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

Notices

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

Active Threads
0 Arlen Ness F-Bomb Pipe Test
Last Post: madnss
Posted On: 2 Minutes Ago
Replies: 22
Views: 8,094
0 2007 883R From Sunny Old England!
Last Post: sportsterpaul
Posted On: 5 Minutes Ago
Replies: 11
Views: 308
0 Keep & Kill
Last Post: Graywolf
Posted On: 16 Minutes Ago
Replies: 18,911
Views: 1,123,395
0 "The Blues" thread!
Last Post: Graywolf
Posted On: 17 Minutes Ago
Replies: 970
Views: 101,761
0 Sifton cams on stock 74 XLCH
Last Post: lajam175
Posted On: 25 Minutes Ago
Replies: 2
Views: 30
0 Pinion shaft holder tool
Last Post: Hippysmack
Posted On: 31 Minutes Ago
Replies: 2
Views: 48
0 Better Brakes
Last Post: RicThompson
Posted On: 45 Minutes Ago
Replies: 23
Views: 1,517
0 Hottie of the day, no nudity.
Last Post: Stairman
Posted On: 1 Hour Ago
Replies: 24,348
Views: 2,490,657
0 Do you like Mexican food?
Last Post: Stairman
Posted On: 1 Hour Ago
Replies: 55
Views: 1,216
0 Covered shocks
Last Post: Heff
Posted On: 1 Hour Ago
Replies: 3
Views: 191
0 Chasing a generator noise
Last Post: bustert
Posted On: 2 Hours Ago
Replies: 5
Views: 204
0 Installing jugs finally but another Q
Last Post: aswracing
Posted On: 2 Hours Ago
Replies: 3
Views: 71
0 Xlh 883 oil tank paint
Last Post: John Harper
Posted On: 3 Hours Ago
Replies: 1
Views: 172
0 ....1
Last Post: Graywolf
Posted On: 3 Hours Ago
Replies: 5,923
Views: 341,649
0 starting rollers
Last Post: Ferrous Head
Posted On: 3 Hours Ago
Replies: 26
Views: 1,077
0 Potato-potato
Last Post: Highly-Dangerous
Posted On: 3 Hours Ago
Replies: 5
Views: 227
6 1983 Ironhead- Final wiring
Last Post: Attaxic
Posted On: 3 Hours Ago
Replies: 36
Views: 2,780
0 is a buell a harley
Last Post: Highly-Dangerous
Posted On: 4 Hours Ago
Replies: 174
Views: 26,935
0 Hot Rods, Rat Rods, and Customs.
Last Post: Stairman
Posted On: 4 Hours Ago
Replies: 4,299
Views: 643,301
0 Official XL Forum Random Image Thread (NO NUDITY!)
Last Post: Graywolf
Posted On: 4 Hours Ago
Replies: 48,941
Views: 7,937,177
0 Tools
Last Post: Eric Von Zipper
Posted On: 6 Hours Ago
Replies: 19
Views: 755
0 55* this morning
Last Post: Eric Von Zipper
Posted On: 6 Hours Ago
Replies: 13
Views: 512
0 77xl sportster
Last Post: Steve9
Posted On: 7 Hours Ago
Replies: 10
Views: 284
0 XR750 resurrecting
Last Post: Steve9
Posted On: 7 Hours Ago
Replies: 30
Views: 2,038
0 You asked for it! "The Tess' Coffee Thread"
Last Post: Steve9
Posted On: 8 Hours Ago
Replies: 11,118
Views: 1,039,818
0 Microsquirt EFI Conversion
Last Post: Tomcatt
Posted On: 8 Hours Ago
Replies: 11
Views: 258
0 What did you do for your sporty Today?
Last Post: Highly-Dangerous
Posted On: 8 Hours Ago
Replies: 7,360
Views: 1,094,727
0 KBS tank sealer
Last Post: Len PA
Posted On: 10 Hours Ago
Replies: 17
Views: 768
0 Lets see your off season builds
Last Post: Iron Mike
Posted On: 11 Hours Ago
Replies: 1,465
Views: 217,917
0 Are There Still Sober Riders On The Forum?
Last Post: Reverend G
Posted On: 12 Hours Ago
Replies: 179
Views: 56,915
More...
Members Birthdays
lineberger, 39dan (62), FstPig (61), jmdajd (57), ironhead 74 (57), erjasn84, Bada Bing (56), ottchuck (55), OutlawTexan67 (53), RAJ (47), Wintersdark (44), robychopper (44), TnsporT (43), MotoSquirrel (36)
Reply
 
