World’s Fastest 50cc Motorcycle Project

Andy Sills on 50cc project bike

A Real Machine
Eric Manning is one of those guys who are driven to make something real and tangible. He’s a guy I know personally, and I am privileged to have the opportunity to shed some light on his recent project. I felt a formal interview would be the best way to get Eric’s ideas across and I have included the Q&A below. Now, I love a good concept rendering as much as the next guy, and virtual “what if” images certainly have their use for marketing, but I get real excited when I see an idea get built and it works as intended. In an industry full of fluff renderings and blue-sky concepts never to be built, here’s a refreshing exclusive to The Kneeslider about a genuine creator who comes from the Build it-Test it-Break it-Build it Again-Go Faster school of thought.

Eric's  50cc project bike

What Manning has meticulously designed is a lightweight, small displacement land speed racer to be used as a test bed for maximizing efficiency of small engines and vehicle aerodynamics. This is real-world privateer development that benefits from decades of experience in building the fastest Bub Streamllinermotorcycles on earth. You see, Eric’s ol’ man is Denis “Bub” Manning, who is no doubt a legend in motorcycle streamlining and a recent AMA Hall of Fame inductee. Bub has been chasing land speed records for close to 40 years, and his son, Eric, practically considers the Bonneville Salt Flats like a second home. When they’re not setting speed records, the father-son duo runs Bub Enterprises, which has become the #1 selling aftermarket exhaust system for Harley-Davidson motorcycles. My dad bought a set of Bub’s high-performance pipes in the early 80’s for his Yamaha 650, and they’ve kept in touch ever since. That bike is in my garage now, still sporting the original chrome Bub pipes and it runs better than ever.

Staged Development
The engine for Eric’s prototype streamliner started life in a 2002 Aprilia RS50, but has been highly modified and runs on methanol and nitrous. Manning enlisted engine builder, Richard Farmer, to whip the little 2-stroke in to shape, the same guy behind the engine development on the recent world’s fastest motorcycle, Bub’s 350mph 500hp V-4 powered streamliner. Last year, Manning’s team ran the 50cc test engine in a stock Aprilia frame, and with the help of BMW record holder Andy Sills in the saddle, they went 77.128mph to break the record in the MPS-AF class that stood for 28 years. Phase I was a success.

Phase 1 50cc record breaker

Phase 1 50cc record breaker

The Phase II machine started life in Solidworks and was fabricated almost entirely out of laser-cut aluminum to form a lightweight, rigid truss-like structure. From what Eric tells me, the sole purpose of the Phase II machine is to dial in specific “modules” such as steering, suspension and the engine. Then, once the designs are proven, the modules will be incorporated into a completely new carbon fiber monocoque construction. This is the kind of systematic development you usually hear about in MotoGP or Formula1, but guys like Eric and his team are proving that all it takes is some good ol’ fashioned ingenuity, determination and the ability to use the tools you’ve got.

Phase 2 Solidworks design

If you have ever experienced a speed event at the Bonneville Salt Flats, then you know the type of people who run machines there. From my own experiences, I would speculate that the desolate location itself is what predisposes these gearheads to maintain a work-with-what-we-got mentality and thereby pride themselves with living in reality to make things work. There are also many factors at play at Bonneville that only add excitement to the challenge such as shifting wind, moisture, traction, heat, lunar tides, running out of beer, and so on. So, it’s not as easy as just going fast, you’re up against planet Earth, too. If you beat these odds, and walk away with that little timing slip, then you’ve accomplished something truly indescribable.

Andy Sills on Phase 2 50cc racer

Bonneville attracts mostly self-taught individuals and highly skilled folks who probably only keep their day jobs so they can afford to go racing. You’ll see men and women, young and old. You won’t hear a lot of “that’s how it’s always been done” or “it’ll never work”. You will hear the occasional “that just can’t be done”, though, if your machine is shaped like a brick and you just don’t have the horsepower to push it through the air. It’s a simple formula and it changes exponentially. But, if you’ve got a fancy degree and little experience, don’t go to Bonneville and tell these guys how to produce horsepower or break records.

Toys Got Bigger, More Expensive
When I first met Eric, it was in the mid 80’s during a family trip out West, and around the time Bub was running the S&S-powered streamliner he called “Tenacious”. I was 9, and I’ll never forget what it was like to see that blue streak shoot across the great white desert for the first time at 270+ mph. Eric and Jack ManningWe were guests in the Manning’s Grass Valley, California home and Eric and I played and talked about cool stuff like dirt bikes, video games and blowing stuff up. I now believe that experience on the salt as a child has had a profound effect on my life. That word “tenacity” has stuck with me all along and I finally know what it means. Bonneville is a surreal place, that’s for sure. So, Eric and I are still doing the same things we were doing as kids, and that, we feel, is what happiness is all about. I know that many people talk about that, but few are lucky enough to get to do it.

