i had this same problem on my 98 yamaha grizzly 600. it has 27 inch vampires and the exhaust is changed up some with a car muffler and bigger piping. otherwise stock. but it only runs 35mph and takes awhile getting there. it starts up no problem and blow no smoke at all. i regreased the primary clutch part and nothing changed. any ideas for me? i ordered a new belt in case its slipping some. i even rode it around with no cover on so i could watch the belt and it all looked fine. I NEED HELP!!! email is toyotaman92@hotmail.com

 

What year Grizzly is it and how many miles are on it? Did it run that slow when you had the stock muffler and exhaust pipes on it?

 

i bought the fourwheeler like that and its a 1998 like i said, but it made it maybe a mile or two faster with the new exhaust over the stock one. any ideas or help would be great. thanks

 

Oh, sorry, when you said, "i had this same problem on my 98 yamaha grizzly 600.", it sounded like you were referring to a previous 98 you had with the same problem as this Grizzly, I didn't know they were one in the same.

Well, I don't know what the top speeds of a '98 Grizzly should be, but I'd guess it's higher than 35mph. Putting a new belt on is a good start. See if there's any change after it's installed. If not, maybe do a compression check on the motor to be sure there's not any internal combustion problems contributing to lack of power. You may want to rule out carburetor problems too by cleaning the carb and checking it over, as well as making sure the air filter is clean and not causing any type of air flow restrictions. Just throwing out some things to check here.

Not being able to hear or ride it, it's kinda hard to diagnose what it could be. Maybe someone with a 600 Grizzly will have some suggestions.

 

In addition to changing the belt, I would also grease the clutch.