Jetting vs temps

fourbarrel

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May 5, 2003
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St George,New Brunswick,Canada
Alright I know this may seem like a no brainer for a lot of you but here goes. Hypothetically will otherwise lean jetting in an SRX be rich as the outside temps rise above freezing? If a sled is jetted a bit lean at colder mid winter temps and the air temps riser above freezing considerably,in the range of 40 to 42 degrees,would that not make the jetting be rich giving the warmer air temps?I keep remembering how the old free airs used to be dogs during the day and then act like a different sled at night with the cooler air and the thing I associate that trait to is the carb jetting being rich needing the colder night air to work properly.
The reason I ask this is I had the centre piston go out on my ported '01 SRX and I'm trying to put a cause to the failure if it was bad gas or an air leak or just the jetting being too lean which is why I asked about the relationship of air temps to carb setting.
 

Well yes, I think that is the idea. Colder temps increase the chances of your pistons melting. What jetting did you have on that at what altitude? Were you going WOT when you seized it?
 
Trail riding at roughly 40mph but not consistently that speed.A lot of up and down corner to corner mainly using first 1/3rd of throttle.Sea level or maybe slightly above and jetting is 152.8 across the board.
 
Sorry, i dont know then, ive always just cold seized or seized at wot. sounds like an airleak or something was clogged
 
That's what I'm leaning towards too but it was over a week since it happened to when I got the engine tore down and the temps have been above 0 Celsius so any ice that may have been plugging up the main has long since melted and the reed cage was not only gasketed but I also had a thin film of silicon on it too and I saw no evidence that there was any compromise of the sealing.The pulse line is solid and was on the fitting solid,the base was sealed up everywhere and the head o rings are all good.
 
I'm no SRX guru, but 152 mains sure seems lean for sea level. However, you weren't near the mains circuit with what you described. What are the needle and pilot settings?
Check boots real close too to make sure you don't have a cracked boot that caused a lean condition.
 


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