Rocky Mountain Dirt Riders

I know there are a plethora of old 300 jetting threads on the site but I did a search and did not find one specifically pertaining to 2017 Mikuni-equipped models.

Has anyone with a 2017 300 installed a JD jetting kit and if so what are the optimal settings for McLean and Calgary area?

I started with JD's recommended 2-7,000 feet settings of 30PJ, RED Needle - 3rd clip and 410 Main and feel the bike is sluggish, not particularly crisp, and has a slight bog when snapping the throttle on the stand at the track, haven't been to McLean yet.

There is no spooge (yet) but the plug is fairly black; I run Motorex + Co-Op gas at 50:1 and my 2017 300 has VForce 4 and an FMF silencer on it, if that makes any major difference.

I have some suggestions from a fellow named Ian (thanks Ian!) here in Calgary that I bought jets to try (S-4 needle jet, 43-75 needle - 1st Clip, 27.5 pilot jet, and 440 main. but JD has been pretty much plug and play for me in the past and I'd like to see if I can sort this JD kit out as much as possible.

I know there are a lot of you RMDRA guys who are pretty good with jetting and I'm wondering if any of you have made JD kit work or have other advice.

If there are any of you that are around 235 lbs and have air pressure recommendations for the AER48 fork I'd like to hear those too.

As always, thanks in advance.

This won't be much of a help, but I slapped a Lectron on from day 1 with the bike. It needed some sorting out and wasnt perfect, but the bike pulls super hard now. Good off idle response, but I still have it a touch rich so itll load up if it idles for a long time. Going to be swapping to a gnarly pipe soon so I figured I would leave it rich. We can meet up for a ride and swap bikes for a bit if you wish and wanna try it out.

I also have VFORCE4's, and a TC 2.1 silencer. I run shell premium gas and motorex and 50:1, but that may change after the gnarly pipe gets put on.

I'm using the JD kit with the 250XC and the 250 always is a bit richer than the 300. I don't think JD nailed this kit as much as past kits. I don't think it's plug and play. More play and plug a few times to get it right.

However, I feel that the JD needle is much smoother than the stock needles. (based on appearance)

I agree with Dirtyboy in that these JD kits are close but still need some tweaking. Have one in a 2017 SX 150. You did not mention your Air screw setting. I would start with turning your AS to 3 or 3 1/2 out [ for MTN riding], if this helps put in a 27.5 pilot. Also try the 2.5 needle position.
Before you start any jetting on these Mikuni's you need to do 3 mods. 1] floats will likely be set 5.5 - 5.8mm, this is off by a mile, set them to 8.0 - 8.5mm. 2] Put a small loop in the float bowl overflow tube. 3] Angle the top of the carb approx. 7 degrees towards the kickstart lever.
If you are still looking for more snap/hit go to the red power valve spring and/or back out the Dolly adjuster.

Trail guy, what is point2?
I hear the 18 is angled as you described stock.

This helps with gas mileage. Make sure the top of the loop is not to high.

Apparently the hot ticket is a 5.75 slide. I've got one of these on order, as well as some larger pilots as my 2018 came with itty bittys. This slide with a S-4 needle jet seems to be the good starting point.