We snorkeled a 98 grizzly 600. Pain in the rear getting 3 tubes out. 1.5 on transmission and 2 inch on the intake. The carb mouth is 2.2. We made a custom air box that use a dirt bike air filter and it mounts on the front fender. LOL, best choke ever, just hold your hand over it to choke it. But, we are not getting good clean crisp power. It cuts out when you get on it. It runs best with a necked down adapter to app 1.25. But still not acceptable. I have lots of experience jetting dirtbikes, but not sure if this is the answer. Quite certain it is getting to much air. I could richen it up. Plug chops are not what I wish to do. That particular model has the plug in the worst place.

 

Never had a snorkel before...... half the time it feels like it's blowing on me..... the other half sucking??????????? Why is it blowing?

 

I was estimating that it was getting to much air.... because it ran better with the snorkel reduced from 2in to 1inch. I found that hard to believe and had a big ? over it feeling like it was blowing back. But I took a gamble and tried going with more fuel on the bases that it seemed to do better on choke... which with the yamaha is actually a enricher instead of air choke. I borrowed about 20 jets from a friend because my 20+ were in the 125 range. The stock for the Grizzly was 145. His turned out to be the wrong type, so I began drilling. It is not quite, well almost perfect having drilled it to the equivalent of a 164. That's alot. It seems to not have all it should yet before, it had stock tires, now it has 28 mudders. So maybe it is close. I will fine tune from here. Probably going to have to do plug chops to know for sure. But the bog is gone and it is strong throughout the entire throttle range