95 XLT SP hard on fuel. - HCS Snowmobile Forums

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Old 03-07-2011, 01:37 PM   #1 (permalink)
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Default 95 XLT SP hard on fuel.

Need help with a 95 XLT SP. I bought is a couple of years ago, and after I got it home realized that it had a twisted crank. I ended up rebuilding the engine with a rebuilt crank, .010 over SPI pistons, new Polaris seals, Winerosa gasket set. While I had the engine apart, I sharpened the bridges in the transfer ports and the intake, and polished up the exhaust port. I cleaned up the carbs, made sure everything was back to stock settings. I also took off the PSI triple pipes that it had on it and put the stock exhaust back on. The timing has also been adjusted to 1-2 degrees advanced.

Now that I am out and driving it and have it broke in abit, I can't seem to get very good gas mileage out of it ( 67 miles on a groomed trail with the girlfriend driving it when it ran out). It also seems to load up when it sits and idles for any amount of time. I have changed the needle and seats, fuel pump and this hasn't seemed to fix my problem.

The clutches are in good shape, Primary is brand new from previous owner, and the secondary is good shape with a new large bushing installed this fall.

I am running out of ideas of what to check next, so please HELP!!!!!

Last edited by snow_crazy; 03-07-2011 at 01:39 PM.
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Old 03-07-2011, 01:49 PM   #2 (permalink)
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Check your jetting. I bet it was richend up about 4-5 steps on the mains with the tripple pipes. Go back to stock settings and I bet you will see a 40 mile gain per tank or better. Also check your clutching as I bet that was chainged drastically for the extra HP the tripple pipes add to them.
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Old 03-07-2011, 02:33 PM   #3 (permalink)
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Jetting is at 190 which is down 2 sizes from stock. Primary clutch has 10MB with a Polaris Bluse spring, which should be close for stock engine (running 8200-8300 rpm). Secondary clutch has the straight 36 with a silver spring.
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Old 03-07-2011, 02:33 PM   #4 (permalink)
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Exactly jetting was changed with triples you should get 16-19 MPG with the 34MM, the 38Mm used 2-4 MPG more fuel.
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Old 03-07-2011, 03:00 PM   #5 (permalink)
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Check that the needle & seats are actually closing off by doing a wet pressure test. The loading up at idle concerns me.....

Also - as said already , jet it as stock. My wife's 95 XLT Special gets 13-14 after leaning down the needle jets 3 sizes, leaving the jet needles in the stock position.

Good luck!

Steve
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Old 03-07-2011, 03:12 PM   #6 (permalink)
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engineman,

Dumb question, but how do you do a wet pressure test?

Next, jetting is completly stock with the exception of the mains being 190 rather than 210. Are you saying I should change my needle jet, and if so, what to?
Thanks
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Old 03-07-2011, 03:24 PM   #7 (permalink)
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A wet test is when the bowls and fuel line are filled with fuel and you put 5 psi or so on the fuel line and see if the level in the line goes down due to leakage. Using a clear fuel line helps in this process a lot. A mityvac is a commonly used tool to provide the pressure.

Regarding the needle jets - the only reason I changed them was to put the needle clip near the center position so I still had adjustability. You could try dropping the needles (raising the clip) one step at a time and see what you find. Obviously check the plugs and piston wash as you do this so you don't lose the motor.

Also - check compression once more just to be sure and take a good look at the intake manifolds for cracks. Maybe even spray around the crank seals when it is runnig to ensure there are no air leaks. You just want to make sure the basics are in good shape before rejetting.

Good Luck!

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Old 03-07-2011, 05:27 PM   #8 (permalink)
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Quote:
Originally Posted by snow_crazy View Post
Jetting is at 190 which is down 2 sizes from stock. Primary clutch has 10MB with a Polaris Bluse spring, which should be close for stock engine (running 8200-8300 rpm). Secondary clutch has the straight 36 with a silver spring.
Stock you should be running 10m weights with a polaris gold or blue spring. 34 degree helix and red secondary spring. 34 mm carbs could be jetted down to 200 mains if they were not opened up. I can't recall what nozzle was stock was but i'd also bet it was changed to a larger one for the psi pipes. That alone is why your fuel economy is in the crapper.
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Old 03-07-2011, 05:33 PM   #9 (permalink)
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Quote:
Originally Posted by too slow View Post
Stock you should be running 10m weights with a polaris gold or blue spring. 34 degree helix and red secondary spring. 34 mm carbs could be jetted down to 200 mains if they were not opened up. I can't recall what nozzle was stock was but i'd also bet it was changed to a larger one for the psi pipes. That alone is why your fuel economy is in the crapper.
X2.....

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Old 03-07-2011, 05:53 PM   #10 (permalink)
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Sorry, but having a brain fart here, what do mean by nozzle?
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