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Discussion Starter · #1 ·
i just bought a bike has a s&s 127 motor with a super g carb and noticed the other day the front pipe gets way way hotter than the back one so i pulled the plugs !! the front plug is grey so is lean and the rear plug is brown so good ! so i sprayed carb cleaner on intake manifolds and no idle change ! so i twisted the throttle and noticed gas from the boot from what i think in the accelerator pump! and if i do it it leaks bad and if u give it throttle fast it bogs no matter how i adjusted it before i knew it was leaking ! what does everyone think ? if i baby it it wont bog but if i floor it from a stop bogs a bit so im thinkin all the gas thats leaking should be going into the motor ? please help im a newby with carbs! also is there anywhere else on these motors it can suck more air in to the cylinder to run lean or do u guys think it needs a bigger intermediate jet ? im at like 6800 ft elevation
 

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If there's fuel coming out of the accelerator pump boot the diaphragm is leaking. That can cause the bog.
You need to fix that leak because it's directly above the hot exhaust pipes !
 

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Discussion Starter · #3 ·
If there's fuel coming out of the accelerator pump boot the diaphragm is leaking. That can cause the bog.
You need to fix that leak because it's directly above the hot exhaust pipes !
yeah for sure not riding it till I do ! would that cause it to be lean to or no? or is there other places it can suck air besides the manifold? or is it time to change jets?
 

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It's not unusual for the plugs to be different colors because the front and rear cylinders operate at different temps.
Ain't gonna hurt to pull the bowl and check things out. Easier to replace the accel pump diaphragm with the bowl off.
 

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Discussion Starter · #5 ·
they do like totally different? one head is hot as shit and other one is cold ! I will pull the bowl and such tonight and see whats up! it came from a place at 6k fet and im at 6800ft so wouldn't think that would mess with tuning that much
 

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If there's no apparent intake leak then I would do a compression test to make sure both cylinders are balanced. Might be a bad valve in the front head or something.
How many miles on the engine ?
 

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Also check the exhaust flanges for leaks.
 

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Discussion Starter · #8 ·
don't really know on miles no odometer !how could I check for a exhaust leak ? also made sure both plugs have spark and that to !
 

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The best way on the exhaust is to remove them and replace the gaskets.
An air leak at the exhaust flange can cause reversion sucking cold air back into the head.
J&P sells all the stuff for the S&S engine, gaskets, pump diaphragm etc..
 

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Discussion Starter · #10 ·
ok cool I try that that front exhaust is bluer and the one that gets hot and with the white plug il try that also hopefully I don't have to mess with the jets just don't want to burn this bike down
 

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Discussion Starter · #11 ·
well tried the comp test and each cylinder had 150lbs comp so good there ! But don't explain why there is oil in the rear cylinder exhaust pipe !! What are ur thoughts there ? Il have the carb stuff tomorrow so fix that issue I hope
 

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Oil in the rear exhaust pipe, and I assume the head, would mean a bad valve guide seal.
 

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Discussion Starter · #13 ·
yeah that's what happened to my raptor !!how hard is it to pul the head and replace the seal
 
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