ADVrider

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

Reply
 
Thread Tools Search this Thread Display Modes
Old 09-24-2014, 11:36 AM   #1
cyclefreak13 OP
Gnarly Adventurer
 
cyclefreak13's Avatar
 
Joined: Aug 2010
Location: NC
Oddometer: 124
No sub frame airhead

Hi everyone. Well I have a 1981 R100RT -fairing(it went to a good home on another RT) and a cozy rocket sidecar. I really like how clean the /2 BMWs are with the sidecar mounts. I don't care for the look of an extra appendage bolted to the side of the bike. I understand the frames are designed totally different and the /7 frames are NOT designed for direct bolt on sidecar work. With that in mind I am planning to go through the entire frame and brace it. Has anyone else already done this? (Yes I have already seen the thread in airheads about frame braces.)

My plan is to modify the frame front to rear with the intention of it looking like it could have left the factory that way. I plan to add HPN style reinforcements to the neck, backbone, and swingarm pivot area. Then side braces like a road race bike. After that I plan to add a cross brace under the transmission. I'd like to add a brace possibly in front of the engine, down by the exhaust crossover. Looking at the frame I'm trying to figure out what to do at the top rear. I would like to use the stock location of the battery, but understand a brace may be needed in this area.

So that's the down an dirty of it. I would appreciate any advice you may have.
__________________
81 R80G/S
09 R1200GS
12 TE449
And many more bikes.
cyclefreak13 is offline   Reply With Quote
Old 09-24-2014, 01:09 PM   #2
MotoJ
Mobtown Hacker
 
MotoJ's Avatar
 
Joined: Apr 2011
Location: Baltimore
Oddometer: 1,179
Sounds like a whole lot of work for minimal gain. Plus, welding all over the frame could produce weak spots. There really isn't any "appendage" to an airhead subframe- typically the main part is a bar that runs parallel to the lower frame and is bolted to front and rear engine mounts, and front and rear upper mounts that are sometimes but not always part of the lower portion. Either way you still have struts from the sidecar frame to upper parts of the bike frame- it gets cluttered, but it's the same on a /2. Then there's usually a cross piece above the battery tray to stiffen the rear subframe (the bike's subframe- not the sidecar subframe). I don't find the subframe on my /7 to be obtrusive at all. It follows the contour of the bike's frame and is painted black- most people don't notice it's there unless I point it out.



Not shown is a piece that bolts to the cross bar between the front frame down-tubes. The front strut attaches there.
__________________
The ladies used to check me out...now they just keep an eye on me.
MotoJ is offline   Reply With Quote
Old 09-24-2014, 07:20 PM   #3
davebig
Another Angry Hun !
 
davebig's Avatar
 
Joined: Jan 2004
Location: Minnesota
Oddometer: 2,900
Motoj is right, the HPN stuff is for blasting along on rough terrain, unless you have allot of structural welding experience, get or build a subframe if you want to add the braces to frame and rear swingarm that the road racers use that may help, but correctly gusseting joints is not just adding metal.DB
__________________
Patience: A minor form of despair disguised as a virture.
Ambrose Bierce
davebig is offline   Reply With Quote
Old 09-24-2014, 08:51 PM   #4
bk brkr baker
Beastly Adventurer
 
bk brkr baker's Avatar
 
Joined: Jul 2006
Location: The Bluegrass
Oddometer: 5,473
EML got around the weakish beemer frame by jacking it up and parking a purpose built frame under it. And the bike looked stock.
__________________
RR's Catnip Hill to Peoria ___Loopin' Seattle to WestFest
It started with some beers __1500 miles to the Dentist
Skeedaddle to Seattle______ A 30 year old on a Three Flags Run
bk brkr baker is offline   Reply With Quote
Old 09-25-2014, 06:18 AM   #5
cyclefreak13 OP
Gnarly Adventurer
 
cyclefreak13's Avatar
 
Joined: Aug 2010
Location: NC
Oddometer: 124
Hmmm, did a quick search for EML and found lots of pictures of rigs, but none of the sub-frame. Anyone have a picture?

The rigs that I have run into locally to me all look like the sidecar was an afterthought. The sub-frames looked homemade and cobbled together. I basically want it to look like the factory said ok you can add that as an accessory, just bolt it to these four lugs.
__________________
81 R80G/S
09 R1200GS
12 TE449
And many more bikes.
cyclefreak13 is offline   Reply With Quote
Old 09-25-2014, 06:26 AM   #6
bk brkr baker
Beastly Adventurer
 
bk brkr baker's Avatar
 
Joined: Jul 2006
Location: The Bluegrass
Oddometer: 5,473
Quote:
Originally Posted by cyclefreak13 View Post
Hmmm, did a quick search for EML and found lots of pictures of rigs, but none of the sub-frame. Anyone have a picture?

The rigs that I have run into locally to me all look like the sidecar was an afterthought. The sub-frames looked homemade and cobbled together. I basically want it to look like the factory said ok you can add that as an accessory, just bolt it to these four lugs.
That's the thing . The EML air-head set up didn't have a sub-frame . They replaced the whole BMW frame with a stronger one of their making.
__________________
RR's Catnip Hill to Peoria ___Loopin' Seattle to WestFest
It started with some beers __1500 miles to the Dentist
Skeedaddle to Seattle______ A 30 year old on a Three Flags Run
bk brkr baker is offline   Reply With Quote
Old 09-25-2014, 06:56 AM   #7
MotoJ
Mobtown Hacker
 
MotoJ's Avatar
 
Joined: Apr 2011
Location: Baltimore
Oddometer: 1,179
Quote:
Originally Posted by cyclefreak13 View Post
Hmmm, did a quick search for EML and found lots of pictures of rigs, but none of the sub-frame. Anyone have a picture?

