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Hello all. I recently purchased a one owner 2002 KDX220 that had been sitting for quite awhile. Currently has new tires, chain, brakes, air filter, plug, carb cleaned etc. It was the original top end so I took that apart this week and replaced it with a Wiseco (first ever top end build). Bike fired up on second kick which was amazing. I put Boyesen power reeds in and removed the snorkel, otherwise stock.

I have a ride coming up in a week so I want to get it idling and running properly. I am working on adjusting the idle as it sometimes will die when coming to a stop, but this thing smokes and throws splooge like crazy.

I believe stock jets are 145/42? I have a new jet gasket coming in case the carb was dipped before I bought it. Does anyone have a recommendation on a jet assortment from Amazon etc that I could get quickly? My hope is to dial it in this week as I will be riding at 1600ft and 600ft for a few days. I plan to re read the jetting guide, but I assume im rich, I also plan to keep an eye on the transmission fluid levels. Looking forward to reading and learning on here!

As others have said, imitation jets from Amazon vary wildly in quality and in the end it's just better to go to Sudco or Jets R Us and get OEM for not much more. The jetting guide is easy to follow as long as you:

• Change one thing at a time and then test

• Pick an oil, and a ratio, and stick with it

• Make sure the rest of the intake and exhaust tracts are mechanically sound

bufftester wrote: ↑07:24 pm Aug 02 2023 As others have said, imitation jets from Amazon vary wildly in quality and in the end it's just better to go to Sudco or Jets R Us and get OEM for not much more. The jetting guide is easy to follow as long as you:

• Change one thing at a time and then test

• Pick an oil, and a ratio, and stick with it

• Make sure the rest of the intake and exhaust tracts are mechanically sound

I 100% agree!

You should have a local shop (well, depending on where you live) that keeps genuine Keihin jets in stock. You can even order through RMATV and get them normally in 2-3 days.

On the jetting, I'd bet you'll probably end up close to a 38/40pj and 150/152 main. I would order all new jets and not reuse the old ones but that's just me. I don't like to deal with varnished and/or aftermarket jets. A good mix to have for your elevation would be 38,40, and 42 pj's and 150, 152, and 155 main jets.

SS109 wrote: ↑07:52 pm Aug 02 2023

bufftester wrote: ↑07:24 pm Aug 02 2023 As others have said, imitation jets from Amazon vary wildly in quality and in the end it's just better to go to Sudco or Jets R Us and get OEM for not much more. The jetting guide is easy to follow as long as you:

• Change one thing at a time and then test

• Pick an oil, and a ratio, and stick with it

• Make sure the rest of the intake and exhaust tracts are mechanically sound

I 100% agree!

You should have a local shop (well, depending on where you live) that keeps genuine Keihin jets in stock. You can even order through RMATV and get them normally in 2-3 days.

On the jetting, I'd bet you'll probably end up close to a 38/40pj and 150/152 main. I would order all new jets and not reuse the old ones but that's just me. I don't like to deal with varnished and/or aftermarket jets. A good mix to have for your elevation would be 38,40, and 42 pj's and 150, 152, and 155 main jets.

Isn't stock jetting 42/145? So you think I would go down on the PJ and up on the main even though they seem to run rich from the factory? I'll just get a few jets as options. I am really looking forward to getting this out on the trails next week.

Swanpuppy wrote: ↑11:22 am Aug 03 2023 Isn't stock jetting 42/145? So you think I would go down on the PJ and up on the main even though they seem to run rich from the factory? I'll just get a few jets as options. I am really looking forward to getting this out on the trails next week.

Yes, that is stock jetting.

What I'm going by is what I've seen other KDX's run at for certain elevations after going through the process to dial it in. For example, my KDX220 is on a 38pj, 150 winter/148 summer main jet at 2000ft ASL. Mains get smaller as you go up in elevation and vice versa. Your 1600 elevation would be close to my jetting so a 150 main would probably be a good starting point. Now, 600ft elevation you'll probably need to go up a step on the main.

On the pilot jet I've noticed that KDX's don't need a lot to keep them running correctly. I've run the 38pj from 1600 to over 8000 and, other than air screw adjustments, have never needed to change it.

