KDXRIDER.NET

I am new to this forum, or any forum for that matter. My dad purchased a 97 KDX 220 last year after much persuasion on my part. He is 220 lbs and a mellow trail rider and I figured this bike would be right up his alley. We took it out twice before winter and it ran great and he really enjoyed it. We put it to bed for the winter with fuel stabilizer. It has sat for about two and a half months. We got it out yesterday and started it up. It started up fine, but doesn't want to idle without giving it a little throttle now and then. I took it for a quick spin around the neighborhood and it ran like a dog of the bottom end when the choke was off. It felt like it needed to clear out but never would reach the RPMs. I turned the choke back on and it ran much better. I let the bike idle and the RPMs would fluctuate quite a bit. I ran it without the choke and the idle would slow until it would sputter and die. If I pulled the choke right before it was going to die, it would jump up in RPMs and idle high. I'm going to his house to fiddle with it this weekend, and wanted some direction from experienced KDX owners. I plan on draining and replacing the fuel, new spark plug, cleaning the air filter, and going through the carb. I was just curious if the fact that the bike runs much better on the choke narrowed things down at all? We are in Utah at approx 4500ft and ride anywhere from 4000 to 10000. Bike is stock, aside from an FMF pipe and spark arrestor Any suggestions would be much appreciated.

Thanks,

I'd start with the gas and the carb, make sure you clean the jets really well , then the air filter. Also replace fuel lines, I've cleaned out carbs before only to have them clog right back up from some gick somewhere further up. Gick is in fact a technical term ( for what I have no idea) . Good luck and I'm sure it'll smooth out.

Welcome and great choice of bike.

The issues you are experiencing are almost certainly linked to the lay-up period and are fuel/carb related.

A no-brainer I know, but you're using fresh fuel and pre-mix, at the correct ratio, right?

If the bike's lumpy at the bottom end and wont rev through the rev range, but runs OK on full choke, it'd suggest (at least to me!), that there's a problem with the carb in switching from the pilot jet (start-up/choke), to main jet (normal running).

Unscrew the bottom of the carb to access the main and clean/replace. If this doesn't do the trick, perform a similar procedure right throughout the carb, with dis-assembly, cleaning and reassembly. It's tedious, but well worth the effort.

Keep us posted and good luck.

Drain out all the old fuel and start with fresh fuel. Don't change anything else and report back. Thanks.

EDIT: DOH!! Welcome to the site. Thanks for that, rbates9.

I would suspect a plugged up pilot jet. But draining the gas and starting new will need to be done anyway so you might as well start there.

Also you said that the bike is stock so you may want to look into replacing the piston. Search "220 piston failure" or "grenade". They have a tendency to break the skirt off and no good comes of it. No good at all.

By the way, Welcome to the site!

Thanks for the warm welcome and all the helpful suggestions. I will start with the fuel this weekend, and go from there. I will be sure to keep you posted. Regarding the piston issue, the previous owner didn't mention if he had ever replaced the piston. What is the easiest way to tell if it is the stocker? Can you tell an OEM piston from an aftermarket piston by just removing the head? Also, we are running golden spectro premix 40:1.

Thanks again!

An OEM should have a letter stamped into the top of it. Like an "A". I think. If you look around you should be able to find the right answer.