The Sportster and Buell Motorcycle Forum - The XLFORUM®
 

Go Back   The Sportster and Buell Motorcycle Forum - The XLFORUM® > SPORTSTER MOTORCYCLE FORUM > Sportster Motorcycle Intake and Exhaust > Sportster Motorcycle Air intake, Carburetor, EFI, Fuel, and Exhaust
XLF Blogs XLF Arcade XLF Disclaimer/Privacy Statement/Terms Of Use

Notices

Sportster Motorcycle Air intake, Carburetor, EFI, Fuel, and Exhaust Problems, advice and/or how tos for Sporster and Buell motorcycle carburators, Electronic Fuel Injection (EFI), Air Intake, Fuel and Exhaust.

Active Threads
0 1979 Ironhead Starter Washer, Bushing
Last Post: Tipofthelake
Posted On: 2 Minutes Ago
Replies: 4
Views: 61
0 Yearly Allotment of Miles
Last Post: a-sad-anorak
Posted On: 15 Minutes Ago
Replies: 1
Views: 9
0 Highway cruise speed
Last Post: rich56
Posted On: 34 Minutes Ago
Replies: 15
Views: 1,035
0 Why such heavy oil in Sportster?
Last Post: rich56
Posted On: 41 Minutes Ago
Replies: 40
Views: 1,314
0 Be Careful Out There!
Last Post: RDHenley
Posted On: 1 Hour Ago
Replies: 5
Views: 229
0 This is gonna hurt.
Last Post: 1skullster1
Posted On: 1 Hour Ago
Replies: 8,123
Views: 1,716,937
0 The last of a dying breed...
Last Post: Bryan1976
Posted On: 1 Hour Ago
Replies: 13
Views: 569
0 Snippets
Last Post: RDHenley
Posted On: 1 Hour Ago
Replies: 173
Views: 15,507
0 Current projects (2 of them anyway)
Last Post: Iron Mike
Posted On: 2 Hours Ago
Replies: 47
Views: 1,805
0 Range With Carby 3.3 Gal Tank
Last Post: smilinbrad
Posted On: 2 Hours Ago
Replies: 90
Views: 46,067
0 WTB: XR1200 Luggage Rack and Tailbag (OEM)
Last Post: kodylk08
Posted On: 2 Hours Ago
Replies: 0
Views: 12
0 Parts
Last Post: NLXL
Posted On: 2 Hours Ago
Replies: 3
Views: 71
0 Shovster build take2
Last Post: kitabel
Posted On: 2 Hours Ago
Replies: 23
Views: 574
0 Tranny oil
Last Post: NLXL
Posted On: 2 Hours Ago
Replies: 11
Views: 187
0 Chinese S&S carbs
Last Post: XL Ed
Posted On: 2 Hours Ago
Replies: 73
Views: 3,405
0 Mikuni Knock Off "REVEALED" !!!
Last Post: davesz1r
Posted On: 3 Hours Ago
Replies: 4
Views: 172
0 Cam needle bearings correct install
Last Post: Nitro57xl
Posted On: 4 Hours Ago
Replies: 7
Views: 166
0 XR mutt race bike progress
Last Post: Ferrous Head
Posted On: 4 Hours Ago
Replies: 31
Views: 1,756
0 Keep & Kill
Last Post: Crusty
Posted On: 5 Hours Ago
Replies: 17,581
Views: 1,019,392
0 1972 Build thread please subscribe
Last Post: rokytnji
Posted On: 5 Hours Ago
Replies: 78
Views: 5,157
0 This week on Craig's list
Last Post: brucstoudt
Posted On: 5 Hours Ago
Replies: 4,716
Views: 626,678
0 ....1
Last Post: bklyngeezer
Posted On: 5 Hours Ago
Replies: 5,590
Views: 324,898
0 What did you do for your sporty Today?
Last Post: Blackesthart
Posted On: 6 Hours Ago
Replies: 6,996
Views: 993,361
0 Carb starting issue.
Last Post: wedge
Posted On: 6 Hours Ago
Replies: 7
Views: 193
0 WTB NOKK needle...
Last Post: Folkie
Posted On: 6 Hours Ago
Replies: 1
Views: 61
0 Hottie of the day, no nudity.
Last Post: trainman
Posted On: 7 Hours Ago
Replies: 20,187
Views: 2,059,621
0 Wont Fire up!
Last Post: Mission1
Posted On: 7 Hours Ago
Replies: 13
Views: 274
0 Poll....what do you wear on your hands?
Last Post: rokytnji
Posted On: 8 Hours Ago
Replies: 229
Views: 34,964
0 How many Sporty seats ya got for one ass?
Last Post: FiftySixer
Posted On: 8 Hours Ago
Replies: 274
Views: 57,862
0 Poll: If you had to have a stock sporty, what would it be?
Last Post: davesz1r
Posted On: 8 Hours Ago
Replies: 605
Views: 191,875
More...
Members Birthdays
flattracker1 (79), al sena (70), SwissXL (56), greendarren7 (49), martian (45), thadf (44), NOGOOD1%€R (37)
Reply
 
