General Carb Question

[2004BC]

Hi,
Quick carb questions. I have a 2005 Chopper, heavily modified engine, 2' drag pipes, no restrictions to speak of, 107 bottom end, 117 top end, cammed etc etc. Super E carb , T-Jet (110k), Int-Jet (33), Main Jet (74), with Thunderjet 3rd circuit. Start up with enricher is perfect, easy, idle is perfect, this circuit seems dialed in. Adjustment is within S&S specs so this part is good. Here are the questions:

1 - No matter where I adjust the accelerator pump it just bogs then screams. All the way out or all the way in. A turn or so off of all the way in (closed, shut off), seems to have the least bog time wise but no where near right. Does this mean my main jet is too big? Change it to a 72?
2 - Riding it the bike is scary fast once it gets past the transition bog. However, it back fires like m-80's going off through the pipes on any decel. I know the pipes have zip for back pressure but I'm keeping them, I like them.
3 - Am I wasting my time trying to make this finicky Super E work and would a G or X just be a better more friendly carb?

Thank you for sharing your experience and opinions!
Bruce

 

[jsousa515]

Hi,
Quick carb questions. I have a 2005 Chopper, heavily modified engine, 2' drag pipes, no restrictions to speak of, 107 bottom end, 117 top end, cammed etc etc. Super E carb , T-Jet (110k), Int-Jet (33), Main Jet (74), with Thunderjet 3rd circuit. Start up with enricher is perfect, easy, idle is perfect, this circuit seems dialed in. Adjustment is within S&S specs so this part is good. Here are the questions:

1 - No matter where I adjust the accelerator pump it just bogs then screams. All the way out or all the way in. A turn or so off of all the way in (closed, shut off), seems to have the least bog time wise but no where near right. Does this mean my main jet is too big? Change it to a 72?
2 - Riding it the bike is scary fast once it gets past the transition bog. However, it back fires like m-80's going off through the pipes on any decel. I know the pipes have zip for back pressure but I'm keeping them, I like them.
3 - Am I wasting my time trying to make this finicky Super E work and would a G or X just be a better more friendly carb?

Thank you for sharing your experience and opinions!
BruceView attachment 69586

Ask Curtis at wild steed works he’s the master

Sent from my iPhone using Tapatalk

 

[2004BC]

Ask Curtis at wild steed works he’s the master

Sent from my iPhone using Tapatalk

Agreed. I buy my parts from him and Donna. Just looking for a quick answer if someone has gone through this already. THANKS!!!
Bruce

 

[Clubba]

I’m dealing with a similar issue. The biggest problem that most people make is they try to dial it in using S&S spec.You have to use the zipper specs. The Excelerator pump needs to be turned all the way off and the intermediate jet needs to be increased. if it’s bogging off of idle, it’s not your main jet. Most likely your intermediate needs to be bumped up. I have that part dialed in. my issue is, I can’t get mine to Cruise smoothly. It wants to be full throttle or off throttle. I’m running a R1 carb (same as G) on a 140” motor so it is unfamiliar territory for me. Good luck brother. Let me know how you make out.

 

[2004BC]

THANKS! I hadn't thought of that and yes, I was following the S&S suggested procedure. I'll bump up the I-jet. I'll see if I have a 34, 35, or 36. Worth the effort and easy to try. I'll let you know how it turns out.
PS, just guessing here but in general on worked bikes (No experience on 140" monster motors though) adding the Thunderjet 3rd circuit and dialing it in has bridged the intermediate to main transition so maybe you don't have that all or nothing scenario. Good luck to you too!
Bruce

 

[Sven]

BOG:
WOT we are talking here is a linear transition of vac to AFR. Without the snap of the wrist, the bike has zero driveability and riding less robust eliminates the bog, right? Bog rips over those jet holes and says bye-bye to the linear. More air fills that void faster than WOT can be pulled out of those jet holes. Throwing fuel at it will help yes. Why? More gas having a chance to equalize the air change in the vacuum metering of it. But at what expense to idle. At what expense to a stumble at midrange, and the the main; for WOT?

I want my plug to read a clean AFR. I am not about to chase the momentary bog and upset the overall tune? I'll inject salt peter into my wrist to eliminate the bog.

 

[Sven]

The pump says two turns out from the first touch point. I'm thinking, this side of supersonic, I WOT that throttle open, air a-com-knock'inn a lean knock on the piston dome; I'd have the plunger a hair trigger away from a perineum.

 

[john sachs]

You need some backpressure with an S&S carb to perform properly. Possible exhaust leak at the exhaust port to pipe is most likely the M-80 pop. The "E" can be bored close to "G" size.
John

 

[Th3InfamousI]

What is the blue putty there for? Do you have a leak at the screws?

Any type of baffle in the drag pipes? If not might want to fab up a little washer baffle to put in there to get some back-pressure and reduce the decel pop since you are keeping those pipes.

 

[Jersey Big Mike]

I was always under the impression that Super E was good to about 100cu and above that a G was recommended, but I'm no expect by any means. My BDM is EFI

 

[john sachs]

I was always under the impression that Super E was good to about 100cu and above that a G was recommended, but I'm no expect by any means. My BDM is EFI

"E" can be bored.
John

 

[2004BC]

You need some backpressure with an S&S carb to perform properly. Possible exhaust leak at the exhaust port to pipe is most likely the M-80 pop. The "E" can be bored close to "G" size.
John

Hi John,
I'll reexamine the pipe/head bolts. I did have a little trouble seating the pipes and keeping them aligned. Thanks for the good suggestion!
PS The gentleman I bought the bike from years ago said you built it. Nice job! I had to wrap both of the handgrips so my hands would stay on. I don't know what's in it but very impressive!!! Thanks!

