Jetting for temperature

Tavmonsta58

Member
May 15, 2017
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Hey all, I have a yamaha blaster stock 230 main jet, stock 32.5 pilot, only about 100 feet above sea level.. I want to know if the average temperature drops about 50F degrees fahrenheit(80-30), how many jet sizes will I have to reduce to compensate(cold air is denser meaning less air meaning I need less fuel to match)?? I ordered a set of boyeson power reeds for my stock cage & the manual says I have to drop 1-3 main jet sizes due to them making richer conditions. Depending on how many sizes you think I should drop, could putting the reeds on compensate for having to jet down? Any advice is appreciated!
 
Presume you still have stock pipe ? Everything else stock except reeds?
I have NEVER heard of dropping jet size with different/aftermarket reeds.
Actually depending on the reeds you have to go up on the main.
Actually cold air is denser , more oxygen by volume. Go up to a 240
 
Yup stock everything other than injection blockoff, the manual I got with the reeds says I should drop 1-3 sizes & they tend to make the bike richer.. There boyeson 630 power reeds & I'd just throw them on the stock cage as well, that's what the manual pictured was the stock cage.

I have also never heard of it, did some research in result of nothing.. But I figure if the manual says I have to drop a size or two that I might be able to throw them on and the leaner cold air will compensate for where I'm jetted at now, or I'd be a bit rich at the worst I figure depending on how much a 50F difference affects jetting?? Figured it'd only be a size or two leaner which would match the size or two I have to drop due to rich reeds. Plug check & adjust from there. & yeah thanks I messed up a bit aha, I knew cold air is leaner :p