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When its cold are you suppose to run your bike richer

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ut doesnt it need to get to temps insiide the cylinder to compensate for the cold weather outside? i never rejet my cr80 from summer to winter. never locked up the bike.

Your bike is probably jetted a bit rich...then by late fall to winter the jetting is "on" due to the colder denser air. If its more responsive in winter and less responsive in summer then this is probably whats going on. I could safely run my winter jetting all year but id sacrifice snappy throttle response once the temps are consistently 60's + (mid Apr-early May) . I go one step leaner at this point.

And I warm the bike up maybe a minute in winter.

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IF it's properly jetted in the first place - then richer for the colder temps.  Some bikes run great with jetting in the ballpark - so you get away with running rich in the warmer temps & not changing for winter.  Other bikes are finiky as shit & need adjustment.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Cold temperatures make the air hold onto moisture better (per my mechanic).  The moisture in the air vaporizes, turning into oxygen.  So when it's colder, you need to richen the jetting for more oxygen.  When it's extremely humid, you again must richen the jetting because the humidity vaporizes and leans out the jetting.

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I usually go up one size on the main, depending on how cold of temps your riding in, usually one size will do, because whens it's below 30 degrees I try to ride in the tighter stuff to stay warm and then I'm not on the gas as hard too.

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Cold temperatures make the air hold onto moisture better (per my mechanic).  The moisture in the air vaporizes, turning into oxygen.  So when it's colder, you need to richen the jetting for more oxygen.  When it's extremely humid, you again must richen the jetting because the humidity vaporizes and leans out the jetting.

You need a new mechanic.

Very very difficult to pull the O from H2O. Well beyond the capabilities of KTM. definitly beyond the ability of a 2t motorcycle.

Cold air is denser than warm air so per volume (lets say what ever your piston can suck in) you have more 0, you have more N, you have more H...

More Oxygen means (simply) more burn and you need to add more fuel to get the correct burn. Its all based on density of the air.

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Cold temperatures make the air hold onto moisture better (per my mechanic). The moisture in the air vaporizes, turning into oxygen. So when it's colder, you need to richen the jetting for more oxygen. When it's extremely humid, you again must richen the jetting because the humidity vaporizes and leans out the jetting.

Your mechanic needs to retake high school science classes.

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The pros actually use a jetting tool which is esentially a barometer to calculate what jetting to use. Ive definitely noticed my jetting going to hell right in the middle of an enduro because a storm came in. But that was actually a four stroke which is way more finicky. My two strokes are very forgiving, I just run them a little rich in the summer.

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The pros actually use a jetting tool which is esentially a barometer to calculate what jetting to use. Ive definitely noticed my jetting going to hell right in the middle of an enduro because a storm came in. But that was actually a four stroke which is way more finicky. My two strokes are very forgiving, I just run them a little rich in the summer.

I thought the 4T was more forgiving to this ? 

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Fuel injected four strokes are wonderful. FCR carburetors have a million adjustments and after markets parts you can put on with even more adjustments. This is all because they are way more finicky. I've got a power now, JD jetting kit, a huge starting jet and an adjustable fuel screw. Now 8 basically just have to turn the fuel screw a half turn out in the winter to be in the ball park to ride in the snow. But I do have to pre heat the engine oil if it gets below 0f at night. I've got a crankcase heater now.

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Smart Carb looks like a good option if you live somewhere with big temp/humidity/altitude variations.

 

I have one on back order, can't wait to try it out over winter.

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