Mule Motorcycles design exercise
Recently, we've shown some designs on The Kneeslider and very quickly, in the comments, readers would begin debating whether it was practical as shown or would even work at all. Richard Pollock, of Mule Motorcycles, and I have been tossing some thoughts back and forth about this and Richard sent me some photos of a build he spent a lot of time and effort on before ultimately finding it didn't measure up. I asked Richard if he would be willing to share the experience with all of you and he agreed.
Mule Motorcycles design exercise
What you see here is a build by someone who can turn out beautiful work time and again, but who doesn't always hit a home run, a part of the process many folks never see. It's easy to think builders can whip up a perfect new bike every time, but even the best builders sometimes have to put their designs together before finding out how the real bike compares to their initial design ideas, that no matter how nice the design looks, the real bike may not live up to the idea the builder had in mind.
Mule Motorcycles design exercise
I'll let Richard fill in the details:
Here’s a story about dreamin’ up some bizarre stuff and turning it into a bike design that was harder in execution than it was in all the pictures and ideas I drew up or dreamed up.
The Vision and design parameters.
The purpose was to build a better mouse trap. After building about 40 streettrackers, a dozen flattrack race bikes and having seen and studied hundreds more, I decided there were a lot of things about the traditional Harley flattrack designs that I thought could be improved upon. I proceeded to draw pictures by the score, of frame layout, pipe routing, swingarm design, oiltank locations, weight distribution, forks, breather systems, fuel tanks, engine mounting, maintenance accessibility and everything else I could think of. One last requirement was to have a design that was simple to duplicate in large numbers. This bike would be a break from the norm in a form of racing that has a death grip on tradition!
Next I built a fixture that would keep the engine and pivot points all in alignment and allow the construction of the frame around the motor. The bike would basically be built with the motor in place the whole time assuring accessibility.
Construction.
My friend Tim Taber handled all the welding and I did all the design, bending and fitting. Bob Stone, who had been doing all my machine work did most of the machining.
We started by making a fairly labor intensive rear motor mount box/swingarm pivot mount. At the front, a steering head was secured in the fixture. What followed was an attempt to form a “Perimeter” upper frame section, the left side being a large oil tank where fore and aft weight bias could be adjusted by the addition of more oil. The right side upper frame member would double as a breather system with the joint at the swingarm pivot being the return outlet for accumulated oil to the cam case. The rear subframe would be a bolt on for ease of repair or replacement.
The swingarm presented its own challenges. I wanted to do a “Gullwing” design on the left side so the rear pipe could wrap under the engine and then come very close to the swingarm and rear wheel down low and sweeping upward. The swingarm ended up being a bunch of curved pieces all glued together in a giant fixture.
Once I had the whole package all together, I decided some of the curves and lines were not to my liking and just cut the whole thing back apart. I put all the pieces in a tub and moved on to other projects. At first it was going to be a race bike for top National racer, Michelle DiSalvo. Another party was supplying the powerplant and when Michelle and he parted ways, the sense of urgency went with it. And so it sits waiting to be reborn.
----------
Richard has some interesting ideas here, the swingarm deserves special attention, so even though it didn't meet Richard's own standards, I think it was a pretty neat build before he pulled the plug. Maybe that is what makes the best builders what they are, even the work they reject is very good, better than what many could do under the best of circumstances.
Thanks for sharing, Richard.
Mule Motorcycles design exercise
Mule Motorcycles design exercise
Link: Mule Motorcycle Street Tracker Update
Link: Mule Motorcycles
{ 34 comments… read them below or add one }
Interesting looking. Perhaps this could have been refined in a solid modeling application before moving to real-life solid modeling. Not to take away from how neat it is to just build something with your hands while eye-balling it, but 3d modeling can definitely help you hone a design, especially if it’s a totally new one, before you get to the really labor-intensive part of building it in real life. Definitely an issue of old-school vs new-school design; sketches vs. sketchup (or inventor, or solidworks…).
I love these topics. Backyard guys doing the business. Whether or not they make it to the ‘big time’ is not the object. It is to create something unique, and more importantly, doing something creative with the little time we have. I have a couple of these archives myself, and am working on another, that hopefully I will ride in the coming months. Keep these articles coming Paul. Good results or bad, all are interesting and thought provoking.
The front mounts of the engine bolt to the head, which means that most of the weight of the engine is carried by the engine itself, along with the different forces applied when the engine runs and moves the bike. Is the HD engine designed to stay in good shape like that, is this a common practice ?