 

[2004BC]

What is the blue putty there for? Do you have a leak at the screws?

Any type of baffle in the drag pipes? If not might want to fab up a little washer baffle to put in there to get some back-pressure and reduce the decel pop since you are keeping those pipes.

I usually use clear silicone on all of my carb adjustment screws so they don't vibrate and go out of adjustment. I ran out so I used blue RTV. No leaks.
Good idea on the baffle. There aren't any. After I get things close I'll do an experiment before and after and see if it helps. First I'll reseat the pipes as per John's suggestion. Thanks!!!

 

[2004BC]

I was always under the impression that Super E was good to about 100cu and above that a G was recommended, but I'm no expect by any means. My BDM is EFI

That was my impression as well but I'm going to do my best with the E before I give up. A lot of good suggestions to try. If not I'll buy a G and change it out. To be continued......

 

[mleach72]

I'm just taking a guess here. Every bike is different, and open pipes certainly throw a wrench in the fan when it comes to tuning a carb. Generally, a bog is usually a sign of being too rich. Your intermediate jet may be too big, and your main jet may be too small. The most common jet combo on here is probably 31/78. 33 intermediate seems a bit big. It certainly shouldn't be too small. This would make sense from your description. Too big intermediate would make the motor sluggish until the main jet comes in. A too small main would lean the mixture. This would explain the bike taking off. You are running an E carb, but jetting between an E and G on the same motor should be very close. You can run the E on big motors, and it should run very well. You will just be leaving some top end hp on the table. Low end torque should be fantastic tho!

 

[2004BC]

I'm just taking a guess here. Every bike is different, and open pipes certainly throw a wrench in the fan when it comes to tuning a carb. Generally, a bog is usually a sign of being too rich. Your intermediate jet may be too big, and your main jet may be too small. The most common jet combo on here is probably 31/78. 33 intermediate seems a bit big, especially on an '05 with smaller valves and restrictor plates, if they haven't been removed already. A 33 certainly shouldn't be too small. This would make sense from your description. Too big intermediate would make the motor sluggish until the main jet comes in. A too small main would lean the mixture. This would explain the bike taking off. You are running an E carb, but jetting between an E and G on the same motor should be very close. You can run the E on big motors, and it should run very well. You will just be leaving some top end hp on the table. Low end torque should be fantastic tho!

Well, then it's time to get to work! No more guessing! I took Friday off, I have missing size jets coming in from Zippers, and all day to get this right. I'll let you know how this turns out. I'm inspired by everyone's help! Much appreciated!!!
Bruce

 

[Jersey Big Mike]

"E" can be bored.
John

Of course, but I was referring to a stock E vs G as there was not mention of it being modified in that fashion.

 

[Clubba]

THANKS! I hadn't thought of that and yes, I was following the S&S suggested procedure. I'll bump up the I-jet. I'll see if I have a 34, 35, or 36. Worth the effort and easy to try. I'll let you know how it turns out.
PS, just guessing here but in general on worked bikes (No experience on 140" monster motors though) adding the Thunderjet 3rd circuit and dialing it in has bridged the intermediate to main transition so maybe you don't have that all or nothing scenario. Good luck to you too!
Bruce

Thank you Bruce


Sent from my iPhone using Tapatalk

 

[john sachs]

Hi John,
I'll reexamine the pipe/head bolts. I did have a little trouble seating the pipes and keeping them aligned. Thanks for the good suggestion!
PS The gentleman I bought the bike from years ago said you built it. Nice job! I had to wrap both of the handgrips so my hands would stay on. I don't know what's in it but very impressive!!! Thanks!
View attachment 69613View attachment 69614

If I worked on the engine/bike, pm me the name of the previous owner, and I'll see if I have the work order. I only keep them for 7 years as required by law. If I did work on it, it's strange that I would not have used 1 of my modified "G" carbs on it.
If that bike was in Ft. Lauderdale, customer 1st name Bruce, I remember it. At the time I worked on it, it had an RB 2 into 1 pro-pipe on it. Baker fixed the trans. under warranty. I'm quite sure it had a "G" carb on it. Made enough power, that it was ripping teeth off the drive belt. IIRC, it had a 124" engine in it.
John

 

[2004BC]

If I worked on the engine/bike, pm me the name of the previous owner, and I'll see if I have the work order. I only keep them for 7 years as required by law. If I did work on it, it's strange that I would not have used 1 of my modified "G" carbs on it.
If that bike was in Ft. Lauderdale, customer 1st name Bruce, I remember it. At the time I worked on it, it had an RB 2 into 1 pro-pipe on it. Baker fixed the trans. under warranty. I'm quite sure it had a "G" carb on it. Made enough power, that it was ripping teeth off the drive belt. IIRC, it had a 124" engine in it.
John

YOU have a great memory!!! That's the guy I bought it from! I got it with the E. It also had about .100" shims on the clutch pressure plate to try and hold the power. Lever was Jack Armstrong hard to pull. Dropped it to .060", much better, but slips and lets loose at redline. Time to change the clutch plates I guess! I took the RB off and put these drag pipes on. It also had metal struts (hardtail) and I put the shocks back in to return it to a softail.
124" engine. That explains why I almost flew off the back of it when I hammered it the first time!!! Thanks! I'll let you know how I make out this weekend.