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Discussion Starter #1
Ok I need help theres a bad lag in the sled when you nail the gas(about 1.5 - 2 seconds), it will run fine at low and high speed but it looses power in the middle? the air to fuel mix screws are set to 2 turns out is this to much? it sits at idle around 3000 rpm is this normal? also the primary clutch seems to stick alittle around 5500 rpm what could this be? can I lube it to help it work better?

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Megan
 

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Megan, it sounds like the sled is a little lean. You may want to get the carbs taken apart and cleaned. You may also want to check for air leaks around the carb boots that attach the carbs to the rotary valve housing and crank seals.
Also with the clutches, you want to have them taken apart and cleaned as well. You dont want to use lube as it attracts dirt and belt dust.


Brian
 

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Discussion Starter #3
Ok my boyfriend has rebuilt the engine this summer and had the carbs rebuilt by a shop in town all rubber gromits were replaces all hoses and bushings relaced the guy we bought it from said he messed with the air to fuel mix screws alot. The clutch was just rusty on the inside so that was the problem with that. the idle is still at 3000 but we think it is from the air to fuel ratio being to high, anyone know the proper screw setting for an 88 formula mx?

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Megan
 

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1988 Formula MX and MX LT: Sea level

Jets PTO ~ 220
MAG ~ 240
Pilot Jet ~ 40
Needle Jet ~ 159 P4
Jet needle ~ 6DH7 (clip position #3)
Throttle valve ~ 2.5
Pilot air screw ~ 1 & 1/2 turns (after lightly seated)
Idle speed ~ 1800 - 2000 RPM

Spark Plug NGK BR9ES gapped at .016"
 
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