Large Spine Frame XS650 / Egli / Rau / Cafe Racer

[rehar]

Where to start... Here is a picture at the time that I started this thread.


I came across an XS650 engine for sale (by Mule/Richard Pollock), combined with some thoughts about a new project bike and inspired by the new Norton Domiracer... I entered the Concepting Phase of my latest project... Of course, I had to utilize components that were in the garage, a complete R6 front and rear ends...

I try to do my designs in 3D. I have alot of data thrown up to www.grabcad.com as well. The Engine is there and the frame (concept). Search for "XS650 Engine" or "XS650 Concept frame chassis" for example.

I usually start with some sketches, I'd put the basic components in place and fill in the from there.

I explored several different frame types, double cradle, trellis, Egli style large spine frame... I had to go with something that was somewhat aligned with vintage of the engine.

Well, all for now...

 

[Jim]

Saw the pic of your bike on another thread. Very cool!!

 

[MaxPete]

Really nice work rehar!

Pete

 

[Mailman]

You are a very talented individual! CAD designing then building your own frame. My hats off to you, really nice work! Please keep the posts coming.

Kind of reminds me of an article I read awhile back, where a guy adapted an old Norton engine to a modern Laverda frame.
https://thekneeslider.com/ala-verda-850-norton-commando-laverda-hybrid/

 

[azman857]

Why not a Featherbed frame? It was good enough for Norton and Tritons? True, it does pre - date the engine...

 

[rehar]

Yes, that 850 commando is gorgeous. Similar frame with another of my bikes:
http://www.returnofthecaferacers.com/2010/12/return-of-citrus-cafe-racer.html

Feather bed bikes - they certainly look cool. Lack of support around the steering head scares the heck out of me though.

 

[Mailman]

Dang! You've got mad skills there brother! If you don't mind my asking, tell us a little about yourself. How did you learn to create and design these bikes?

 

[rehar]

By the way - the new NORTON DOMINATOR was an inspiration for this XS650 project.
And here was another concept (line drawing) that almost made the cut... It came down to this or the large spine. This was really close.

 

[rehar]

Skills? Who me? Well, I've been riding since I was 10. Been a Mechanical Engineer for many years (mostly Consumer Electronics and Aerospace). Owned a lot of different bikes over the years. Came to the conclusion that nobody was producing what I wanted to buy. I decided, hey - I can design, I'm a mechanical engineer... I just have to design and build the bike(s) myself! I would like to eventually put some bike into production/start a company, etc... Who knows, maybe someday. So - in the meantime, any excuse to buy a tool (an investment), I bought. Please don't make fun of my messy garage. A little unorganized, too small, not enough time in the garage to clean... Maybe some day... Ha ha...

 

[rehar]

By the way - anyone know how much an XS650 frame weighs? 60.8lbs!

 

[rehar]

Large spine selected. Start with some small bits. The Swing arm pivot (SAP) on most modern sport bikes have a lateral adjuster for slack, tolerance and perhaps assembly capability. So - great place to start, SAP, SHOCK mount, front engine mounts.
The left SAP mount has a locking feature for the SAP Bolt and the right side - the small protrusion there screws in and out for the adjuster and sides fit an R6 SAP Bolt.

 

[mrtwowheel]

I can appreciate all of that. I have bought wheels to build one of those stands for a hard tail, to adjust the chain etc. My next thought is, what do you do when you're riding around and nature calls, and you have to run into a gas station or McDonalds without a side stand? Sort of like, how do astronauts do it in space?

Edit, Took another look, I see the side stand now.

Scott

 

[member3480]

Wow that's cool I wish I had those skills on a computer.
Here is one like your design I built some years ago and there is a video on youtube
I WANT TO SEE MORE haha

 

[rehar]

Geometry:
Rake/Trail: 24°, 97mm (3.8")
Wheelbase: 1425mm (56.1")

I originally designed the frame with a 4" X .083" tube. What I can find for the Egli style frames is anywhere from 3 - 4" diameter.

With the height of the engine and it's location and small diameter neck... This just didn't look right... That tube was about $150.
I decided to go with 3"X.083". I was able to buy a 20' piece, with cutting down to 6' lengths for $70! What a deal!

 

[rehar]

ok, moving forward...

24lbs so far! Huge weight savings!

 

[Jim]

You using 4130N seamless?

 

[rehar]

4130 is the material of choice, however, thin wall 4130 stops right around 2" ~2.25".
4130 is a great material and really not that much more money than cold rolled 1020.
So the large tube is 1020 CR, all the other tubes are 4130.

 

[Jim]

...thin wall 4130 stops right around 2" ~2.25".

Yeah you're right. Didn't think about that....
Hell, at 3" by 083 wall... pot metal would be strong enough
Lookin' good!!!

 

[Mailman]

Man you weren’t kidding when you said large spine frame! This is the first I’ve seen it.
That frame looks SO robust, you’d never guess it is so much lighter!
By the way, as a former welder and fabricator by trade, let me just say I can really appreciate how clean all of your tube joints are. If you’ve never done it, it is incredibly difficult to fit a round tube at an angle to another round tube without winding up with gaps at the joint.
Next, you gotta show us your welds! Haha!
Great work, really enjoying this. By the way I like the way you canted the engine forward , it reminds me of Norton’s.

 

[rehar]

The 4" Tube, if I used it, would have been able to hold just over a gallon of fuel... It would have been so large that I probably would have had to use the frame for auxiliary fuel tank! I was advised not to rotate the engine too far forward, oil pick ups and what not... My original "sketch" up at the top had the engine much further forward (rotationally). It's still forward, but not as much as I wanted. More on engine placement later.

Yes, fish-mouthing tubes is a major pain. That took alot of time and few scrapped pieces of tubing. It's amazing how complex a joint can be and how hard it is to wrap my brain around which way to remove material! When considering the frame style, this was a point of consideration - The Egli style/large tube spine frame has far fewer joints than a trellis frame (although I am partial to the trellis frame).