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 Snippets
Last Post: Crusty
Posted On: 5 Minutes Ago
Replies: 513
Views: 72,694
0 Keep & Kill
Last Post: Graywolf
Posted On: 8 Minutes Ago
Replies: 25,499
Views: 1,492,325
0 This is gonna hurt.
Last Post: Graywolf
Posted On: 10 Minutes Ago
Replies: 9,079
Views: 2,123,780
0 Official XL Forum Random Image Thread (NO NUDITY!)
Last Post: Graywolf
Posted On: 17 Minutes Ago
Replies: 52,471
Views: 8,855,033
0 04 Sportster refurb and build.
Last Post: XL Ed
Posted On: 23 Minutes Ago
Replies: 31
Views: 1,867
0 The Strociek Project
Last Post: spacecoast
Posted On: 1 Hour Ago
Replies: 62
Views: 4,377
0 Hottie of the day, no nudity.
Last Post: Stairman
Posted On: 1 Hour Ago
Replies: 33,016
Views: 3,885,865
10 1983 XR 1000 Starting Issues.
Last Post: ChinCactus
Posted On: 2 Hours Ago
Replies: 7
Views: 285
0 Video - Why Tire PSI Should Be Checked Often!
Last Post: ChinCactus
Posted On: 2 Hours Ago
Replies: 1
Views: 88
0 video & pics
Last Post: cal43
Posted On: 3 Hours Ago
Replies: 571
Views: 59,763
0 Hot Rods, Rat Rods, and Customs.
Last Post: cal43
Posted On: 3 Hours Ago
Replies: 4,814
Views: 957,086
0 Hot Chicks on Hot Bikes
Last Post: cal43
Posted On: 3 Hours Ago
Replies: 12,604
Views: 2,982,239
0 Tachometer Suggestions
Last Post: 1983Sporty
Posted On: 7 Hours Ago
Replies: 0
Views: 35
0 1983 Roadster
Last Post: Jeff
Posted On: 8 Hours Ago
Replies: 76
Views: 5,102
0 Early 1967 XLCH Tach
Last Post: Douglas
Posted On: 10 Hours Ago
Replies: 0
Views: 38
0 72 ih stroker advise needed
Last Post: rocketnorton
Posted On: 12 Hours Ago
Replies: 15
Views: 782
0 Ironhead engine problem?
Last Post: Ferrous Head
Posted On: 16 Hours Ago
Replies: 36
Views: 1,619
0 Clutch squeal ? Bad throwout bearing ?
Last Post: Tomcatt
Posted On: 19 Hours Ago
Replies: 95
Views: 20,592
0 Acceptable Voltage Drop-Starter Circuit
Last Post: ZTatZAU
Posted On: 19 Hours Ago
Replies: 58
Views: 2,073
0 1968 ex barn dweller thread
Last Post: GA_Ironhead
Posted On: 21 Hours Ago
Replies: 205
Views: 21,082
0 Starter gaskets 74 XLH1000
Last Post: Chuckthebeatertruck
Posted On: 21 Hours Ago
Replies: 5
Views: 183
0 Starting?
Last Post: Briank
Posted On: 1 Day Ago
Replies: 4
Views: 198
0 ....1
Last Post: Graywolf
Posted On: 1 Day Ago
Replies: 6,287
Views: 382,322
0 Iree's late night cafe
Last Post: Graywolf
Posted On: 1 Day Ago
Replies: 2,172
Views: 375,188
0 "The Blues" thread!
Last Post: Graywolf
Posted On: 1 Day Ago
Replies: 1,074
Views: 148,055
0 a definitive sportster chain conversion pros and cons list
Last Post: splineman
Posted On: 1 Day Ago
Replies: 18
Views: 548
0 HAMMERPerf 90" In the Works
Last Post: splineman
Posted On: 1 Day Ago
Replies: 1,641
Views: 247,083
0 90" of Street-based FUN coming downunder
Last Post: Turbo Sporty 48
Posted On: 1 Day Ago
Replies: 345
Views: 69,436
0 NOS cases
Last Post: Ferrous Head
Posted On: 1 Day Ago
Replies: 21
Views: 815
0 Video - Servicing the External Breather Catch Can
Last Post: DK Custom
Posted On: 1 Day Ago
Replies: 0
Views: 97
More...
Members Birthdays
garryd (73), Chooch (70), kicker (64), Calgaich (61), skinnyboy (59), RogerB, Tonyb65 (56), sunkenloot (46), scoobs48, zman69 (40)
Tags
jets, jetting, needle, shim, shimming

