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 Big bore Stroker problem
Last Post: Iron Mike
Posted On: 5 Minutes Ago
Replies: 1
Views: 12
0 Gear Spacing Question
Last Post: ferretface
Posted On: 6 Minutes Ago
Replies: 15
Views: 308
0 New oil tank
Last Post: Hippysmack
Posted On: 16 Minutes Ago
Replies: 48
Views: 3,469
0 Late XLCH front end - any good?
Last Post: mikethebike61
Posted On: 19 Minutes Ago
Replies: 19
Views: 460
0 Keep & Kill
Last Post: Crusty
Posted On: 28 Minutes Ago
Replies: 18,349
Views: 1,089,091
2 My 1275 Hammer Conversion..
Last Post: Bryan1976
Posted On: 42 Minutes Ago
Replies: 199
Views: 18,443
0 Heads Up Display in your Helmet
Last Post: sportsterpaul
Posted On: 47 Minutes Ago
Replies: 7
Views: 156
0 Bike wobble question
Last Post: Ferrous Head
Posted On: 55 Minutes Ago
Replies: 3
Views: 40
0 what brand of spark plug do you use?
Last Post: glbsportster
Posted On: 55 Minutes Ago
Replies: 343
Views: 86,076
0 One More Ohio Meet & Eat?
Last Post: sportsterpaul
Posted On: 1 Hour Ago
Replies: 30
Views: 1,760
0 How Do I Install An Inline Fuel Filter (Carb Model Rubbermount)
Last Post: boomerguy
Posted On: 1 Hour Ago
Replies: 24
Views: 105
0 ADVICE?Is it supposed to look this cool or am I running lean?
Last Post: sportsterdoc
Posted On: 1 Hour Ago
Replies: 1
Views: 23
0 Fyi
Last Post: sportsterdoc
Posted On: 1 Hour Ago
Replies: 5
Views: 220
0 Any Teamsters?
Last Post: sportsterdoc
Posted On: 1 Hour Ago
Replies: 3
Views: 96
0 Most common rattle locations?
Last Post: Ireeman
Posted On: 1 Hour Ago
Replies: 21
Views: 658
5 about the 1999 Sportster Right Fork converting to dual brakes
Last Post: salmanmr
Posted On: 1 Hour Ago
Replies: 2
Views: 88
0 WTB: Mainshaft Thrust Washers
Last Post: ferretface
Posted On: 1 Hour Ago
Replies: 2
Views: 50
5 Favourite grips?
Last Post: glbsportster
Posted On: 1 Hour Ago
Replies: 79
Views: 22,360
0 Official XL Forum Random Image Thread (NO NUDITY!)
Last Post: Graywolf
Posted On: 2 Hours Ago
Replies: 48,601
Views: 7,859,768
0 Any wealthy forum members?
Last Post: Steve9
Posted On: 2 Hours Ago
Replies: 11
Views: 242
0 Stock vs. Modified
Last Post: 60Gunner
Posted On: 2 Hours Ago
Replies: 293
Views: 100,844
0 Forward controls
Last Post: jsandidge
Posted On: 3 Hours Ago
Replies: 2
Views: 82
0 Iron Mike Comment on WTB/WTS Parts
Last Post: Tim The Grim
Posted On: 3 Hours Ago
Replies: 12
Views: 513
3 86 To 03 HD Forward Controls, Modified To Fit 1980
Last Post: IronMick
Posted On: 3 Hours Ago
Replies: 14
Views: 13,581
0 too much oil in primary
Last Post: randy3934
Posted On: 3 Hours Ago
Replies: 20
Views: 629
0 KT - 2020 - Where Eagles Dare
Last Post: sportsterpaul
Posted On: 4 Hours Ago
Replies: 68
Views: 15,623
0 Oil leak
Last Post: Ferrous Head
Posted On: 5 Hours Ago
Replies: 45
Views: 2,034
0 1969 Shifter shaft bushing
Last Post: brucstoudt
Posted On: 6 Hours Ago
Replies: 10
Views: 370
0 Hottie of the day, no nudity.
Last Post: Stairman
Posted On: 7 Hours Ago
Replies: 23,058
Views: 2,351,014
0 What Carb
Last Post: npaisnel
Posted On: 7 Hours Ago
Replies: 12
Views: 463
More...
Members Birthdays
jdhickm (85), Chip (72), Chief4x4 (70), willyobiker (68), CBryant (67), XLCH69 (64), sage (61), Butch (61), VettesRule (58), jerseyjeff (58), TheExecutioner (55), SalTheWop (55), manic_mechanic, pauldmedic16 (46), BluegrassXL (42), Superman
Reply
 
Share Thread Tools Display Modes
  #41  
Old 1 Week Ago
Hippysmack's Avatar
Hippysmack Hippysmack is offline
XL FORUM TEAM MEMBER
 
Join Date: Jul 2014
Posts: 6,547
Sportster/Buell Model: Xl1250S
Sportster/Buell Year: 98
Other Motorcycle Model: Kawasaki Vulcan 500
Other Motorcycle Year: 95
Reputation: 6529417
Hippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond repute
Default

Patrick I'm still taking in that PDF.
For posterity, I've never seen it before, but I can relate.
Even though the article is about auto engines, he has mention to dry sump engines but the piece is geared toward wet sump.
But the breathing portion is relative.

