Tech Tips!

by Jonathan Teraji

 Questions and Answers

about the Stator
The stator, in conjunction with the rotor (big brass looking thing) that covers it, is responsible for your YSR's spark, lighting, and charging system. We will try to simplify it for you. Under the rotor, there are 3 coils; the source,the pulsar, and the lighting/charge coils. The source coil allows a spark to be generated, the pulsar tells your bike when to make a spark at the spark plug, and the lighting generates the voltage to light your headlight (headlight ONLY,) and the charge coil charges the battery.

That's about as simple as we can make it, and for trouble shooting, and/or coil replacement it is thorough enough. Magneto, (Located under the Left Engine Cover)
Front view of stator after rotor removal

 How do you remove the rotor? There is one correct way, you add the rotor puller tool to your tool collection. It is inexpensive and removes the rotor quickly and easily. Use a gear puller? Be my guest! We sell rotors also. We have them in stock. Would you like to know how much they cost? Big Bucks! The rotor puller is way cheap!
Now then, how about those pesky 3mm allen screws that hold the stator plate to the engine case? Before you strip them, get a small punch, put in center of allen bolt and give it three or four good raps with a hammer. Then take your 3mm allen wrench and try to break the screw loose. It takes way more torque to break this little screw loose than you would think. If it doesn't break loose, rap it again. This is way easier than drilling out the buggered up screw, or using an easy out, our buying a new left case cause it's buggered up.

The back view of the stator shows you the proper routing

Wires coming from Stator up to wiring harness


Trouble Shooting
Kill Switch: on=infinite resisitance, off=0 resisitance
Spark Plug Cap: 4k-6k ohms
Ignition Coil: Primary (organge to coil base)=0.7-1.1 ohms
Ignition Coil: Secondary (Plug wire, no cap on, to coil base)=5.7k-8.5k ohms
Pulsar Coil: White/Red to Black=16-24 ohms
Source Coil: Black/Red to Black= 264-396 ohms
Lighting/Charge Coil Yellow/Red to Black= 0.16-0.24Ohms White to Black 0.24-0.36 Ohms
Wiring: Check all connections, then re-check!
Spark Plug Replace
CDI No Static Check Possible


Lighting/Charge Coil
The lighting/charge coil frequently goes bad. When replacing pay particular attention to your soldering skills. Also the copper wires from the coil are covered in an enamel. Before soldering, sand off about a 1/4" of the enamel on the end of the wire, if you don't, the connection will not be good.

Source Coil

When replacing this coil, make sure you orient it correctly

Pulsar Coil

This one is easy to replace
We hope information on this page will help you with your stator questions.


Be very careful when checking for spark that there is no gasoline in the area,
or a gas water heater if working your garage!
(This may sound stupid,
but we could give you a long list of names of people who have set their bikes on fire,
not to mention the house.)

That's it for this month, shoot me some E-mail if you have specific YSR questions and I'll do my best to answer them as time allows, and/or suggestions for topics in "Tech Tips!" Remember this page is for you!

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