Looking for help Jetting Grizzly 660 above 8000 feet. Currently running 147.5 main and needle clip in the center with K &N air filter. Runs ok at 4800 feet. Dealer Jetted it the last two times. Apparently they don't know what they're doing either! Any help would be appreciated!

 

I was told that I didn't need to worry about mine unless I got above 10,000 feet. Doesn't sound like my dealer has any better info than yours. What year Grizz?

 

As altitiude increase the air becomes thin, so you need to jet down. However if the air is also colder then you will need to jet back up. It's a trial and error process.