When yamaha went to the 660cc motor in the griz, did they just increase the displacement from the 600cc or was it a totaly redesigned motor? I was told the 600cc griz motor was not a 5 valve motor like the 660c and not as efficient as the 660. It this true? I know the 660cc motor is one the best all time motors and so I was just wondering about the old 600cc motor. Thanks for any answer. BTW, what years did they make the 600cc griz and what did you think about it?

 

I've had both the 600 and the 660. I think the 600 came out in 98 if i'm not mistaken? The 600 was a solid rear axle machine and the engine was oil and fan cooled, supposedly the engine came from some XT600 off road motorcycle I believe. I think the 98 Grizz 600 was also Yamaha's first auto belt drive machine. When the Grizzly 660 came out in 03 I think? it was a completely new machine from the ground up, liquid cooled motor with the 5 valve head, diff-lock, digital dash, independant rear suspension. Both are great machines, I had no trouble with either of mine.

 

I too had both, in fact the 600 was my first venture into the ATV world after many years on dirt bikes. The 600 was a good machine (never had a bit of trouble with it) but it was a rough ride compared to the liquid cooled IRS 660 version. I got rid of mine because I wanted to move up to a liquid cooled engine because at the time I did a lot of mowing with mine and it would overhead from time to time (hours of slow going work).

I was on a reservation list to get a 650 Prairie for quite a while, but just before they became available Yamaha came out with the 660 Grizzly (the '02 model year) and I ended up getting that one instead. Feature-wise the most notable additions were IRS and a front diff lock. The 660 was a noticable step up in power but as it turned out it would eventually overheat as well after mowing for hours. It wasn't long after that when I acquired a tractor and a bush hog so I didn't have to use the ATV for mowing any more. I still used the ATV for dragging logs though, and it had no problem with that. However when used for play, I could ride hard all day (on the Hatfield McCoy trail system) and not feel beat up like I did on the 600...