Hanging idle

S

SWEDE

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Joined
Nov 30, 2004
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1,421
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northern michigan
My sled 01 sx 700r has always had a bit of a hanging idle. I have played with fuel screws and 1 7/8 turns out seems to minimize it, but it's still there at times. Now I'm putting in a engine with trail ported cylinders and ported case with srx reeds and I'm not sure what to do with my fuel screws. I'm going up to 150 main jets and stock number 3 needles with this new engine. Any help with how to set this up would be appreciated!

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Keeping stock exhaust. Many thanks already to mr. Viper for the help with main jets and needles already!

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you can run 47.5 pilot jets and fuel screws at 1.5 out, that will richen it up some down low, set your idle speed to 1400-1500rpm, should be no idle hang then.
 
Well you nailed it, my sled has never idled so good with those pilots and 1.5 turns out on the fuel screws! I have a little stumble or flat spot just off idle that I'm not sure about. My first thought is the fuel screws need to be turned out some, but that doesn't make sense to me with it idling so good very snappy with no idle hang. This engine does have Boysen reeds. Could that make a difference in my settings?

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I was just riding it around and thought that too. It seems like the the stumble so to speak could be a lean miss

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try to ride it and just barely lift up on the choke lever at that rpm youll know if its lean or rich, if it gets better its lean, if worse its rich.
 
You can tell the diffrence between a lean and rich motor pretty easy once you expirence both, at least in my opinion a lean stumble drops rpms where a rich conditions slows down the rpm gain. If that makes any sense. I notice this when its warm.
 
Ok, I'll try the choke thing before I lower the needles. Mr. Viper have you ever had a ported 700 with stock exhaust with the needles on position 4?

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I have 10 acres that I've been riding around on and I've checked the plugs repeatedly and to me they look kinda lean even with this warm weather

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I have 150 main jets, seems like that wound be a lot of fuel on the top end, but I'm still learning

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Well, I tried choking it a bit when it was hesitating and that made it worse. Hmm, I'm at a bit of a loss. Wonder if I didn't clean something good in my carbs. Idle is great and full throttle is ok, it's in the midrange it's hesitating bad.....


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Sound simular to what I experienced last year mid season. I had a terrible mid range hesitation between 6000 and 7000 rpms. Sometimes it was better, sometimes it would get much worse. My snowmobile would start fine, idle great and would cruise at 5500 good. 7500 to 8500 rpms was also ok. But the midrange from 6000 to 7000 was a constant pain. I chased that problem around for a month, cleaning carbs over and over and trying different tunes thinking I was lean or rich. Even swaped out coils, spark plugs, and CDI box etc.... Many members tried their best to help. I had a thread about it called " Bad Hesitation ".
 
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