I have an 04 grizz with 300km on it, when I'm doing some crawling or slow bush whacking every once in awhile it sputters. I have to ride with the side covers off or it does it lots, and if the covers are on and I have ridden for a while slow or fast and shut it off it will sputter for the first few seconds, when I start to ride again. I asked the dealer what was going on, and he told me they run hot untill the first service. Has anyone had the same problem.

 

They will run hot forever. A lot of people have that problem. I had it with my 02. It has been happening for three years now. You would think Yamaha would fix it by now.

 

Cheeky, your dealer is FOS. There is a recall on the 03 Grizzly and the 04 model was upgraded to fix the problem of overheating. Try calling another dealer if you can, if you have no other dealers in your area contact Yamaha through the web and get some advice.

To help with vaporlock on my Griz I removed the ball bearing inside of the gas cap to help the tank breathe easier. I have read that the ball is a check valve for the breathing of the gas tank. If in the event the ATV is overturned the check ball will prevent the gas from spilling from the breather tube.

You can also relieve vapor lock by unscrewing the gas cap to break suction in the tank.

 

Go to highlifter, drop $40 on that heat wrap stuff and wrap your header pipe from the front back past the carb with it. (or you can go cheaper and just find the same stuff someplace else). Sure it sucks, sure yamaha should have fixed it, but just do this and you shouldn't have that problem anymore. Mine did it once, I did that the next week, and I haven't seen one symptom yet. that was 2 years ago I think.

 

I need to do the header wrap also. I was going to do the jett hot coating, but don't know where to get it done. HL would do it, but they had to send it off, so I was going to see if I could go direct and cut out the middle man, but never followed up on it.

After 2 years of riding, mine finally did it too... at the worse possible place... Marengo!

 

One trick that I have done on motorcycles is to take the exhaust pipes off and spray a few coats of high temp "grill" paint on the inside. This will last for about a year or more on motorcycles if done right and it helps greatly to direct the heat out of the pipe. If I ever have a problem with high temps on our Griz I will "paint" and wrap the pipes at one time.

 

Jet Hot is the best professional way to go, but is a pain, cause you have to take off the header and send it off, plus its expensive. I said forget it and just bought that heat wrap. Worked good. Sad still that we have to do this kind of thing with new quads.

 

We own a late 03 model and have not had a problem with overheating to date. I have had the gastank vaporlock a few times, but by removing the check in the gas cap, problem solved.

I wonder if the exhaust pipe heat is only part of the overheating problem on some of these Grizzly ATVs. The engine is closed in and there is not much in the upper section of the body to let excessive heat escape. Take this and add a leaned out mixture and slow ride/ hot day and I can see the problem waiting to happen.

 

Pretty sure, cause the carb is very close to the exhaust pipe. Not much space at all between it. I think thats the main problem. I got that heat kit from yamaha, and noticed that the aluminum guard there has a new piece that goes between the pipe and carb. Old one didn't have that I don't think. The new one didn't fit right either. Only has 2 bolts that would even line up, and they didn't do it right, so I spent forever and a day trying to get it on there right so it wouldn't vibrate. Dealers suck.

I value that fiberglass wrap stuff a lot more than the crap yamaha put here and there.

 

Like everyone says this is a problem and mine did it also, the Yam fix it kit helps. Have you ever looked in the tank to see if the gas was what looks like boiling? Mine would do this and I asked around and found out that there is a winter time gas and a summer time gas (not that we can pick witch one we want it's whats delivered to the stations). The gas companies won't deliver summer fuel untill there out of winter and when the winter fuel is in a Grizz and it gets to warm it will vaporlock and boil in the tank. I had no idea there was a cold weather fuel and hot weather fuel ( I thought the guy at the shop was full of it) but it turns out there is.