TW200 Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter #1
i just traded for a 1987 tw200, i am having an ignition problem, sometimes the bike runs fine but most of the time it acts like the timing is jumping and erratic and the engine is pre- igniting / knocking and usually wont idle . when i disconnect the brown wire from the black box ( cdi unit )it runs very smooth but has less power ( maybe no timing advance ..? )i know the 87 has a different cdi unit, is the source coil and trigger coil interchangeable with other years

and do other year cdi's completely diferent or are just the connectors different.
 

·
Registered
Joined
·
540 Posts
if youre in phoenix Az area I can help you



before going hog wild, we need to determine if the cdi is really the cause. You say it run good and bad, we need more details on this.

does it cold start fine

does it idle cold fine

does rev cold fine

or

does it have its poor running condition after its been running for awhile

answer same as above when hot have hour+ of riding



does it show the same conditions repetitively/ consistently
 

·
Registered
Joined
·
10 Posts
Discussion Starter #3
all is fine cold or hot when the brown wire is disconnected from the cdi except it is slightly sluggish. with all cdi wires connected there is no consistency, sometimes it starts fine and runs fine, sometimes right off the bat it wont idle, knocks ( pre ignites )and when reved up misses.

the carb is perfect so we can take that out of the equation. my guess is that when the source coil wire ( brown ) is disconnected it simply runs off the battery but doesnt quite get the same energy as the source coil.

coil readings are ok, pickup coil g-w is 895 ohms and pickup r-br 453 and br to ground is 35

i dont have a wiring diagram for the bike, if anyone has a 87 diagram i would love to see it...!

neutral swith is disconnected, side stand switch is unplugged and so is the clutch switch.

i dont have any test readings or specs on the cdi box so i cant test it but thats hit and miss unless you have a factory " load " tester.
 

·
Registered
Joined
·
540 Posts
ok then----- btw Never count out a carb.......

now make sure there is no cut, broken, shorted wires, intermittent shorts anywhere. I have seen pinched wire coming out of the clutch cover from when people were fix an oil leak or changing the primary sprocket.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #5
thanks for the input but without a wiring diagram its much harder to trace anything withot peeling the whole harness appart however there are no exposed wires under the cover ( i checked) the 87 was an odball as things changed in 88. for background info , in 1984 i was the official mechanic for bmw at the national rally at laguna seca, in 1981 i built and was the mechanic for the paris to dakar rally bmw and in late 83 built the winner for the craig vetter mileage rally at sears point among other things, so i can safely state that the carburetor is fine.. but yes, it is not a point to be overlooked...!
 

·
Registered
Joined
·
10 Posts
Discussion Starter #8
wow, thanks, its so much easier to navigate in the dark with a flashlight...i mean a wiring diagram.. it kind of points to the cdi box, especially when the motor runs smooth again for a bit everytime i knock the cdi against the frame... touchy little buggers..

i have a REALLY odd cdi box on my honda quad.. the stock box will only fire when you touch it.. all you have to do is put one finger on it, no pressure, no squeeze, just touch it when hitting the starter button and it fires right up.... ive tried wrapping it with foil and grounding it thinking that the touch was grounding it... nope, no success.. no rhyme or reason. the quad runs great with an aftermarket box so now i keep the stock box as a spare.. of course they make cheap aftermarket cdi units for honda... the cheapest i can find the cdi for the tw is $220...going down baja in 4 weeks so my girlfriend can have a "toy ' to ride on the beach...

thanks for all the help, two brains are better than one..

thanks.

eric
 

·
Registered
Joined
·
1,123 Posts
Interesting stuff. I have a 91 that was running like junk (would run ok for a bit then fall on its face and act like it was running out of gas). I suspected the CDI and confirmed this by swapping in a known working unit from another bike.



