Pilot jet and jetting

[GG221]

Currently running 172, 42, NECJ clip #2 from top. This is what I run at about 5,000 feet and ~70 degrees F and it feels pretty good, maybe just slightly rich. I went for a ride at 1000 feet and ~32 F with the same jetting.
When I checking my pilot jet with the air screw before riding... I started at 1.5 out and turned the air screw in, as I was turning in the idle began to slow. I start turning back out to 1.5 and it is higher. I get to 1.75 out and it is racing fast. I keep going out 1/4 turn at a time and the racing fast idle does not change. From 1.75 all the way to 3 out it was the same very fast idle and did not change rpm. So I went back to 1.5 where it just barely slowed down and sounded a lot better.
I thought that this meant a rich pilot jet, is that correct?
I started to ride and the bike would bog for a second off idle, I turned the air screw in to 1 and the bog went away. Bike ran fine for most of the day. A few times while hill climbing with the throttle open it would bog and almost die, I would have to clutch and rev through it and the bog went away. This happened about 6 times in 6 hours. Here is a pic of the plug that I put in before the ride. My bike also seemed to be overheating easier than usual.
What do you think? Probably lean needle because of the open throttle bog? What about the pilot jet? I?m also confused because still seeing lots of spooge out of the pipe.

 

[(F5)]

So what kind of motorcycle do you have? I don't keep track of everyone else's bikes.

So, I'm not going to be much use due so seasonal festivities. However I will say two things with clarity.

1. Plug readings are a road race tool for choosing the main jet, and then only under strict conditions. Ignore the plug.

2. Spooge means you have a rich condition 'somewhere ' in the rev range. It doesn't tell you where.

3. Think of issues by throttle position not rev range.

4. Try a different needle for giggles. It might suit your gas or elevation better and is the critical jet for a dirtbike.


Ok that's 4 things but aside from craft beer we also do fantastic Sav Blanc.

 

[GG221]

2018 300 XC.
I am most concerned with the pilot screw. I had an extremely fast idle at 1.75 and it did not change as I turned it all the way out to 4. I thought that it would begin to slow again, is this normal?

 

[(F5)]

Turning AS in makes it richer. If you needed to be at 1 to stop it bogging I'd try a 45. Then start fooling with the needle.

 

[Jacob 'Berg]

2018 300 XC.
I am most concerned with the pilot screw. I had an extremely fast idle at 1.75 and it did not change as I turned it all the way out to 4. I thought that it would begin to slow again, is this normal?

The air screw allows more air into the mixture as you turn it out (leaner). Turning clockwise will reduce the air flow, making the mixture richer. If you are getting a fast idle at 1.75 turns out from a lean mixture, turn the screw clockwise to richen the mixture. This should eliminate the racing idle. If you are still getting a racing idle at 1 turn out from fully closed, you will need a richer pilot jet.

 

[rodent]

You're lean.......I imagine '18 would be the same.

 

[barossi73]

Try clip 3 also,this will enrich from 1/16 to 3/4.
The NED needle clip 2 would give you a half clip option between NEC 2 & 3
(You said it seemed to run hotter,and bogged on hillclimb,presumably at a partial throttle opening where you are on the needle circuit)
A slightly lean needle can feel crisp on the flat,but has no guts under load,like on a hillclimb)
Change 1 thing only at a time,and keep in mind the circuits overlap a little,so 1 change may slightly affect the operation of another.
eg.changing pilot will have a slight effect on the initial throttle opening when the needle comes into play,and vice versa.
If you find improvement from enriching both pilot and needle then it may also be worth bumping the main up 1,especially if you are wide open throttle a lot.
Theres no harm in going richer,other than it will burble,and potentially foul a plug...going to lean however can overheat/detonate/get expensive quick

 

[webmaster]

Where is your idle screw at? Make sure you reset idle when changing needle/pilot... It shouldn't be all the way in and nearly coil bound....

jeff

 

[Jakobi]

What everyone else said.

Rather than upping the pilot I'd up the diameter on the needle.

 

[barossi73]

Jakobi,hope youre out of harms way over there m8.
Looks truly horrific.
Upping the diameter would make him leaner tho?
I interpreted his post as looking for a richer setting to compensate for a lower altitude?

 

[(F5)]

I just saw the picture of what part is on fire. Its friggin all of it by area. Had some mates from Sydney over, getting charcoal arriving airborne from 50km away.

Can barely stand to read the news.

 

[Jakobi]

Jakobi,hope youre out of harms way over there m8.
Looks truly horrific.
Upping the diameter would make him leaner tho?
I interpreted his post as looking for a richer setting to compensate for a lower altitude?

I hear you. I think similar to upping the pilot. Going richer. Go up from a J to a H! (which is actually a thinner needle).

Thanks for the thoughts mate! I'm up the pointy end. We have lots of scrub, but not heavy eucalyptus fuel loads. We've had a few decent fires, but nothing to the scale of what is happening down south.. and some rain has been falling as well.