The Sportster and Buell Motorcycle Forum - The XLFORUM®
 

Go Back   The Sportster and Buell Motorcycle Forum - The XLFORUM® > SPORTSTER MOTORCYCLE FORUM > Sportster Motorcycle Era Specific and Model Specific > Ironhead Sportster Motorcycle Talk (1957-1985)
XLF Blogs 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

Active Threads
0 Who runs 70wt. oil
Last Post: Steve9
Posted On: 8 Minutes Ago
Replies: 94
Views: 12,080
0 2019 xl1200 suspension upgrade
Last Post: Tomcatt
Posted On: 13 Minutes Ago
Replies: 8
Views: 120
0 1970-71 XL Fuel Tank ?
Last Post: Parker 1000
Posted On: 25 Minutes Ago
Replies: 0
Views: 11
0 Post up how many wheels you have in your household
Last Post: bustert
Posted On: 28 Minutes Ago
Replies: 16
Views: 411
0 A few more filter options
Last Post: Tucsonmax1
Posted On: 40 Minutes Ago
Replies: 6
Views: 825
0 Official XL Forum Random Image Thread (NO NUDITY!)
Last Post: Ireeman
Posted On: 53 Minutes Ago
Replies: 46,851
Views: 7,460,687
0 Oil Leak ??????
Last Post: ftwflh
Posted On: 59 Minutes Ago
Replies: 24
Views: 425
0 2010 Sporty will not fire! Tried everything, HELP!!!
Last Post: kxrwcer52
Posted On: 1 Hour Ago
Replies: 10
Views: 162
0 What did you do for your sporty Today?
Last Post: rokytnji
Posted On: 1 Hour Ago
Replies: 6,749
Views: 930,959
0 TSM / TSSM / HFSM - How to disable alarm and/or replace unit
Last Post: caffieneracer
Posted On: 1 Hour Ago
Replies: 280
Views: 127,087
4 greetings from quarantine!
Last Post: rokytnji
Posted On: 1 Hour Ago
Replies: 8
Views: 126
0 Keep & Kill
Last Post: Crusty
Posted On: 1 Hour Ago
Replies: 16,323
Views: 926,851
0 XR1200 for trail riding
Last Post: rokytnji
Posted On: 1 Hour Ago
Replies: 10
Views: 827
0 Low Profile Scissors Lift
Last Post: NLXL
Posted On: 2 Hours Ago
Replies: 15
Views: 240
0 Hottie of the day, no nudity.
Last Post: Stairman
Posted On: 3 Hours Ago
Replies: 17,936
Views: 1,808,584
0 XL Parts '04 up
Last Post: Jcolleyoh
Posted On: 4 Hours Ago
Replies: 0
Views: 38
0 '04+ Starting Issues, Do You Have Them? - Poll
Last Post: boomerguy
Posted On: 4 Hours Ago
Replies: 322
Views: 76,600
0 1960 XLCH in the UK
Last Post: chilly
Posted On: 4 Hours Ago
Replies: 250
Views: 29,048
0 what part numbers do i order if i want a power vision tuner?
Last Post: shanneba
Posted On: 5 Hours Ago
Replies: 2
Views: 87
0 Progressive 444s vs Bitubo twin adjustable
Last Post: sportsterpaul
Posted On: 8 Hours Ago
Replies: 1
Views: 42
0 Intake seals, glad I checked them
Last Post: sportsterpaul
Posted On: 9 Hours Ago
Replies: 2
Views: 178
0 Sportster Tank Art
Last Post: Bryan83taco
Posted On: 9 Hours Ago
Replies: 227
Views: 236,931
0 Why cafe a sportster?
Last Post: Merch131ho
Posted On: 10 Hours Ago
Replies: 269
Views: 89,650
0 Spark Plugs
Last Post: glbsportster
Posted On: 10 Hours Ago
Replies: 88
Views: 52,685
0 What did you do to your EFI Sporty today?
Last Post: Joe_jeep
Posted On: 10 Hours Ago
Replies: 3,963
Views: 776,094
0 Corona Virus
Last Post: Tim The Grim
Posted On: 10 Hours Ago
Replies: 379
Views: 19,253
0 Hot Chicks on Hot Bikes
Last Post: trainman
Posted On: 10 Hours Ago
Replies: 10,697
Views: 1,969,437
0 74' XLCH wiring question
Last Post: Hippysmack
Posted On: 11 Hours Ago
Replies: 4
Views: 154
0 Resto-Repair 84 ironhead
Last Post: ferretface
Posted On: 11 Hours Ago
Replies: 26
Views: 1,588
0 never mind
Last Post: Hippysmack
Posted On: 11 Hours Ago
Replies: 153
Views: 15,429
More...
Members Birthdays
ralphy, rpcycle (69), shag (67), roadcapDen (66), oedius (63), Coolride (58), 1965XLCH (54), fingerpie (49), Pacer88888 (48), Smitty001 (42), wiccaboa (42), Homiejaime (34), Popedizzle (31), Moker (17)
Reply
 