Now I have been attempting to repair my broken CDI, and after removing the case and potting compound (and not doing much else) I have taken it for a test ride... it runs much the same as you describe yours running with the brown wire disconnected. It no longer is completely unridable due to random problems that would often bring me to a halt in traffic, but it also does not have the "power" that it did before.



Have to wonder if I wiggled something that fixed the first problem, but also broke something else causing it to have very little power....
 

·
Registered
Joined
·
10 Posts
Discussion Starter #10
it definitly is the cdi box, every now and then when it runs if i wiggle, tug/push the cdi wires by the box the bike will cut out, if its running rough the reverse happenned, it would run fine... and finally i decided to " squeeze ' the box and it would run fine... so, now i have two small pieces of wood across the box held on with a hose clamp, runs like a champ...

so, for now, its fixed untill i get a new cdi... ive had 4 tw's thru the years an 89, 91, a 2002 and now this 87 and this is the first one that gave me trouble, there great little " do it all " bikes...and wonderful to teach someone how to ride
 

·
Registered
Joined
·
540 Posts
your cdi box maybe repairable.

if you are wiggling wires and it makes it run good/bad. you may have a broken wire inside the wire insulation where the wire enters the box. pull on each wire carefully and if the insultation stretches slightly at the enterance of the box- bingo do a little surgery and solder the wire and save yourself some bucks.
 

·
Registered
Joined
·
211 Posts
If you are going to take it apart to fix it, get pictures so we have pics of the inside of my 91 and your 87
I know this is of no help but there is a place in BKK that fixes CDI's. I will get my GF to give them a bell and see if she can findout any details about how to remove the potting other than heat.

If there are any legal redily avaiable chemicals to mix. Aparantly this guy fixes them for about 30 dollars. then re pots them. Might be interesting to find out if they can be copied or reproduced on the cheap here. I imagine if they could the chinese whould have done it though.



C D I Center Co., Ltd. in Rajthevee, Bangkok, ThailandCompany Overview:

Company Statistics: View

.Contact Details

Address:1000/1-2 New Auruphong Road, Rajthevee, Bangkok, 10400, Thailand

Telephone:662-2158688.Fax:662-2167815.



Good luck...looks bas%*!d getting that compound off.
 

·
Registered
Joined
·
1,123 Posts
It would be great to know how the pros do it. There is a link towards the top of my post in general forum that discusses chemicals to dissolve the potting compound. I didn't really feel comfortable with that process though as an amateur. Would share the link but am working from my phone
 

·
Registered
Joined
·
1,123 Posts
I know it is different than your 87, but I can confirm no change in mine being "sluggish" still as you say, with the brown wire disconnected. Also runs the same with yellow and black w/ white disconnexted. Still working from my phone, so haven't chexked wiring diagram to see what these circuits are. Bike only needs the 4pin connector, 2pin connector, and red wire to run the same as it is now.



Don't try to unplug the 4pin connector when the bike is running !!! You will get electrocuted... it hurts pretty bad... the wife called me a dumbass... It turns out one of those wires feeds the coil or something ;P
 

·
Registered
Joined
·
76 Posts
I just got an 87 and it does the exact same thing. One day it will run 70 mph down the road, then it wont run, will barely idle, wont rev, sputters, etc.. I too have been through the carb three times, it is not the carb. Did you ever replace the cdi and confirm?
 

·
Registered
Joined
·
76 Posts
Well I unplugged my brown wire and it ran for a few seconds, then it died.. now it wont start at all????
 

·
Registered
Joined
·
116 Posts
I just got an 87 and it does the exact same thing. One day it will run 70 mph down the road, then it wont run, will barely idle, wont rev, sputters, etc.. I too have been through the carb three times, it is not the carb. Did you ever replace the cdi and confirm?


my 87 did the same thing when i got it. it would stummble and buck like the coil was not firing or something, i had to pull over on the side of the road for a few minutes then it would make it a few hundred yards and it would do it again. new CDI is the ticket
 
1 - 20 of 22 Posts
Top