finnyfarm
L1 Scorpion - The Great Snowmobile
Posts: 4
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Post by finnyfarm on Jan 14, 2012 15:44:14 GMT -5
I have a 1979 tkx 440 w/ a mikuni 36, does anyone know what the stock jet sizes were? It's running really fat after it warms up. Any tuning help would be appriciated
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Post by obj1 on Jan 15, 2012 11:01:59 GMT -5
290 main, 35 pilot and 125 power jet. clip in middle of needle. run GOOD oil and 92 or better non-ethanol fuel. Keep air intake system in place.
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Post by scorpionsense on Jan 22, 2012 0:10:36 GMT -5
Can you tell me what needle to run in this carb? Can you tell me why a non-power jet carb runs about the same jetting? If the power jet is useful, wouldn't a non power jet carb be lean at WOT? OR If a non power jet carb works with this jetting, wouldn't a power jet carb be rich on top? The amount of air at full throttle doesn't change so why the powerjet difference?
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Post by scorp11 on Jan 22, 2012 2:35:33 GMT -5
Can you tell me what needle to run in this carb? Can you tell me why a non-power jet carb runs about the same jetting? If the power jet is useful, wouldn't a non power jet carb be lean at WOT? OR If a non power jet carb works with this jetting, wouldn't a power jet carb be rich on top? The amount of air at full throttle doesn't change so why the powerjet difference? Needle - 6DH4 in 1979. In 1980 if you had the update kit installed, they switched to a 6DH21, Stock in 1980 was 6DH4, same as 1979 I suspect if you were running a non powerjet carb, you would be looking at closer to a 360 main jet in it for this motor. The 1980 Stings and TK's actually came with a 360 or 380 main jet in the power jet carbs from the factory. Only to be leaned out later by a TSB. There were no non-powerjet carbs on these from the factory. I know guys who have switched out of the 36 mm power jets to a non powerjet single carb and all of them ended up with a 38 mm Mic with around that 360 main jet. A guy I talked to had a formula for what size power jet + the main jet = a regular carb with no powerjet circuit, but I don't remember it. And yes, the non-powerjet carb had a bigger main.
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