Running out of Gas

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Johnny
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Running out of Gas

Post by Johnny »

I just have a general question. Why do bikes (2 strokes) rev higher just before they are about to run out of gas?
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Indawoods
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Post by Indawoods »

Getting more air than fuel.... A lean situation.
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Post by Johnny »

So if you bike feels better while its running out of gas, (more power, crisper etc.) it probably means you should go to smaller jets?
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Indawoods
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Post by Indawoods »

A lean running bike always feels like that just before you melt the piston....
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Jeb
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Post by Jeb »

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Johnny wrote:So if you bike feels better while its running out of gas, (more power, crisper etc.) it probably means you should go to smaller jets?
Do a wide-open throttle (WOT) chop - that'll tell you if you can drop the main jet size.
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2001kdx
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Post by 2001kdx »

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Indawoods wrote:A lean running bike always feels like that just before you melt the piston....
Hahahaha :mrgreen:
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2001kdx
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Post by 2001kdx »

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Johnny wrote:So if you bike feels better while its running out of gas, (more power, crisper etc.) it probably means you should go to smaller jets?
That's like saying 'If my bike runs stronger with the choke on, do I need richer jets'

Johnny, No offense, but it doesn't sound like you have a whole lot of expertise in this area (neither do I) but, that means it is very possible that you're jetting isn't spot-on, making the leaned out, gas starving bike perform better. Do a plug chop as Jeb mentioned, I need to do one myself at this point.
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fuzzy
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Post by fuzzy »

A 2-stroke will in fact do just as inda says. You can lean-lean-lean and it will keep making more and more power....Right until (right before) the piston sticks. A "perfect" tune is a very fine line. Most will be happy with a good running bike on the error-side (very slightly rich).
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Post by Johnny »

Thanks for all of the input fellas. And to 2001 kdx, you are correct, I do not have alot of expertise in this area. I purchased my kdx in August of 06 and my kx in July of this year so I am very new to dirtbikes and 2 strokes especially. But thanks to this site and my own searching and tinkering I have learned alot and continue to learn. Hell, last week was the first time I took the jets out of a carb. I have really become addicted to the whole dirtbiking thing. I just love it. My goal is to become a good enough rider and mechanic to be able to knowledgable get my boys into it at a young age. They are currently 2.5 and 2 weeks.

This past weekend I was out at TnT in Chester SC and managed to take a trip over my handlebars while coming off a pretty decent jump. I landed on my back pretty hard while the bike fell on top of me but luckily I did not break anything, just scraped up my back pretty bad. Oh well, I'll be back there this weekend trying the same jump!!!!!
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2001kdx
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Post by 2001kdx »

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Johnny wrote: I'll be back there this weekend trying the same jump!!!!!
That's the spirit :supz:
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