ADVrider

Go Back   ADVrider > Bikes > Old's Cool > Airheads
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 12-03-2009, 06:41 AM   #1
DeutschMark OP
Full Tilt Boogie
 
DeutschMark's Avatar
 
Joined: Aug 2008
Location: Grand Haven
Oddometer: 261
Lightening Airhead Lifters

Has anybody lightened airhead lifters with any success? The old Dr. Curve article mentioned elongating the oval hole on the lifter.

If anyone has done this, how much weight is safe to remove?

Thanks.
__________________
89 BMW R100RS
97 Suzuki DR350
And away we go!
DeutschMark is offline   Reply With Quote
Old 12-03-2009, 08:57 AM   #2
Stagehand
+/- V TDSPP
 
Stagehand's Avatar
 
Joined: Oct 2004
Location: Shawangunks
Oddometer: 24,921
every little bit helps, I guess.

No idea.
__________________
Unintentional psychokinesis.
Stagehand is offline   Reply With Quote
Old 12-03-2009, 10:48 AM   #3
Wirespokes
Beemerholics Anonymous
 
Wirespokes's Avatar
 
Joined: Jul 2002
Location: Jackson's Bottom Oregon
Oddometer: 7,748
Never thought of it. I wonder about using titanium? Would there be a metalurgical problem between them and the cam?
__________________
Wanted: Dead, smashed, crashed or trashed gauges
BMW GAUGE REPAIRS - TACH*SPEEDO*CLOCK*VOLT METER *PODs & LIGHT BOARD*
Wirespokes is offline   Reply With Quote
Old 12-03-2009, 04:18 PM   #4
skrub
Gnarly Adventurer
 
Joined: Jan 2008
Location: Sanford Mich.
Oddometer: 258
I once aponatime owned one of the Butler&Smith short rod factory race engines. It did not have the utra trick lifters. I have heard thay where titanium and had to be welded in a vacuum chamber. Some one once made a lifter with a ti button on the top to prevent the push rod from pushing through because of the high spring rates used on the hugh cams. I had an idea to use a R65 lifter its a cup the push rod rides in the bottom. Then the side can be drilled or slotted with no fear of damage. The push rods then need to be longer, Jegs sells a kit ala cut to fit for a hemi eng.
skrub is offline   Reply With Quote
Old 12-12-2009, 08:43 PM   #5
bmwhacker
Still on 3 wheels
 
bmwhacker's Avatar
 
Joined: May 2009
Location: MONTANA NATIVE from NATIVE MONTANA
Oddometer: 4,085
Seems like you would only lose a couple of grams....pass on breakfast and take a good dump and you'll likely lose more.......
__________________
http://555navigator.blogspot.com

Living proof you shouldn't play with matches
ABC# 1992
bmwhacker is online now   Reply With Quote
Old 12-12-2009, 08:51 PM   #6
BrianK
F'in' half ass lookie boy
 
BrianK's Avatar
 
Joined: Dec 2008
Location: Boston, Manxachusetts
Oddometer: 852
Quote:
Originally Posted by bmwhacker
Seems like you would only lose a couple of grams....pass on breakfast and take a good dump and you'll likely lose more.......
Yeah, but that's not reciprocating weight.... at least, I HOPE NOT!
BrianK is offline   Reply With Quote
Old 12-12-2009, 09:00 PM   #7
bmwhacker
Still on 3 wheels
 
bmwhacker's Avatar
 
Joined: May 2009
Location: MONTANA NATIVE from NATIVE MONTANA
Oddometer: 4,085
Quote:
Originally Posted by BrianK
Yeah, but that's not reciprocating weight.... at least, I HOPE NOT!

__________________
http://555navigator.blogspot.com

Living proof you shouldn't play with matches
ABC# 1992
bmwhacker is online now   Reply With Quote
Old 12-12-2009, 10:32 PM   #8
bmweuro
Mad Scientist
 
bmweuro's Avatar
 
Joined: Nov 2003
Location: Chico, California
Oddometer: 3,313
I have built a lot of airhead race motors in the past 25 years and this is an area I would not tuch on a street bike. If you ever rev the motor you will crack a lifter and on the street you will never notice the added performance. If your looking for cheap reliable horse power in a Boxer you can do 2 things.

up the compression and port match the heads.
bmweuro is offline   Reply With Quote
Old 12-12-2009, 11:15 PM   #9
Rob Farmer
Beastly Adventurer
 
