Ok so the DJ150 went off and wrong. Odd how the peak numbers are, basically, identical.. But the curves are not.. Notice how well the HP curve is holding, on out past 9k with the 140.. I'm thinking next move would be to test ride DJ144 with 2N and Dyno if promising.. The idea is staying just under 13:1 for the entire RPM range..

 

Updated w 144/2N test..

 

Talked with "Mike" at DynoJet. He is a jetting specialist. There is no flow differences between DynoJet DJ and CJ jets. The CJ jets are shorter - by about a third - to allow for issues with some bowl designs.. My 144 is definitely a DJ and the results I got (.8 richer over the DJ140) are what is expected.

I am considering putting in the stock slide spring. This would be an attempt to lean the low/mid by delaying the uncovering of the main jet until a high enough RPM is reached to accommodate the extra fuel of the 144..

The other consideration is to remember that a Dyno run is a diagnostic tool only. The bike will not see a snap and hold to WOT, in 4th gear, from below 4k, in the real world.

So, as Mike also suggested, if it carbs cleanly and runs like a raped ape - go with it..

 

My thoughts are that if I use the stock spring, set the fuel screw more toward lean, figure out how to put the needle to 1N (there's no room for the washers on top of the 1N setting), that the low/mid would certainly be leaner than it is now..

 

If you are rich in the low to mid and perfect in mid to top, why not set the needle/MJ for somewhat rich in mid to top then step down on the pilot which should affect pretty much the whole range moving everything lean? The pilot does not stop flowing after some particular rpm, right?

 

The pilot system flows minuscule amounts of fuel during one of two high vacuum situations - closed throttle deceleration, closed throttle idle.. It provides an AFR at idle and a starting point - a starting AFR - during the transition to the needle. It does not flow enough fuel during lower vacuum operations (any significant throttle opening) to have an effect on AFR. If it weren't for the decel popping, I would still have the stock #35 in my bike. Putting it another way - the pilot system is designed to flow just enough fuel to provide an idle when a strong vacuum is applied to its' port..

 

Since the FMF system needs lots of fuel up top and less in the low/mid compared to the stock header+slipon, I wonder if all one has to do is buy the exhaust system and a big main jet. I can't get the low and mid lean enough with the DJ needle and DJ spring.. Wouldn't it be interesting if a perfect setup for the FMF system is stock needle, stock spring, stock Pilot, big main jet?

 

I have a feeling you are going to try this..... I Look forward to the results of your test. Thanks for all the work you put into this. And your many contributions to the forum.

 

Don't do it !!!!!

 

But....... I do enjoy learning of your efforts. Really, you've done alot of cool tweeks to your carb and settup. Thanks !