Premium fuel doesnt run any cooler or hotter, it just takes a hotter spark to ignite. Unless the fuel is actually combusting in the tank then an upgrade in octane shouldnt make a difference.

 

premium fuel takes a hotter spark to ignite? new one on me,the higher the octane,the lower the flashpoint,hense easier to ignite

going to a hotter or colder plug doesnt make referance to the "spark" it produces,,,it makes referance to the amount of heat the plug itself either retains,or disipates

you will want to go to a "hotter" plug in the winter months because the plug will retain heat,and go down to a "cooler" plug in the summer months where heat is an issue

 

your right,if he has fuel combusting in his tank,it wont make any differance what octane he is running,he will have a front seat to a grizz BarBQ

 

And less to deal with between his legs!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!![img]i/expressions/face-icon-small-shocked.gif[/img]
02 650 camo

 

I called the dealership today. They claim that since I was at a higher altitude in tennessee it was running lean. They say they can installl a larger jet in the carb and make iit run richer which may become a happy medium. According to the Gps unit we had we were only at 2000 to 2500 feet. I am going to try the higher octane and wrap the pipe between the carb wiith header tape first I believe and see what happens.. I didnt have any problems in the hottter months like July when I purchased it. Last week when it started was Tennessee around 45 degrees in the morning when we started out and around mid 70s in the hottest parts of the day. The engine and coolant are not getting hot, its the fuel in the carb next to the factory pipe. You could actually hear the fuel in the carb boil sitting still with the engine off and strong vapors I assume from the vent pipes. Why cant Yamaha fix this. From what I have heard the last two or three years lots of people have been fighting this problem.

 

You should not need to re-jet for 2000 feet.Thats crazy.Thats also no answer for the fuel boiling in the float bowl.When you go up in altitude the air gets thinner which means you need LESS fuel.There are less oxygen molecules.These guys never get this right.We are in Indiana and our altitude here is 800ft ASL.We ride in West Virginia at Hatfield/McCoy all the time and NO ONE re-jets.............this incls Prairies,Grizzs,Kodiaks,Eiger and even two Polaris's.The exhaust wrap will do wonders.The guy that did his took the exhaust off and wrapped it that way.It has not came off.Thats where a huge percentage of that heat is coming from.From everything our three has tried that by far was the biggest help.Good luck
02 650 camo

 

The Dealer is either FOS or they do not know what they are doing. The higher in altitude the quad is moved the more the air (oxygen) thins out. The air thins out and the jet size remains the same causing the engine to run rich.

I would think twice before returning to that dealership.

Using higher octane fuel will help as it has a higher boiling point.

Also, the higher the octane rating, the higher the flash point. The octane rating is boosted to prevent pre-ignition caused by higher cylinder temperature and compression.

High performance engines can actually retard timing to compensate for use of lower than recommended octane rated fuel. Retarding an engine will have a cooling effect on the cylinder temperature, just as advancing will cause higher cylinder temps.

 

That dealer has it bassckwards on the altitude and rich/lean. I always see vapor come out of the fill hole when removing the gas cap on the Grizz I ride with, an 02 with heat kit update. Never made it have an operation problem for it. The thing just throws off ALOT of heat.

 

If you are running lean, your engine is going to be hotter which makes your pipe get hotter and maybe causing your fuel to boil. When they adjusted your valves they may have created a lean situation. If you didn't have a problem before the valve adjustment it's almost guarinteed that is what's causing it. Put in a new plug run it til it gets hot and check the plug condition. If it's white or ash gray, you are lean. Rich will be black and sooty. If your air/fuel mixture is right it will be light brown.
You can switch to a coolant like Engine Ice. That will make your motor run a little cooler but I still think your problem is in your valves. Have them readjusted by someone else.

My wife has been using the bucket to move a lot of dirt lately and has caused the red light to come on but she said the engine never sputtered. The Grizzly can run hot without boiling the fuel.

 

i have had the same problem with my 05 grizzly with less than 25 hours on it. it sputered out on a hill causing it to roll backword which resulted in considerable damage to the machine yamaha canada says there's nothing wrong with the bike. now i have a brand new quad which is useless. i don't know if it was boiling fuel or what. any suggestions as to what i can do? do you know of other instaces of this?

Thanks for any help or advise you can give me.