Need some info on my 84 xt600 and my Yamaha Factory Service manual is with a friend who took a trip to Mexico. My bike just recently has been hard to start and when does start has been popping and sputtering under load and in neutral at 3,600 + rpm's. Somedays it starts and act fine and others it never acts all right. I thought it was the carb and have cleaned it out a few times and then after riding get the same results. It usually starts acting up after it's been running 30-60 minutes. Today I put a timing light on it a relized while kicking it over it was only lighting the timing light once every three kicks on average. Also the spark looked pretty weak while kicking it over until I put a battery charger on it while kicking, that seemed to make it better (a nice blue spark vs. the previous blue/orange spark). When it did start it would idle for 30 seconds then the timing light would go out and the bike would die. When I rev it in neutral it would rev to around 3,600 then miss (the timing light would go out) then it would die, then come back on and the light would light back up, so I think I have narrowed to ignition . I am just not sure what part, I checked ohms on the red and brown wires to the stator and got 209 ohms. I also started checking the stator per Elctrux web-site and it checked out ok if I did it right anyway. Revved to 2,500 rpm and voltage was 13.5 and revved to 5,000 rpm and voltage dropped to 12.2 (not sure if this is right, but their sight said under 14.5 was OK. I am not sure what the ohms should be on the coil or how to check it for that matter. I feel helpless without my manual. Could some one steer me in the right direction on diagnosing this thing. Unfortuneatly I hae no one around here to swap parts with either, so I will have to try and get it right the first time, all help will be greatly appreciated. Thanks a lot, Jason...

Pretty vague problem I think, but let's start at the beginning.
Your bike does not need battery power for the ignition, as it is CDI ignition. Check this by removing the battery from the bike and kicking over. No sparks - I am wrong.

Then, if it cuts out at 3600+ rpm's and kicks in again below that value it seems to me that the 'high-speed pickup' ofthe ignition is faulty.
There's, next to the brown and th red wire going into the engine (to stator) also three other wires going in: white / green, white / red, and green. Colors vary with type but they are easy to identify as they are on a separate plug together, and they are not the white ones that go to rectifier / controller.

Now, measure between white / red and green and between white / red and green. Also, between white / red and white / green to check. If any of these are not the correct value (get them from manual) there's your problem, pickups to be replaced.

Further, it might be that coils that behave perfectly OK when cold are misbehaving when warm. Can only be verified by exchanging or with very specialised equipment.

Good luck!
Auke

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Auke
http://aukemarieke.blogspot.com

Does anyone have these values as I don't have access to my manual, like I said above. My friend has it who is on a trip in Mexico. Thanks, Jason..

He must be A good friend to lend your manual.
I've had trouble getting timing lights to flash consistently with cdi ignition, think it depends on the quality of the light.

Coil
Neg to orange .8 OHM
Orange to plug cap 17K

Charge coil
red-brown 200

Pluse coil
Green - White/red 90-130
Green - white/green 90-130

Stator White/white .23-.38

__________________
Winston
85 xt600Z
02 YZ250

Also check the spark plug cap for resistance. It should be around 5K ohms. Keep in mind that this bike is 22 years old, and nothing lasts forever. The shop I work at has gradualy gone to the policy of replacing the stator with all pickups and the CDI as a unit. Then you have a dependable ignition system. Before anyone says this is too expensive and redundant go out and price any newer bike that will do what this fine old XT will do.

Here are my findings which seem strange, but this is what I got

Coil Neg to orange .8 OHM I got 1.4 ohms
Orange to plug cap 17K Showed open????

Charge coil
red-brown 200 219

Pluse coil
Green - White/red 90-130 119
Green - white/green 90-130 119
Stator White/white .23-.38 It showed open until I turned the bike over then flashed to 202 then when coming to rest would show closed (seemed strange to me).

I am going to try a new stator and a new coil. There was no spark after checking these values for the first 10-12 kicks, then the plug started showing a strong spark, this issue has been very intermitent. I am ready to just replace all of these electronic parts with new and be done with it. Bill, were is the best place to buy these parts in the USA. Thanks, Jason..

The open between the plug cap and the orange will definatly kill the spark, now like bill said remove the cap by unscrewing the wire and test the cap 5K and re test the coil orange to plug cap wire should have around 12K. If one of these are open replace it and you should have good spark.

I would re-test the stator with a better meter or try a diferent scale ( don't spin the motor it can fry the meter),this winding is only for charging the batt and not related to the ignition at all. If the bike will run check the voltage at the batt if it is 14V or so don't bother changing the stator.

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Winston
85 xt600Z
02 YZ250

Ok, I tried the rewound stator, then a new coil and cap. It is still doing the same thing I ordered a new CDI on E-Bay from the New Zealand Guy from another post. Although I had the stator rewound could the pick-up still be bad, if so can I replace the pick up only? Thanks, Jason. Looks like I am collecting a lot of spare parts I am anxious to be able to .

Hi Slicks
My 3AJ starts to misfire after riding for 20 minutes,or when engine gets warm.
I have also cleaned the carbs and checked valves etc and am now think its an electric problem. I want to try a new coil first then maybe have to get a new CDI.
Did you get a new CDI for your bike from Ebay and if so has it fixed the problem?
Has anyone else used one of these aftermarket CDI?
Thanks