i just bought an 02 grizzly 660 about 2 months ago and have many problems with it first it doesnt like to start good at all usually battery runs dead before it starts then it has a jet kit in it and in high range when i try to go fast it doesnt go over 20 mph or it starts back fireing and doesnt run good i was wondering what that is from

 

Did you check the spark plug.

 

yes we just put a new sparkplug on and its working alittle better but still backfire alittle bit

 

Sounds like youhave a couple of issues.
Check the intake valve clearance for the hard starting issue. Those motors are known for the intakes tightening up, and loosing compression, which makes for hard starting on a cold motor.
The primary pulley weights are gonna need to be relubed, to make it go over 20mph, this is common, and is part of regular maint on these yamaha automatics. It probably hasnt been done in quite awhile, and may even be coked up with mud and dirt.
The backfire is from lean, so check the float bowl for crud, if you find any, the carb will need cleaning. At a minimum, flush out the float bowl. Is the air filter box, lid, still attached, or have holes in it?

 

Nope no holes in the air filter box but its running much better today without any back fire or starting problem but its 32 degrees outside and i let it sit in the sun alittle this morning but its working fine on a day like today

 

Not sure about your power problem, but I'll tell you about the very hard to start problem and what I did. Mine was starting just like you described, the battery would die long before it would start. It got so bad that after about a week of this,I had so much gas in the oil that it was never going to start. I had heard about the valves getting too tight so I bought a repair manual and did the valve adjustment, what alot of work just taking things apart to even get to the valves but well worth the effort indeed. all valves were so tight I could not even get my thinnest feeler guage between them.
Now after valve adjustment, this Grizz of mine starts before it has time for the engine to turn over!! well thats how i descibe it. it starts that easy. It has never ever started this easy and i bought it new in 2002.
I am willing to bet if you adjust your valves that most of these problems you have will go away. But while your doing this you really should take your carb of and at least check the float level, mine was too high.

 

ya the thing is i hate about yamahas is u have to take the whole wheeler apart to get to anything u want to fix this should be fun im 16 and i work on fourwheelers alot and am trying to train to be a mechanic so this will give me some good experiences.

 

SillyPhil is dead on... I had the exact same problem with my 02 Grizzly... hard starting in the cold weather... The valves were too tight... once adjusted... It starts great...

 

how do u adjust the valves??

 

anyone kno how to adjust the valves