I've got a friend who has about 10 hours on an 04 Grizzly 660 that keeps fouling plugs. We're almost at sea level. I'm thinking either the choke is sticking or the float is off. I doubt the stock jetting is off but I'm asking if there are known problems of this nature with Grizzlys.

 

How long since the air filter was cleaned and reoiled? Was it over oiled?

 

2004

 

Id start by cleaning and reoiling the air filter. If it was dirty, that would lead to running rich. All look for small rodent nests in the air snorkle area .
Its posible the enrichener(choke) is leaking, but its a long shot.

 

Thanks, I've got him checking out the intake system. I thought he might have delved into it a little deeper.
I haven't checked his bike yet, just wondered if this was some common problem. I found that this is supposed to be a 42mm mikuni bsr. I'm quite familiar with them as that is what is on my DS. It could be a sticking choke or torn or leaking CV diaphram. He's complained about poor mileage and fouling plugs since day one.