially" lose the CDI. If anyone also has a link to a thread that talks specifically about the testing procedure for the CDI that would be great. I am only able to find threads that give some information here and some there....not all in one thread.



Thanks.
 

·
Registered
Joined
·
60 Posts
The answer is YES. A couple years ago I had issues with my bike, idled fine but that was it. Give it throttle and the hesitation made it impossible to ride. CDI fixed it. Went camping a few weeks ago and took my buddies TW up with us, he had said it wasn't running too well - but I figured I would have plenty of "down" time to dial it in as it sounded like a fuel issue. Spent a great deal of time with the carb, it's nice and clean now - but still no joy. Swapping tanks did not help either. Started checking wiring and for some reason bumped the CDI ............... and the bike started running fine!!!!

This bike has an intermittent CDI. Rode around the remaining days of the trip, left the side cover off and the CDI hanging so I could tap it against the carrier when it started running bad again.

YES - I have proof positive that they can be intermittent. Never would have guessed and only accidentally stumbled on it! By the way - both bikes are '87's.
 

·
Registered
Joined
·
77 Posts
Discussion Starter #3
Thanks EaglesCall for the real-life experience. I've noticed that 87's seem to have CDI problems. Does that issue carry over to newer bikes? Mine is an '06 and I'm wondering if the CDI is basically the same throughout the years? I think the earlier CDI had spade connectors and the newer ones have a single plug, but other than that are there any real differences? I guess I'm wondering if a newer CDI can be intermittent? Thanks.
 

·
Registered
Joined
·
60 Posts
I can't speak to the newer ones, but by looking through the forums I would say all years have problems with the CDI at some point. The '87 is different as my buddy just picked up a couple off of eBay. One was supposed to be for an '87 and the other for an '88. Both of them have an extra yellow wire on them so I'm guessing neither of them are for an '87.
 

·
Registered
Joined
·
10 Posts
According to the local Yamaha dealer. The model TW200T/TC is a 1987 with a 9 wire CDI. The model TW200EU/EUC is a 1988 and newer 10 wire CDI. They changed the charging wiring. This is what they said, anyone with different info please let me know. Got my bike running this evening so I'm going to see if I need the yellow wire connection. Thanks, Al
 

·
Registered
Joined
·
10 Posts
According to the local Yamaha dealer. The model TW200T/TC is a 1987 with a 9 wire CDI. The model TW200EU/EUC is a 1988 and newer 10 wire CDI. They changed the charging wiring. This is what they said, anyone with different info please let me know. Got my bike running this evening so I'm going to see if I need the yellow wire connection. Thanks, Al
I checked the running out put of my charging system and it is at 14.8v above idle, it is 13.4 at idle..... without the yellow wire connected.... don't know what the long range effects will be but will post, if any. Al
 

·
Registered
Joined
·
10 Posts
The CDI is a computer control of the bike, I believe it controls the electrical systems of the bike, ignition and charging. Al
 

·
Registered
Joined
·
77 Posts
Discussion Starter #9
Its been a while since I've been on and I do have an update to my situation. I found a lightly used CDI from a 2002 with 2100 miles on it for $60. When it arrived, I installed it in 30 seconds and fired the bike up. It started right up and idled fine, but when I started to rev it up the same symptoms arose. When it revs above about 1/2 to 2/3 throttle it starts to cut out (even when its sitting in my driveway running, without riding it). Its almost like it gets out of timing or something, but I know these bikes are have a fixed timing. I've now replaced the carb and the CDI with no improvement. Does anyone have any suggestions? The bike runs great at idle and even at low RPM, but as soon as you start to wind it up the problem begins. Its gotten worse since I bought the bike. The last time I rode it back from work it was all I could do to get it to 55mph on the flats. Any advice would be greatly appreciated. Is this something that could involve the stator or coil?
 

