I hope this subject is in the correct forum.

I have a 2005 Yamaha Kodiak 450 4x4. Bought it brand new. Love this thing. Mid-size ATV, locking front differential, good range on 4 gallons of gas, reasonable weight, low center of gravity. It has never given me any kind of trouble whatsoever...until last weekend.

I live in Boise -- evelation about 2500 feet. My wife and I were riding up near 9000 feet over Labor Day weekend. And it had what feels like a fueling or carburator problem. I thought it might be a lack-of-air issue but the air cleaner is fine.

The problem is this. It accelerates fine -- good and hard. But when I let off the throttle, it hesitates without power for less than about 1 second. Then power comes back and it seems to run fine. If I gently back off throttle, the problem doesn't pop up. It's only if I instantly let off throttle. Say, from max throttle to mid-throttle.

I thought perhaps it was the elevation we were riding at since I assume it was tuned for the ~2500 ft elevation of Boise. But I've ridden near 9000' previously with no problem. Also, my brother was with us. He has an identical machine and his ran fine, no problems.

I drained fuel out of carb but that didn't help any. Oil is fine, oil filter is fine. I checked the valves myself at 150 miles with no adjustment needed. It currently has about 1200 miles on it. I have not had time yet to pull the spark plug and look at its color. One thing to note...these things don't come from the factory with a fuel filter (which is just about the most ridiculous item to save $.02 on, IMO) so I'm leaning toward a piece of cr@p in the jet. Just my hunch based on its behavior and what I know now.

Anyway, if anyone here has experienced a similar problem, I'd appreciate any feedback. I'm planning on pulling the carb this week sometime. It's been many, MANY years since I've tinkered with a (gasp!) carburetor, so I hope I remember how to put everything back together!

 

My yamaha did the same thing. Junk in the carb, pull it off and take it apart. Clean the part and put back together. Reinstall and have fun

 

Junk in the carb was the problem on my Dads also. He has cleaned it a few times now. Trust me, if he can do it, so can you.

 

and put a fuel filter on to prevent in the future.

 

you have a small piece of ? dirt, varnish ,junk in the jets take the cab apart a clean it real good blow out the tiney holes . and put a second fuel filter on it ,it should have one in the tank (fine screen)

 

It's possible that you needa high altitude carb kit. I was recommended to get one at 2500'. Also there may be something with the spark plug wire/adapter. Something about the resistance changing over time, especially in the desert. Do not leave fuel in it if you are going to be gone awhile, as it can turn to crap quicky, even with Stabil. If you are not going to run for 30 days or more, drain the tank.

 

You may concider lowering the needle one notch and if that helps but doesn't fix it.....next smaller main jet.

Mine does the same thing at higher elevations especially when hot, but runs killer at sea level and 50 deg.

Pulling the bowl will tell you if you have junk in the carb. You gotta do it anyway to get to the jets.

 

My bet is that you have a slightly clogged jet, and maybe sluggish slide.

They are easy to take apart to clean. Personally, I like B-12 Chemtool.

Be sure to blast the stuff through all the little holes in the throat of the carb.

When you aren't going to ride for a few days, it is a good idea to shut the fuel off and run the carb dry, or use the float bowl drain.

 

Re-jet for altitude.