Just wondering how many have encountered this? I've had my 06 Grizzly for what will be 5 years this fall. I've read many threads where people say this is impossible or Yamaha would have fixed it. LOL yeah right. Mine will always do it after 20 minutes of lugging it in hard trails at low speeds. I run a lot of additive in my gas to get the octane up do to the lack of high octane gasoline available locally. Just looking to see what dealings others have had with this? Do the 700's do this as well?

 

My question is this?
Where do you live that you can't get pump gas with enough octane to run in a stock Griz?
A lot of octane boosters have alkie in them to boost the octane. If you use a lot in the mix, there is your problem.

 

my question is why are you running high octane fuel? we run crappy 87 purple farm fuel through our 02 and and it has survived 21,000 kms.... how do you know your fuel is boiling?

 

I only seen it once on my friends 03 660 , but he was stuck going up a steep hill while pulling a 500lb ATV trailer. That was 4 years ago and the ATV never did it again.

 

The 07-08 700's did have a gas boiling issue. The fix was as simple as a bigger gas tank breather valve/filter!

 

Thanks Guys ...(doctorturbo) yeah i was kinda wondering if all the octane booster i was adding was lowering the boiling point...i read gas can boil anywhere from 102-almost 400 degrees depending on how it was mixed...(unclebubbles) My grizzly tends to die or backfire easily on 87 octane...just normal on road or checking cows in the pasture is fine but after jetting, exhaust, cdi box, oversized tires..etc..etc... it runs much better on the high octane...as far as how do i know. turn the key off its sounds like its at a rolling boil, open the tank and look in(proved to be a bad idea it was wanting to splash out)...yup definitely a rolling boil......(TLC) yeah it mostly happens when following a long line of slow riders up steep hills...if i can fly it never happens...(Dodge57Hemi) that sounds like something worth trying ...i know my vent is open..but im sure i can find something bigger!

 

Oh and Drturbo...just fyi i Live in a town of 1800 people which is the biggest in our county its an hour drive to the nearest station that sells a high octane racing type fuel everything here is 87 unless you special order(55gal min) and i dont use enough to justify doing so.... Thanks again everyone!...It's not what i consider a big problem was just curious as to what others had seen!

 

[QUOTE][
Thanks Guys ...(doctorturbo) yeah i was kinda wondering if all the octane booster i was adding was lowering the boiling point...i read gas can boil anywhere from 102-almost 400 degrees depending on how it was mixed...(unclebubbles) My grizzly tends to die or backfire easily on 87 octane...just normal on road or checking cows in the pasture is fine but after jetting, exhaust, cdi box, oversized tires..etc..etc... it runs much better on the high octane...as far as how do i know. turn the key off its sounds like its at a rolling boil, open the tank and look in(proved to be a bad idea it was wanting to splash out)...yup definitely a rolling boil......(TLC) yeah it mostly happens when following a long line of slow riders up steep hills...if i can fly it never happens...(Dodge57Hemi) that sounds like something worth trying ...i know my vent is open..but im sure i can find something bigger! /QUOTE]

Ok, now I have a clearer picture of what is going on.
Is your Griz carburated or F.I.?
Your Griz shoud not back fire on 87. Something is wrong.

First thing I would check is the valves. My KFX is starting to do that and I know the valves need adjusting.

How does the plug look? Sounds lean. And this could be the problem. Pull the choke on just a little bit and see if the problems go away. If carburated richen the idle mix up a touch.

Anyway, good luck and let us know.

 

Yamaha had a recall to put heat wrap under tank to prevent this when i worked at a yamaha dealer also put it on fuel line.

 

It is a carb. Valves are fine recently adjusted. Runs as it has since new. Yamaha said minimum 91 octane from the factory. Like i said really no complaints, was just curious. Mine was post recall and has the rather thick insulation under the tank.