Warrior Running Rich With Aftermarket Parts

Hey guys. I hope somebody can help shed some light on this one....

So my warrior has been sitting for a while since it broke the woodruff key. I fixed that, then it wouldn't idle except on choke. So I go through the carb real good and fixed that issue. Then the recoil "blew up" and the electric start quit, so I fixed up the recoil and found a burned out fuse. I replace the fuse and now everything is basically back to normal. Now I notice that the warrior runs fine until you get to about 3/4 throttle where it starts cutting out. I figured it was running lean since I recently put on a UNI Pod Filter that goes right on to the carb, and the quad already had an FMF MegaMax II slip-on. So I put in a 150 main jet (larger) and now it runs fine until only 1/2 throttle. Come to think of it, the warrior started doing this right after I put on the UNI Pod Filter (which was right before it broke the woodruff key). So it would seem the warrior should be running lean right? Don't aftermarket intake and exhaust parts make motors run lean? But since it ran worse with the bigger main jet, it must be running rich. How could that possibly be, and what can I do?

I suppose I could put the stock jet back in and lower the needle. Or I could buy a smaller main jet.

Could there be something wrong with my pipe? I took off the spark arrestor and the pipe appeared clear.

I was planning on getting a new HMF pipe, but I'd like to know if there's some serious problem before I go spend $250 on the quad.

Thanks for any help!

what notch is the needle clip on?

By the way, the carb seems to get gas all over the exterior of itself, I was thinking maybe it needs a new gasket between the bowl and the rest of the carb. Could that be part of the problem?

Inspect your spark plug. Check it's condition to see if it is running rich or lean. If I were you I'd replace it if you haven't already. Do that and see what happens. Could be that simple. If that doesn't do it, rejet to stock and see how it runs to get a baseline, then go from there as far as jetting. Also, check the intake boots.

yes drive it around for a bit and then pull plug and see what it looks like and yes replace the bowl gasket

I haven't checked the needle notch yet. What's the stock position? I'll be taking the carb apart for like the 5th time soon so I'll check then. Whoever put on the pipe did not jet the carb, so maybe they just adjusted the needle.

middle or third down from top is stock setting

Wow thanks for all the uber quick replies! I don't have a car at the moment so I can't go get a new plug yet, but I probably could a little later today.

OK so I decided I'm going to buy a carb kit tomorrow. It has all the O-rings and most of the brass parts and it's $23 from a dealer that's in a nearby town. So I'll use basically everything in the kit and see if that helps. I'll replace the plug and check the intake boot on the cylinder for any cracks/holes. And while I have the carb apart I'll check the needle position and use a stock size main jet. By tomorrow or maybe Thursday I'll be able to try all this and post an update. In the meantime I'll fiddle with it as I can and check here for any other suggestions.

Also, make sure the accel pump is wroking correctly and not leaking.

OK so guess what...I changed the plug and it runs so much better! I never thought a plug would make that much difference on a 4 stroke. I guess I'd never changed the plug in it cause it had some weird Champion brand plug (not even the right one), and I run exclusively NGK when I put in different plugs. So I put in a basic NGK D8EA which seems to work good in all my Yamahas. It still starts hesitating when you reach about 3/4 throttle, but jetting should fix that. I'm gonna wait to mess with the jetting though since after it ran that good I was confident enough to order my brand new HMF pipe, which may make it run differently, perhaps needing the larger jet that is currently installed. So I'll give an update with pics when I get the new HMF

I know what and where the accelerator pump is in the carb, but how do I know that it's functioning correctly? To tell the truth I don't even know what the heck it does

wow!!! I wonder who the idiot was that put a Champion in it lucky it didn't burn a hole in piston or **** up the valves

you have a FMF Megamax 2 right ? if you wanna sell it cheap when you get you new pipe let me know

Cool beans dude! A worn/old plug can make any engine run like ****! And a champion plug is just a joke. Only good plug they make are the ones for the 5.4l 3v fords so they don't freakin brake off in the hole. Bosch not far behind, imo. The accel pump litterally squirts a stream of raw fuel into the carb from teh inlet side (air box side). Just remove the intake boot from the back of the carb, look at the inlet and you'll see a brass "stem" sticking up, hit the throttle and you will see the stream of fuel it shoots out.

If it just has a filter hanging on the end of the carb then there just isn't much support for the intake boot. When the boot pops a hole it may be small but it'll create enough of a leak to run just as you described. If you can ride it a lil, reach down & just give the carb a tug while maintaining a steady throttle speed. It'll likely act dumb as hell if it's leaking. In the mean time, figure out a way to support that carb or you will bust the boot.