I'm new to this site but not new to Quads. My current quad is a 05 eiger I bought new and so far its been a great quad. This winter I got married and took the quad from the farm and did some maintenance to it. Now I'm looking at maybe jetting and removing the spark arrester in it and also the air box mod. I don't ride in forests or public trails. We have land we mud in an then do snow removal in the winter. When i took my quad out I noticed that when i started it up it was cold blooded an didn't like running without the choke until fully warmed. Also when i accelerate an then completely shut off the throttle it back fires, but if i put my choke on full an let off it won't backfire. To me it seems like its running lean. Am I correct? I've looked this site over pretty well and figure that bumping up a few jet sizes wouldn't be horrible idea. I'm just wondering how much. Where I live its around 1500ft elevation. Any help would be appreciated.

 

Yes, those are symptons of running lean. I bought a kit that came with several main jets and a needle jet. I went with a 135 but my altitude is 250-300ft. Also suggest adding an inline fuel filter. You may find this helpful. Keihin 32CVK Disassembly

 

Yep I figured it was. I was thinking a 130 or 135 for mine with all the mods I want to do. O ya I've had a inline fuel filter for quite a while. My carb kept getting clogged with junk before I did. Yep lol I printed that out the other day and am glad I did. The only thing keeping me from doing it now is Im not sure how to get that throttle body plate on the exhaust side of the quad off.

 

Just to update. I have a twin air filter, and the spark arrestor out and my carb has a 128 main and the mixture screw out three turn and its running a lot better. When I looked at my pilot jet it was pretty clogged so I cleaned that out also. I might need to richen the idle mixture screw just a little but other than that it runs like it should. I'm around 1500ft and my temps are around freezing.

 

These are well known to come lean from the factory. I changed to a UNI filter and run a larger main jet, but that's all I've done.