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Replacing needles

B

brewer45

New Member
Messages
7
Age
61
Location
Manitoba
Country
Canada
Years Snowmobiling
15
Snowmobile
1999 SKS 700
I'm going to clean my Keihin carbs and install carb kits. As far as I know they're stock. PT0-185/MAG-190, 38 pilot, R1368G needles. I picked up a couple of 1371G needles hoping to clean up bottom to midrange RPM. Burbly from idle to about 5000, then smooths right out but smells really rich in that RPM range and my buddy riding behind me the other day had to back off because of my exhaust fumes. Plugs are clean though. Will I be hurting anything with the 1371 needles on #3? This is a '99 SKS 700. Never played around with jetting before, thanks.
 
I would honestly put a set of reeds in it first, the one thing I regretted not doing to my 700.
I've since learned Polaris stock reeds were never that great and given the age of yours I can guarantee they are not sealing that tight anymore.
 
850Switchback said:
I would honestly put a set of reeds in it first, the one thing I regretted not doing to my 700.
I've since learned Polaris stock reeds were never that great and given the age of yours I can guarantee they are not sealing that tight anymore.
Click to expand...
I put Boyesen dual stage reeds in when I did the top end a couple of months ago. Boyesen states that it might run lean at idle and richer at higher RPM, but mine is rich on the bottom to mid.
 
Ok that takes care of that.
Go ahead and try it, those sleds were pig rich stock. That needle number sounds familiar but its been many years since I screwed around with re-jetting mine.
What elevation are you running at?
 
850Switchback said:
Ok that takes care of that.
Go ahead and try it, those sleds were pig rich stock. That needle number sounds familiar but its been many years since I screwed around with re-jetting mine.
What elevation are you running at?
Click to expand...
Low, Canadian prairies 270 m (880 ft). I'm gonna put a fuel pump kit in also in case that has anything to do with it. 1371G were used in the '98 RMKs I believe.
 
I wouldn't bother with the pump yet, just pull the crankcase impulse line to make sure the diaphragms arn't leaking fuel thats getting sucked into the lower end. All that pump does is help get the fuel to the bowls. The fuel inlet needles & floats control the fuel level in the bowls, all that looked good and the float heights are set right?
Also what spark plugs are you running, those ducati ignition engines really liked the factory RN57YCC Champions since they were developed for it.
FYI the 97&98 engines were completely different cylinders and heads so be careful pulling info from those years.
 
I just remembered something, your sled as that altitude compensation system in the airbox. If you don't intend on operating it at higher elevation you should look into disconnecting it because its probably trying to screw with making it richer at sea level.
Edit: nevermind, I think that was just the RMKs
 
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850Switchback said:
I just remembered something, your sled as that altitude compensation system in the airbox. If you don't intend on operating it at higher elevation you should look into disconnecting it because its probably trying to screw with making it richer at sea level.
Click to expand...
I'm trying the Champion Powersport plugs 8904, seems just a bit cleaner on idle. Haven't been into the carbs yet to check float level. I don't think I have the altitude compensator, just two nipples on the air box.
 
One other thing, the Keihins adjustment screw are an AIR adjustment to the low end mixture not a fuel screw like the Mikunis. So they are doing the opposite when you adjust them and if they are plugged up, you get a really rich mixture down low.
 
850Switchback said:
One other thing, the Keihins adjustment screw are an AIR adjustment to the low end mixture not a fuel screw like the Mikunis. So they are doing the opposite when you adjust them and if they are plugged up, you get a really rich mixture down low.
Click to expand...
So I wonder if I just dropped one notch on the 1368 needles instead might help. They're in the #3 position now.
 
I kind of remember doing a needle change on mine, but I had an SLP single on it so I was tuning for that also. I thought the needle change was to clean up that low end burble you are noticing, I remember having that too. I had the boost bottle too but turns out that was just covering for the crappy reeds.
I would clean the carbs first, that air adjustment draws from an orifice in the face of the carb throat, so if its plugged with clutch dust or something that will never work correctly and you'll be chasing it around.
Like I said earlier, those 99&00's were pig rich stock so you have a lot of room to play around.
 
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