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I have 3 probably dumb questions...17' 150XC-W

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OK, the dealership where I bought my bike told me run 50:1 and they had jetted it as part of the delivery process. I think the bike runs well enough but I get quite a bit of spooge out of the muffler. 

1. Would going to 60:1 or even 80:1 reduce the spooge? Is this even a big deal, I'm thinking the packing would get saturated quickly.

2. Would I have to re-jet the carb if I change the premix ratio?

3. I'm going to start using VP gas (ethanol free), should I go with a higher octane and would I this also be cause for re-jetting?

Thanks, I've not owned a 2-stroke in 17 years and even then, I had a good buddy set my bikes up for me.

 

Edited by Hulley

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My US version manual says 60:1. My bike came with stock jetting which was too rich, and it spooged a lot. Leaning the jetting helped with that, but did not eliminate it. I still am a little rich.

 

 

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60:1 is what my KTM manual says. I know some dealers tell folks to go much wetter, I think to cover their butts, but I go with the KTM recommendation.

Assuming you haven't changed the jetting and its stock, you don't need to change the jetting. But changing the oil ratio does have impact on your jetting. I was taught: More oil makes the gas mixture leaner, because the oil and the gas are flowing thru the same jet opening.

Ethanol free gas is good, but you do not need more than 93 octane. For sure, the higher VP gas, like VP110, is unneeded for a stock KTM. 

I run 91 octane ethanol free gasoline in my 300XCW

Just checked my user's manual for my '17, and it says "all XC and XCW" want 60:1 with "super unleaded 95 ROZ / RON 95/ PON 91"
PON is pump octane number, and 91 is pretty standard Premium unleaded in the US except in the Mountains and CA

Edited by pat22043
confusion on rich and lean
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50 minutes ago, pat22043 said:

60:1 is what my KTM manual says. I know some dealers tell folks to go much wetter, I think to cover their butts, but I go with the KTM recommendation.

Assuming you haven't changed the jetting and its stock, you don't need to change the jetting. But changing the oil ratio does have impact on your jetting. More oil makes the gas mixture leaner.

Ethanol free gas is good, but you do not need more than 93 octane. For sure, the higher VP gas, like VP110, is unneeded for a stock KTM. 

I run 91 octane ethanol free gasoline in my 300XCW

Just checked my user's manual for my '17, and it says "all XC and XCW" want 60:1 with "super unleaded 95 ROZ / RON 95/ PON 91"
PON is pump octane number, and 91 is pretty standard Premium unleaded in the US except in the Mountains and CA

Yeah, my manual says 60:1 with 91 octane too, but the dealer told me they run 50:1 and they re-jet the carbs before delivery.  The Ace Hardware near me sells VP fuel and I was thinking of picking up their 91 or 93 octane, probably 91, so that I have ethanol free fuel. The local stations that have E-free are only 87 octane. Hmm, if I switch to 60:1, wont that richen the fuel mixture?

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12 minutes ago, Hulley said:

 50:1 ... Hmm, if I switch to 60:1, wont that richen the fuel mixture?

It depends on your religion. Fundamentally, 50:1 and 60:1 are not that different.

Some argue that the oil displaces gasoline thru the jets, so more oil means less gasoline and it causes a leaner mixture. And thus less oil means more gasoline and a richer mixture.

Other folks argue exactly the opposite.

So in my theological view, going from 50:1 to 60:1 will have less oil and more gasoline. Your mixture will be richer and you need to lean out the jets to get back where you started.

But I fundamentally believe it makes so little difference that things like altitude, air temp, relative humidity, etc. overwhelm the change in oil mix ratio.

For woods riding, no one jets that close to the edge anyway.

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