Rob Farmer's Avatar
 
Joined: Aug 2002
Location: Loughborough, Leicestershire. England
Oddometer: 4,969
Siebenrock have light weight cam followers, Valves and pushrods. Not cheap though.
Rob Farmer is offline   Reply With Quote
Old 12-13-2009, 05:22 AM   #10
Beemerboff
Beastly Adventurer
 
Joined: May 2005
Oddometer: 2,209
The real problem is that the lifters dont get a straight push at the rods , so for a top race engine you want to be welding up the holes and re machining them so that they do- said to be worth 500 revs by those that should know.
__________________
Adelaide Hills, Australia. 93 R100 GS, 77 R75/7 ,70 BSA B44VS, , 86 R80 G/S PD, 95 BMW Funduro F650 ST
Beemerboff is offline   Reply With Quote
Old 12-13-2009, 07:08 AM   #11
DeutschMark OP
Full Tilt Boogie
 
DeutschMark's Avatar
 
Joined: Aug 2008
Location: Grand Haven
Oddometer: 261
Quote:
Originally Posted by bmweuro
I have built a lot of airhead race motors in the past 25 years and this is an area I would not tuch on a street bike. If you ever rev the motor you will crack a lifter and on the street you will never notice the added performance. If your looking for cheap reliable horse power in a Boxer you can do 2 things.

up the compression and port match the heads.

I've already got the compression part covered. I've got a set of late 9.5 pistons and I'm going to dual plug, so I'll bump it a little more. I also have a Scheffer/Edelweiss asmmetrical cam ordered and already have some Mikuni carbs. This should be a peppy airhead! When the heads are done I'll have the machinist use 44mm intake valves.

As far as the port matching goes, I pulled the heads and planned to do a little smoothing and casting flash removal, but there doesn't seem like there is much to remove. The intakes are clean, with only a little casting flash. There is a small hump on the bottom of both intake ports that could be smoothed over and a booger size piece of flash on the short radius of one intake. Is this what you are referring to?

On the exhaust side, there is a small step outward all of the way around the area where the head transitions to the spigot. Are there any gains to be had by removing this?
__________________
89 BMW R100RS
97 Suzuki DR350
And away we go!
DeutschMark is offline   Reply With Quote
Old 12-13-2009, 07:48 AM   #12
RecycledRS
Along for the ride
 
RecycledRS's Avatar
 
Joined: Nov 2008
Location: Vancouver Island
Oddometer: 1,033
The ridge meets flush with the exhaust pipe. Any smoothing you do should be done with a small length of exhaust tubing in place to match up to first.
__________________
_____________________________________
"There's a fine line between a shearing and a skinning"
RecycledRS is offline   Reply With Quote
Old 12-13-2009, 10:25 AM   #13
bmweuro
Mad Scientist
 
bmweuro's Avatar
 
Joined: Nov 2003
Location: Chico, California
Oddometer: 3,313
Quote:
Originally Posted by DeutschMark
I've already got the compression part covered. I've got a set of late 9.5 pistons and I'm going to dual plug, so I'll bump it a little more. I also have a Scheffer/Edelweiss asmmetrical cam ordered and already have some Mikuni carbs. This should be a peppy airhead! When the heads are done I'll have the machinist use 44mm intake valves.

As far as the port matching goes, I pulled the heads and planned to do a little smoothing and casting flash removal, but there doesn't seem like there is much to remove. The intakes are clean, with only a little casting flash. There is a small hump on the bottom of both intake ports that could be smoothed over and a booger size piece of flash on the short radius of one intake. Is this what you are referring to?

On the exhaust side, there is a small step outward all of the way around the area where the head transitions to the spigot. Are there any gains to be had by removing this?
What year and size motor is this? What are the heads off of?
bmweuro is offline   Reply With Quote
Old 12-13-2009, 10:36 AM   #14
DeutschMark OP
Full Tilt Boogie
 
DeutschMark's Avatar
 
Joined: Aug 2008
Location: Grand Haven
Oddometer: 261
Quote:
Originally Posted by bmweuro
What year and size motor is this? What are the heads off of?
1989 1000cc with original heads.
__________________
89 BMW R100RS
97 Suzuki DR350
And away we go!
DeutschMark is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
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 On

Forum Jump


Times are GMT -7.   It's 04:33 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014