The Harley-Davidson Riders Club Great Britain

+++ HARLEY-DAVIDSON RIDERS CLUB GREAT BRITAIN - ESTABLISHED 1949 +++


Go Back   The Harley-Davidson Riders Club Great Britain > Technical > Evo Big Twins
©2000-2012 Harley-Davidson Riders Club

Evo Big Twins
Evolution Big Twin 1984 -1999

Reply
 
LinkBack Thread Tools Display Modes
  #41  
Old 17-08-2008, 01:55 AM
Scotty Scotty is offline
Non Member
 
Join Date: Feb 2008
Posts: 920
Re: Tuning S&S Carb

Sound good bro, enjoy you trip.
Reply With Quote
  #42  
Old 17-08-2008, 09:56 AM
Simon_A's Avatar
Simon_A Simon_A is offline
Reps Liaison Officer
 
Join Date: Dec 2002
Posts: 1,573
Re: Tuning S&S Carb

I've been following this thread since it started, as I have been running an S&S 'E' on my Heritic for over 10 years & 45000 miles now.
During this time I have installed an SE4 cam & 2 into 1 and found no reason to re-jet from the original. The only other mods have been to change the foam filter for a K&N. In 10 years the only problem I have encountered was the pump operating rod seizing in the casting due to the action of aluminum corrosion on the steel rod. There is a definite flat spot on the transition between jets that I did once tryed to adjust out with the pump setting with limited success. Overall the carb has been very good.
My question is what, if any benefits will I get by spending 30 on a 'Yost tube' ? will this remove / help the flat spot.
__________________
Sussex Coaster (getting our mojo back) (bu--er seem to have lost it again) (95 Heritic, 82 FXB, 76 175SS, a couple of Triumphs and a Norton)


Reply With Quote
  #43  
Old 18-08-2008, 02:09 AM
Scotty Scotty is offline
Non Member
 
Join Date: Feb 2008
Posts: 920
Re: Tuning S&S Carb

Quote:
Originally Posted by Simon_A View Post
I've been following this thread since it started, as I have been running an S&S 'E' on my Heritic for over 10 years & 45000 miles now.
During this time I have installed an SE4 cam & 2 into 1 and found no reason to re-jet from the original. The only other mods have been to change the foam filter for a K&N. In 10 years the only problem I have encountered was the pump operating rod seizing in the casting due to the action of aluminum corrosion on the steel rod. There is a definite flat spot on the transition between jets that I did once tryed to adjust out with the pump setting with limited success. Overall the carb has been very good.
My question is what, if any benefits will I get by spending 30 on a 'Yost tube' ? will this remove / help the flat spot.
No mate, the yost tends only to work on the main jet and not the intermediate. But if you get the jetting bang on and the pump right you can get it to where its barely noticeable.
The difference is easy to see. Before you install it take the air filter off and rev the motor past half throttle and you will see the fuel pull up in the center of the carb. Install the power tune and when you do the same you will see a marked difference in the fuel, it comes through as a much finer mist than before and so gives a much better burn. You can usually go down one if not two sizes on the main jet and doing so it gives you better gas mileage on motorway journeys.
And the better atomizing of the fuel gives around 4-6 horses, i dynoed a Fatboy (Evo) with and without the tube years ago and it gave 5 more hp. The bike was giving me around 55-60mpg at 80ish mph.

Another answer is this from XXX Carburetors in the States, they reckon it gives you what the Yost does and also goes toward eliminating the lag between jetting circuits, i ant tried it yet, you can get it from the link i have posted in a post above on e-bay in the US. (about $50)
Here's a link so you can have a read.
productinfo

You can also get the Yost from here eBay Motors: Yost Power Tube for S&S Super E (item 320213095002 end time Aug-26-08 06:57:39 PDT)
for $41 + $4 postage to the UK
Reply With Quote
  #44  
Old 18-08-2008, 07:54 PM
Simon_A's Avatar
Simon_A Simon_A is offline
Reps Liaison Officer
 