Reply
 
Share Thread Tools Display Modes
  #1  
Old 18th May 2012
seanchrist seanchrist is offline
Biker
 
Join Date: Aug 2011
Posts: 12
Sportster/Buell Model: 1200 Sportster Low
Sportster/Buell Year: 2006
Reputation: 19
seanchrist is an unknown quantity at this point
Default Shimming a Needle

My '06 Sporty seems to be running a little weak in the mid-range area, although it's fine at idle and wide open. I think I'm running a bit lean in the mids, but not sure. I'm wondering what a "normal" amount of shimming the needle is. To preface, I'm still somewhat of a newbie, but I'm not afraid to dig-in and get dirty.

Here's the set-up:
'06 Sportster 1200 low.
Samson Exhaust Straight Shots with 1/4 baffles, so 2" openings
Arlen Ness Big Sucker Stage II Intake
CV Carb w/ Main Jet: 200 & Slow Jet: 50
CV Performance Velocity Needle w/3 small brass shims
Mixture ~2 3/4 turns

Suggestions?
Reply With Quote
  #2  
Old 18th May 2012
Don Burton's Avatar
Don Burton Don Burton is offline
Senior Master Custom Bike Builder
 
Join Date: Apr 2006
Location: The Warm Southeast! U.S.A.
Posts: 7,257
Sportster/Buell Model: XL 1200 Gone
Sportster/Buell Year: 2006
Reputation: 395253
Don Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond repute
Default

Compared to your enormous 200 main jet and 50 slow jet your needle might be leaner but................! You might want to ask Ken at CVP if he thinks your CVP needle should be shimmed. I know that he tries to get them close enough so that they don't need it as his needles aren't restricted by the EPA. One thing is for sure. You don't want to be running on the taper of the needle at cruise. Anyhow, I have to wonder how you ended up with such huge jets?
Reply With Quote
  #3  
Old 18th May 2012
seanchrist seanchrist is offline
Biker
 
Join Date: Aug 2011
Posts: 12
Sportster/Buell Model: 1200 Sportster Low
Sportster/Buell Year: 2006
Reputation: 19
seanchrist is an unknown quantity at this point
Default Jets

I think I'm going to go back to a 48 slow jet, but previously, I had a 185 main jet that would sometimes cause my engine to cut-out if I gunned it going up hills (even with a full tank of gas). The 200 seems to have solved that, but I could swap that out for a 195 possibly. I should have the bike put on a dyna, but I don't have $300 bucks to have someone else tune it for me.
Reply With Quote
  #4  
Old 18th May 2012
Bruce's Avatar
Bruce Bruce is offline
Old Fart M/C Club
 
Join Date: Feb 2007
Location: Cool Ridge WV
Posts: 1,689
Sportster/Buell Model: 883/NRHS 1250 custom
Sportster/Buell Year: 2002
Reputation: 247674
Bruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant futureBruce has a brilliant future
Default

Yes the jets are looking on the large size (might try a 180 and a 45 or 48 slow jet) for you engine combination. Engine could be running rich in the mid rang causing your problems. Also your exhaust might be causing a little reversion in the midrange. What do your plugs look like?
__________________
Ride safe!
Member of "The Cell #2"
Reply With Quote
  #5  
Old 18th May 2012
Don Burton's Avatar
Don Burton Don Burton is offline
Senior Master Custom Bike Builder
 
Join Date: Apr 2006
Location: The Warm Southeast! U.S.A.
Posts: 7,257
Sportster/Buell Model: XL 1200 Gone
Sportster/Buell Year: 2006
Reputation: 395253
Don Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond repute
Default

Quote:
Originally Posted by seanchrist View Post
I think I'm going to go back to a 48 slow jet, but previously, I had a 185 main jet that would sometimes cause my engine to cut-out if I gunned it going up hills (even with a full tank of gas). The 200 seems to have solved that, but I could swap that out for a 195 possibly. I should have the bike put on a dyna, but I don't have $300 bucks to have someone else tune it for me.
With the jets that you are running, I suspect that you're rich all the way around. If your engine is cutting out when you "gun" it then it runs fine after a brief period, a lean main jet isn't the likely problem. You have some other issues which might include the accelerator pump, needle and/or your exhausts. I would lean this carb back out with stock main and slow jetting then tune one circuit at a time. You did say that you had baffles in your exhaust, is that correct? If not, fix that first. The Mikuni web site has a Tuning Manual for their HSR 42 carburetor which gives some great on the road exercises that show you how to test your main jet for proper size. The guy that wrote it (Joe Minton) knows more about H-D carburetors (including Keihin CVs) than anyone else I know. You can't just look at your plugs. If you want to check your plugs you have to do so systematically while cutting the ignition off at different throttle settings like steady cruise, after a mile or so, and again at WOT. There are plenty of threads that here that will help you with that.
Reply With Quote
  #6  
Old 18th May 2012
seanchrist seanchrist is offline
Biker
 