Of course, following the jetting guide is the only way to know for sure what YOUR bike likes.

BTW, another thing that can make your bike smoke like crazy is that the silencer packing is fully saturated and/or the pipe has a lot of oil in it. Also, make sure to set your float height to 18mm and not the factory spec.

Great information, I appreciate it. I have a few sizes on order and will play with them.

Keep in mind that the PJ is metering fuel at ALL throttle positions, whereas the main is only playing from about 1/2 to full, with the needle in there for midrange. If your PJ is way rich, nothing you do on the other 2 will change your rich condition. Thats why you always set your PJ and starting AS settings and build on that. Every bike is slightly different and you can have identical bikes with identical mods running different jets, you just need to find out what your bike likes.

Quick update on where I am with the bike. Trailered the KDX along with a friends WR250X, and my TTR125 up north in Wisconsin for this weekend. The rear shock now appears to be leaking slightly so I will need to figure out how to rebuild that.

I started working through the jetting guide, the air screw would not stay in position.... turns out when the previous owner rebuild the carb he decided to not install the spring, o ring, etc. So the screw just spins on its own when the bike is running. Makes setting anything up impossible, so I will be off to the hardware store to try and find a spring that fits. If anyone has rough specs on it please let me know, I am simply assuming its .5" and I'll take the screw along with me.

yes, that picture is where I assumed .5". There is no time to order anything as the ride starts on Friday. I did manage to get a screw and o ring to fit. I am working through the jetting process, which isn't going super well. The spring wont be the same spec so getting the pilot jet correct isn't right. I will have to try and get it so it idles and runs reasonably well with what I have.

Get some blue loctite and coat the threads of your air screw with it and then let it air dry. Do that a couple times to build up a layer, should help keep the screw in position while still being able to get it out. Kind of a poor mans nyloc fastener.

I think the jet block gasket was causing some of my issues. I replaced that and it holds idle very well. 40PJ, needle I raised the clip to 2nd from top, and haven't looked at the MJ yet. Still needs some adjustment to get the low power it had before but it's idling, running, pulling gears with a lot less smoke. The trails we will be on this weekend are very tight single track, mainly 1st and 2nd gear with minimal open areas, so if I have time I will do a chop test for the MJ. My tank had a hole I did some ghetto plastic welding and put an epoxy patch over the top, that seems to be holding as well. Thanks all, we will see how she goes this weekend.

If you need it in a pinch the loctite like bufftester mentioned will work. I lost the spring one time and needed it to stay put for a ride in the morning. I wrapped the threads with a couple of layers of the white plumbers "tape" and it held the screw in place for the day.

update time. My tank patch did not hold, it was leaking the entire weekend and my new tank cap was leaking as well. The rear shock started leaking after the trip up, but it worked adequately. Overall the bike performed amazing. This is unbelievably better than my DR650. Friday/Saturday AM was tight single track with some rocks/log jumps and sand. Saturday evening/Sunday AM was mud/rocks up in the Keweenaw peninsula in the UP of Michigan. The jetting was pretty good but im sure can be dialed in further, but it would rip easily to 40-50mph for open logging road routes.

Tank repair needs to be done, and I may send the shock to be rebuilt. After that the bike needs some cleaning, higher headlight output, graphics for a HP boost, etc. Excellent bike.

Congratulations on the ride. Nothing like riding to find out where the problems are (besides racing). :-)

Does anyone know of options for a rear shock rebuild? I would like to get it sent out for new seals, bump stop, etc. Thanks!

How about Jeff Fredette racing.
https://www.frpoffroad.com/itemgroup/fr ... ty-items-2

Jeff is about 2 hours from me. I have not been able to get a return phone call or email. He was my first pick, but I am not getting any responses.

Swanpuppy wrote: ↑07:29 am Aug 22 2023 Jeff is about 2 hours from me. I have not been able to get a return phone call or email. He was my first pick, but I am not getting any responses.

Maybe he's on vacation.

Does anyone have any other recommendations for a rear shock rebuild? FRP off-road is non responsive, almost like the company no longer is in operation. Thanks!