So why do this? Well, I can tell you that these people take going fast very seriously. But, most importantly, it’s about having fun in the process. One thing I’ve learned about the Manning’s, is they never joke about speed or horsepower. Everything else is pretty much fair game and they are truly a joy to be around. I’m not sure if it’s the water in Grass Valley or what, but they sure know how to enjoy life!

Interview with Eric Manning:

B.Case: Your Phase I project was a stock Aprilia RS50 running a modified engine, with your Phase II creation being a complete ground-up purpose-built machine. Will the Phase III machine be an evolution of the current chassis, but with a streamlined shell to go after the absolute 50cc record of 144mph?
Eric Manning: Phase III will be a full streamliner with a carbon monocoque frame. The idea behind the transitional bike is to test and refine the steering, suspension and the engine package. I wanted to cut that development down dramatically and test each of the components separately on the Phase II motorcycle. These modules will be in the final carbon frame.

B.Case: Last year, your rider, Andy Sills, set a record with the RS50 at 77.128mph. What was it like to break a 28-year old record with your first project?
Eric Manning: It was incredible knowing that we got the record. You look in the record book and think that you have a very good shot at it, but when you factor in the wind & track conditions the odds get a lot smaller.

B.Case: Describe what it's like to design and build a machine from scratch, and then test it on the hallowed Bonneville Salt Flats proving grounds?
Eric Manning: Bonneville is the last place in my mind for a privateer to compete. The rules are based on safety, not what sponsors of the big manufacturers agree on and that makes it very special. Innovation is not a dirty word at the salt. You can't get banned for a good idea.

B.Case: You say this year was all about testing the new purpose-built frame and suspension. What sort of things did you learn with the new setup once you hit the salt?
Eric Manning: One of the first things was the difference in traction for handling. We had steering issues. Our bike is more of a streamliner and bit more challenging to ride at low speeds. The frame design itself was very easy to work on and maintain.

B.Case: Being that the Kneeslider readers are a fairly technical bunch, can you describe for me your design guidelines for things like weight distribution, ground clearance, rider positioning, and traction?
Eric Manning: Well the most important design challenge was the packing for Andy on the bike. Trying to get the frontal area to the bare minimum was the first goal, and then using Solidworks FEA, I was able to design the frame with a comfortable safety factor. The real bulk of the design is the packing of the sub components. That was really tough to keep it simple.

B.Case: I noticed you've utilized some rapid-prototyping techniques with some of your part designs. Are there other teams at Bonneville using this approach?
Eric Manning: I don't know to what extent the other teams are using that technology, but it has sure taken a lot of the wasted time out the project. When you’re dealing with complex machine parts or castings, the RP parts can save weeks of expensive manufacturing.

B.Case: Bonneville has got to be one of the flattest, most surreal environments on Earth. As we accelerate faster and faster towards alternative vehicles, do you feel there will always be pioneers like you proving their designs out on the salt?
Eric Manning: Sure, I think that what it's all about. To push the limits of any technology defiantly pulls in pioneers. Half the fun being at Bonneville is seeing the off the wall designs people come up with.

B.Case: Your dad told me once how a salmon inspired the extremely low-drag shape of his "Seven" streamliner. Will the same sort of aerodynamic "biomimicry" play a role in your designs?
Eric Manning: Yes, and no I'm not ready to share those designs yet. We are sponsored by Solidworks, and they have a Flow program that we are using to design our shape. We plan to head to the wind tunnel in full scale when ready.

B.Case: Now in the motorcycle hall of fame, your dad has been a pioneer in motorcycle streamlining for 35+ years. Would you say the Salt Flats are like a second home for you?
Eric Manning: There are very few times that I wasn't at the salt. I met my wife, Delvene, at the Australian salt flats at Lake Gairdner.

B.Case: You've got a 7-month old baby boy named Jack, and he's already been to the Salt Flats. No doubt, Jack is going to have some very big salt-encrusted shoes to fill. Is it safe to say that Bonneville is in your family's blood?
Eric Manning: Yes, land speed racing is very close to my family and will continue to be.

B.Case: Where can we follow the project and find out when you’ll be testing the machine next?
Eric Manning:

Manning’s 50cc LSR Specs:
• 2002 Aprilia RS 50
• Methanol Fuel with Readline Oil Premix
• Metrakit: Engine modifications (Cylinder, Piston, Crank, Primary, Reeds)
• Pingel: Nitrous Express Kit, remote starter, accessories
• Barnett Clutch
• Custom Fuel Injection with NX control
• Custom frame purposely designed for land speed racing
• Laser cut and CNC bent aluminum alloy

Andy Sills on Phase 2 50cc racer

Eric Manning's 50cc racer detail

Eric Manning's 50cc LSR racer

Eric Manning's 50cc engine closeup

Andy Sills and Eric Manning

All pictures supplied by Eric Manning.
Links: 50cc LSR   Bub Speed Trials at Bonneville



  1. Dorzok says

    Looks promising. In the first pic, it’s already blowing Dude’s hair off and it ain’t even moving.

