x trainer jetting

[hometownguy71]

new guy here..recently picked up a 23 xt.im loving this bike overall,however im not understanding the jetting.ive jetted tons of snowmobiles and older mx bikes..i believe these bikes come delivered lean for anyone at sea level up to 800 ft.it came with a 145 main.i noticed it felt lean at first but,its been a dozen years since i had a 2 smoker.,,so anyway,i have changed the pipe to a fmf and removed the spacer.i changed the main to a 158 and put a suzuki necj needle in the second position..what is so odd to me is that i see multiple videos of guys at 5-9k ft running a 158..so my thought is that i still must be lean?.my bike exhibits some kind of knock on decel.im thinking it is pipe knock due to a lean condition?.i noticed i had a bunch of spluge running from the head/pipe connection so i pulled the pipe off and found the orings absolutly melted.strange for a pipe with 2hrs on it?i changed the orings and used rtv.ive ran the bike agian and still have pipe knock.anyway,sorry to be so long winded.im curious where other xt owners have there bikes jetted at?thanks

[F5 Dave]

Sorry no real help here, I have z 21, different engine. I did change from std to a Fatty, and bought a couple of needles to try.

But the pipe swap cleared up the banging and stumbling and doubled the power everywhere. So I never tried the other needles. And I'm fairly fussy.

Odd thing is the FMF orings failed after two rides.

[hometownguy71]

update..i decided to try going up in main size and see how the bike responded.i also pulled the air filter cage and used some hole saws to drill it out.ive been trying to buy a rr cage but oos everywhere.anyway,i put a 165 main in there and daamn.what a difference!pipe bang is 90% gone!the bike seemed to have gained 40% power also.ive concluded that these bikes come dangerously lean if your anywhere from 0 to 1000ft.145 main according to the chart is for 10000k ft!.im going a 170 main as soon as it arrives in the mail.im not really caring about mpg,i would much rather have a healthy engine!with the 165 i still have no spluge at the silencer,so im confident it will still run even better on a bigger main.

[AvB]

I'm interested in this too. I got a 2023 with only a couple of hours use on it, fitted with a 300RR pipe. It also had a 145 main. I went up to 158, and the bike feels great to me but yes, I similarly get a decel knock at times. I haven't opened up the airbox at all yet, thinking the power is more than enough for me, but perhaps I should do it.

I tried a 40 pilot but it was definitely too rich.

Also lifted the needle a notch, but that was too burbly/ stuttery so I went back to the stock clip #2 position on the stock N1EK needle.

Hey, here's a question: the 300RR uses an N2ZW needle. Since I'm using an RR pipe I would have thought it might be more suitable. I have one here, and when I measured it, the top diameter is the same but it's a lot fatter down at the bottom. Like 0.3mm difference, which is quite a lot, so it should make it leaner at half to 3/4 throttle.

Does anyone use a N2ZW needle in their X-Trainer?

[Toro5xi]

I’m at sea level and riding in 50 60 degree weather so decided to go with a 158 main as suggested in the jetting chart.
I was surprised to see the stock jet was a 145 when the jetting chart said it should be a 155. Prior to change I thought I heard the occasional ping but not now. Hopefully get to the track in a few weeks to see how it runs but so far just around the yard feels good. Perhaps has a little more power but in any case pulls clean right off idle.