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Discussion Starter · #1 ·
Hey guys, here's my set up on my 03 440, L/C domes, 25 pilots, needle in #3, and 320/310 jetting. I also installed S4X clutch kit and I'm running 87 octane pre-mixed with IPONE synthetic oil at 40:1. NGK br9es gapped at .018
The sled performs very well at higher rpms but lately whenever I'm below 5000 rpms it runs very poor almost like on one cylinder and when I remove the plugs they always have some unburnt gas on them. I read one of Tom Whites post on this forum stating the inlet valves in the bowl should be cleaned after these sleds burn high octane fuel as it hardens up the valves and causes excess fuel in the cylinder, or I'm tempted to switch to Amsoil and maybe use 91 octane instead of 87....

What are you guys using in your sleds and what in your opinion could be causing the low end poor performance.......thanks for the help
 

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I always run 91 octane whenever I get the chance. I like how it performs better over 87 octane. My personal preference.
 

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Definitely run 91 oct whenever you can, which is always for me. Also clean those inlet valves. While you have the carbs off, check to make sure your reed petals are sealing completely and not chipped or broken on the ends.
 

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Discussion Starter · #5 ·
Well I put 91 octane in her, opened the air screw from 1 turn to 1 1/2 turns and new plugs same type BR9ES and just came back from a rip and runs much better. Lets hope it lasts........
 

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I agree with everyone on the 91 or higher octane - why not ? what's the extra cost, a couple of bucks at most..........

Also - i've heard running the NGK BR9ECS is a better plug for the 440 / that's what i've switched to - they are expensive from Ski Doo - but i get them at Auto parts store for $ 3.99 each
 

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snocanuck said:
Hey guys, here's my set up on my 03 440, L/C domes, 25 pilots, needle in #3, and 320/310 jetting. I also installed S4X clutch kit and I'm running 87 octane pre-mixed with IPONE synthetic oil at 40:1. NGK br9es gapped at .018
The sled performs very well at higher rpms but lately whenever I'm below 5000 rpms it runs very poor almost like on one cylinder and when I remove the plugs they always have some unburnt gas on them. I read one of Tom Whites post on this forum stating the inlet valves in the bowl should be cleaned after these sleds burn high octane fuel as it hardens up the valves and causes excess fuel in the cylinder, or I'm tempted to switch to Amsoil and maybe use 91 octane instead of 87....

What are you guys using in your sleds and what in your opinion could be causing the low end poor performance.......thanks for the help
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Definitely take Tom's advice and take the time to check the reeds and inlet valves and levelling floats, also check the primer for leakage (again, Per Tom) even if your sled seems to run a bit better. That way your not trying to tune around an unknown problem.

I might up your pilots a tad to 30's or 35's (I run 35's in one of mine and 45's in the other). Word has it the 03's like it a little richer in the pilot circuit.

I run 91-94 whenever I can (87 is last resort but sometimes no choice), and I mix 33:1 (Ipone) as it is supposed to help the rings seal a little better at low RPM.

For plugs, BR9EYA's have worked very well in all our sleds (03 & 04 440s, even 600 SDI's) and the ECS have not worked so well (on the SDI anyway). I gap the 440's at .022" to .023".

I also run the air screw at 1.5 turns and Needle clip on 3rd.

BTW - what's your engagment at? I believe it should be around 5200-5400 with an S4X.
 

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Discussion Starter · #8 ·
dslater said:
snocanuck said:
Hey guys, here's my set up on my 03 440, L/C domes, 25 pilots, needle in #3, and 320/310 jetting. I also installed S4X clutch kit and I'm running 87 octane pre-mixed with IPONE synthetic oil at 40:1. NGK br9es gapped at .018
The sled performs very well at higher rpms but lately whenever I'm below 5000 rpms it runs very poor almost like on one cylinder and when I remove the plugs they always have some unburnt gas on them. I read one of Tom Whites post on this forum stating the inlet valves in the bowl should be cleaned after these sleds burn high octane fuel as it hardens up the valves and causes excess fuel in the cylinder, or I'm tempted to switch to Amsoil and maybe use 91 octane instead of 87....

What are you guys using in your sleds and what in your opinion could be causing the low end poor performance.......thanks for the help
[snapback]697676[/snapback]​
Definitely take Tom's advice and take the time to check the reeds and inlet valves and levelling floats, also check the primer for leakage (again, Per Tom) even if your sled seems to run a bit better. That way your not trying to tune around an unknown problem.

I might up your pilots a tad to 30's or 35's (I run 35's in one of mine and 45's in the other). Word has it the 03's like it a little richer in the pilot circuit.

I run 91-94 whenever I can (87 is last resort but sometimes no choice), and I mix 33:1 (Ipone) as it is supposed to help the rings seal a little better at low RPM.

For plugs, BR9EYA's have worked very well in all our sleds (03 & 04 440s, even 600 SDI's) and the ECS have not worked so well (on the SDI anyway). I gap the 440's at .022" to .023".

I also run the air screw at 1.5 turns and Needle clip on 3rd.

BTW - what's your engagment at? I believe it should be around 5200-5400 with an S4X.
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Thanks for the tips, I will check the valves before anything else ,and I'm going to try the BR9EYA plugs and 30 pilots, and will run 91 from now on, one other thing, when I shut it off after a run, I sometimes need to depress the throttle in order for it to start again, will the fatter pilot correct that ? how much pin weight are you running in your primary ? mine engages at +- 5000 rpm with S4X KIT. Overall I'm ok with the performance but I don't think it at it's best , might be because of the 87 octane, but will see in the next few runs if theres any improvement with the 91 octane and BR9EYA plugs.
 
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