Hey folks. I have a 2001 Big Bear 400 4x4 that stopped running a couple of months ago. I had originally checked for spark and it was okay (I'm thinking maybe it was intermittent), which led me to rebuild the carb, but now I have no spark. I took the bike to a certified Yamaha dealer and they told me it was a bad stator.

I bought a used stator off of Ebay (seller said it was good) and still no luck. Just for the heck of it, and since I had a little more time this past week, I tested the original stator with my ohmmeter. It passed. My question is: can a bad stator still pass a resistance test? I've since checked a lot of wiring, the coil and switches and they all come out okay as well. Part of me wants to go ahead and buy a new stator from Ricky Stator and the other part doesn't totally trust the mechanic's diagnostics. Thanks for the help.

 

Well if it tested good and you are sure then something is wrong when its on the machine. Is it grounding out? are you sure the connections are good? did you try contact cleaner? Btw I've bought from Ricky Stator myself.. excellent people, highly recommended.

 

ATV MAN-

When it's on the ATV I'm pretty sure it's grounded well. Checking the ATV's wiring was the easier part, and anything I was not sure of was re-grounded or cleaned. That goes for the connections from the stator to the rest of the bike as well. Intersetingly enough, the connection on the rectifier that sends juice to the stator was extremely dirty and suffered some corrosion. I cleaned it very well but still no luck. Thanks for the help.

 

Pull the flywheel and check the shaft key. ( it locks the flywheel to the shaft) They are known to break. While the flywheel is off, clean and check the stator pickup.

 

Do know for sure your CDI box is good? if none of your stator wires run to ground and you have conunity to each other IMO that part of test is good, Did your used stator have the pickup coil with it? If your replaced all of them with differant one than prolly okay, than I would focus on the CDI box...I know this sounds cheesy BUT if works for me about 90 percent of the times...Take an screwdriver handle an hit the CDI with screwdriver while you are pushing the starter button to see if its sparks while you hit box..

 

When my Big bear lost its spark ,it was because of a bad ingnition coil ($80), much more common of a problem then a bad CDI or Stator.

Alway cheak the cheaper parts first.

 

Thanks for the responses guys. The used stator I bought came with everything. I actually found out about a test in one of my shop manuals that was not in the other one and is only used for the 99- newer 400s. One of the stators had a resistance outside of the specs. I'll have to check the other one. I think the flywheel key is good but I'll double-check next time I get a cghance to work on the bike. I like the screwdriver idea- Bubba engineering. Have already tested the coil and plug cap hoping those were the culprits but they tested out good. Keep 'em coming if you all think of anything else.
Thanks,
Josh