I’m asking the question bc I’m building a rig myself, and I wonder if it would be ok to hang the engine to the frame like that, or add some brackets for additional support … I chose the safe way and additional bracket, but may be it’s overkill ?
Just keep going. I have great admiration for those who how are unabashed enough to share their efforts even though they may be ridiculed. The next one may measure up to your standards.
Nicolas – check out the air-cooled Buells. They have a combination: cool, minimal bracket that hangs from the front head down to a lower engine mount. Also, Victory’s engine mounts are on the outside of the heads…but bear in mind, those heads could use a more stout set of bolts into the block.
cool bike Richard.
MikeC…agree, thought provoking either way.
I think it is an interesting concept as a chassis, and the structural link from the neck to the swing arm pivot appear sound. I’d like better shots of the rear suspension, he apparently put a lot of thought into it.
As Hoyt stated, a minimal front engine bracket is needed. This has more to do with the construction of the engine; the HDs were never intended to be hung. The aluminum cylinders are under tension on their studs; and this is a balanced tension that increases with engine heat. They are relatively loose when cold, so not to pull studs out when hot. (I’ve seen that!)
Cool project, why did he stop? I can picture oil in the frame, stompin’ motor, shift light, etc.
Jim
The more I study it the more I like it.
Jim
Very cool bike! I’d at least get it together and make a street bike out of it, even if it’s not going to be used for competition.
There were a few areas concerning tubing bends that I was not satisfied with. The only way to correct them was to cut it apart and re-do it.
From a personality/psychological standpoint, I see the projects in my head and can think of little else until I actually dig in and start building. The downside of this personality quirk is that I can get to the finish of the projects and work out all the design issues in my head well before I get it completed in metal. But once it’s complete mentally, the unfinished “Metal” project is just taking up space I’d rather use for next brainstorm. However, sometimes I fall in love with the project and still have the desire to finish it and ride or race it. My current wacky brainstorm project is a speedway bike with half a Harley Sportster engine in it. It’s been done with Iron Sportsters, but not like this one! Hopefully you’ll see it here first!
Mule,
Thanks for showin’ us your stuff.
That was a lot of bending, cuttin’ and fittin’!
I look forward to your one lung project.
Jim
Beautiful frame work and welds! The shape actually reminds me a little of a vintage trail bike exhaust chamber…
Let’s see what’s next.
-todd
Bitvhen!!!! i love it, thank you for showing that custom work is re-engineering the design as the needs dictate. Great Work
C’mon!
Fill up that engine in there and see if it’ll fly!
Orrrr….hehhehehe…better yet….get a engine from Eric Buell!
Oh sweet Mother of Revenge and Humiliation!
Giddyup!
The asymmetry in the rear suspension is really appealing. It’s not a style i see a lot of in frame/chassis design. I think the post has a great message: sure you can fix all your apparent mistakes with no consequence in a CAD program, but you really don’t learn anything from the experience. Obviously, this is why 90% of “concepts” never leave the page or the computer screen.
Derek, I was going to respond to the computer design angle, but you said it perfect, not to mention the fact that a good Pro-E program is $25K. I’d rather be in the garage then at a desk anytime! I work with a programming wizz for triple clamps and stuff I need to have dimensioned by a pro.
Maybe a couple of down tubes at the front to make it a duplex frame instead of those dodgy, weak looking brackets fixed to the cylinder head..That would make the frame stronger and would realy make the bike worth finishing.
I have more pictures somewhere, but there were two triangular plates that picked up the two breather ports, the same ones that hold the carb on. These plates tied the heads to the right frame tube. Joining the two frame spars above the V, was a piece of “Aero”, oval shaped tubing. This tube picked up the standard top left Sportster motor mounts on the cylinder heads. So between the front two adjustable, heim-jointed mounts, the rt side upper mounts and left side to the crossways aero tube all working in concert with the extremely robust rear mount at the swingarm pivot, the motor wasn’t going anywhere. If there was a potential problem, it was that of being too rigid. Unless you’re running Nitro, I doubt you’d ever pop the top end off of a Sportster motor anyway. Sportster cases are a very beefy (heavy), casting and with 8 studs holding the topend on, I can’t see a problem.
Which is precisely the point of this project! How would anyone ever know what’s possible if nobody out there in the world ever tries it?
You want me to try something? Just tell me I can’t do it or it won’t work.
Hey, I personally think it’s beautiful, I love the lines and asymmetry.
I find the design appealing … this one speaks to me.