Share Thread Tools Display Modes
  #31  
Old 4 Weeks Ago
John Harper John Harper is offline
Master Custom Bike Builder
 
Join Date: Apr 2012
Posts: 3,445
Sportster/Buell Model: XLH 883
Sportster/Buell Year: 1991
Reputation: 1875556
John Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond reputeJohn Harper has a reputation beyond repute
Default

I really can't say what size your jets are, since the real orifice for the jet is actually further inside than the hole you can see in the photo. Can you post up a "head on" shot to compare actual orifice sizes? Maybe a picture taken from the threaded side of the jets?

Also, having the straight screw slot might lead to some burring on the inside of the opening of the jet in your picture. If the jet has some kind of special "contouring" I would think a burr would potentially interrupt any special flow characteristics. I have also heard roughly the same thing about the Keihin jets as IXL2Relax, but no evidence to verify the veracity of this "urban legend" about Keihin jets versus aftermarket. Take a close look at the Keihin 42 jet, look at the irregular opening it has. Even worse than the knockoff 45.

John
Reply With Quote
  #32  
Old 4 Weeks Ago
Tomcatt Tomcatt is offline
Dazed & Confused
 
Join Date: Feb 2019
Location: Never Never Land
Posts: 1,375
Sportster/Buell Model: XL1200C
Sportster/Buell Year: 2017
Other Motorcycle Model: BMW R9T
Other Motorcycle Year: 2015
Tomcatt has disabled reputation
Default

Quote:
Originally Posted by IXL2Relax View Post
I presume, because I don't know exactly, that it means the physical shape of the orifice - which may very well involve chamfering...

I don't have any technical data - simply that 'I've heard' they are specifically contoured...
They are "contoured" in that the length of the orifice (hole) is regulated.

Keihin jets sizes are based on their orifice diameter. A 42 pilot jet has a .42 mm hole.

Mikuni jet sizes are flow ratings and the orifices are tapered.

FWIW the jets for the Holley 4 bbl carbs we ran were also flow rated. Flow on those being controlled by the diameter and length of the orifice both of which varied.

These are precisely reamed and gauged pieces. Run pieces of steel wire thru them to "clean" them (or check their size) and damage those carefully reamed orifices and you will change how they flow. After you judiciously "clean" one with the tip cleaner for your oxy-acetylene torch you might as well buy a new jet...
__________________
2017 XL1200C in Wisconsin, USA
Reply With Quote
  #33  
Old 4 Weeks Ago
D-RAIL D-RAIL is offline
Biker
 
Join Date: Jun 2020
Posts: 16
Sportster/Buell Model: XLH1200C
Sportster/Buell Year: 2001
Reputation: 10
D-RAIL is an unknown quantity at this point
Default

Pull the carb apart, clean it really good with carb cleaner and use compressed air to blow out the ports. If that doesn't fix the problem at least you can cross it off your list of things to check and it's easy enough to do.

D
__________________
Less is more! 2001 XL1200C
Reply With Quote
  #34  
Old 4 Weeks Ago
DéDé's Avatar
DéDé DéDé is offline
Greasemonkey
 
Join Date: Mar 2013
Location: South West Germany
Posts: 137
Sportster/Buell Model: XL 883
Sportster/Buell Year: 04
Other Motorcycle Model: 2010 Wide Glide, Fat Bob
Other Motorcycle Year: 2012
Reputation: 62280
DéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to behold
Default

news...rode today
#42 is good tunable, but I have to turn it out 3 full turns for good satisfying idle, and good throttle response - no coughing, runs good, stock OEM 45 will be perhaps the right jet, but now we´re happy with the result. Will see how it is when weather is warmer.

