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2017 250x jetting questions

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Hello,

Finally got my 1st ride on my new bike on the weekend. Weather was about 45-50 F, Elevation 4400-4800 ft. Im trying to use the spankys jetting guide to get this bike tuned up. So I started with the pilot jet. The only way I can get this bike to idle (barely) is with the throttle adjustment screw turned all the way in, and airscrew at 2 turns out. I cant get a "fast idle" no matter if I go in or out from 2 turns out, barely idling is as fast as I can get it. If I go to a smaller pilot jet (spanky says to do this if you are 2.5 or more turns out on air screw, will I be able to back off my throttle adjustment screw? Is there any issue having the throttle adjustment/idle turned all the way in? I guess what I'm asking is what is the relationship between air screw and throttle/idle screw (if any). When temps climb will I be backing idle off? 

While riding the bike I had good throttle response when cracking it open (0- 1/4 throttle), but a few hill climbs when I opened it up (1/2 to 3/4) it was a bit boggy so I think I need to drop needle down one notch. After I do this, I'll put a new plug in and do a throttle chop to test main jet. Its still early season and I'm riding on studs so I know as temps rise it will change my jetting a lot and I will have to adjust accordingly. 

 

Any thoughts or comments on the air screw/ throttle position screw? Any other comments or suggestions? 

Jetting is stock currently.

thank you in advance!

 

 

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The idle adjuster just raises the slide the same as slightly twisting the throttle. While it doesn't hurt anything it isn't right if it's all the way in.

I would ride it more to make sure everything is well broken in before jetting but if you want to put in smaller pilots, it should let you back out the idle adjustment and go in on the air screw.

If it's bogging and not sputtering you want to drop the needle clip, raising the needle to make it richer.

These bikes are very rich from the factory. Too rich is better than too lean.

 

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Your getting close to my elevation. Jetting stock is waaaaay to rich. 2 Stroke runs better lean than rich. Raise your needle clip to slot 2. Put a 45 pilot in there. Change your main jet to 170. Pretty good up to 75 degrees. Hotter it gets you could go lower main jet, these setting will get you dialed in pretty good.

To your point about bogging, your too rich on the needle. Don't lower the clip, put the clip in slot 2 from the top. You will see a big difference on the hit.

After you get these baseline settings then you can work on your air screw. Your going to be somewhere between 1.25 to 2.00. I would set it at 1.50 and adjust from there depending up temp etc.

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I have a 45P NECJ #2 needle and 172 main in the bike currently. I've been running this on a new top end on the my 250X for break in but after my ride today, I'm going to definitely lean out the main and probably put in the NEDJ needle....    temps have been between 50-70 and I ride from 4400 to 8000 most of the time.   The Suzuki needles do wonders for the stock 250X.. 

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^ I ran the stock needle for a bit and went to the Suzuki needle. Mid is lots better. I was loading up some on decel, air screw wasn't helping. I dropped the pilot to a 42, a ton better no load up and instant throttle. All I've heard in this needle is it's pretty rich so you need to lean it out. You should consider a 42 pilot. I've seen a lot of posts from lower elevations running the 42 pilot with the Suzuk. My range is like yours 4000 to 9k.

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8 hours ago, Titanite said:

Hello,

Finally got my 1st ride on my new bike on the weekend. Weather was about 45-50 F, Elevation 4400-4800 ft. Im trying to use the spankys jetting guide to get this bike tuned up. So I started with the pilot jet. The only way I can get this bike to idle (barely) is with the throttle adjustment screw turned all the way in, and airscrew at 2 turns out. I cant get a "fast idle" no matter if I go in or out from 2 turns out, barely idling is as fast as I can get it. If I go to a smaller pilot jet (spanky says to do this if you are 2.5 or more turns out on air screw, will I be able to back off my throttle adjustment screw? Is there any issue having the throttle adjustment/idle turned all the way in? I guess what I'm asking is what is the relationship between air screw and throttle/idle screw (if any). When temps climb will I be backing idle off? 

While riding the bike I had good throttle response when cracking it open (0- 1/4 throttle), but a few hill climbs when I opened it up (1/2 to 3/4) it was a bit boggy so I think I need to drop needle down one notch. After I do this, I'll put a new plug in and do a throttle chop to test main jet. Its still early season and I'm riding on studs so I know as temps rise it will change my jetting a lot and I will have to adjust accordingly. 

 

Any thoughts or comments on the air screw/ throttle position screw? Any other comments or suggestions? 

Jetting is stock currently.

thank you in advance!

 

 

My son races at the Calgary track its at 3400 ft we run a 42 pilot stock needle and a 170-172 main depends on temp hope that helps 

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My son races at the Calgary track its at 3400 ft we run a 42 pilot stock needle and a 170-172 main depends on temp hope that helps 


Awesome info as I am in Calgary also. thx!

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On 20/03/2017 at 5:56 PM, RMK800 said:

Your getting close to my elevation. Jetting stock is waaaaay to rich. 2 Stroke runs better lean than rich. Raise your needle clip to slot 2. Put a 45 pilot in there. Change your main jet to 170. Pretty good up to 75 degrees. Hotter it gets you could go lower main jet, these setting will get you dialed in pretty good.

To your point about bogging, your too rich on the needle. Don't lower the clip, put the clip in slot 2 from the top. You will see a big difference on the hit.

After you get these baseline settings then you can work on your air screw. Your going to be somewhere between 1.25 to 2.00. I would set it at 1.50 and adjust from there depending up temp etc.

Question: Pulled carb apart last night, put in a 48 pilot (all I have right now), and needle is in position 2, so I dropped it to position 1 (clip as high as it will go). Should I just switch to the 1 leaner needle (N3CW)  or try it in slot 1 on stock (N3EW?) Any issues with being in slot 1?

Thx

 

Edited by Titanite

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5 hours ago, Titanite said:

Question: Pulled carb apart last night, put in a 48 pilot (all I have right now), and needle is in position 2, so I dropped it to position 1 (clip as high as it will go). Should I just switch to the 1 leaner needle (N3CW)  or try it in slot 1 on stock (N3EW?) Any issues with being in slot 1?

Thx

 

we run the leaner needle in the factory clip position

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Don't get too far ahead of yourself with the needle. Sounds like you may need a 45 or even 42 pilot. I would get that dialed as you were with Spank's jetting guide and then start tuning the needle. Once you get the right pilot  you will have back the idle screw way out to lower the idle speed.

 

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