08 600 RMK and Carbs

[Sleddogg]

Little help needed..
This is my wife's sled and it has always been a touch boggy on low end. Like just the first 1/8 throttle. After that it screams.
When we first bought it I had smaller Pilots put in for our elevation. (8000-10000).
Just recently the bog got worse.
So after talking to my dealer I decided to tackle the problem yesterday on the mountain and played with the needles and he told me to try adjusting the fuel screws as well.
I did all this and there seemed to be no difference at all. with any of my adjustments. The Fuel screws were about a half turn from being all the way in and they were not exactly even.
After playing with different things and reading different things on here I have a few questions.
Are they Fuel Screws or Air screws on that sled.
Are her Carbs the TM38s?
What would be the first thing to try and rid the very low end bog?
I figured I would find out a little more on here and then rip into them and clean them all up as well as try whatever advice sounds good!
Thanks guys!

 

[bigfoot]

They are fuel screws, do you know what size pilots are in it?

 

[theultrarider]

The fuel screws are the big plastic ones on the side (right) of each carb. If you pull the airbox off, you will find the AIR SCREWS! they are also on the the right side but are small brass screws hidden where the airbox sits on the end of the carbs. Back those out a half a turn at a time to lean it out a little. That should clean up your bottom end.

 

[bigfoot]

The fuel screws are the big plastic ones on the side (right) of each carb. If you pull the airbox off, you will find the AIR SCREWS! they are also on the the right side but are small brass screws hidden where the airbox sits on the end of the carbs. Back those out a half a turn at a time to lean it out a little. That should clean up your bottom end.

Ultra the 07 and 08 600 carbed sleds no longer have the brass screws. We have to buy idle air bleed jets to adjust mixture like you used to be able to do with the brass screws. Pain in the arse!!

 

[Sleddogg]

IIIII seeeee..
Ok. That makes sense now.
I will try the half turn thing.

I am not sure the size of the Pilots yet, but I soon will!

So as far as setting the Fuel screws correct then what is the best way to do that..? I screwed them evenly in and out and didn't find any noticeable difference.
Thanks guys!! Awesome help.

 

[Sleddogg]

Disregard my last message then..!
So do I might need Air Bleed Jets..?
Is this what I have read on here that have numbers like .6 and .9?

 

[theultrarider]

Ultra the 07 and 08 600 carbed sleds no longer have the brass screws. We have to buy idle air bleed jets to adjust mixture like you used to be able to do with the brass screws. Pain in the arse!!

Thanks for educating me Bigfoot. I was mistaken. That is a pain in the butt!

 

[bigfoot]

Disregard my last message then..!
So do I might need Air Bleed Jets..?
Is this what I have read on here that have numbers like .6 and .9?

Sleddogg, you probably do, but need to know whats in there first, find out what the idle air jets are and pilots are, then we can help you out.

 

[bigfoot]

Thanks for eduacting me Bigfoot. I was mistaken. That is a pain in the butt!

No problem Ultra, you wouldn't believe how dissapointed I was when I went to adjust those and found out they didn't have them anymore!

 

[Sleddogg]

Ill Dig into it tonight..
Thanks Bigfoot

 

[bigfoot]

No problem.

 

[Daggerboat]

Today I rode the 600 for the first time this year (finally enough snow)....From 3500' the fuel screw is still too rich at 1/2 turn (280 main #1 needle)....I'm going to 1/3 fuel screw while I replace the stock .6 pilot air jets with .9.....This motor is SO FAT on the bottom end I would also install leaner pilot jets if it wasn't such a pain in the a$$ with the oil lines being TOO short from the oil pump to carbs!!

 

[CROW]

Those oil lines come off real easy. Just curious how you can tell if it's lean or fat on the bottom?

 

[Daggerboat]

Those oil lines come off real easy. Just curious how you can tell if it's lean or fat on the bottom?

I don't like removing oil lines unless I have to....My 600 runs great , I'm just trying to improve the fuel economy and I can tell by the gurgle sound of the exhuast under 1/4 throttle that that's where the fuel is going

 

[CROW]

I've got the bog, miss, gurgle or whatever just off idle also. Just wasn't sure if it was a lean condition or fat.

 

[theultrarider]

I haven't seen a poo lean out of the box yet! When you let it sit and idle do you have the big black spot in the snow as you try to take off? After idling for a while does it just not want to go, then little by little clean up and start to run? That would be fat!

 

[CROW]

Well, I should have given a little more info. Stock it would leave a black spot. I changed pilots to 40, paj to 1.0, screws 1 out, needle #2 position, 390 mains for 0-2000ft, with an SLP airbox kit. with this setup, no more black spot, but has a weird hesitation right off idle. I raised the needles one notch, same. Fuel screws in, fuel screws out, .9 paj, up to 45 pilots, all sorts of combos...still there????

 

[Sleddogg]

What is the proper way to find the correct setting for the fuel screws then?

I didn't have time to get the sled apart tonight..
Quick question.. I have taken the airbox off several times but haven't taken the carbs off yet.. is it fairly easy to do it? i am very familiar with older sleds but not the new ones. Looks like just clamp and plug and a few lines. Anything to be worried about?
Thanks again!

 

[theultrarider]

What is the proper way to find the correct setting for the fuel screws then?

I didn't have time to get the sled apart tonight..
Quick question.. I have taken the airbox off several times but haven't taken the carbs off yet.. is it fairly easy to do it? i am very familiar with older sleds but not the new ones. Looks like just clamp and plug and a few lines. Anything to be worried about?
Thanks again!

Sleddog,
Hate to say it but trial and error. I live in Alaska and our air density is way different here. All 2 stroke are WAY fat on the bottom end here for some reason other than just elevation. Maybe someone around you can speak up and give you a good starting point. Here, on most poo's I have my hands in the fuel screws end up at 3/4 to 1 1/2 turn. Most being 1/2 to 1 turn out. But that is for here.......Turn them about 1/2 turn at a time. you will knnow it when you get it right. run it around at just off idle to 1/4 throttle. When it is clean and crisp, that is where you want you fuel screws to be set at. Removing the cabrs is pretty straight forward. Just make sure to note which lines go where and make sure they all get hooked back up!

 

[Daggerboat]

Sleddog ,basically I will gradually lean the feul screws until a noticeable loss of throttle response then turn them out 1/8 turn....You need to have EGT gauges to get PTO/Mag sides exactly right