Sorry stock main jet should be 122 not 128, I bumped mine up to 128 because of running to lean. If wanted to you could bump it up to a bigger main jet like a 132 at sea level to give it more performance but if happy with the way it is you could just clean the jets all up. Did you drill out the fuel needle adjuster on the bottom of the carb yet? It's covered by a little cap an that'll help you tune it.

 

It was already drilled out, meaning someone had been thru the carb B4. That seemed odd for a 2000 mile quad. I set it to factory specs according to my service manual.

 

Where can I get bigger jets? Im an old hot rodder and all about performance!

 

It's a Keihin CV carb, you can get jets at most cycle shops. Or you can go to denniskirk.com. They are a little pricey, but they ship really fast. I also upped the main jet and all I run is the UNI air filter. I do recommend one, they are more durable than the stock filters and easier to clean/re-oil IMO. I think I went up to a 130 main jet. THese quads are known to be lean from the factory. Might want to adjust the air/fuel mixture as well.

Are you running alright now?

 

Its hard to know how she really runs because for the last 3 years Ive probably never run her ove 20MPH. Mostly 5 to 10 mph mowing and plowing. That is changing this year as move her to a 5500 acre ranch I hunt on, so upping the jet for better high speed performance might be a good idea.

 

You can get jets from most cycle shops. Sense it was altered before you might want to make sure all the jets are stock. If you take that top bowl off the carburetor and cut 3 coils off the spring inside you'll increase throttle response out of the hole. Don't cut to much though or else you'll have to get a new spring. With a bigger main jet your quad will get up to speed faster when floored. I removed my spark arrestor out and put a twin air filter in so my quad was running very lean that's when I learned about jetting.

 

OK, the saga continues and it's not going well. Got down to the ranch and put the carb on. Wouldnt run at all with the 130 jet. Went back to the 122 and it starts and idles fine but when you hit the throttle it only revs up a couple thousand rpms. It also sputters when running and then backfires big time when the motor is turned off.

I guess it's time to spend 450 bucks on a new carb becaue Im going nowhere fast!

 

From my understanding, the main jet has little to do at start up. The main jet kicks in upon giving it throttle. I don't know what you got going on. If you got junk in your jets, sometimes just spraying air or carb cleaner is not enough to clear them. Sometimes you got to use a really small wire. You should be meticulous when cleaning the carb, take out all the removable jets, needle, etc and spray carb cleaner thru every opening until it comes out the other side. Make sure the float doesn't have a hole in it. Check that the float needle moves freely up and down with the float.

What does your plug look like? Are you fouling it out?

 

Ok, I cleaned the carb, super simple. Found debris and cleaned thoroughly. Still sluggish out of the hole. Once up, she rides fine. why?? Does the needle jet have anything to do with this? Does it rise and fall with the diaphragm?

 

OK guys this saga continues. I sent my carb off to be rebuilt. it came back beautiful. I got down to the ranch and put it on. Same problem. The machine will start with difficulty, it will idle but it pops and sputters and backfires. The plug comes out wet. Could this be an ignition problem?