Super g carb jetting

rbh

rbh

New Member
IMG_0597.PNG s&s 117 585 cams grumpy pipes no baffle.
I have a hesitation from 3000 rpms
Under full throttle 80 main jet not sure of intermediate jet. 2 - 1/4 turns out on air .
Seems a little lean to me but not sure.
I have attached a pic of the plug. This was 3rd gear wide open throttle then I hit kill switch and pulled plug.

Thanks in
 
Butch Cassidy

Butch Cassidy

Active Member
... plug does look somewhat lean ... before you get to far down the road, check for an air leak. Use WD40 and mist the intake manifold and around the carb and backing plate while it is running. Try not to get any in the air intake...
Once you have done that with no change in rpm, then time to check for proper jetting. S&S can tell you your standard jet sizes for your setup... I have a 107" and mine are 31/76 and it runs perfectly. Your sizes should be larger.
 
Th3InfamousI

Th3InfamousI

Administrator
Staff member
rbh said:
View attachment 44700 s&s 117 585 cams grumpy pipes no baffle.
I have a hesitation from 3000 rpms
Under full throttle 80 main jet not sure of intermediate jet. 2 - 1/4 turns out on air .
Seems a little lean to me but not sure.
I have attached a pic of the plug. This was 3rd gear wide open throttle then I hit kill switch and pulled plug.

Thanks in
Click to expand...
Hesitation at 3k is the intermediate jet.

You need to go up on that or your air bleed.

Sent from my 2PS64 using Tapatalk
 
rbh

rbh

New Member
Hesitation is from say 3000 up throttle wide open it acts as if it's breaking up,lack of gas.Just bought it several months ago I'm sure it was never tuned properly. I have already checked for air leaks with wd and starting fluid no problems on that end.
 
SMCT

SMCT

Active Member
3000 up throttle wide open it acts as if it's breaking up,lack of gas.Just bought it several months
Click to expand...
if you have not changed the spark plugs, I would start there.
 
Butch Cassidy

Butch Cassidy

Active Member
... also, a carb does not respond like FI .... you can't just slam the door open... it creates a 'dead spot' ... an absence of proper air pressure that will cause a momentarily flat spot in acceleration. Try again, but roll on the throttle... don't slam it open...
 
desertdawg

desertdawg

Member
95 CID and larger=
intermediate jet range 31-36
main jet range 72-86
fuel/air mixture-3 turns out
make sure float level is properly set. (service manual describes and has picture)

I highly recommend you watch two S&S videos on you tube. First one "carb jetting and tuning", Second "drag pipes exhaust: carb jetting and trouble shooting. I highly suspect your exhaust may be causing you some problems. Anyway the first video describes the bleed air circuit and how you can change that orifice to get better transition from intermediate to main. By the way my wife's 06 Mastiff is stock except Vance & Hines 2 into 2 and it really works well with 31 int and 78 main jets. the air bleed is the stock .040. Swapping intermediate is a pain as you have to remove the bowl every time so it just going to take so time to find the right jet. The more air that flows through the engine means the more fuel you need to find that desired 13:1 or so air fuel mixture.
 
Gmutoagrsv

Gmutoagrsv

Active Member
Any update on this thread? I am having the same issue. Except I put a different air cleaner on my bike and then started having this issue. It did have a k&n before I swapped the air cleaner
 
cdogg556

cdogg556

Guru
Gmutoagrsv said:
Any update on this thread? I am having the same issue. Except I put a different air cleaner on my bike and then started having this issue. It did have a k&n before I swapped the air cleaner
Click to expand...
Are you running a spike air cleaner? If you are and you aren't running it in the vertical position and have it horizontal, or pointing forward then you will have that hesitation, at least I did on my 05 Bulldog, try running it vertically and see if it changes anything, that is if that's what your running.
 
BWG56

BWG56

Guru
Gmutoagrsv said:
Any update on this thread? I am having the same issue. Except I put a different air cleaner on my bike and then started having this issue. It did have a k&n before I swapped the air cleaner
Click to expand...
Try removing the Auxiliary bowl vent plug item #14

If the S&S teardrop air cleaner is being replaced with an aftermarket air cleaner be sure to remove the auxiliary bowl vent screw (#14). Never use a velocity stack on a street driven motorcycle! Poor throttle response will be experienced
 

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Dusty.B

Dusty.B

Member
Removing the auxiliary vent screw should make a big difference if the tear drop is gone. Night and day when once I took mine out when I changed to a velocity stack. & ive never had a problem with a stack. Except it trying to suck my pant leg inside
 
Gmutoagrsv

Gmutoagrsv

Active Member
I did post a spike on horizontal. I swapped the plugs and went for a ride yesterday it runs great until I grab a handful. I got back looked at the plugs and they're really lean looking. I took the whole thing off and tried it at idle and the same issue. I can see fuel being sprayed into the carb from the outter nozzle. At slow or gradual acceleration or throttle control it's fine. But falls flat on its face when I really get on it.
 
cdogg556

cdogg556

Guru
Gmutoagrsv said:
I did post a spike on horizontal. I swapped the plugs and went for a ride yesterday it runs great until I grab a handful. I got back looked at the plugs and they're really lean looking. I took the whole thing off and tried it at idle and the same issue. I can see fuel being sprayed into the carb from the outter nozzle. At slow or gradual acceleration or throttle control it's fine. But falls flat on its face when I really get on it.
Click to expand...
Try it vertical and see if it makes a difference
 
Dusty.B

Dusty.B

Member
Ok so it sounds similar to a problem I had on my bulldog. Mine would run fine if I twisted the throttle slow to get the Rpm up but would fall flat when I romped it, I ended up needing to lower my main jet, if it's flat when you romp it, it's most likely to do with the main needle. You're using the int. Needle for most of your riding unles you dog it a lot, but when you romp it you're only using the main needle. Is there a chance your int. Jet is too small causing the lean looking plugs, and the main is too big causing the flat spot when you romp it. Just my .02, those carbs are finicky, the only true way to tune is to dyno, if al else fails maybe try a shop that can test and tune for you


Also, I've ran a spike in vertical and horizontal, mine ran better vertical as well for some reason
 
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Gmutoagrsv

Gmutoagrsv

Active Member
Dusty.B said:
Ok so it sounds similar to a problem I had on my bulldog. Mine would run fine if I twisted the throttle slow to get the Rpm up but would fall flat when I romped it, I ended up needing to lower my main jet, if it's flat when you romp it, it's most likely to do with the main needle. You're using the int. Needle for most of your riding unles you dog it a lot, but when you romp it you're only using the main needle. Is there a chance your int. Jet is too small causing the lean looking plugs, and the main is too big causing the flat spot when you romp it. Just my .02, those carbs are finicky, the only true way to tune is to dyno, if al else fails maybe try a shop that can test and tune for you
Click to expand...
I have been and can ride around town nice and easy. Just cruising maybe 50-55 mph. It's fine. But occasionally I grab some and that's when it happens. I don't feel comfortable diving into the jetting at this point although I have a feeling that's what it is.
 
cdogg556

cdogg556

Guru
I run a 78 main jet, 32 idle and 3 turns out on the mixture screw, that's were it runs best for me, I tried turning it back a 1/4 turn but then it started sneezing/coughing so I went back to 3 turns out and it runs great.
 
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