CDI Confused!!

[tmlawr]

350 yamaha big bear 4x4 1996

intermitent performace problems, I have changed the plug several times, carb kit, rejeted for pipe, new ignition coil,

still run like a peace of ****!

but sometime runs great. limited time

won't rev up now, seem to try but just wont go!!! backfile or pops a little

I think it may be the CDI but manual says no way to test it.

Dont want to buy one for $200 bucks and it be something elese

Is there any way to check the CDI ???


Could a spark plug cap cause this severe of a performance problem??

[wilkin250r]

Your stator is fairly easy to test. It's just a bunch of coils of wire. You test it with an ohmmeter, if the resistances are good, your stator is good.

Same with the coil.

However, your CDI isn't nearly so simple. It's a rather complex bit of electronics. The repair manual only gives one method for testing the CDI, by process of elimination. Test everything else, if all other components check out fine, the problem must be the CDI.

[2muchquad]

i have seen that problem before in the past,it was on a suzuki dr 350 trail bike though.it ended up being the sparkplug boot was faulty.never know though but its worth looking into

[prepracing]

yes....sparkplug gap, loose sparkplug, plug wire/boot, air intake boot from carb to your motor could be loose. Have also seen them run like that after the carb was put back on and was not sitting level, that will affect your float and make it run like crap sometimes and still run good part of the time. Those are some simple things I would check, along with the other things that have already been mentioned.

[prepracing]

also not sure how the choke works on yours, but you might also check it and make sure its not stuck half way on or something. Good luck