I also do not see any functional problems with the concept.
What’s not to like??
Very interesting frame and swingarm design. I’d love to see how the exhaust would look. Lots of potential.
“One last requirement was to have a design that was simple to duplicate in large numbers.” —- That’s what caught my eye. Why isn’t someone doing this? There have to be thousands of guys out there that would love to build a bike starting with a simple well sorted frame. Kit cars are common — where are all the kit bikes?
jos
I really like it. The overall look of the bike appeals to me. It’s actually pretty similar to something I’ve been sketching over and over again for months now, a short-wheelbase motard/cafe racer hybrid (sort of), but with a parallel twin instead of a vee.
really cool design, Mule.
For the frenchies who follow this blog, am I the only one for whom that bike recalls a 103 SP ?
http://images04.olx.fr/ui/1/21/75/1801675_1.jpg
(take it as a joke, only)
Ok,
Lets take a poll:
How many votes for Mule to finish this bike?
I say go fer it!
Jim
You know, I have a 750cc single Sportster that could be installed and the swingarm is still totally intact! I wonder?
finish it
Definitely finish it.
It may not end up in competition or as a showbike, but you had a good, unique idea. You owe it to yourself to see it become a bike.
And we want to watch.
“You know, I have a 750cc single Sportster that could be installed and the swingarm is still totally intact! I wonder?”
There’s one way to find out
To John Sutherland, I have this response. “Where are all the kit bikes?”
I’ve been building the “Streettracker” type bikes since about 94. Transitioning from serious hobby, to Ultra serious, almost full time business, I’ve tried many things in an attempt to make some decent money at this. And I’ve had literally thousands of inquiries over the years. I don’t keep detailed notes but I store the trends of requests in my memory banks. Here are a few of the highlights that nobody in the industry seems to care about.
1. If Harley built a genuine streettracker that didn’t weigh 640lbs, there is an un-Godly amount of people that would buy them.
2. Same for Triumph!! Actually even more so. I built a concept bike for Triumph of America which got a huge response and later was purchased by and now resides in the Barber Museum. But Triumph introduced the Scrambler and I never heard another word from them.
3. The only way to build a Streetracker is as a one off custom build. Everyone wants a different motor, so as far as mass-production is concerned, standardizing the package is only about 50% feasible.
4. And specifically to your comment John, The cost of building a kit chassis is pretty high also and my experience has shown that there are only three kinds of customers. The first wants to buy his bike ready to ride right away. The next wants to do everything himself from the ground up and buys as little as possible. The last guy comes to me fairly regular. He wants to build a bike(but has never done it and has no idea about the actual costs invloved), or just wants to swap a front end or wheels out.
There are only two frame builders in the country still doing it as a business. In roadracing, the production bikes are incredible and require only suspension tweaking. Same in Motocross, Trials and the new 450 class of Flattrack. Ron Woods of Woods Racing, no longer deals with motorcycles as a product line. Only quads.
In the world of choppers, there is only one motor ever used. So mass producing cheap frames from cheap materials is easy. I’m surprised they aren’t available at Walmart yet! So that leaves a guy me stuck in Limbo-land. Halfway between art and a business where I could make a living. Maybe if I started building Bobbers or Rat-bikes or joined the “Boardtracker, but with a 72″ wheelbase Brigade”, I could go mainstream. But I think a bike should be ridable and safe AND look like art, so that’s what I strive for. Enough rambling. I do take all praise and especially criticism very well. I have friends that like to pick my stuff apart and that hepls me the most, if there’s anything left when I get done picking my stuff apart!
Pretty impressive work, regardless of the outcome.
I fully appreciate that not all things nork together for good when it comes to machines!
I like this guy.
-todd
What a Gem there Mule! Finish it & I’d take it downtown any old day or night. Even in the rough it still is a stunner. Thanks for showing us the process.
i love to look at your (mule’s) work.i especially like the fact that you just build stuff.keep it up,you rule!
to Mule:
Nice!
I understand that the bike may not quite have fulfilled your dream, but it may for somebody else! What I mean is that completed, I’m sure you will have a completely sale-able piece of art that some lucky guy/gal will appreciate for a loooong time. Think of it this way – Da Vinci’s sketches, flawed or not, fetch staggeringly high prices. His work was unique, and in it’s own way helped shape the future. Ditto with your bike here. Finish it, get it out of your head, make even more space for creative action!
I’m sure a LOT of us would love to see this bike completed.
All the best,
Alexander