I don’t know if I need a bigger hammer or not! I have a 98 Grizzly 600. A while back, the gas would leak out because, apparently, the needle was not seating to shut the gas off. I bought a carb overhaul kit and installed it, but now have a new problem.

We found the rubber carb mount cracked, so we replaced it with a new one when we removed the carb. When we started it up, it started easily and idled nicely. I drove it around the bottom of our track and it felt nice and maybe a little stronger than before. I then opened it up to about half throttle and everything was good. I punched it to full throttle and the response was great. I then held wot and suddenly it felt like the engine died. I came off the throttle and it was running great again.

I then took it down to a straight stretch and held wot. It accelerated very well, but after a couple seconds felt like it ran out of gas, then picked up, then ran lost power again and continued this every second or two.

First thing I did was double check the fuel level. It was just above the fuel bowl joint, so it seems to be pretty close to right. We went back in and found the main jet was a 144 instead of 145 (apparently the aftermarket kits have different sizes than the original Makuni jets). We have tried the 145, 147.5, 150, and 152.5, all of which give the same result. The larger jets still stumble, but it seems as if the bike recovers faster. We raised the needle 1 notch but did not notice any difference.

We didn’t have a new plug to install, but used a slightly used one that was a little black, but when we checked it it looked as if it was burning off as it was not as black as original. (The local store was out of plugs for this thing so we have a few on order.)

I know this is a long post, but I am hoping somebody will read it and suggest something simple I have apparently missed.

Thanks for any suggestions.