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Jetting for a Yz250x at sea level

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Ok I wanted to ask a very simple question...

the yz250x is slightly different to the mx bike and when I got the bike it was jetted to

main 180

primary 52

n3ew needle set at clip 3 (this is the european specs for a yz)

air screw 2 and a 1/4 turns out

Ran like a pig, so it was surging and just not great to ride

so I changed the jetting to what the stock jetting is here in australia for an mx bike

main 178

primary 50

n3ew needle set at clip 2 (australian spec)

air screw at 1 and a 1/4 turns

Its been hot the last coiple of days here and I was really bumming around on log jumps rocks hills and not really working the bike.

bike was gluggy very low and went fine as soon as the needle came into play so 1/4 turn onwards goes really well and on the main seems ok too.

Im thinking the pilot jets too big and until I get out and give it a good hard ride will I really know?

pondering on a 48 primary jet and a 175 main jet and leave the needle alone

I have spooge a little on the pipe and smells rich at idle but great on the juice

I know we have threads on here for the yz but this has slightly different timing so its retarded which would also say go smaller main and smaller primary

thoughts would be good

regards Dazz

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Doesn't matter if it's an x,y, or Z. Spankys jetting guide works.

If it does this, change this. Does that, change that.

Sounds like you need to determine if the pilot is right by testing your air screw setting.

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Thanks and yeah it makes sense too.......i think needle main is right as it goes well in those areas. Just bogs down low..........yep thanks ......Firstly when it cools down i will take it out for a thrash...a proper thrash

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Mine is stock jetting with less than 1 hr on it.  Had to back out AS to 2.5 turns to get it to idle.  It feels good on the needle.  1800ft 70 degrees.

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Mine is stock jetting with less than 1 hr on it. Had to back out AS to 2.5 turns to get it to idle. It feels good on the needle. 1800ft 70 degrees.

Go down on the pilot and leave the main alone if you like it on the juice.

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Quick update. ....went to a 48 primary jet and its much better now you can feel a bit of surging on the needle....so the bikes just not quite there....was thinking of going to a suzuki needle?

Whats a slightly finer needle going from the yamaha n3ew

The Suzuki needle cleaned up the 1/8-1/4 throttle stumble for me.

NECJ (p/n 13383-37FE0) $11.54

mine works well with MJ168 PJ45 clip#3 at 1000 ft elev.

There is also a slightly leaner NEDJ needle.

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I love the Suzuki needles (NECJ, NEDJ, NECW, NEDW) which are a 3 taper needle instead of a 2 taper needle like the Yamaha needles.  Remember that the Suzuki needles need a main jet 1 to 2 sizes smaller that the N3Ex needles due to their smaller tip / 3rd taper.

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I love the Suzuki needles (NECJ, NEDJ, NECW, NEDW) which are a 3 taper needle instead of a 2 taper needle like the Yamaha needles. Remember that the Suzuki needles need a main jet 1 to 2 sizes smaller that the N3Ex needles due to their smaller tip / 3rd taper.

I meant to ask which of those Suzuki needles are used at sea level?

Regards Dazz

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I meant to ask which of those Suzuki needles are used at sea level?

Regards Dazz

Everything you ever wanted to know about the NECJ / NEDJ needles:

http://www.thumpertalk.com/topic/1161464-suzuki-necj-needle/

Short version - the NEDJ needle is 1/2 clip richer than the NECJ; the NEDW needle is 1/2 clip richer than the NECW.  The NExJ has a straight diameter of 2.745mm  and the NExW has a straight diameter of 2.735mm - the 'W' needles are one step richer on the straight diameter than the 'J' needle..

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FWIW i run a 42 pilot , necw in second clip (might go to a nedj in second for winter ) and a 158 main 

i mix at 40-42;1

 

suzuki needles allow you to run leaner on the main , maybe a 165 would work for you

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Hi guys,

I'm from the East Coast of South Africa riding at sea level mostly.

Struggling to find the sweet-spot with my 2018 YZ250X jetting.

What would you guys recommend for me?

I've read all other topics on this but most of them are at altitude...

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13 hours ago, Mike_SA said:

Hi guys,

I'm from the East Coast of South Africa riding at sea level mostly.

Struggling to find the sweet-spot with my 2018 YZ250X jetting.

What would you guys recommend for me?

I've read all other topics on this but most of them are at altitude...

45 pilot

suzuki nedj needle clip 2 

work on the main with plug chops ( research plug chop )

mix 40-50:1 with low flash point full synthetic oil

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Thanks for the reply kxrob.

Unfortunately I only have a 172 & 175 main and 45 & 48 Pilot.

Also only have the N3EW and N3CW needles.

Currently installed 175/48 with N3EW clip 2. Doesn't ride smooth.

Running 40:1 Motul 800 with unleaded 95.

What suggestions with what I've got?

Also what setting for Air Screw?

Thanks.

Edited by Mike_SA

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