Hey guys, 1st post here.
I just purchased a 2000 600 Grizzly with only 604 miles. Like new in all respects but, I am having some issues that I am thinking are all fuel related. I am thinking of putting in a fuel filter. I cannot understand why there isn't one in the system originally but it is all original and there is no filter. Is there a good reason why there is not a filter? I have a friend with a Honda that didn't have one and he was having a few fuel system issues that were cleared up with a filter and he is running good for a couple of years now. His ran good up to the time of some problems that a tech couldn't cure but a filter seems to have cured. That is why I would like to add a filter and , I don't really understand why there isn't one there from the factory.

 

There is a filter, two in fact. Both are on the ends of the pickup pipes in the fuel tank. Remove the fuel tap assembly to clean them. However they are just fine mesh plastic and don't catch the grit that blocks carb jets and makes the float needle stick open, so an in line filter may be a good idea. However paper element ones have a nasty habit of air locking if you run out of fuel. So if you run out, and put the tap on reserve, they don't let the fuel through.

 

 

Thanks for the replies guys. I have downloaded the service manual and will use it as a guide for cleaning up the carb. I have put an inline filter on it and went for about a 15 mile ride in the hills around here. It runs quite well and there is very good throttle response. The idle speed adjustment is very touchy and it was set too low initially. Are these quads real hard on fuel? It seems to have gone thru about 3/4 tank already in the 25 miles I have put on it. I pulled the spark plug yesterday before the last ride and it was somewhat carboned up telling me it is running very rich. The inline fuel filter I put on yesterday still looks like new - no sign of junk in the tank yet. I am going to do an oil/filter change tomorrow or the next day because I don't know how old the oil is.even though it looks real good.

 

Yams have a reputation of being thirsty but if the plug is sooty, the most likely cause after a long lay up is choke sticking. Most Quads have an excess fuel type "choke" so if it sticks open, you get excess fuel all the time. Can be the cable, or the plunger in the carb, which is extremely difficult to get out if well stuck. Rodent nests in the airbox, or snorkel tube can also restrict airflow.

 

I would take the tank and carb off and clean them all. Install a inline filter like you did. also check the bench setting on the air fuel mixture screw. That can cause it to run rich or lean. It is easy to adjust to perfection once you get the bench setting. Most yamahas are 2 turns out from lightly seated. Put a new spark plug in it and see how that goes. I personally mix 2 gallons of 110 and 3 gallons of 91 non oxi gas in my wheelers because I don't run them allot. Good luck with it I will be starting a full rebuild on a 600 here in a month or so.

 

Thanks guys. Is there any way to know if the choke sticks open? With the 'excess fuel type choke' would it also be idling somewhat higher if it was sticking? There really doesn't seem to be much resistance to the choke cable and almost no change in the engine rpm or starting ability. It does start easily but that may be expected here in the Parker Az. area as it is warm.

 

If the choke is stuck, the spring will not shove the plunger back down, which pulls the cable, so no tension on the cable at the handlebars, but it is difficult to tell. Yes the revs rise a bit with choke on, but not all that much so someone who has never experienced how it used to idle, may not notice. I would be very wary of altering the idle jet setting. They are factory set, and unless someone has been "fiddling" with it, should not need re-setting.

 

I presume you are referring to the pilot screw. That is the only one referred to in the service manual and it says 3 1/2 turns out.

 

the air fuel mixture screw it is on the bottom side of the carb on the head side. guess it is called the pilot screw that is odd that many turns Never seen a Yamaha especially that small be that many turns.