[robg]

Just when I thought I had it licked... and in fact hadn't had a problem with it since I vented my original side panels (and then added the 04 panels soon thereafter)...

Yesterday my gf and I were on a ride maybe ten miles north of my house. We were in a narrow canyon climbing up some rock ledges. She was on my Rincon and I was on my Grizzly. Temps were in the mid 80's with a variable breeze and virtually no humidity as is the case in the high desert of Northern Nevada.

She, being bew to the sport, wanted me to ride the Rinny up the worst stuff. So after getting the Grizz up, I'd park it, walk back, and get the Rinny.

After the third instance of this, I got back on the Grizz to continue, and it died. I heard the sound and smelled gas... so I pulled off the seat and left side panel and saw gas draining out the bottom of the carb. I tapped it with a rock and it stopped. I figured the float was just stuck.

I let it sit for a few minutes, and then started it. It fired up fairly easily, but almost immediately, it did it again. This time, gas was rushing out of the drain hole AND also one of the breather holes up near the top -- which didn't have a hose connected to it since I lost track of that hose ages ago.

Stupid me didn't think to turn off the fuel valve... instead I lost almost half of my gas all over the quad and the ground.

We took off the fuel cap and the gas in the tank was clearly boiling. We decided to let it sit for a while. We kicked back in the shade and dug for quartz crystals for an hour. Then I decided to ride with the left panel off. It behaved the rest of the day.

In the past when I'd have fuel boiling problems, it was NEVER this bad. The most it'd do is just vaporlock and sputter. This was more like the gasoline was carbonated and had been shaken up.

I'm still kicking around what to do about this... it seems that more ventilation is required, so I'm gonna dig my old side panels back out and vent them some more. I'm also considering one or two fans to help force the hot air out of the engine compartment. Lastly, I'm considering a Cool Can setup for the fuel system -- running from the tank into a fuel pump, and then through a small transmission cooler with a fan, then back to the carb.

I'm determined to lick this once and for all.

Rob

 

[xtremegrizz]

Well Rob I have to admire you for atleast your persistence in trying to combat the problem. Wish I had some ideas for you but I don't, all I can say is good luck and keep us updated. Mike

 

[outerlimit]

The '04 Grizzlys have more than just new side panels. They also have extensive under tank heat shielding, and I wonder if you could purchase that for your Grizzly.

It was pretty hot here in southern Utah today as well, and my Grizzlys engine fan was on continuously for 45 minutes at one point. I had no gas boiling problems despite the increased engine temperature, and despite the clutch housing being so hot I could not lay my leg against it without getting burned. So maybe the "other" changes made to the '04 Grizzlys will work for you.

I had my own problems today though ... over backwards while trying to climb a particularly tough climb.

 

[james]

Rob, checkout atvquadsquad.com, there is some good discussion about Yamaha, and their response to this problem, including what Outerlimit was saying about the extra parts, in addition to the 04 panels. Apparently Yamaha has a whole heat kit available for Grizzlies built prior to 04.
By the way, sounds painfull Outerlimit, sorry to hear about that, nice to see that you can still type, how is your machine......

 

[outerlimit]

It was a slow motion low range rock crawling type of backwards tipover. The front tires hit a rock, which popped the front end straight up into the air. I let off the gas and got on the brakes, but it just balanced there for what seemed like a minute before slowly easing over backwards. Bent front rack was only damage, and that has already been straightened.