He says:
In common road engines, it is usually required to have a crankcase pressure slightly lower than the atmospheric one because this will impede any oil leakages: common target value for the crankcase pressure is around 20 to 30 hPa lower than the atmospheric pressure.

However,
The actual amount of vacuum is dictated by each manuf. and I believe that has to do with seal limitations.
Since wet sumps have the oil pump submerged as a sump pump, scavenging isn't as big an issue as dry sumps in concern of higher vacuum.
Gravity does overcome vacuum in that instance.
Not arguing the weights of gravity against vacuum.
But our engines have a disconnect between the pump and scavenge oil.
That is where the conundrum exists and the affects of vacuum and windage affect what the pump is able to find in order to remove.

I made a conversion chart for pressure measurements.
20 to 30 hPa is roughly 8-12 in of water column.
http://www.sportsterpedia.com/doku.p...k:ref:genmsr04
So there is a difference in vacuum allowances for Sportsters as opposed to autos.
__________________
Reference the XLFORUM'S Sportsterpedia for additional technical information & advice

In Search of Fuel, Sunshine and a Steady Idle.

Last edited by Hippysmack; 1 Week Ago at 20:04..
Reply With Quote
  #42  
Old 1 Week Ago
IronMick's Avatar
IronMick IronMick is offline
Rider Of The Iron Steed
 
Join Date: Dec 2003
Location: London, ON Canada
Posts: 32,465
Sportster/Buell Model: XLH
Sportster/Buell Year: 1978
Reputation: 1213037
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
If we were not already confused, This will make sure we indeed are!!!...

https://core.ac.uk/download/pdf/72787231.pdf
...
Hhmmm, looks like it is a download from the UK, but the thesis was done at the University of Windsor in Ontario, Canada
__________________
Mick
IronHead Forever!

Visit Mick's WebSite
[And Check Out My Autobiog]
Reply With Quote
  #43  
Old 1 Week Ago
Hippysmack's Avatar
Hippysmack Hippysmack is offline
XL FORUM TEAM MEMBER
 
Join Date: Jul 2014
Posts: 6,547
Sportster/Buell Model: Xl1250S
Sportster/Buell Year: 98
Other Motorcycle Model: Kawasaki Vulcan 500
Other Motorcycle Year: 95
Reputation: 6529417
Hippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond repute
Default

Elevation may have something to do with the vacuum per region.
Not entirely versed on that aspect.
Reply With Quote
  #44  
Old 1 Week Ago
Hippysmack's Avatar
Hippysmack Hippysmack is offline
XL FORUM TEAM MEMBER
 
Join Date: Jul 2014
Posts: 6,547
Sportster/Buell Model: Xl1250S
Sportster/Buell Year: 98
Other Motorcycle Model: Kawasaki Vulcan 500
Other Motorcycle Year: 95
Reputation: 6529417
Hippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond repute
Default

This is what I wanted to see.
Matching this to the 57-71 and see the changes.



If the drawings are right now (please check).
Here is what I've been seeing but not being able to convey.
71 900< wet sumps easier than 72 1000> ?

The big change (in CC pressure points) between my two drawings is the starting point and amount of closed vacuum on upstroke due to the gear widths.
The positive pressure points are the same between the two different bores.


Last edited by Hippysmack; 1 Week Ago at 08:51..
Reply With Quote
  #45  
Old 1 Week Ago
thefrenchowl's Avatar
thefrenchowl thefrenchowl is offline
Senior Custom Bike Builder
 
Join Date: Nov 2006
Posts: 2,952
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: 227151
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

No, Hippy, correction, red line indicates tower slot closed hence vaccum creation:



If tower slot is open, whichever you want to look at it, crankcase is open to A.P. So, 72 > 76 from BDC to 90 deg ABDC, crankcase can admit air from A.P. via timing cavity = no vaccum.

This was the timing adopted on the KR quite early by the race dept after testing.

I believe this was to cancel some of the vaccum which was probably a tad too high when tower slot closes at BDC.

I do say "can admit", not "admits" cause, with inertia and rotating speed, I'm not sure at all oil mist escaping on the downstroke will have time to fully reverse its direction from BDC to 90 Deg ABDC.

So this 72 > 76 breather timing could be similar thinking (which certainly works) to RFE and RFA on the cams, take advantage of gas inertia to better scavenge oil mist from crankcase.