There is a taper part on the stock jet, which closes from the threads to the hole, this taper part is different on the 45 jet, will try to show you later in a pic.
It could be that this tapered area is not sealing the thread and fuel can pass thru + thru the jet hole - too rich

thx for all your comments and help
Reply With Quote
  #35  
Old 4 Weeks Ago
DéDé's Avatar
DéDé DéDé is offline
Greasemonkey
 
Join Date: Mar 2013
Location: South West Germany
Posts: 137
Sportster/Buell Model: XL 883
Sportster/Buell Year: 04
Other Motorcycle Model: 2010 Wide Glide, Fat Bob
Other Motorcycle Year: 2012
Reputation: 62280
DéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to behold
Default

20200609_183058 (2) by DéDé1963, auf Flickr
20200609_182628 (2) by DéDé1963, auf Flickr
Reply With Quote
  #36  
Old 4 Weeks Ago
DéDé's Avatar
DéDé DéDé is offline
Greasemonkey
 
Join Date: Mar 2013
Location: South West Germany
Posts: 137
Sportster/Buell Model: XL 883
Sportster/Buell Year: 04
Other Motorcycle Model: 2010 Wide Glide, Fat Bob
Other Motorcycle Year: 2012
Reputation: 62280
DéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to behold
Default

now this taper area...
20200609_182401 (2) by DéDé1963, auf Flickr


you shurely see the OEM one
Reply With Quote
  #37  
Old 4 Weeks Ago
wedge's Avatar
wedge wedge is offline
XL FORUM TEAM MEMBER
 
Join Date: Jun 2010
Posts: 11,603
Sportster/Buell Model: 1200R
Sportster/Buell Year: 2005
Other Motorcycle Model: 5 bikes and 1 quad
Reputation: 5733610
wedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond repute
Default

OK, so with the Keihin that mix screw is a fuel screw, so getting three turns out sounds about right for a stock 42. You needed to supply more fuel to get the idle mix right.

So, how is the transfer from idle to just off idle? Is there a stumble. Slow hand on the throttle and feel for it. If there is a stumble, then you may need a bit more to near 3.25 turns. Possibly the stumble will not tune out. You find that out test riding.

Basically you just proved that you do need a good 45 to tune it to where the idle will be in the two turn area. As long as that 45 doesn't make the transition pig rich.

So, to be more precise, the idle is handled with the screw, so within reason you can tune the idle good within a range of two or three pilot jets.

Where you will feel it and see the difference on plugs is in the transfer from idle to where the needle comes into play. It's a small part of the curve, so this is where people can easily be off in tuning and never know.

You are on the right track so at least you will not be one of them.
__________________
A Biker is not just any guy who rides... that's a motorist.
A guy that gets up and rides again after every crash... that's a Biker.

Whitworth Fork Brace: http://xlforum.net/forums/m...outme&simple=1
Reply With Quote
  #38  
Old 4 Weeks Ago
DéDé's Avatar
DéDé DéDé is offline
Greasemonkey
 
Join Date: Mar 2013
Location: South West Germany
Posts: 137
Sportster/Buell Model: XL 883
Sportster/Buell Year: 04
Other Motorcycle Model: 2010 Wide Glide, Fat Bob
Other Motorcycle Year: 2012
Reputation: 62280
DéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to behold
Default

no stumble from idle to off idle, runs strong, this bike is completely stock. The only added part is an K&N filter insert in oem ham can.
My friend ordered already an oem ''45 jet for spare.
But for now he´s happy how it is
Reply With Quote
  #39  
Old 4 Weeks Ago
wedge's Avatar
wedge wedge is offline
XL FORUM TEAM MEMBER
 
Join Date: Jun 2010
Posts: 11,603
Sportster/Buell Model: 1200R
Sportster/Buell Year: 2005
Other Motorcycle Model: 5 bikes and 1 quad
Reputation: 5733610
wedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond repute
Default

Quote:
Originally Posted by DéDé View Post
no stumble from idle to off idle, runs strong, this bike is completely stock. The only added part is an K&N filter insert in oem ham can.
My friend ordered already an oem ''45 jet for spare.
But for now he´s happy how it is
Then it's fine. The only issue that three turns out creates is the possibility that with less tension on the spring it can back out as you ride. I had mine at around 3 turns for a long time before I went to the 45, and it never fell out, or moved out of adjustment so you will most likely be just fine on that front too.
Reply With Quote
  #40  
Old 4 Weeks Ago
DéDé's Avatar
DéDé DéDé is offline
Greasemonkey
 
Join Date: Mar 2013
Location: South West Germany
Posts: 137
Sportster/Buell Model: XL 883
Sportster/Buell Year: 04
Other Motorcycle Model: 2010 Wide Glide, Fat Bob
Other Motorcycle Year: 2012
Reputation: 62280
DéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to beholdDéDé is a splendid one to behold
Default

Quote:
Originally Posted by wedge View Post
Then it's fine. The only issue that three turns out creates is the possibility that with less tension on the spring it can back out as you ride. I had mine at around 3 turns for a long time before I went to the 45, and it never fell out, or moved out of adjustment so you will most likely be just fine on that front too.
this is true, less tension with 3 full turns, I know
thx
Reply With Quote
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



All times are GMT +1. The time now is 03:50.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
XL Forum® - Linson Media LLC