Join Date: Dec 2002
Posts: 1,573
Re: Tuning S&S Carb

Thanks for the very comprensive answer. Something to think about.
I've never been able to match the economy of a Mikuni.
__________________
Sussex Coaster (getting our mojo back) (bu--er seem to have lost it again) (95 Heritic, 82 FXB, 76 175SS, a couple of Triumphs and a Norton)


Reply With Quote
  #45  
Old 26-08-2008, 08:27 PM
finley347
Guest
 
Posts: n/a
Re: Tuning S&S Carb

I am from the USA and know that over hear it is damn near impossible to tune the S&S E without proper exhaust pipes. If you are running drag pipes or any other type of open exhaust you will have problems getting good results from the carb through its whole range of operation. You need a certain amount of back pressure for the carb to work right. Hope this helps, have a great day.
Fred
Reply With Quote
  #46  
Old 27-08-2008, 03:19 AM
Scotty Scotty is offline
Non Member
 
Join Date: Feb 2008
Posts: 920
Re: Tuning S&S Carb

Quote:
Originally Posted by finley347 View Post
I am from the USA and know that over hear it is damn near impossible to tune the S&S E without proper exhaust pipes. If you are running drag pipes or any other type of open exhaust you will have problems getting good results from the carb through its whole range of operation. You need a certain amount of back pressure for the carb to work right. Hope this helps, have a great day.
Fred
My friend the super G works very well on a big displacement motor (100" and over) with drag pipes if you are tuning it for top end hp.
As you rightly say it is difficult to tune the super E for drag pipes as it is to tune any carb for drag pipes, as drag pipes only work on large displacement motors anyway.
Reply With Quote
  #47  
Old 28-08-2008, 12:07 PM
the_monster's Avatar
the_monster the_monster is offline
PR
 
Join Date: Oct 2005
Posts: 4,408
Re: Tuning S&S Carb

The best way to the cure the 'flat spot' between jets is to be smooth on the throttle - roll it on rather than a heavy hand handed snapping open, this will also help reduce excess fueling (your black smoke out the the exhausts) and return improved mpg.

Tuning any carb is never an exact science as performance will from day to day due to weather - eg on a damp cool day you will getting more bhp than a hot dry one as the oxygen (the O in H2O) content in the air is higher. similarly, a bike set to run perfectly at sea level will get progressively worse as your height above sea level rises due to the corresponding reduction in oxygen in the atmosphere.

if you want a perfect setup, you stand more chance with EFI due to the number of sensors that are processing info such as air/fuel mix and burn and adjusting the loadings accordingly.

As for concept that drag pipes only work on large displacement motors - that is utter tosh, it is the length and bore of the pipe that is critical - the S&S tuning guide that comes with the carb will give you the optimum length and bore size.

All performance improvements are a trade off between torque and hp, if you are are after better grunt from low speed go for a more torque based setting, if you want top end performance (eg max mph) look at getting max hp.
__________________
hear no Evo, see no Evo, Ride no Evo

everyone know knows TC stands for Tart's Cart really
Reply With Quote
  #48  
Old 28-08-2008, 12:56 PM
Scotty Scotty is offline
Non Member
 
Join Date: Feb 2008
Posts: 920
Re: Tuning S&S Carb

Quote:
Originally Posted by the_monster View Post
As for concept that drag pipes only work on large displacement motors - that is utter tosh, it is the length and bore of the pipe that is critical
Oh dear here we go again...Monsterman knows it all and tries to put me down in the process

Here is a bit of copy and paste from Nightrider website and a link for you to read.

"If you are serious about making horsepower on the street with your Harley-Davidson, drag pipes will not fit into your engine program plans. Serious street power requires a serious exhaust system. Exhaust systems like the SuperTrapp 2-1, Hooker, White Bros. E-series 2-1, Vance&Hines, Khrome Werks and Cycle Shack 2-2 Slash Cut exhaust have a long track record of "making power". The familiar sound of a drag pipe may be music to a "bikers" ears, but the performance rider hears the labored acceleration as the motorcycle moves by.

