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1965 Honda CP77 — Ulsan Metro City, Rep. Korea
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Jetting for higher altitude, and needle jet info!

Fuel System: Gas (Petrol) tanks, Carburators
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GG
honda305.com Member
Posts: 154
Joined: Tue Apr 13, 2010 10:45 pm
Location: Costa Rica

Jetting for higher altitude, and needle jet info!

Post by GG » Thu Apr 30, 2026 6:47 pm

Hello to anyone at higher elevation!

I live at 5,000' (Costa Rica) and had to jet my main's at 125 - runs great, and my slow jet at 35 (in order to pass smog). It runs ok - a bit richer slow jet would be better, probably.

HOWEVER - the latest vía crucis was with my needle jet. I had accidentally put one of the needles from the generic ebay carb kits in my right carburetor, and it was terrible. Terribly rich between 2500 and 4000 rpm's, and no amount of adjustments would fix it. On a tip from Michael Stoic I just pulled everything apart, laid it all out on the bench, and noticed that the needles were different colors. I figured out which was the original, put that one it - eureka! That's all it was. Both sides are perfectly the same.

Moral of the story - keep your original needle jets! I don't think there would be any way to run the replacement needles at all. Too small at the tip. And it seems that the originals are hard to find. (Sigh)

I hope this helps anyone at higher elevation.

GG

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