rich all summer?

[Banshee_19]

Hey guys. My shee was running rich all summer. Ran really good around 20 degrees celcius and now I have a ride planned for tomorrow, and the forecast is for -20 degrees celcius. Will I be ok with the same jetting? It seemed to run fine today when it was -18 degrees celcius. See up here in canada we have a thing called snow, its white fluffy stuff and it happens when it gets cold. Thats for some of you southern folk on here. lol. I am not worried about the performance loss, I am just wondering if I will be ok with it for a day, then my engine is coming apart for a re-build.

[sheefreak]

Help me out here, 40 deg. celcius difference works out to be how much of a difference in Farenheit? They are not linear are they?

[Fireman-hott]

It will be fine if it was a little rich when it was warmer. Just a matter of how much more rich was it?

Being colder will make it even more rich. Think of oil, when its cold its takes longer to move the same amount of liquid than when its warmer. Same with Air. Less air = richer.

something like 15*F move one jet size up/down depending on wether the temp went up/down.

[BANSHEEMANIAC]

It will be fine if it was a little rich when it was warmer. Just a matter of how much more rich was it?

Being colder will make it even more rich. Think of oil, when its cold its takes longer to move the same amount of liquid than when its warmer. Same with Air. Less air = richer.

something like 15*F move one jet size up/down depending on wether the temp went up/down.

im not sure but i think you are bass ackards on that? you run LEANER in colder weather.

[Fireman-hott]

No.

More air = More Fuel

Less Air = Less Fuel

 

Cold weather = More dense air = less airflow

Warm weather = less dense air = more airflow

[kubiac3]

If your running a mixture of 40:1 or 50:1 I have a idea for ya. Your bike is probably fine the way it is, BUT when you get there and it seems to be running lean, just take some oil and dump a small amount in your gas tank and shake the bike to mix it in there good. that will richen up your bike and you wont have to deal with jetting when your on a small 1 day ride. Just dont dump alot, just a small amount. Its called ghetto tuning.

[ClimbAnyHill]

Go leaner..

See for us Southern Cali people, I get to ride trails in 88 degree temp tomorrow! :biggrin:

[moneybags]

im not sure but i think you are bass ackards on that? you run LEANER in colder weather.

 

Im with you on this

No.

More air = More Fuel

Less Air = Less Fuel

 

Cold weather = More dense air = less airflow

Warm weather = less dense air = more airflow

 

 

I think that your are mistasken on the

 

Cold weather = More dense air = less airflow

 

But I am a newbee and not positive about it

 

My 2 cent

[moneybags]

The higher the elevation the thiner the air. The more richer you would run.

 

At sea levle the air would be thicker then say 4500 feet

 

I am not trying to starte a bi_ch fight so I will save it for now tell somebody elce rings in on this

 

If I am wrong then

[BANSHEEMANIAC]

Im with you on this

I think that your are mistasken on the

 

Cold weather = More dense air = less airflow

 

But I am a newbee and not positive about it

 

My 2 cent

[BANSHEEMANIAC]

No.

More air = More Fuel

Less Air = Less Fuel

 

Cold weather = More dense air = less airflow

Warm weather = less dense air = more airflow

i still think you are just thinking wrong. colder air makes you run leaner. this is why when you run nitrous oxide you have to put more fuel in the motor. nitrous oxide is non flammable. all it does is freze the gas and air. think about it.

[Washburn]

Colder weather=leaner. Barometric (sp) pressure

[sheefreak]

Why do we think a choke makes the ckt richer, and you usually need to use the choke in the winter????????

 

Also, Kubiac3, rich/lean is not a ratio of oil to fuel, it is a ratio of air to fuel. So what actually happens when you add more oil and use the same jets, you get less fuel which would actually cause your bike to run leaner. Boy, this thread is all F'd up.

[BANSHEEMANIAC]

here ya go! --- {question} why do temperture changes affect my jetting?} the answer is, as air gets colder, the molecules become closer together in a given volume(HIGHER DENSITY); COLD AIR contains more oxygen than the same volume of warm air. more oxygen in a volume of air means than the same jet sizes will not deliver enough fuel to burn the oxygen that you are getting in the cold weather, in turn you run lean. ..........and this is to sheefreak. {why do premix ratio changes effect my jetting} just like temperature and elevation changes, altering the amount of fuel delivered by the carbs in a given volume of air will result in a rich or lean condition. by changing how much oil is in the premix, you also change how much fuel is available to burn. since the oil in the premix is intended to lube the crank, it is burned off in the combustion precess, however the oil thats in the oil/fuel mixture displaces the amount of fuel that is available for the air to burn; more oil means less fuel and less oil means more fuel, from an air/fuel ratio standpoint. example... you change your premix ratio from 32:1 to 100:1, every gallon of fuel will contain less oil, so more fuel; from a air/fuel ratio standpoint there is more fuel to be burned so your jetting will be to rich and you will need to jet leaner. in contrast, going from 40:1 to 20:1 means that for every gallon of fuel will contain more oil, so less fuel; the air/fuel ratio will be to lean and you need to jet richer. basically a higher ratio will require leaner jetting and a lower ratio will require richer jetting. sheefreak is right on this. :thumbsup:

Edited November 25, 2006 by BANSHEEMANIAC

[Banshee_19]

well here is the update, I was out for a 5 hour, 58km ride today in -20 degree celcius weather. The quad was very hard to start but once it was at running temp it ran well. It seemed to drink more gas then expected. I was suprised at how well it ran in the cold weather without changing jets. And now it time to start the rebuild!!