Youllbe2nd
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Does anyone find the mag cyl runs hotter than the other two on a piped viper? Running at sea level here so last year I ran 165 mains, 147.5 pilots, needles at 3.5 screws at 2.5 turns. I ended up smoking the mag side piston. Pistons were all slightly out of spec and due for replacement. Piston wash looked pretty good but for some reason the mag side heated up and melted the piston on exhaust side. Wash looked richer on pto and mid cyls than compared to mag. Do the pipes heat that side up more?? Trail ported viper with slp pipes. This year can't decide where to start. I'm thinking 50 pilots, 165 mains needles at 4.0 and can't decide on fuel screw cause honestly not sure what they do exactly? I will be breaking the sled in with this set up with premix in the tank. Does anyone run their mag side a little richer? Maybe just keep my 3.5 needles but run the mag at 4 and go to 50 pilots? Opinions please 
not looking for exact jetting specs but more just wondering if guys are running staggard jetting given this viper has that goofy wacky head. Thanks all!!
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not looking for exact jetting specs but more just wondering if guys are running staggard jetting given this viper has that goofy wacky head. Thanks all!! Sent from my E6560C using Tapatalk
Fuel screws can cause lean or rich settings. Are the heads cut? Rule of thumb no more then 2 turns on them.
I have an slp piped mrviper700 trail ported 04 viper. Don sent a setup sheet here is how I ran it last year elevation 1000'
Mains 162.5 all three
Pilots 47.5
Needle #4
Half a bottle of nos race octane booster.
I ran this in -10f with no issues and 35f without making adjustments(should have lowered the needles) no fouled plugs was just rich.
I believe aggressive clutching can make a slight difference but I have never personally expirenced that issue.
Do you run non-oxy gas?
Mains 162.5 all three
Pilots 47.5
Needle #4
Half a bottle of nos race octane booster.
I ran this in -10f with no issues and 35f without making adjustments(should have lowered the needles) no fouled plugs was just rich.
I believe aggressive clutching can make a slight difference but I have never personally expirenced that issue.
Do you run non-oxy gas?
Youllbe2nd
New member
Youllbe2nd
New member
Any idea what your fuel screws are set at? Your setup is almost exactly where I started with this sled a few years ago. There are times I have no choice and have to run ethanol gas. I personally think booster does **** all and is expensive, 2cents. SLP Recommends two sizes up for the ethanol junk so I think I'll be close here with the setup I mentioned. I might just chalk up that piston meltdown to shit gas and a beat piston. It was very close...the ring never stuck at all. It was running. It even had a decent compression reading when i found it. I think it toasted on decel because it didn't even hiccup the whole day. Anyway il be putting egts on it this year. So hopefully that will give me a better idea of how even each cyl runs. I just want to dial in my carbs first! When im happy with the wash and plug color then I'll start to work off the egt. Can anyone explain exactly what the fuel screw does?
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its your needle setting, too lean... you can put any size main jet in it wont keep it from burning down because its not running wide open its doing the damage on the mid range cruise circuit of the carb. The viper uses leaner needles and nozzles then a srx does and has way more ign. timing in the same area. Heat=detonation=melted piston
fuel screws will not keep it from burning down either, they control the idle circuit, if you need to go more then 2 turns out to control idle hang or a bog, you need to go up 1 more size in pilot jet.
fuel screws will not keep it from burning down either, they control the idle circuit, if you need to go more then 2 turns out to control idle hang or a bog, you need to go up 1 more size in pilot jet.
Youllbe2nd
New member
Great thanks. That's what I figured. I'll try 50 pilots, 2 turns out and needle 4.0. Had idle hang at 2.5 turns with the 47.5 pilot. Ill probably end up dropping the main back down to 162.5 but i gotta test first. Do you ever run the needle richer on mag side?
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Nos works and this based on these test results in a knock engine not my opinion.
http://www.fuelexpert.co.za/Octane-Booster-Shootout.php
Mainly insurance against bad gas.
http://www.fuelexpert.co.za/Octane-Booster-Shootout.php
Mainly insurance against bad gas.