Share Thread Tools Display Modes
  #1  
Old 2 Weeks Ago
02vette 02vette is offline
Biker
 
Join Date: May 2011
Location: TN
Posts: 23
Sportster/Buell Model: XLCR
Sportster/Buell Year: 1977
Reputation: 10
02vette is an unknown quantity at this point
Default Recommended Keihin Jet Sizes ? - 100% Stock XLCR

Hi guys. Just finished up a nut and bolt restoration on my 1977 XLCR. After an initial 6 mile ride I noticed the following.

Bike idles excellent. Idle mixture screw set a 1 full turn out from close.

Engine seems to bog during while rolling the throttle past 1/4 turn. I'm thinking this is caused by transitioning from the slow speed circuit or jet to the main jet.

Bike is 100% stock except for a Dyna S ignition. Intake and exhaust are the 49 state "loud" setup. Stock P cams. Stock 9:1 compression.

Current jet sizes are 90 slow speed and 175 main. I'm thinking these are a bit on the fat side. Location is Knoxville, TN.

What jets sizes will get me close? Thanks much.
Reply With Quote
  #2  
Old 2 Weeks Ago
02vette 02vette is offline
Biker
 
Join Date: May 2011
Location: TN
Posts: 23
Sportster/Buell Model: XLCR
Sportster/Buell Year: 1977
Reputation: 10
02vette is an unknown quantity at this point
Default

Quick note about me. I am a retired HDMC employee of 30 plus years. Worked as a Factory Mechanic Tech at both the PDC " Willie G Product Development Center " and at Juneau Ave., Milwaukee WI as a Factory Tech.
Reply With Quote
  #3  
Old 2 Weeks Ago
ryder rick's Avatar
ryder rick ryder rick is offline
Senior Master Custom Bike Builder
 
Join Date: Jun 2008
Location: Cornelius, OR
Posts: 9,017
Reputation: 1103193
ryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond repute
Default

Which carb? If it is the Kehin butterfly with no fast idle, your best option is to grab up a CV or a VM-38-9.
The first gen Kehins are not well thought of. You can fotz with the drill pattern if you are brave and determined. The transfer ports are under the welsh plug in the top of the carb.
__________________
Ryder Rick "I know right from wrong, but sometimes, wrong feels right"
Reply With Quote
  #4  
Old 2 Weeks Ago
Hopper's Avatar
Hopper Hopper is offline
Senior Master Custom Bike Builder
 
Join Date: Dec 2007
Location: Australia
Posts: 9,370
Sportster/Buell Model: XLCH 1000
Sportster/Buell Year: 1977
Sportster/Buell Model #2: 75 motor in Norton frame.
Other Motorcycle Model: 42WLA 45, Harton, Narley
Other Motorcycle Year: 1942
Reputation: 256674
Hopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant future
Default

Take a look in the Ironhead Tech Stickys Index here http://xlforum.net/forums/showthread.php?t=465866
Theres a thread in there on Tuning Keihins with lots of info.

My 77 XLCH came stock with a 165 main and .75 low speed jet. But the CR has totally different exhaust so may have been jetted different. With a decent air filter and pipes on my CH I run, from memory, about a .85 slow and 175 main.

They are a decent carb when jetted right. Never had problems with mine. Tried a few others over the years, Mikuni VM38 and an Andrews Super 45 Tillotson and ended up going back to the stock Keihin these days.

Biggest problem I ever had with the Keihin was a worn out ignition auto advance unit that caused carb farts off idle. Like they say, most carb problems are electrical.
__________________
In theory there is no difference between theory and practice. In practice there is.
Reply With Quote
  #5  
Old 2 Weeks Ago
ryder rick's Avatar
ryder rick ryder rick is offline
Senior Master Custom Bike Builder
 
Join Date: Jun 2008
Location: Cornelius, OR
Posts: 9,017
Reputation: 1103193
ryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond repute
Default

You must have gotten a good one, there are some that have a horrible off idle stumble/flat spot and the term KaSneeze became familiar among tuners. Steady state at 60mph and it sneezes.

