Help ! Ive got a 1985 honda xl125r and it wownt start , bt i have a spark bt not a very good spark(brand new spark plug) so i think it is the cdi unit unless anyone has any other solutions ??

Unfortunately, the ONLY thing you can do is replace the cdi box....what REALLY sucks is that those cdi boxes were only used by Honda for 2 years...85 & 86...all the other years/bikes had MUCH cheaper units on them...And DO NOT, I repeat DO NOT waste your time on a USED part that is 30 years old!!! There is NO WAY to test a cdi box!!! Bite the bullet & buy a NEW one if you want to fix it & forget it.....there are new ones available online from a company in the UK for about $259.00 I speak from personal experience with this EXACT issue & once you replace the cdi box, that bike will run (providing everything else is good)

Best of luck!



JJ

find a running sr 250 and swop his cdi unit with yours if the bike runs, fine. if not put his cdi back in and try again. if the good bike now starts it will indicate that your cdi is faulty. the cdi is located under the tank inside the frame. don't buy a second hand cdi unless you can test it on a working bike. they are very expensive and you don't want to buy a dud

1.2 U.S. quarts

Had similar problem with a 125cc scooter I worked on. First crank of the engine showed spark on first compression and wouldn't spark anymore until you would wait 10-15 minutes. Then it would give only one spark again.

Found it to be a faulty CDI box.

You can't test or repair a CDI box, only replace it. Electrical parts that are purchased, cannot be returned so, you need to be sure it's not the pickup coil, pulse coil,secondary coil, plug wire, plug cap and spark plug itself before you purchase a box. By checking the specific resistances with a ohm meter on the previous mentioned components, will help determine if it's the box or not. Hope this helps!

Check your standard factory specs for spark plugs, it sounds like ur bike getting OVERHEAT!

Did you happen to check the over head valve camshaft? Ussually that bike , w/ age happen to be more tha 10 yrs old, cam shaft, valve guide are worn out and out of clearance! Check it please!

Hope that make your bike be reliable again!

Hi and welcome to FixYa,

On Asian versions of an 84 Honda XR200R, the CDI unit has six wires:

• blue/yellow - pulse generator
• black - to ignition coil
• black/white - engine stop switch;
• green - ground;
• green/white - pulse generator
• black/red - exciter/charging coil at stator.

The ignition coil has 2 wires:

• green - ground;
• black - to CDI

Good luck and thank you for asking FixYa.

No it will not work.

go to your local honda dealer or a good library and look up the exact make and model of your bike and get the plug wiring code for the cdi,most bikes i know aere different from each other in the cdi wiring,if you get it wrong the first time,you will fry the cdi and they are quite expensive to replace..hope this helps

Hi and welcome to FixYa,

If somehow, the CDI could be opened up, then component level repair maybe tried. There would be 2 final transistors that actually do the switching; 1 for each coil. Offhand, it would appear that 1 of those 2 is faulty. Otherwise, replacement is the only option.

Incidentally, in some versions, a fault in the tachometer could also cause one of the CDI's output to fail.

Postback results of tests.

Good luck and thank you for using FixYa.