·
Registered
Joined
·
24 Posts
Its been a while since I've been on and I do have an update to my situation. I found a lightly used CDI from a 2002 with 2100 miles on it for $60. When it arrived, I installed it in 30 seconds and fired the bike up. It started right up and idled fine, but when I started to rev it up the same symptoms arose. When it revs above about 1/2 to 2/3 throttle it starts to cut out (even when its sitting in my driveway running, without riding it). Its almost like it gets out of timing or something, but I know these bikes are have a fixed timing. I've now replaced the carb and the CDI with no improvement. Does anyone have any suggestions? The bike runs great at idle and even at low RPM, but as soon as you start to wind it up the problem begins. Its gotten worse since I bought the bike. The last time I rode it back from work it was all I could do to get it to 55mph on the flats. Any advice would be greatly appreciated. Is this something that could involve the stator or coil?


Have you added an inline fuel filter? Some won't pass enough fuel for high rpm under gravity flow. Also I doubt this would be it but a partially blocked fuel vent might cause your problem. If you haven't already done it, rev it up til it misses and open the fuel cap to eliminate the vent, if it smoothes up then the vent is the problem. I would also replace the plug...it could be the cause of high rpm miss. I would check that the plug wire is completely seated on the plug. Are the valves in spec? Turn the choke full on while it's missing. If it smoothes up it's starving for fuel. Could be the float set too low or blockage in the carb or the filter/vent mentioned above. Check for intake leaks by squirting wd40 or starter fluid around the carb boot while it's running



The service manual supplement for my 08(downloaded from the old site) has a detailed section for troubleshooting the ignition system, including how to check each component with a multi meter. If it's not fuel feed, valves out of spec, or a faulty ignition system component then there's not much left but shorted/intermittent wiring or connections. Well maybe valve timing but if that hasn't been messed with that probably isn't it. Hope this helps, good luck. Joe
 

·
Registered
Joined
·
18 Posts
Its been a while since I've been on and I do have an update to my situation. I found a lightly used CDI from a 2002 with 2100 miles on it for $60. When it arrived, I installed it in 30 seconds and fired the bike up. It started right up and idled fine, but when I started to rev it up the same symptoms arose. When it revs above about 1/2 to 2/3 throttle it starts to cut out (even when its sitting in my driveway running, without riding it). Its almost like it gets out of timing or something, but I know these bikes are have a fixed timing. I've now replaced the carb and the CDI with no improvement. Does anyone have any suggestions? The bike runs great at idle and even at low RPM, but as soon as you start to wind it up the problem begins. Its gotten worse since I bought the bike. The last time I rode it back from work it was all I could do to get it to 55mph on the flats. Any advice would be greatly appreciated. Is this something that could involve the stator or coil?


I'm assuming that you've replaced the spark plug, checked all the wiring and connectors, bypassed the neutral switch, clutch switch, side stand switch, safety relays etc.(as a test only) and shorted out, or replaced the resistor in the spark plug cap already.



It could be the stator, the pulser coil, or the ignition coil. When the CDI went out on my '87, it damaged my stator. My Yamaha parts dealer (a smart guy), said that the CDI and stator coil often need to be replaced together. He didn't know why, but that's what they had observed in the shop. My theory is that an intermittent short in the CDI may draw excessive current from the high voltage winding in the stator coil, and eventually burn it out. ( the high voltage stator coil uses wire that's about the thickness of a fine hair. It's so fine that if you take one apart it's hard to see with the naked eye.) In my case, the stator coil originally tested "in spec" for resistance, while the bike was running rough, like yours. As the problem got worst,the ignition went dead, and the coil tested "open circuit" (blown). "Aha" I thought, that's it ! I replaced the stator. The original, intermittent problem was still there! I then replaced the CDI and the bike has run beautifully ever since ( for 4 months and 2500 kms).



My advise is: 1) Go through the ignition trouble shooting procedure that's in the shop manual, step by step. Don't skip anything or take any shortcuts. If everything checks out 100%, then

2)Swap out the ignition coil (because it's easy) - if you can find one.

3)Replace the stator (and the pulser coil -while you're at it- if you can get a cheap one).



I'll put my money on the stator, because of my theory, but you need to keep all the above options open to be sure to find the problem.
 

·
Registered
Joined
·
18 Posts
I'm assuming that you've replaced the spark plug, checked all the wiring and connectors, bypassed the neutral switch, clutch switch, side stand switch, safety relays etc.(as a test only) and shorted out, or replaced the resistor in the spark plug cap already.