Patrick
__________________
Flat Head Forever
Reply With Quote
  #46  
Old 1 Week Ago
mrmom9r's Avatar
mrmom9r mrmom9r is offline
XL FORUM TEAM MEMBER
 
Join Date: Jan 2011
Posts: 2,235
Sportster/Buell Model: dragbike
Sportster/Buell Year: 1960
Reputation: 256632
mrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant futuremrmom9r has a brilliant future
Default

Closing at BDC eats HP through pumping loss. They figured out pretty quickly that it could be left open longer with no negative effect thus reducing that loss.
Reply With Quote
  #47  
Old 1 Week Ago
Hippysmack's Avatar
Hippysmack Hippysmack is offline
XL FORUM TEAM MEMBER
 
Join Date: Jul 2014
Posts: 6,547
Sportster/Buell Model: Xl1250S
Sportster/Buell Year: 98
Other Motorcycle Model: Kawasaki Vulcan 500
Other Motorcycle Year: 95
Reputation: 6529417
Hippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond repute
Default

Patrick, you're right. But I was just thinking in terms of where the vacuum stopped building.
45 deg to TDC is where one piston is going up and the other going down so I didn't count that as more vacuum.
But like you said earlier, the higher up in the cyls that is anyway.

mrmom, that of course, sounds right. Less drag on upstroke.

But now I come to 77-up which closes at BDC with the one way valve.

Would that be deemed as an acceptable pumping loss due to EPA regs?
But the vent still went to atmosphere until 79.
I found some information on the changes made starting Dec, 1977.
The MoCo made some changes by then but were reluctant in going all out.

Harley Davidson and the United States Clean Air Act of 1978:
http://www.sportsterpedia.com/doku.p...story:99xx-01f

Last edited by Hippysmack; 1 Week Ago at 18:29..
Reply With Quote
  #48  
Old 1 Week Ago
Hippysmack's Avatar
Hippysmack Hippysmack is offline
XL FORUM TEAM MEMBER
 
Join Date: Jul 2014
Posts: 6,547
Sportster/Buell Model: Xl1250S
Sportster/Buell Year: 98
Other Motorcycle Model: Kawasaki Vulcan 500
Other Motorcycle Year: 95
Reputation: 6529417
Hippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond repute
Default

BT's kept the timed breather years after the Sportster stopped using it.
I don't know why as I haven't looked into them very much.

Here is what I see as 1977-present Sportster engine breathing.
There are a lot of differences;
1 or 2 breather valves, valve size and construction, venting from the cam cover or heads and added influences everywhere...

Reply With Quote
  #49  
Old 20 Hours Ago
Hippysmack's Avatar
Hippysmack Hippysmack is offline
XL FORUM TEAM MEMBER
 
Join Date: Jul 2014
Posts: 6,547
Sportster/Buell Model: Xl1250S
Sportster/Buell Year: 98
Other Motorcycle Model: Kawasaki Vulcan 500
Other Motorcycle Year: 95
Reputation: 6529417
Hippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond reputeHippysmack has a reputation beyond repute
Default

Quote:
Originally Posted by Hippysmack View Post
But now I come to 77-up which closes at BDC with the one way valve.
Would that be deemed as an acceptable pumping loss due to EPA regs?
[/url]
OK, I'm depressed nobody answered this.

I made some more drawings.
The figures are not accurate since I've found nobody that CC'd their crankcase and gearcase.
But the thought is the same.

This one is just an extension of the degree wheel drawing regarding vacuum.


This one shows that even though they went back to closing the breather at BDC, crankcase pressure didn't suffer for it.
The holes opened up in the cam wall increased the volume of crankcase air.
The pistons are the same, travel is the same.
But in 77> engines, vacuum is lowering a bigger amount of air.
Reply With Quote
  #50  
Old 13 Hours Ago
bustert's Avatar
bustert bustert is offline
XL FORUM TEAM MEMBER
 
Join Date: Jul 2008
Posts: 10,072
Sportster/Buell Model: 1200s
Sportster/Buell Year: 2001
Sportster/Buell Model #2: xlch
Sportster/Buell Year #2: 1974
Reputation: 3254109
bustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond reputebustert has a reputation beyond repute
Default

tec evolves and it makes sense to let the engine do its thing by natural flow function than trying to time things. if you take the timing window out of the picture, will operate like the evo, as long as flow out the vent valve can be maintained. the big issue here is the way oil is removed from the flywheel compartment, big restriction but needed due to design.
the japanese are ahead of the curve, americans are toooo slow. ex: americans used egr valves and controllers, japan made it a function of the engine. crank vent and vacuum part of the engine function and no need for pcv cross ventilation which closed off under high loads so had to backup through the atmospheric side to air cleaner.
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 04:03.


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