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Ok first off thanks for any help that I get on this. I have an 09 raptor 90 that I am having issues with. I have had it at the shop many many times, more times then my daughter riding it. I was told that the carb and jets are getting clogged. I have drained the carb and checked the jets and they appear to be free of any clog. ( just looking threw the holes right?) Well here is my question. I am able to get the quad started, but it has to be wide open choke. When I hit the throttle it wants to bog down and stall, sometimes the only way to get it to go is when its on wide open choke. How do I know when I have the correct settings on the throttle screw and idle screw on the carb? Is there anything else I can do to fix this issue. Thanks again.
 

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Check the other threads. We have this issue pretty well covered. The pilot jet seems to be the main problem. The center bore on the oem pilot is .32mm. That is amazingly tiny. I have bored mine open to .37mm. There is a 37 pilot available from e-ton dealers but using a #79 drill bit will get you opened up. It may not seem like much but has helped ours immensely! It is very hard to see through the pilot. If you are looking just slightly off center, you won't see through it. Ours would get blocked very easily. I posted in the other thread how I fixed that. Read the other threads and give the pilot jet a try. Post your results. Ours is an 09 also and when the pilot was not clean, it had the hard start and would not idle unless the choke was on. Basically, the choke is cutting the amount of air mixing with the gas and making it richer, but since the pilot jet is partially blocked, it is trying to run extremely lean thus the choke is masking the pilot lean condition. The engine runs on the pilot for the first 1/8 to 1/4 throttle and as the needle raises, the main comes in. Without the pilot flowing enough fuel, your initial throttle is way too lean and won't rev. With the .37mm in ours, the engine revs faster and stronger than ever and the plug looks nice and tan. If you have other questions, post up or PM me. I'm no expert but have learned a lot though this process.
 

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cprtaught2,

Check out the thread at the top of this forum, it will walk you through how to clean the carb and upgrade the jets. Hopefully it will save you some cash by not having to go to the shop. If you have any questions as you work your way through just post them here.

One thing to remember when you are done for the day, turn off the gas and drain the bowl on the carb. Even the bigger jets will clog if you leave gas in the carb.
 

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Good luck.

I've changed jets (2 different sizes), cleaned the carb (spend more time cleaning it/working on the quad than my son does riding it), brought it to the dealer, etc.

Simply put - these quads are junk. E-Ton did a horrible job on this one. If Yamaha feels the need to outsource...they should check with Honda or Can-Am so our kids can ride their wheelers instead of watching them sit in the garage/yard.
 

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mine is a 2011 model and i have never had this issue.
30+ hours riding and storage as well and no blockages.
I wonder if it has been fixed in the newer models.
 

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mine is a 2011 model and i have never had this issue.s
30+ hours riding and storage as well and no blockages.
I wonder if it has been fixed in the newer models.

+1 my sons raptor is also a 2011, knock on wood no issues here as of yet. I usually take better care of my quads than my own car and I drive a bmw lol.
 

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I wonder what has changed in the 2011 model.
I will check both the older and newer owners manuals and maybe there is a fix for this problem for you guys with older bikes.
 

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cpr - so you have 2 of the 90's. Here is a thought. It may take a little time and effort but here it is. Swap carbs between the two. Run both and verify one runs great and the other doesn't. Don't clean anything out, just swap the carbs. That should give you a good direction on what is going on. If the problem moves, you know it is carb related, if it doesn't, then you may have a fuel flow problem. Speaking of this, our Polaris 90 had an inherent problem with pinching the fuel tank vent line when you removed the front fender and reinstalled. If the fuel tank is not venting correctly, or enough, a vacuum builds in the tank and will not flow much fuel, will idle ok but will not accept throttle. Will not flow enough fuel to supply need. You can check this by loosening the cap and running it. Also check that fuel flows freely out of the hose going into the carb. Maybe there is something blocking flow between tank fitting and carb inlet. Trying to come up with some more things......
 
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