2004 660 raptor perplexed

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OtisBlkR1

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2004 super clean/like new, Yamaha 660 Raptor bone stock, picked it up yesterday from a friend, he had local shop rebuild the carbs (it sat to long unused. Less than 10 total hours on 4 wheeler, almost showroom clean. All that said, it idles fine, but midway through the throttle it sputters, backfires a tad and then launches like a two stroke.. things a beast! Jive checked the carb boots, cleaned the air filter & used a healthy dose of carb cleaner on it to no positive result. I'm leaning towards carbs needing synked.. your thoughts ? Things rubber powerful, just falls on it face mid throttle before launching fiercely.
 
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I had a similar problem with and 01 raptor 660. I ran a few ounces of seafoam through the tank and the problem went away.

I never figured out the culprit. I just figured there was a piece of trash in one of the jets that seafoam broke free??

Good luck with it. I sold the bike shortly after that and went back to two wheels and blue smoke
 
I think these use a CV type carb with a butterfly throttle plate and a vacuum operated slide valve. It's possible that the slide valve is hanging up or that there is trash in the main jet or buildup on the needle. The needle regulates fuel through the main jet at part throttle. Check that the slides move freely and that the jets are clear.
 
Originally Posted By: OtisBlkR1
Guess I know what I'm doing tonight.

thumbsup2.gif
 
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Also unrelated I stopped and picked up a new uni air filter tonight and a couple of fresh spark plugs for it here shortly I'm going to pull the carburetors off open them up carb clean them and blow out all the ports with my air tank and put it back together have at that point after reassembly it still runs like [censored] I'm going to be at a loss and beyond my skill set maybe I could find a YouTube video about properly syncing twin carbs
 
I called my friend that I bought the squad from and it was at the local shop less than 30 days ago getting the carburetors rebuilt I called the shop and explain the situation to them that he had it in they supposedly fixed it he drove it up and down the alley and then sold it to me of course I brought it home and something wasn't right so I bit the bullet and take the quad back to the shop tonight knowing they know who I am and they know who he is and they will try and make it right
 
One thing is for sure...
just slapping on some pod filters is going to really mess up the jetting

Make sure it runs good stock before messing with it more
 
I think those are a CV type carb, with the diaphragm. Also It's a little weird being a single with twin carbs. IIRC it's a 5 valve head. The large carb feeds 2 of the intake valves, and a smaller carb feeds the remaining intake valve. I don't know if I have all that correct, I do remember a bit of a strange set up when they came out.

1.) get it running right first
2.) if you decide to go with the pod filter, get the correct jet and needle kit from a reputable company.
 
Originally Posted By: Brybo86
One thing is for sure...
just slapping on some pod filters is going to really mess up the jetting

Make sure it runs good stock before messing with it more


Im not sure where you got the idea that I put "pod filters" on it ? the factory foam air filter was replaced with a UNI brand foam air filter. Its a direct replacement drop in inside the air box. Other than that the machine is 100% bone stock..

With that said, the problem has been found. My friend had the shop order a OEM replacement carb rebuild kit for this machine and the shop installed it.. The shop called al little bit ago to inform me that the carb was put together with the wrong size needles.. that's why its running odd.. So the shop is telling me that I need to order another kit $70 and $170 in labor to correct the issues.. My argument to them is that they ordered the wrong kit, why should I be liable ? Luckily I have friends in the parts department that's going to investigate the situation and get back with me tomorrow. Im only letting them to the leg work (labor charge) so if doesn't correct the issue they cant claim any of this is my fault with a incorrect install. Ill update when I see a resolution to this story.
 
I haven't been on in a few, so to conclude this story. The real problem was the bras ring that control's fuel flow was left out by the Honda shop during the first install. It was not a needle issue. I had the parts boys order a FMF replacement jet kit and the correct brass ring and the shop senior tech reinstalled it all himself.. The raptor is a beast.. not so much as a miss since the machine was picked up.
 
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Originally Posted By: OtisBlkR1
I haven't been on in a few, so to conclude this story. The real problem was the bras ring that control's fuel flow was left out by the Honda shop during the first install. It was not a needle issue. I had the parts boys order a FMF replacement jet kit and the correct brass ring and the shop senior tech reinstalled it all himself.. The raptor is a beast.. not so much as a miss since the machine was picked up.


Good to hear!! It's hard to find a nice clean original Raptor that old. Most I see are pretty trashed / hacked.

Please Post Pics!!
 
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