  2. todd says

    Nice. is there a speed-tow vehicle involved or will it start from a start?

    Also, great to hear that SolidWorks is a willing partner. They have an excellent package to work with.


  3. FREEMAN says

    This is absolutely fantastic! This completely reminds me of Burt Munro and his Indian. Those Phase II photos scream Burt.

    I would love to see how fast that 50cc can go.

  4. Jeff says

    High speed wizzer . I wonder If there is a record using a 3hp Briggs and Stratton for a powerplant ?

  5. Wave says

    This looks really exciting. The approach is about 100% more scientific than good old Burt Munro could have managed. Do you think this would be the most expensive 50cc two-stroke bike ever built? It’s a great category to set a record on because people just love trying to go as fast as possible on their little 50s from the time they’re little kids. Great stuff, can’t wait to see what speed it’ll do with the body on!

  6. Denis Martyn says

    My hat is off to those who compete for the LSR in whatever category they choose. With very few exceptions there’s no fame or glory in it. There’s certainly no money. They do it for the love of it, and the thrill of going fast on something they built themselves. It takes a huge amount of dedication, time, and their own money to do it. I admire them a lot. They enrich our sport, and one way or another we’re all better off because they’re out there doing what they do.

  7. todd says

    “There’s certainly no money.”

    Well, one must consider all the exhaust pipes BUB sells, maybe there’ll be a line of expansion chambers? Just look at what the Bonneville title and record did for Triumph.

    I agree though, this isn’t NASCAR and I admire the people out on the salt too.


  8. motoxyogi says

    What are the existing records? The only ones i’ve heard of were from the 60’s or 70’s with zundapp or kriedler. Anybody know?

  9. says

    When you consider a road racing chassis, steel trellis or aluminum spar frames offer some desired flex, so putting a more rigid cf frame in its place would throw variables into the mix that would then require the ‘whole’ to be re-evaluated.

    Those variables applied in a straight line at Bonneville don’t seem to be at play (sorry for stating the obvious), so it seems the transition from phase II to phase III is a smart way to go with the cheaper aluminum test bed in phase II.

    Are there any concerns in going from aluminum to cf when applied to this type of chassis that could cause a slight apples to oranges comparison?

    Best of luck. Cool deal.

  10. says

    Good question hoyt, and I’m sure that’s the part Eric can’t discuss! After all, Bonneville is a competition! But, interestingly enough, there is a great book that came out last year by John Stein called World’s Fastest Motorcycle (available through the Motorcycle Books tab above) that describes some of the challenges the Bub team faced when converting the Tenacious II (steel cage) streamliner to the #7 (carbon fiber monocoque) streamliner.


  11. JC says

    They are talking FIM records here, and do not think the most recent 2008 records are posted yet.

    If anyone knows where to find them, I would like to know!

    The 144mph hour record they are after is SCTA however, Buddfab record.

  12. James says

    There is something about a 50cc nitrous motor on meth that just makes me laugh, congrats on a great build!

  13. ROBERT VANZEE says


  14. Skunkworks Racing Vespa says

    absolutely stunning piece of kit , I love the smell of Methanol and 2 stroke oil ! I am planning a stab at the 250cc record on Vespa , which is only 86 mph on Salt . I’m moving to Australia , so I’ll be doing at Lake Gairdner , you’ve just given me some great ideas , thanks and good luck . I can almost smell the engine and hear the scream now …..

  15. Motomech says

    Around 1991, I campained a Honda NS50 in the CMRRA(Calif. Mini Road Racing Accosc.)and since they placed it in the modified class when it was stock(it was one of the first, big wheel, liquid-cooled minis), so I procceded to modify it. During the course of that season and the next I added a KX 60 piston(bringing displacemnet out to 58cc), CR80 ign., trans, clutch and intake. The pipe was custom hydra-formed and the chasiss was much modified and resembled the early Aprilla RS50. Tires were used Michelins off the frt. of Honda RS 125 racer(given to me by Rodney Fee).
    It was clocked w/radar at Streets of Willow(up the long start straight)@ 71 M.P.H. The Honda Optional analog(cable-driven)tach burried @ 15,000 r.p.m.
    I was racing w/ a then 11 year old Johnny Hopkins and we thought about regearing it for him and giving some speed records a shot, but we were having too much fun going around in circles.
    I often read about top speed numbers for minis that make me groan, but the content of this article nicely shows what it takes to get into the 70’s m.p.h. w/50cc’s and beyond. Well beyond