OK, my plans to leave my bike stock until my riding skills exceeded its capability went out the window when I bought a slip-on, filter and jet kit from another member this week. I know that jetting is voodoo science and every bike is different, but I would like to get some opinions on where to start so hopefully I get close the first time. Setup:

- FMF PowerCore 4 slip-on, stock header
- Uni Foam Filter
- DynoJet 2182 jet kit
- KDX 200 snorkel
- Riding mainly between sealevel and 2' below sealevel depending on rainfall

A couple of questions:

- What combination of main and pilot jets would you suggest I start with?
- What clip position on the DynaJet needle?
- I want to pull the carb and clean it when installing the jets and needle, but if I need to rejet will I have the pull the carb again, or can I rotate it and access the jets?
- Any other words of wisdom would be appreciated!!

 

Follow the Dynojet instructions, I believe that is the clip on the 3rd notch from the top, 124 main jet, leave the Pilot alone...I forget where the air-fuel screw is...I think it is 1.5 turns out from lightly seated. You CAN use the 120 jet, probably, as long as you make sure you keep the KDX snorkle in.
You CAN rotate the carb to get to these items, but, you have the float to worry about, as well as dropping dirt into the bowl, etc. I always just grit my teeth and take the darn thing out. I think it's best to do it that way.

 

+1 on following DynoJet's instructions.

If things aren't running perfect after you do that, then email DynoJet (via their website) and let them know what your exact setup is, what altitude you live at, and what the problem is. Be specific! In my experience, they are VERY GOOD at getting back to you quickly with a recommendation customized to your exact situation.

 

I have a similar setup and used the Stage 1 & 2 Dynojet kit. I stuck to the instructions and it worked fine for me. I'm on the 3rd clip and I think the 124 main. I think those should be a good starting point for you. Afterwards you can tweak it via the mixture screw.

Oh ya, you might want to pull your smog crap while you're at it.

 

Really, your riding 2' below sealevel. I would try and stay away from sea water & sand, it has a tendancy to get into everything, then it wears out.

 

Thanks guys, appreciate the real world input.

I was kidding. I'm in flatlander country in N. Florida and the woods get very wet with the seasonal rain at times. The water and mud is unavoidable but I keep the bike off the beach. Now the jeep is another story....

 

Or you can just buy a Dial-A-Jet kit, install it and pretty much forget it, since the OEM jetting is lean already. It is a proven fuel adder with reviews from DirtBike!, MXA, Motorcyclist, and others. Highly accepted in the ATV and snowmobile markets but snubbed in the old school motorcycle world. Although Dick's Racing uses them on his tricked out MX racing carbs.

As a fuel adder it simply uses the vacuum draw of a lean engine to siphon a gas/air mix as needed. When the vacuum is high, the fuel/air mix added is high, when low the fuel/air mix added is low or even stops. That doesn't happen with hard jetting. You get what the jets allow past. And by the way, the jetting circuits in the carb work under the same principles of fluid dynamics in a vacuum. The Dial-A-Jet is simply another circuit to add fuel and is externally adjustable.

Just saying, you can tear your carb apart several times for jetting, or you can do it once with an adjustable system that has proven to work quite well. I've got a bit over 20 years experience with the regular Dial-A-Jet and will tell you I put it in, then opened up my airbox, then went big bore with a full reverse cone megaphone exhaust and have yet to change the adjustment. The plug is virtually perfect tan, exhaust end has consistent color and the performance doesn't change from temperature or altitude extremes that I encounter. Friends and some KLX650 riders on the Yahoo KLX650 group have had the same experience. No one I've known has found anything less than an improvement in performance.

But if you enjoy tearing carbs apart - have at it. This was simply a suggestion to consider as an alternative to the same old/same old from the invention of the carburetor. See what the media says, and I guarantee you neither DirtBike! nor MXA are afraid to call a spade a spade, there is no big buck advertising at risk and I doubt that would matter either.

Last note, Mikuni uses a similar set up, but pumps raw fuel with their PowerJet set up, no air mix for atomization. Those are the people who KNOW carburetors and they use the same fluid dynamics process to compensate on fuel mix.

 

I don't recall anyone that actually uses a Dial-a-Jet that complains about it. It's something to seriously consider!

 

The more I read on the dial-a-jet the more I like it. Does seem to bridge the gap between a purely mechanical carburetor and and EFI. I suspect it may actually help to optimize both mileage and power by adapting itself towards to a known A/F ratio.

 

This jetting discussion brings up some interesting perspectives. I have no issue with Mark's Dial-a-Jet, as they seem to work. I've never used one, but the reason I've never used one is that once I get my jetting right...and that usually only takes a short experimentation ride or two...I never have to mess with it again. On the many race bikes I've had over the years and the dual sport bikes I've used on my big trips out west, I've never rejetted or found the need to putz with the jetting after initial setup. Now, I'll also add that I almost always took the given bike and did all the mods I was going to perform on the bike and do them upon getting the bike and do them all at once. Whether riding in Death Valley or going over Imogene Pass in Colorado at over 13,000 feet, my bikes were very rideable, had good response, and yielded good fuel mileage. I will add, however, that the bikes I rode in those different extremes were nearly all DS bikes with CV carbs. CV carbs have better latitude at dealing with different altitudes. My race bikes didn't have CV carbs, but I didn't take them to riding venues like CO and other western locations with wildly varying altitudes.