Just to be sure this is the first generation version with the metal choke arm and no fast idle linkage.
Reply With Quote
  #6  
Old 2 Weeks Ago
Hopper's Avatar
Hopper Hopper is offline
Senior Master Custom Bike Builder
 
Join Date: Dec 2007
Location: Australia
Posts: 9,370
Sportster/Buell Model: XLCH 1000
Sportster/Buell Year: 1977
Sportster/Buell Model #2: 75 motor in Norton frame.
Other Motorcycle Model: 42WLA 45, Harton, Narley
Other Motorcycle Year: 1942
Reputation: 256674
Hopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant futureHopper has a brilliant future
Default

Yep that's the one. The 38mm original as fitted in 76-78. The one with the fancy choke arm I think was the 34mm from 79 onwards.

One thing I do is run my intake and exhaust pushrods one flat looser than the factory spec. Helps stop sneezing/carb farts at cruising speed. A new auto advance unit helps stop it at idle and just off-idle. Plus I run both O rings and the later type rubber sleeves over top of them on the intake manifolds to make sure it's sealed up tighter than a really really tight thing. Plus air-filter support bracket to keep manifold straight and sealed.
Reply With Quote
  #7  
Old 2 Weeks Ago
thefrenchowl's Avatar
thefrenchowl thefrenchowl is offline
Senior Custom Bike Builder
 
Join Date: Nov 2006
Posts: 2,886
Sportster/Buell Model: KHK
Sportster/Buell Year: 1954
Sportster/Buell Model #2: IronHead XLH
Sportster/Buell Year #2: 1978
Other Motorcycle Model: XLRTT
Other Motorcycle Year: 1966
Reputation: 196379
thefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant future
Default

CVs might be OK if you just plod/ idle about with your bike...

But they kill the high RPM...

Stick with early 76/79 Keihin, not quite on par with Tillotsons, but not far...

My guess is your idle is a tad rich.

Play with the idle screw and the butterfly stop screw till you get a nice idle about 900rpm and get no spit backs when running say in 2nd/3rd gear in both violently opening and closing of throttle...

The idle should also be just fat enough to allow the engine to start dead easy. If struggling on start up, idle mixture is too lean.

Early Keihin came out with 100 idle and 180 main (1mm and 1.8mm), you're not far out.

Last point, make sure you have the idle channel rubber plug fitted at the bottom of the vertical idle channel inside the float chamber: the idle get its gas from the main jet tower, not from the bottom. If the plug is not there, your idle will always be too fat.

Patrick
__________________
Flat Head Forever
Reply With Quote
  #8  
Old 2 Weeks Ago
IronMick's Avatar
IronMick IronMick is offline
Rider Of The Iron Steed
 
Join Date: Dec 2003
Location: London, ON Canada
Posts: 32,226
Sportster/Buell Model: XLH
Sportster/Buell Year: 1978
Reputation: 1079200
IronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond reputeIronMick has a reputation beyond repute
Default

Quote:
Originally Posted by thefrenchowl View Post
... Stick with early 76/79 Keihin...
I do not know about E76 and previous, but late 76-78 Keihin is 38 mm. 1979-on is 34 mm. The 38 mm is the better performing of the Keihin butterfly carbs.
__________________
Mick
IronHead Forever!

Visit Mick's WebSite
[And Check Out My Autobiog]
Reply With Quote
  #9  
Old 2 Weeks Ago
thefrenchowl's Avatar
thefrenchowl thefrenchowl is offline
Senior Custom Bike Builder
 
Join Date: Nov 2006
Posts: 2,886
Sportster/Buell Model: KHK
Sportster/Buell Year: 1954
Sportster/Buell Model #2: IronHead XLH
Sportster/Buell Year #2: 1978
Other Motorcycle Model: XLRTT
Other Motorcycle Year: 1966
Reputation: 196379
thefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant futurethefrenchowl has a brilliant future
Default

Hi Mick,

I was thinking all the early Keihin that have an accessible idle screw and a single cable!!!

For sure, Keihins butterfly carbs with no idle adjust screw to be seen and twin cables are bad...

So you are right!!! early 76 were still fitted with Zenith carbs...

Patrick
Reply With Quote
  #10  
Old 2 Weeks Ago
ryder rick's Avatar
ryder rick ryder rick is offline
Senior Master Custom Bike Builder
 
Join Date: Jun 2008
Location: Cornelius, OR
Posts: 9,017
Reputation: 1103193
ryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond reputeryder rick has a reputation beyond repute
Default

Quote:
Originally Posted by thefrenchowl View Post
Last point, make sure you have the idle channel rubber plug fitted at the bottom of the vertical idle channel inside the float chamber: the idle get its gas from the main jet tower, not from the bottom. If the plug is not there, your idle will always be too fat.

Patrick
The idle will be fine it is the main jet that gets bypassed with the plug removed.

This happens because the hole that transfers fuel to the low speed jet is opened to the float bowl with the plug removed, and un metered fuel flows into the main jet passage. It's like removing the main jet (or doubling it's size)
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 15:00.


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