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Discussion Starter · #1 ·
I need help guys. I got this 04 660 and it dont run right. I had it idling good before. But then I was screwing around with the 2 fuel air screws on the bottoms of the carbs. I set them at 2 and 1/2 turns out. It idles low now so im going to put then back at the 3 and 1/2 turns out tomorrow. I got 145 and 150 jets in it right now. Cant remember the other jet sizes off hand. It'll idle but as soon as I touch the throttle it bogs and dies. If I feather it i'll finally get a backfire out of it and a flame out of the pipe about 3 inches long. It revs up easier with the choke on. So thats why im thinking its in the carb. The reverse sensor green with white strip wire has been cut and grounded to the battery and the parking brake green with yellow wire has been cut and taped off by its self. Both were cut a few inches from the ecu to rule out a broke or bare wire. Neither made a difference. It has a hfm slip on which doesnt fit up right. Stock air box with lid. When I redid the clutch (thanks to the brother) I put a 102mm cylinder with new piston and rings. I replaced the 2 exhaust valves while I was in there because it was having problems before the rebuild where the brother would go about a mile and the wheeler start backfiring and loose power untill it slowed down for a while. Then go about another mile and samething. Thought maybe one of the valves wasnt sealing. I had the carb rebuilt and that never made a difference. I tried cleaning the jets and thats hasnt helped either.
 

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Master of the Electron
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Your pilot jets are most likely dirty - clean the carbs correctly.
 

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Discussion Starter · #3 ·
Ok so I took the carbs back off and think I did a pretty thorough job. I pulled all jets and let them soak in brake parts cleaner (Its all I had tonight). I took the two jets off in the front where air comes in at. The two 22.5, the single 95, and the 145/150 jets. I unscrewed both holders(?) what the needle slides down into. Took o rings off and soaked them. Took out the floats and needle valve sets. Unscrewed both pilot (?) screws. Pulled the tops, needles, and slides off. Sprayed the carb out a few times. Then blew it out with air. I poked a small peice of wire thru the jets to clean them. It did seem to make a little difference but still cant rev it when choke is off. There is a spot when the choke is at about half on and it idles up and I can rev it up. If I put it at full choke it idles down a little. And if I turn it off it idles lower yet. It seems to smoke up the garage pretty quick. Dark smoke like its running rich. If you think I missed anything cleaning it out im all ears.
 

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Master of the Electron
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Lebaron, did you run wire through the pilot jets? THey need to be sprayed, rodded out with wire, sprayed again, blown out with air, then looked thru at a bright light to see if there's anything left blocking... if you don't see perfect, cylindrical rays of light coming through, clean some more. It really is the only way.

Beyond that, what are your mods (Just the slip on?) and what jet sizes and needles are you running?
 

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Discussion Starter · #5 ·
Sorry it took so long to get back here. I took a small wire and poked thru the jets and all the side holes. When I looked thru them into the light they were spotless. So they shouldnt be the problem. Im running 145/150 main jets. What needles are you talking about? If your talking about the vacuum slide needles how do I find the sizes? They should be stock. One of the needles I had to change because it poped out some how and smashed the spring. And the only way to get another spring was to buy the whole needle kit from yamaha. I droped the needle one clip down on both sides (one clip from top of needle). But that didnt make any difference. Would it be any better to buy that whole header to match my slip on? I didnt want to cuz its kinda pricy but if it gets the wheeler running i'll get it. I am thinking about getting a better air filter. The filter on it now I think was oil soaked. But I think im going to keep the lid on. Unless someone has a better idea. Id like to get rid of the vacuum slides. Is there a kit for that or would it just be a waste of money. Im not planning on racing it or topping it out. I just want it for the trails.
 

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Double check the modifications for the speed limiters.

I had the same issue, would idle great but would bog and backfire off idle.

Turned out one the the limiter changes made by the previous owner had a loose connection.
 
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