Join Date: Aug 2011
Posts: 12
Sportster/Buell Model: 1200 Sportster Low
Sportster/Buell Year: 2006
Reputation: 19
seanchrist is an unknown quantity at this point
Default

With the stock slow jet, it was 'farting' really bad during deceleration, and the 48 helped that immensely. Before I put the shims on the needle, it was cutting in-and-out during regular cruising, and the shims corrected that, though still leaving it kind of weak. I'll test the accelerator pump and see how it acts.
Reply With Quote
  #7  
Old 18th May 2012
Don Burton's Avatar
Don Burton Don Burton is offline
Senior Master Custom Bike Builder
 
Join Date: Apr 2006
Location: The Warm Southeast! U.S.A.
Posts: 7,257
Sportster/Buell Model: XL 1200 Gone
Sportster/Buell Year: 2006
Reputation: 395253
Don Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond repute
Default

Quote:
Originally Posted by seanchrist View Post
With the stock slow jet, it was 'farting' really bad during deceleration, and the 48 helped that immensely. Before I put the shims on the needle, it was cutting in-and-out during regular cruising, and the shims corrected that, though still leaving it kind of weak. I'll test the accelerator pump and see how it acts.

Do you have baffles in your exhaust? Poor baffling can cause popping on decel, poor slow speed performance and poor performance when whacking the throttle open. Did you go straight from a 42 to a 48 slow jet or did you try a 45 first? If your bike is running lean during regular steady cruising you likely need a thinner needle in the straight portion. If shims are making a difference in this area, that means that you are cruising on the taper which isn't a good thing and will kill your gas mileage. What kind of gas mileage are you getting now?
Reply With Quote
  #8  
Old 18th May 2012
seanchrist seanchrist is offline
Biker
 
Join Date: Aug 2011
Posts: 12
Sportster/Buell Model: 1200 Sportster Low
Sportster/Buell Year: 2006
Reputation: 19
seanchrist is an unknown quantity at this point
Default

These are the baffles in it: http://www.samsonusa.com/A-116.html They take the 2 1/4" pipe down to 2". The carb originally had a 45 slow jet in it which is why I went to a 48. How/where do I get a thinner needle?

Thanks for your help.
Reply With Quote
  #9  
Old 19th May 2012
Don Burton's Avatar
Don Burton Don Burton is offline
Senior Master Custom Bike Builder
 
Join Date: Apr 2006
Location: The Warm Southeast! U.S.A.
Posts: 7,257
Sportster/Buell Model: XL 1200 Gone
Sportster/Buell Year: 2006
Reputation: 395253
Don Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond reputeDon Burton has a reputation beyond repute
Default

Those straight through two inch ID baffles are causing some of your problems. A better baffle would be one that has a diverter in it. I'd put some better baffles in there and put your 45 slow jet and stock 180 main jet back in there and see how it runs at slow and moderate throttle settings. Ken hasn't provided the measurements of his CVP needles son I don't know what would be a thinner needle on the straight portion. The N65C Keihin needle is the thinnest needle in that area that I know of and it is likely thinner than your current needle but I don't know about your current needle for sure. H-D can't get the N65C from Keihin anymore. I happen to have a new one that I used for brief testing. How is your current gas mileage?
Reply With Quote
  #10  
Old 19th May 2012
seanchrist seanchrist is offline
Biker
 
Join Date: Aug 2011
Posts: 12
Sportster/Buell Model: 1200 Sportster Low
Sportster/Buell Year: 2006
Reputation: 19
seanchrist is an unknown quantity at this point
Default

Current gas mileage is suffering for sure. Not sure exactly what it is, but it ain't good. How small of an exit diameter should I be shooting for? I was really hoping to get some better horsepower than a stock set-up.
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 14:01.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
XL Forum® - Linson Media LLC