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RSRBOB
RSRBOB, Technician
Category: Motorcycle
Satisfied Customers: 867
Experience:  Former Factory Service Rep, Dlr Line Tech, Service Manager, General Manager, Store Owner
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I HAVE A 1997 YAMAHA BIG BEAR 350 ATV. LOST ALL SPARK. HOW

Customer Question

I HAVE A 1997 YAMAHA BIG BEAR 350 ATV. LOST ALL SPARK. HOW DO YOU CHECK IGN. COIL @ WHAT SHOULD THE OHMS BE?
Submitted: 5 years ago.
Category: Motorcycle
Expert:  MOT. MASTER TECH replied 5 years ago.
hey gordy
first check to see if you have power going to the coil (12.8 volts ).
to check the ohms of the coil you have to check two sides :

primary side is the two small wires or connectors on one side of the coil , it should read from 0.3 oms to 15.

secondary side is from the spark plug cap to any one of the small conectors or wires , it should read from 2K ohms to 18K ohms ( K is 1000's)

cheers

Customer: replied 5 years ago.
I have no power going to the coil how do i check that.
Expert:  RSRBOB replied 5 years ago.
Hi Gordy,
I will help you get through the diagnostics of this electrical system.
Since Yamaha actually made 3 different models and specs vary slightly, I will try to note specs for all 3 models when they differ from each other for your clarity.
First the 2wd:
Ignition coil - 0.42 ohms +/-15% and 6.4K ohms +/-15%, primary and secondary, in that order
pulser coil or pick up coil: Red to white wire - 510 ohms +/-10%
Charge Coil or Source coil: Brown to Green - 300 ohms +/- 10%


4wd
Ignition coil - 0.4 ohms+/-20%, 7.1 ohms +/-20% (primary, secondary in that order)
Pulser coil or pick up coil: white and green wire to white and red (w/g_w/r) 510 ohms +/- 10%
Charge Coil or Source coil: Brown to Green - 300 ohms +/- 10%


4wd "SE"
Ignition coil - 0.42 ohms +/-15% and 6.4K ohms +/-15%
Pulser coil or pick up coil: Red to white wire - 510 ohms +/-10%
Charge Coil or Source coil: Brown to Green - 300 ohms +/- 10%

One thought to keep in mind when you are dealing with a complete loss of spark is you are generally not going to find one resistance reading being off by 16% instead of 15% causing the trouble. Almost always if you have a problem with a coil, you will find it is either shorted out completely (no resistance) or completely open (no continuity). If you were looking for a misfire, then you might have specs that are slightly out of range causing the issues.
The other thought to keep in mind is do not over look ignition controlling circuits either. If everything checks out in the ignition system, then the ignition controlling components should be checked. These are things such as switches and relays that ground the ignition normally in case of faults.

If you have any more questions, feel free to ask.
Thanks
RSRBOB
Also, if you do have additional questions, please specify exactly which Big Bear you have.
RSRBOB, Technician
Category: Motorcycle
Satisfied Customers: 867
Experience: Former Factory Service Rep, Dlr Line Tech, Service Manager, General Manager, Store Owner
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