Jetting: Premix ratio vs. jetting

NM_KDX200

Member
Dec 29, 2002
441
0
We all know that changing the pre-mix ratio changes the amount of gas in the mixture. And we all know (right!?!) that 32:1 is _leaner_ than 40:1 when it comes to gas.

Now, suppose your bike is jetted perfectly at 32:1 and you run out of gas. Your buddy has extra gas, but it's mixed 40:1 (same oil- that's why he's your bud). How much will this throw off your jetting? The equivalent of 1 main jet? Less? Will it be "the bike won't even run, "dramatic", "noticeable", "barely noticeable", or "zilch"?

I'm just trying to get a feel for how much premix ratio affects jetting.
 

76GMC1500

Uhhh...
Oct 19, 2006
2,142
1
I'd put it somewhere between barely noticeable and zilch. I normally run at 32:1 at sea level. When riding around 2000 feet, I've run the bike at up to 16:1 (unintentionally) but it seemed to lean the bike out just right for the altitude change.
 

DLHamblin

Member
May 27, 2005
268
0
NM_KDX200 said:
We all know that changing the pre-mix ratio changes the amount of gas in the mixture. And we all know (right!?!) that 32:1 is _leaner_ than 40:1 when it comes to gas.

Now, suppose your bike is jetted perfectly at 32:1 and you run out of gas. Your buddy has extra gas, but it's mixed 40:1 (same oil- that's why he's your bud). How much will this throw off your jetting? The equivalent of 1 main jet? Less? Will it be "the bike won't even run, "dramatic", "noticeable", "barely noticeable", or "zilch"?

I'm just trying to get a feel for how much premix ratio affects jetting.

I doubt you would notice unless the bike already on the brink of too rich.
 

NM_KDX200

Member
Dec 29, 2002
441
0
Good responses. I needed 2 gallons of premix the other day so I used about 1/2 a container and about 2 gallons of gas (in a 5 gallon can). I'm sure it's somewhere between 30:1 and 40:1 and pretty sure it's more in the middle than the extremes. Anyway, just wondering how sensitive the bike might be and thought I'd get your experiences. I'll mix it 32:1 next time I'm at a real gas pump and can meter the gas.
 

FruDaddy

Member
Aug 21, 2005
2,854
0
Take a Sharpie with you and at every gallon, stop the flow and put a marker, that will give you a better shot at it the next time you can't meter it properly.
 
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