throttle "lag" and decel popping
Thread Starter
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Outstanding HDF Member
Joined: Aug 2008
Posts: 3,078
Likes: 6
From: Michigan
throttle "lag" and decel popping
Maybe I'll get a better response with my very own thread, sorry to the bro I butted in on...
My evo hesitates when I crank the throttle from idle, sometimes even almost stalls out. Also coughs and act like it's gonna stall when I down shift and then hit the gas to go around a corner. Quite by accident I found that pulling up the enrichener just slightly eliminates the lag/cough when I punch it from idle, so figuring I was running lean I opened the fuel mixture screw about 1/4 turn thinking that would help, but it didn't. Also alot of decell popping, which I kinda like. I was shooting flames out the back, but from experience, found a loose connedtion from battery which cleared up the missing that was causing unburned fuel to be pushed thru. This is after having the S&S carb apart and cleaned thouroghly and replacing everything on the accelerator pump side. When it's running at higher R's no problems, infact it pulled 84 HP and 92 ftlbs of torque on the dyno (after which I started hearing a squeek, or chirp from the primary if I pull in the clutch and let it out, or goose the throttle at low speed, need a heavier duty clutch?) Any suggestions?
(Man I must love this ol bitch, cuz if my wife gave me this much trouble I'd be single again!!!)
My evo hesitates when I crank the throttle from idle, sometimes even almost stalls out. Also coughs and act like it's gonna stall when I down shift and then hit the gas to go around a corner. Quite by accident I found that pulling up the enrichener just slightly eliminates the lag/cough when I punch it from idle, so figuring I was running lean I opened the fuel mixture screw about 1/4 turn thinking that would help, but it didn't. Also alot of decell popping, which I kinda like. I was shooting flames out the back, but from experience, found a loose connedtion from battery which cleared up the missing that was causing unburned fuel to be pushed thru. This is after having the S&S carb apart and cleaned thouroghly and replacing everything on the accelerator pump side. When it's running at higher R's no problems, infact it pulled 84 HP and 92 ftlbs of torque on the dyno (after which I started hearing a squeek, or chirp from the primary if I pull in the clutch and let it out, or goose the throttle at low speed, need a heavier duty clutch?) Any suggestions?
(Man I must love this ol bitch, cuz if my wife gave me this much trouble I'd be single again!!!)
Road Warrior
Joined: Dec 2008
Posts: 1,639
Likes: 2
From: Australia
Definitely accel pump adjustment - adding extra fuel via the enrichener fixes the prob.
I dont know S&S carbs, but usually you can bend the accel pump rod or adjust the mechanism some way to get some more fuel into the engine.
check the accel pump is working by taking the air cleaner off and quickly opening and closing the throttle, you should see a steady stream of fuel coming from the nozzle. if not you have a blocked nozzle or fuel path.
I dont know S&S carbs, but usually you can bend the accel pump rod or adjust the mechanism some way to get some more fuel into the engine.
check the accel pump is working by taking the air cleaner off and quickly opening and closing the throttle, you should see a steady stream of fuel coming from the nozzle. if not you have a blocked nozzle or fuel path.
Cruiser
Joined: Dec 2008
Posts: 236
Likes: 0
There is an acc. pump adjustment on the right side of the carb. Back it out in 1/8 turn increments and test sitting still. Quickly crack the throttle and listen for any hesitation. Also, what int. jet are you running? If my memory serves me correct you should be at a .295 or .31. As for the air/fuel screw, that is not going to adjust anything except at idle. That setting should be turn in until ready to die and then turn out until ready to die and set in between those settings. Long story short, assuming everything was allright before you took the carb apart I would suggest going after the acc. pump adjustment.
Road Master
Joined: Sep 2009
Posts: 761
Likes: 9
From: lewisville, nc
There is an acc. pump adjustment on the right side of the carb. Back it out in 1/8 turn increments and test sitting still. Quickly crack the throttle and listen for any hesitation. Also, what int. jet are you running? If my memory serves me correct you should be at a .295 or .31. As for the air/fuel screw, that is not going to adjust anything except at idle. That setting should be turn in until ready to die and then turn out until ready to die and set in between those settings. Long story short, assuming everything was allright before you took the carb apart I would suggest going after the acc. pump adjustment.
Cruiser
Joined: Dec 2008
Posts: 236
Likes: 0
Not to sure how to post pics but these are real easy to see and get access too. The air/fuel screw in dead center on the top of the carb with a knurled flathead screw and the accel pump adjustment is on the right side of the carb above the accel pump bellows. Let me know if this helps
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Outstanding HDF Member
Joined: Jul 2008
Posts: 2,115
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From: SoCal
hey there
just bored and came across this
do you have the S&S manual?
http://www.sscycle.com/admin/uploads...ns/51-1012.pdf
that's the E/G Manual
and here's a "quick tune"
http://www.sscycle.com/modules/tuning/index.php
that also points out which is what ie the air/fuel screw, idle screw, accelerator pump, etc
actually, here's a somewhat better link to the same info with bigger pics
http://www.bikernet.com/SandS/PageVi...sp?PageID=1198
teach a man to fish....
just bored and came across this
do you have the S&S manual?
http://www.sscycle.com/admin/uploads...ns/51-1012.pdf
that's the E/G Manual
and here's a "quick tune"
http://www.sscycle.com/modules/tuning/index.php
that also points out which is what ie the air/fuel screw, idle screw, accelerator pump, etc
actually, here's a somewhat better link to the same info with bigger pics
http://www.bikernet.com/SandS/PageVi...sp?PageID=1198
teach a man to fish....
Last edited by JustDave71; Nov 1, 2009 at 04:09 AM.
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Thread Starter
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Outstanding HDF Member
Joined: Aug 2008
Posts: 3,078
Likes: 6
From: Michigan
hey there
just bored and came across this
do you have the S&S manual?
http://www.sscycle.com/admin/uploads...ns/51-1012.pdf
that's the E/G Manual
and here's a "quick tune"
http://www.sscycle.com/modules/tuning/index.php
that also points out which is what ie the air/fuel screw, idle screw, accelerator pump, etc
actually, here's a somewhat better link to the same info with bigger pics
http://www.bikernet.com/SandS/PageVi...sp?PageID=1198
teach a man to fish....
just bored and came across this
do you have the S&S manual?
http://www.sscycle.com/admin/uploads...ns/51-1012.pdf
that's the E/G Manual
and here's a "quick tune"
http://www.sscycle.com/modules/tuning/index.php
that also points out which is what ie the air/fuel screw, idle screw, accelerator pump, etc
actually, here's a somewhat better link to the same info with bigger pics
http://www.bikernet.com/SandS/PageVi...sp?PageID=1198
teach a man to fish....