The Sportster and Buell Motorcycle Forum Get Lowered  

Go Back   The Sportster and Buell Motorcycle Forum > SPORTSTER MOTORCYCLE ZONE > Sportster Motorcycle Era Specific and Model Specific > Ironhead Sportster Motorcycle Talk (1957-1985)
XLF Gallery XLF Classifieds XLF Blogs XLF Shout XLF Arcade XLF Disclaimer/Privacy Statement/Terms Of Use

Ironhead Sportster Motorcycle Talk (1957-1985) For all those that wanna talk about Ironhead Sportster Motorcycles

Members Birthdays
motobraz, dwr302, xlchjoe (60), rider31 (54), Viper (42), KJcrownRRdriver (42), krafty (38), EezyE (37), SmokeyXL (34)
Bison Motorsports
Biltwell
Speedway Instruments
CV Performance

Burly
Reply
 
Share Thread Tools Display Modes
  #1  
Old 4th November 2012
78ironhead 78ironhead is offline
Senior Chief Master Mechanic
 
Join Date: Mar 2009
Posts: 977
Reputation: 1213
78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about
Default 1979 Keihin carburetor

Ok, i have a 1979 ironhead with the stock keihin carb with a S&S air cleaner, i noticed that the po filled the hole for the float bowl vent in the backing plate with silicone, blocking the vent, why ? Is there a reason for this when installing the S&S air filter assembley ? Doesn't the bowl need to be vented ?
Reply With Quote
  #2  
Old 4th November 2012
big andy's Avatar
big andy big andy is offline
Land Speed Record
 
Join Date: Dec 2009
Posts: 771
Sportster/Buell Model: xlch
Sportster/Buell Year: 1973
Reputation: 15506
big andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of light
Default

I had the same situation on my bike the vent hole was bloked off but the vent hole for the keihin was in a different spot so i just drilled it out on the back of the plate there was a small circle where the hole needed to be just drilled it out no worries
__________________
hell on two wheels
Reply With Quote
  #3  
Old 4th November 2012
runingmouse's Avatar
runingmouse runingmouse is offline
Senior Chief Harley Engineer 1st Class
 
Join Date: Apr 2007
Location: North East US
Posts: 1,392
Sportster/Buell Model: xlx
Sportster/Buell Year: 1985
Sportster/Buell Model #2: XLCH
Sportster/Buell Year #2: 1979
Other Motorcycle Model: Sprint ss
Other Motorcycle Year: 1967
Reputation: 1345
runingmouse has a spectacular aura aboutruningmouse has a spectacular aura aboutruningmouse has a spectacular aura aboutruningmouse has a spectacular aura aboutruningmouse has a spectacular aura aboutruningmouse has a spectacular aura aboutruningmouse has a spectacular aura aboutruningmouse has a spectacular aura aboutruningmouse has a spectacular aura aboutruningmouse has a spectacular aura about
Default

The float bowl should have it's own vent, and hose for overflow. Off the bottom of the float bowl.

The hole on the air cleaner. Is where the crankcase vent would hook. I've seen these just pointing to the ground, off the crankcase cover (cam cover). There's no advantage to block that off that I know of. Or just run it to the ground. But I've seen it many times.
Reply With Quote
  #4  
Old 4th November 2012
big andy's Avatar
big andy big andy is offline
Land Speed Record
 
Join Date: Dec 2009
Posts: 771
Sportster/Buell Model: xlch
Sportster/Buell Year: 1973
Reputation: 15506
big andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of light
Default

s+s super b bendix and keihin butterfly carbs have the same bolt pattern but the super b baking plate has the vent hole higher. On the back there is a dimple for you to drill out to fit the keihin carb

Last edited by big andy; 5th November 2012 at 04:13..
Reply With Quote
  #5  
Old 5th November 2012
78ironhead 78ironhead is offline
Senior Chief Master Mechanic
 
Join Date: Mar 2009
Posts: 977
Reputation: 1213
78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about
Default

Heres a pic, the hole with the arrow is filled with silicone, right behind it is a vent hole that goes to the float bowl.

[IMG][/IMG]
__________________
Heres at it and to it and to it again, if you don't do it when you get to it, heres by God hopen you never get to it to do it again.
Reply With Quote
Know Thy Hog

  #6  
Old 5th November 2012
big andy's Avatar
big andy big andy is offline
Land Speed Record
 
Join Date: Dec 2009
Posts: 771
Sportster/Buell Model: xlch
Sportster/Buell Year: 1973
Reputation: 15506
big andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of light
Default

Just un plug the hole Looks like that plate was on a keihin then someone fitted it to a s+s and pluged the keihin hole
Reply With Quote
  #7  
Old 5th November 2012
78ironhead 78ironhead is offline
Senior Chief Master Mechanic
 
Join Date: Mar 2009
Posts: 977
Reputation: 1213
78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about78ironhead has a spectacular aura about
Default

Thats on the keihin, but with the plate off, vent open, the idle mixture screw has to be out 3 to 3 1/2 turns to make it idle, with the plate on and the vent blocked off, i have it 2 1/2 turns out to make it idle. I put a .80 slow jet in it, that helped.
Reply With Quote
  #8  
Old 5th November 2012
big andy's Avatar
big andy big andy is offline
Land Speed Record
 
Join Date: Dec 2009
Posts: 771
Sportster/Buell Model: xlch
Sportster/Buell Year: 1973
Reputation: 15506
big andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of lightbig andy is a glorious beacon of light
Default

The open hole is for the s+s carb but you need the blocked hole un blocked and then set the idle mixture .And if you need the mixture out 3 to 31/2 turns out with the plate off unblokck the hole and put a bigger slow jet in you need that vent open with the plate on and the mixture screw should be out 2 to 2!/2 turns out max,If you have the screw out more than 2 to 21/2 turns out the slow jet is to small
Reply With Quote
  #9  
Old 5th November 2012
hogmania hogmania is offline
Chief Harley Engineer
 
Join Date: Oct 2010
Posts: 518
Sportster/Buell Model: xlh
Sportster/Buell Year: 1980
Reputation: 1595
hogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura abouthogmania has a spectacular aura about
Default

Keihin carbs float bowl vent overflow is on the bottom of the bowl, should have a small hose which should be routed below the engine so any fuel that might come out does not run onto the hot engine parts which could light up up pretty good. The hole in the backing plate your referring to should not be blocked.
Reply With Quote
  #10  
Old 5th November 2012
IronMick's Avatar
IronMick IronMick is offline
Rider Of The Iron Steed
 
Join Date: Dec 2003
Location: London, ON Canada
Posts: 26,813
Sportster/Buell Model: XLH
Sportster/Buell Year: 1978
Reputation: 114270
IronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud ofIronMick has much to be proud of
Default

Quote:
Originally Posted by hogmania View Post
Keihin carbs float bowl vent overflow is on the bottom of the bowl, ...
That is the overflow, but it is not the vent. The vent effects atmospheric pressure in the bowl, and is the hole in the face of the carb into the air cleaner.
Reply With Quote
Know Thy Hog

Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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

Forum Jump


Custom Search

All times are GMT +1. The time now is 03:55.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
XL Forum - Linson Media LLC