Drag pipes do have their place. It is on the drag strip where the engine runs in a very narrow RPM band. On the street, stick with proven winners."

If you are serious about making horsepower on the street with your Harley-Davidson, drag pipes will not fit into your engine program plans. Serious street power requires a serious exhaust system. Exhaust systems like the SuperTrapp 2-1, Hooker, White Bros. E-series 2-1, Vance&Hines, Khrome Werks and Cycle Shack 2-2 Slash Cut exhaust have a long track record of "making power". The familiar sound of a drag pipe may be music to a "bikers" ears, but the performance rider hears the labored acceleration as the motorcycle moves by.

Drag pipes do have their place. It is on the drag strip where the engine runs in a very narrow RPM band. On the street, stick with proven winners.
Exhaust Systems

As i said, drag pipes come into their own when you run them on big inch engines, they are next to useless on a street bike as they virtually produce no back pressure, back pressure is needed for torque lower down in the rev range this is what gets the bike up to the horsepower.
Drag pipes are commonly used on BIG drag engines and if you look closely Mr Monsterman you will see that drag engines do not have longer tuned length pipes as they dont rely on back pressure.

I will repeat myself, puttin drag pipes on a normal street engine will do you no favors when it comes to power on the street....Take this advise or leave it, i am not going to get involved in another petty argument with you about stuff like this again Monsterman, you just seem to like to cause shit.
V-twin Cafe/Nightrider is a very highly respected Harley performance site around the world, if you want an argument go take it up with them...

And just as a note to you folk on this site who need to find some quality info on most stuff Harley (in the engine dept) whether it be Evo, Twincam or Sportster, have yourselfs a look around this site.
I have found it invaluable over the past 10 years or so.Motorcycle Performance Guide for Harley-Davidson

Last edited by Scotty; 28-08-2008 at 12:59 PM.
Reply With Quote
  #49  
Old 28-08-2008, 01:04 PM
the_monster's Avatar
the_monster the_monster is offline
PR
 
Join Date: Oct 2005
Posts: 4,408
Re: Tuning S&S Carb

you would the same Scotty that runs Khromewerks AR100 dragpipes on his mega softail

- read the thread it is the length and bore that are critical to performance, as with any pipe .
__________________
hear no Evo, see no Evo, Ride no Evo

everyone know knows TC stands for Tart's Cart really
Reply With Quote
  #50  
Old 28-08-2008, 02:02 PM
Scotty Scotty is offline
Non Member
 
Join Date: Feb 2008
Posts: 920
Re: Tuning S&S Carb

Quote:
Originally Posted by the_monster View Post
you would the same Scotty that runs Khromewerks AR100 dragpipes on his mega softail

- read the thread it is the length and bore that are critical to performance, as with any pipe .
AR 100 pipes are more or less the best 2 into 2 pipes on the market........Whats your point???
SuperTrapp vs AR100

"Read the thread" What thread?
We were talking about whether drag pipes are efficient on a street motor, and as the article clearly states they are not!

Again i stress as the article says, drag pipes are useless for a street bike, they offer virtually no performance gain unless they are used on a drag bike...This i have already stated.....Why are you harping on about length and bore?

The guy above (finley347) was talking about DRAG PIPES, that is what i aimed my answer about, it was you that said i was talking "UTTER TOSH" you are wrong in that statement, you just aint man enough to admit it...

Your comments on fuel injection on this thread are also unwarranted, the guy that started the thread (Simon_A) was looking for help with tuning the S&S carb, how do you think you are helping?

Everyone knows fuel injection is more efficient than a carb, you are just stating the obvious. And if you cant be arsed (or are incapable) tuning the flat spot out of your carb then thats your problem, i have tuned it out of mine, its not a major achievement, just a little knowledge.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On




All times are GMT +1. The time now is 07:57 AM.


The Harley-Davidson Riders Club of Great Britain

The Harley Davidson Riders Club Great Britain has no official connection to the Harley-Davidson Motor Company, we just ride their motorcycles and support the brand. All trademarks are acknowledged


Content Relevant URLs by vBSEO 3.0.0