Jet tuning tips for a 97 YZ250

JohnnySmitty775
Hello,
I recently purchased my first bike and was wanting to tune it for my altitude but can't find a good jetting chart. The current altitude I'm at is about 5,600 above sea level. Just came here to see if any had some good recommendations that they've ran or have some good charts i could go of. Appreciate any help!
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Pirate421
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MA US
Pirate421 5/8/2019 5:46am
5/8/2019 5:46am
If you go on the pro circuit website they have jetting recommendations for almost all two strokes. I’m pretty sure they use California and sea level as their base but you could start there and lean it out for your elevation. If you can somehow get your hands on a manual or ThumperTalk forum has a lot of jetting recommendations in the yz section. Those motors were the same for a long time so shouldn’t be too hard to find something that works over there.
1
JohnnySmitty775 5/8/2019 7:05am
5/8/2019 7:05am
Pirate421 wrote:
If you go on the pro circuit website they have jetting recommendations for almost all two strokes. I’m pretty sure they use California and sea level...
If you go on the pro circuit website they have jetting recommendations for almost all two strokes. I’m pretty sure they use California and sea level as their base but you could start there and lean it out for your elevation. If you can somehow get your hands on a manual or ThumperTalk forum has a lot of jetting recommendations in the yz section. Those motors were the same for a long time so shouldn’t be too hard to find something that works over there.
Yeah i picked up a service manual and it has your factory jets put that's it. Thank I'll check those out!
captmoto
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captmoto 5/11/2019 9:52pm
5/11/2019 9:52pm
This is from MXA for 1997. Like has been mentioned go with your manual recommendations for your elevations.
1997 Yamaha YZ250
Jet…Stock…Recommended
MAIN…170…stock
PILOT…48…stock
NEEDLE…N4DG…stock
CLIP…3rd
AIR SCREW…1-3/4 turns

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