04 Grizzly 660 driving me nuts - Yamaha Grizzly ATV Forum
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post #1 of 2 Old 05-21-2019, 01:33 PM Thread Starter
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04 Grizzly 660 driving me nuts

I bought this well used Grizzly last year and it has been a real pain in my a$$. It was fouling the plugs, wasn't tuned very well, kept running after I turned it off, went through several starter relays etc. To date I have rebuilt the top end, new starter, new carb, new choke cable, new throttle cable, new starter relay solenoid, new cdi, dogged wiring issues, new voltage regulator and winch power source.
I have spent countless hours on this thing and got it to run pretty well, then it just decides not to work. It is still fouling the plug and I have one hell of a time getting it tuned properly. I was at my wits end and finally took it in to Cool Springs Power Sports here in Franklin, Tn. They had it for over two months found the starter was pulling 3 times the amperage and was draining the battery. They said they worked on the carb, but they could never get it to run just right. One day they said it worked pretty good then the next day it wouldn't do anything.
At this point I have it running, but it struggles when I give it some throttle. I have worked the fuel/air mix screw and just can't get it to run right. It is still fouling the plugs and I really don't know why after all of the top end work I did to it. Valves lapped, new piston and rings, valve leak test done etc.

I am at my wits end and have no idea where to go now. Any suggestions besides taking it out back and putting it out of my misery. I hope to get it running so I can sell it unless someone wants to buy it for a project.
Thanks all

Semper Fidelis
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post #2 of 2 Old 05-21-2019, 01:50 PM
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What carburetor did you use? A factory one or Chinese eBay special?

Have you replaced jets in the carb to try and tune it?
It does sound like a jetting g issue, but that's my best guess at this point.
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