The rigs that I have run into locally to me all look like the sidecar was an afterthought. The sub-frames looked homemade and cobbled together. I basically want it to look like the factory said ok you can add that as an accessory, just bolt it to these four lugs.
http://www.ideal-seitenwagen.eu/down...April-mail.pdf

Scroll down to page 22. I believe that is a Piekert subframe. I've seen them on EBay.DE for less, but used. Chris at BoxerMetal can source them too. That's about as factory OEM as you can get for a Beemer. You can attach a Ural, Dnepr, or Steib sidecar without much trouble, and anything else too, with modifications.
__________________
The ladies used to check me out...now they just keep an eye on me.
MotoJ is offline   Reply With Quote
Old 09-25-2014, 08:19 AM   #8
Jim K in PA
Studly Adventurer
 
Jim K in PA's Avatar
 
Joined: Mar 2011
Location: Pocono Mountains, PA
Oddometer: 911
It can be done, but takes some planning and skill. My R90S frame was extensively modified by Bob Pelikan when he converted it to sidecar duty. Frame mounting points were added with sleeves; cross bracing added, gussets added to the swingarm pivots, and tubing added to the front drops for stiffness and mounting the fairing. He also converted it to monoshock, which kicked the battery to the curb. Lots of pics in my thread linked in my sig.
__________________
Jim K in PA
1979 BMW R100T - Otto - Returned to the road - 5/12/11
1975 BMW R90S Hack - Olga - Olga's story - adopted 3/22/14
Viktor - Coming to a thread near you - eventually
Jim K in PA is offline   Reply With Quote
Old 09-25-2014, 08:48 AM   #9
jaydmc
Beastly Adventurer
 
Joined: Sep 2008
Oddometer: 1,001
The sub frame we make is not all that intrusive. However if you do want to go ahead and remake the frame of your bike, one of the main reasons I would suspect that EML and others just made up new frames for the bike is that the frame tubing is very thin on these bikes. Having had to repair a few while I never have taken a Micrometer to one to figure out just how thin I would guess it to be about .065 wall tubing. Most frame tubes are much thicker walled. As it is so thin I recommend TIG welding in order to be able to better control the heat of the weld.
Jay G
DMC sidecars
866-638-1793
www.dmcsidecars.com
jaydmc is offline   Reply With Quote
Old 09-25-2014, 02:51 PM   #10
cyclefreak13 OP
Gnarly Adventurer
 
cyclefreak13's Avatar
 
Joined: Aug 2010
Location: NC
Oddometer: 124
Jim K, I have looked at Olga many times, and this is basically what I'm wanting to do. Any chance you can post some pictures of the frame neck modifications? I don't recall seeing that area of the frame.

Jay, I have a Miller Tig I have been using for several years, and this is what I was planning to use. I was also planning to use .120 wall tubing for any modifications. Is it worth using 4130 or should I stick with 1020 or 1018 steel?

Thanks everyone for the feedback. I understand it may be easier and cheaper in the long run to use a subframe. I'm just stubborn in what I want .
__________________
81 R80G/S
09 R1200GS
12 TE449
And many more bikes.
cyclefreak13 is offline   Reply With Quote
Old 09-25-2014, 04:05 PM   #11
Jim K in PA
Studly Adventurer
 
Jim K in PA's Avatar
 
Joined: Mar 2011
Location: Pocono Mountains, PA
Oddometer: 911
Quote:
Originally Posted by cyclefreak13 View Post
Jim K, I have looked at Olga many times, and this is basically what I'm wanting to do. Any chance you can post some pictures of the frame neck modifications? I don't recall seeing that area of the frame.

I understand it may be easier and cheaper in the long run to use a subframe. I'm just stubborn in what I want .
Stubborn? I can relate . . .

Tough to get shots of the frame neck due to the fairing, but I honestly do not think anything was modified or strengthened there. Best shot I have at the moment is this one:



You can see the added tubes that somewhat brace/stiffen the front down tubes and also provide the upper landing point for the fairing mounts. Note that Bob placed the welded sleeve for the through bolt mount between the main and secondary fairing struts.
__________________
Jim K in PA
1979 BMW R100T - Otto - Returned to the road - 5/12/11
1975 BMW R90S Hack - Olga - Olga's story - adopted 3/22/14
Viktor - Coming to a thread near you - eventually
Jim K in PA is offline   Reply With Quote
Old 09-25-2014, 04:41 PM   #12
davebig
Another Angry Hun !
 
davebig's Avatar
 
Joined: Jan 2004
Location: Minnesota
Oddometer: 2,900
If you have a TIG welder this isn't your first rodeo http://weldingdesign.com/processes/u...ners-correctly
The HPN boys know what they're doing and emulating they're gussets wouldn't be the worst thing. Our adv sidecar builders in this country have completely different approaches so suit yourself.Good luck.DB
__________________
Patience: A minor form of despair disguised as a virture.
Ambrose Bierce
davebig 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 08:54 PM.


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