It could be the stator, the pulser coil, or the ignition coil. When the CDI went out on my '87, it damaged my stator. My Yamaha parts dealer (a smart guy), said that the CDI and stator coil often need to be replaced together. He didn't know why, but that's what they had observed in the shop. My theory is that an intermittent short in the CDI may draw excessive current from the high voltage winding in the stator coil, and eventually burn it out. ( the high voltage stator coil uses wire that's about the thickness of a fine hair. It's so fine that if you take one apart it's hard to see with the naked eye.) In my case, the stator coil originally tested "in spec" for resistance, while the bike was running rough, like yours. As the problem got worst,the ignition went dead, and the coil tested "open circuit" (blown). "Aha" I thought, that's it ! I replaced the stator. The original, intermittent problem was still there! I then replaced the CDI and the bike has run beautifully ever since ( for 4 months and 2500 kms).



My advise is: 1) Go through the ignition trouble shooting procedure that's in the shop manual, step by step. Don't skip anything or take any shortcuts. If everything checks out 100%, then

2)Swap out the ignition coil (because it's easy) - if you can find one.

3)Replace the stator (and the pulser coil -while you're at it- if you can get a cheap one).



I'll put my money on the stator, because of my theory, but you need to keep all the above options open to be sure to find the problem.


BYE the WAY - Are you sure that the new CDI you got is Good ? Do you have a friend with a TW that you can test it on ? I have to wonder why a used CDI is for sale.........
 

·
Registered
Joined
·
168 Posts
i just had this very same problem i would look at the wiring coming from your stator very closely
 

·
Registered
Joined
·
77 Posts
Discussion Starter #16
So I had totally forgotten about this thread until yesterday when someone replied. I apologize for not updating it, because I did actually figure out what the problem was and it had nothing to do with anything electrical. My neighbor happens to be an old motorcycle mechanic and I persuaded him (1 case of Miller longnecks) to check the bike out. I explained to him what the symptoms were and told him that I was fairly sure it was the CDI or other electrical component. He listened to my story and then started the bike up for himself. It didn't take him 15 minutes to fix the bike, and it had nothing to do with anything electrical or fuel related. In fact, I didn't even have to buy a part. The problem was (drum roll)........the valve adjustment. Apparently the adjuster for the intake valve was too tight which was causing the valve to float, but only at the higher rpm's like I was riding at 50+ mph. The bike would idle just fine and even run around the block ok, but as soon as I would get out on a stretch of road it would start to run crappy in spurts. I swore that it couldn't be that simple....it HAD to be something complicated in the circuitry of the CDI or something like that, but after a quick valve adjustment he sent me out on a ride and the bike has no problem whatsoever. It has WAY more power and is really smooth on the top end.

Moral of the story is don't head down the road of buying parts to fix a problem you're SURE is something complicated before you check everything SIMPLE first. I never would have thought a valve adjustment would cause the bike to run spuradically at high rpm's but I can tell you first hand that it does. I hope this helps someone else out.....I admit I feel kinda stupid now that its all over. I definitely will head to my neighbor's house with a six pack before I pull out my wallet the next time something happens to my TW.
 

·
Registered
Joined
·
1,704 Posts
Good story, Admitting to one's mistakes is a sign of wisdom. Giving credit and beer to those that deserve them is also good business and contributes to future successes. Tom
 

·
Registered
Joined
·
168 Posts
+1 for routine maintenance ! hope your neighbor showed you how to adjust your valves correctly
 

·
Banned
Joined
·
10,664 Posts
Any troubleshooting project should ALWAYS begin with a complete tune-up. Always. Might not fix the problem, but that makes for a long list of what you know it ain't.
 

·
Registered
Joined
·
13 Posts
I checked the running out put of my charging system and it is at 14.8v above idle, it is 13.4 at idle..... without the yellow wire connected.... don't know what the long range effects will be but will post, if any. Al


Hey Al,



I was wondering if you had any long range effects from running that 10 wire CDI.



Thanks,



Scott
 
1 - 20 of 20 Posts
Top