You are talking the Dyno Jet kit. I am talking about the Dial-A-Jet fuel adder that works as a fuel mix injector activated by acoustic and vacuum wave patterns in the intake.

When the mix is lean the intake draws a vacuum, sucking, that you can actually hear. When the mix is adequate there is still the draw through the throat, but there is less vacuum beyond normal so there is less fuel drawn through the Dial-A-Jet nozzle - which is effectively another fuel inlet like the needle jet, but operating off of vacuum and acoustic wave patterns in the intake. Think about that vacuum fitting that keeps the pollution valve or a vacuum petcock open, you use that vacuum draw on the other side of the carb mouth to smooth out fuel supply instead.

I cannot explain the acoustics part, but if you consider the sonic waves in an exhaust system, especially in a two stroke expansion chamber, there are also sonic waves working in the intake.

The guy who developed the Dial-A-Jet realized both could be taken advantage of to create what is effectively an injector that only adds fuel when the wave pattern and/or vacuum is right. It works a bit most all of the time, but adds more as draw is higher. The claim is the Dial-A-Jet can effectively take care of 35% of the fuel needs. Clearly jetting a couple sizes small creates the leanness or if jetted at high altitude, the leanness comes when going down in elevation. That is when the Dial-A-Jet adds fuel.

Sound kind of wild, but it seems MXAction, DirtBike!, and Motorcyclist have tried either the Dial-A-Jet or Inellijet and find what ever it is, it works. The ATV and snow mobile community uses them a whole lot more because of elevation changes and hop up for the ATV, and elevation change and temperature change for the snow mobiles. Fact is the system is also used by some of the watercraft people as I found out from a friend yesterday. Seems he's used them on his two strokes and then his brother used on on his TRX450R.

Go to the site, see what the Dial-A-Jet and Intellijet are. They are comparable, but do more than the Mikuni PowerJet, another snow mobile and drag racing trick for wide open fuel supply, not for full range above idle like the Dial-A-Jet. Again, don't believe me, check out the comments from two of the top off road magazines in the country, MX Action and DirtBike! Since Thunder Products does almost no advertisement there is no reason for either one to say anything but the truth since there is nothing to lose.

My carb only needed to come off one time for jetting and installing the Dial-A-Jet. I'm hoping the same thing will be the case with the TM36-68 when I put it on and put the Dial-A-Jet from the CVK on it. Actually it might be a non-issue since the Dial-A-Jet body is mounted on the intake boot clamp that will hopefully be reused on the 36.

 

If I set the rpm at 1300 the bike will not die with the fuel screw turned all the way in. What could cause that result. Could to large of a pilot jet cause this?

 

Thanks klx678. Understand now. I just got to get the pilot jet figured out first.

 

Damage to the fuel screw seat that causes it to not fully shut off the fueling at idle... That is about the only issue that won't have other affects.. I assume your bike will idle fine at 1300 RPM..? That is where it is suppose to be set to...

 

Just go ahead and set the fuel screw to a tiny bit out from lean idle drop.. leave idle set to 1300 - 1500 rpm..

 

Yes idle fine at 1300. If the seat was damage would it be the screw or the carb? There is a reason I'm asking.

 

Could be one, the other, or both.. Only really matters that you can still get a lean idle drop..

 

When I was soldering on my extension the jet took a tumble off the vise onto the concrete floor. It looked OK but it was hard to tell if it had a bend but I do suspect it landed on the needle end. When ahead and used it but could a slightly bent tip damage the carb. Also there was a small amount of solder on the threads the had wicked up. I cleaned it the best I could be there was a slight tight spot so it was hard to tell it it was the seat or the solder. It's free now.

 

Could your solder be slightly oversize and hitting inside the body?

On the other side of the whole thing, according to Mikuni's tuning chart and I'm sure Kiehin is the same, the pilot and mix screw will only affect just off idle up to 1/4 side movement at most. That won't do anything with your "doggy rpm" unless you're talking down around 2500 or less. The slide moving up and the needle are the mid throttle. From there it is what power can be had from a 250.

I'm wondering if you are expecting a bit much with the CVK. My bike hits harder at around 5000 rpm, below that it has some power, but not a lot. Pretty much what I expect from a 250 though. It will pull strong, for what it is, from around 4000 up, hits stride around 5000-8600 rpm, above that is over rev territory.

On a side note this is the Dial-A-Jet set up:

This is about what it looks like in my air boot:



Difference is I attached it to my air boot band clamp.

This is another picture I "borrowed", showing the dial from which it gets its name. The dial, holes are air inlets, there is a boot with filter for off roading to cover it. The smaller the hole the richer the emulsion, more fuel less air, larger hole vice versa. The carb throat draw sucks fuel and air atomizing it at the needle going into the carb as a mist.



Mix is drawn through the needle tip in the center area of the carb mouth. Closer is better, another reason I attached at the band clamp and they now also have a pro mount that attaches to the carb, but I didn't want to do that.

 

Thanks for the dial a jet info. Definitely something to consider.

Yes my doggy feel is below 2500 rpm. If I'm moving along slowly with the clutch out, RPMs under 2000, and full throttle the bike I get a slight "nothing" for a slight second then the power build the closer I get to the 4000 mark. After that now issues. That was one reason I asked about what happens when you drill the slide. Does it delay the movement of the slide or allow the slide.to move quicker. I would have thought drilling would have reduced the vacuum effect on the slide and make it work slower.