Carb jetting/help

[Laan1237]

Hey all new to the forum and sleds, just picked up a 2002 rmk 800, previous owner said they have it jetted for the mountains, now my question is, this season I'm not to sure if I'll make a mountain trip as I am new to the sport and want to get some time and feel for the sled, I plan on riding out at my buddies cabin which is lake isle, near Edmonton Alberta, as well as the Pembina river, my question is do I have to adjust the jets or can I leave it in the mountain set up? Also is this somthing hard to do?

 

[turbolover]

If he has it jetted for high elevation it will melt pistons at low elevation. The jets don't allow enough fuel and it will run to hot.
I know that sounds backward. Too little fuel (lean) is hot. Too much fuel (rich) is cold.
The fuel actually keeps the exhaust cooler so it won't melt things.
Changing the jetting isn't hard if you are mechanically inclined at all.
Turn off the fuel.
Pull the airbox, should just be a rubber strap or several holding it in place.
Then the carburetors each have a screw that holds the clamp around the rubber carb boot.. Loosen those and pull the carbs loose. That should be a rack carb. (One piece unit) You can rotate it upside down. Don't kink any of the cables. There should be an access drain on the bottom of each carb. (it will have a short stubby hose on it)
Inside will be a 1/4 inch brass jet with a hole in it. Remove that. DONT lose the little brass washer.
Ask a dealer or a mechanic what the jetting and clutching specs should be. Put the new bigger jet in and replace everything.
Box or bag your parts so when you do go to the mountains you have em.
You will also new to replace the clutch weights and spring to better perform at your elevation.

Sent from my DROID RAZR HD using Tapatalk

 

[Laan1237]

Alright thanks, put in bigger jet? Is it not just an adjustment like turning a screw? Also they never said anytning about the clutching do you thjnk that's been changed too?

 

[turbolover]

The jets are sized in numbers. Like a 370, 380, 390. The bigger the number the more fuel it will flow. Richer jet.
If you change jets that much for altitude then it will need heavier weights and a possibly a lighter spring. Motors have more horsepower at lower elevation because of denser air. They can swing bigger weights, lighter springs and steeper helix angles at lower elevation.
At 7-9000 feet the sled will have lost as much as 20% of the power it is capable of making at sea level. You have to change the clutching so the motor stays in the designed rpm power band.

Sent from my DROID RAZR HD using Tapatalk

 

[turbolover]

Call a good sled shop in your area. They can hook you up with jetting and clutching specs for where you are going to ride.
It isn't hard to change those parts. Getting the right combination of them can be as much art as it is science. They are all connected. If you change one area the other has to follow suit or you're going to have a machine that runs like crap and you won't be happy with it.

Sent from my DROID RAZR HD using Tapatalk

 

[Laan1237]

If he has it jetted for high elevation it will melt pistons at low elevation. The jets don't allow enough fuel and it will run to hot.
I know that sounds backward. Too little fuel (lean) is hot. Too much fuel (rich) is cold.
The fuel actually keeps the exhaust cooler so it won't melt things.
Changing the jetting isn't hard if you are mechanically inclined at all.
Turn off the fuel.
Pull the airbox, should just be a rubber strap or several holding it in place.
Then the carburetors each have a screw that holds the clamp around the rubber carb boot.. Loosen those and pull the carbs loose. That should be a rack carb. (One piece unit) You can rotate it upside down. Don't kink any of the cables. There should be an access drain on the bottom of each carb. (it will have a short stubby hose on it)
Inside will be a 1/4 inch brass jet with a hole in it. Remove that. DONT lose the little brass washer.
Ask a dealer or a mechanic what the jetting and clutching specs should be. Put the new bigger jet in and replace everything.
Box or bag your parts so when you do go to the mountains you have em.
You will also new to replace the clutch weights and spring to better perform at your elevation.

Sent from my DROID RAZR HD using Tapatalk

Thanks, put in a bigger jet, can not just adjust it?

 

[Laan1237]

Hey guys so is there 2 carbs on this sled? Because the parts desk chick only sold me the one jet. My problem is my polaris dealer is closed on Sunday, is there anywhere eles I could get jets for this sled that would work?

 

[Spaarky]

Jet per cylinder. So you need two. Anyone that has Mikuni jets may have what you need.