Share Thread Tools Display Modes
  #31  
Old 24th October 2020
ryder rick's Avatar
ryder rick ryder rick is offline
Senior Master Custom Bike Builder
 
Join Date: Jun 2008
Location: Cornelius, OR
Posts: 9,430
Reputation: 1114996
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 kitabel View Post
So, THAT'S why they use big cams: to lower the compression!
Nope it's the opposite.

Long duration cams need the compression ratio to run/work.

Or did you forget your Smiley?
__________________
Ryder Rick "I know right from wrong, but sometimes, wrong feels right"
Reply With Quote
  #32  
Old 24th October 2020
kitabel kitabel is offline
Chief Know It All
 
Join Date: Oct 2019
Posts: 406
Sportster/Buell Model: 883 Evo
Sportster/Buell Year: 1989
Reputation: 169469
kitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant futurekitabel has a brilliant future
Default

Long duration cams need the compression ratio to run/work
Like the KR!
Reply With Quote
  #33  
Old 24th October 2020
brucstoudt's Avatar
brucstoudt brucstoudt is offline
Senior Master Custom Bike Builder
 
Join Date: May 2010
Location: Pottstown PA.
Posts: 14,135
Sportster/Buell Model: xlch
Sportster/Buell Year: 1960
Reputation: 621719
brucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond reputebrucstoudt has a reputation beyond repute
Default

i have a set of brass 2 pc.intake clamps by Arlen Ness i bought new back in the 80's.best clamps i've ever had.they'e attached to a Super B.strong enough to hold that big long carb without a brace.his sales pitch for those clamps was a picture of him standing on a carb with one foot.
__________________
72 1000cc barrels and heads, s&s 41/2'' flywheels, sifton cams, s&s super B w/ zippers thunderjet w/yost powertube, andrews gears,and shafts, competition engineering kevlar wet or dry clutch, 72 oil pump, morris magneto w/auto advance and single fire module, cycle electric generator w/electronic regulator,73 cu.in.
Reply With Quote
  #34  
Old 24th October 2020
ryder rick's Avatar
ryder rick ryder rick is offline
Senior Master Custom Bike Builder
 
Join Date: Jun 2008
Location: Cornelius, OR
Posts: 9,430
Reputation: 1114996
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 can't make enough compression on a side valve.
They have their own miserable compromises.
Reply With Quote
  #35  
Old 25th October 2020
Ferrous Head's Avatar
Ferrous Head Ferrous Head is offline
Blind Owl
 
Join Date: Jun 2009
Location: Sunshine Coast
Posts: 6,016
Sportster/Buell Model: XLB, XLCH, Sporton
Sportster/Buell Year: 1962
Sportster/Buell Model #2: XLCH
Sportster/Buell Year #2: 1966
Other Motorcycle Model: XLCH (Another one)
Other Motorcycle Year: 1966
Reputation: 1385550
Ferrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond reputeFerrous Head has a reputation beyond repute
Default

Quote:
Originally Posted by kitabel View Post
So, THAT'S why they use big cams: to lower the compression!
Depends on the term "big" I guess.

At lower RPM's (read kick starting speeds) cams having very late closing intake valves don't make good compression.

In fact at the lower rev range when the engine is running they are still down on many "small" cams like P's and PB's.

What this means is you can start the bike more easily but you lose torque at the lower RPM's.
At higher RPM's this is negated by the inertia effect of the incoming charge, so, no woriies.

If you want to reclaim some of that torque the normal course of action is to increase the static compression ratio.

I'm seeing over 210 PSI cranking pressure on my current race engine despite running Andrews X grinds. This is with JE pistons and the heads have been decked. Cylinders were left alone but lapped into the heads.

I've got 60 thou clearance on the valves. So far, that's been good.
__________________
"I know only too well the evil that I propose. But my inclinations get the better of me."
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 01:28.


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