Mule Shows the Potential Hidden in the Sportster - The master works his magic and makes it look easy

The Michigan Mafia Sportster by Mule Motorcycles

The Michigan Mafia Sportster by Mule Motorcycles

Here's an orange and black Sportster headed to Michigan, the "Michigan Mafia." It started out as a bike I was building for myself. A 1995 Sportster frame with an 02 Buell M-2 Cyclone motor. We did quite a few mods to the frame, moving the shocks forward about 6” and building an entirely new rear subframe. Added to the seat rails are sections of 1x2 rectangular tubing split down the middle leaving a 1x1 channel. Attaching these gives a nice flat surface on the seat rails for the mounting of an XR750 tail section. Then we welded in a pan under the seat rails leaving a large “cavity” area for all the electrics which tuck away nicely.

The Michigan Mafia Sportster by Mule Motorcycles

The Michigan Mafia Sportster by Mule Motorcycles

Up front are custom A&A triple clamps holding the 58mm USD MV-Agusta F-4 forks and 6-piston front calipers. The wheels are both 19” front Morris castings (late 70’s OEM from Harley), widened by Kosman. The front being 2.75 x19’ with the rear 3.50 x 19”. Tires are DOT approved “Golden Tyres” provided by importer Chris Carr. Front rotors are Brembo 320mm turned down to 310mm and fitted with Brembo buttons to custom inner carriers. The rear caliper is a 2-piston Brembo on the left side while on the right there’s a Sprocket Specialists aluminum sprocket and DID chain.

Kosman widened the 19 inch wheels with Golden Tyres imported by Chris Carr

Kosman widened the 19 inch wheels with Golden Tyres imported by Chris Carr

The swingarm is stock except for relocated shock mounts and has Racetech shocks holding it in place. New bearings, bushings and hardware. The frame and swingarm both being powdercoated gloss black. The rear sets are custom with Bates peg rubbers and a Storz rearset shift lever assy. On the right side we used a Brembo rear master cylinder from a Yamaha R-1 and made an offset brake lever.

An aluminum 883R Storz fuel tank sits on top with a First Klass Glass XR750 seat base. Paintwork was provided by David Tovar at Superbike Paint. The custom tank stickers were made locally and covered by a generous clearcoat! Seat pad comes from Saddlemen who by the way are a huge supporter/sponsor of all levels of flattrack racing.

Head work by Branch O'Keefe

Head work by Branch O'Keefe

The volume is provided by a 1200cc Buell motor with the heaviest Sportster crank and rods balanced by Hoban Brothers in Wisconsin. Branch-O’Keefe did the heads and cylinder boring, with Andrews cams and a 44mm Screamin’ Eagle CV carb. The entire motor is powder coated wrinkle black. Note that the primary has a forward inspection cover so you can turn the crank with a wrench(!) and the entire clutch relief “Lump” was cut off the case, rotated and re-welded in place. This allows the use of a stock Buell clutch cable and clutch lever yet with wider stainless Mule flattrack bars.

Closeup of primary case modifications

Closeup of primary case modifications

We custom made our own manifold from an S&S bolt-on style giving a bigger mounting hole. Mark McDade built the pipes and then we ceramic coated them black. Revival Cycles provided the “Classic” Motogadget gauge and we made a custom mount that consisted of three pieces. An aluminum plate machined to fit the custom triple clamps, a gauge mount and a section of a Joker Machine Sportster headlight mount. All three pieces then welded together. A small battery box secures a Shorai Lithium battery that weighs less than two lbs. and trims about 11 lbs from the stock battery weight. The battery is very close to the 3 qt Moon “Chopper” oil tank that we enlarged by another half quart and added all new fitting locations.

Oil tank modified for extra capacity

Oil tank modified for extra capacity

The bike is currently in the jetting/tuning stage, but so far, it starts in about .02 seconds when you hit the button!! And runs hard! Power should be hovering just under 100 at the wheel, but the dyno is a cruel mistress, so we’ll see what she has to say.

Link: Mule Motorcycles

Work in progress

Work in progress

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Comments

  1. Bicho says

    MASTER MULE is showing you the way,H-D!To me,the xr 750 is the perfect example of a purebreed mechanical race “horse”……………balanced stance,muscular yet light and elegant,extremely well proportioned and the fastest thing on an oval of compacted dirt.Just like this build………..perfetc :)

  2. Randy says

    Very nice! Exactly what the “XR1200″ should have been. Though if the factory did it they could fairly easily have two carbs (throttle bodies?) on the right and the exhausts on the left.

    Is that the stock swingarm? Ungodly heavy – can fairly easily use the pivot portion and larger section thin wall CrMo tube to build a stiffer and much lighter swingarm.

  3. says

    Double Whoomp for the bike. I can appreciate the fine work, design, and man hours put into this project. Nice tank decal but paint is over the hill. Sorry after looking at XR’s for 45 yrs. the paint, well enough said. Wish it was mine. Z

    • says

      Zip, when a guy orders a custom bike, he gets to decide on his own paintjob. To me the orange/black says XR750, yes, but it’s like the yellow/black Kenny Roberts paintjob on an XS650. I’d rather never see another one for the rest of my life. :-)

      And on the Cro-mo swingarm comment, there are many things than can/could be done. The list is endless.
      Unfortunately, the budget usually isn’t.

      • Miles says

        mule, what does the bike pictured weigh? Have you considered doing a tracker build on a new Street 750, and do you think it’d come out lighter (or have better performance) than a sportster based build?

        • says

          Two things that are on the agenda for this build are dyno runs and a trip to the scale. The goals were 100hp at the wheel (not the crank) and 430 lbs. The last minute change to cast wheels probably added some weight (15lbs+), but we’ll see what the scale says. The MV forks are not the lightest, but having lifted a set of stock forks, these are infinitely lighter! The build had a component list which dictated some of the weight. That said, I have another two Harleys right on the heels of this build which should be a bit lighter and they’ll both will be weighed as well. Hopefully you’ll get to see those here as well. If I had the chance to build one as light as I possibly could, several things would be different. But, usually, the customer throws a list at me and that sets the stage. Periodically I get to do whatever I want. Then I get to make decisions based on my experience of power components and lightweight-ness.

          On the new 750 Harley, I would love to build a bike using that motor. Not too stoked with the stock chassis package, but I need to see one all stripped down without all the fluff. Maybe underneath, there’s a nice roller. And it will be interesting to see if they do some motor development at the factory. Of course they COULD, but will they? So the answer is yes! I would love to cut into one.

  4. Randy says

    Mule, I think the bike is great

    I just mentioned the swingarm as it’s a common thing to do with Prostock Sportsters. I couldn’t believe the difference in weight between a CrMo unit (and extended 4″) compared to a stock unit. At the time (2005) our local racer/builder offered to do my swingarm for $500. I was tempted but that’s a slippery path paved with money.

    I seem to remember almost 10 pounds difference, That seems too much but that’s what I remember, The small tubes of the stock unit are very thick.

    • says

      On a stock Harley, weight is not even mentioned in the design dept ever. Almost no part could be made heavier! If the bike vibrates like mad, make the parts heavy enough to be vibe-proof. I agree 100% on the swingarm and in fact I’m having aluminum arms made for the Triumphs as we speak. I wanted to get aluminum arms made for the 3) HD’s I had in work, but schedule didn’t allow. Two years wasn’t enough time. :-( Stock frame is pretty heavy too, but when building a bike from the ground up, it comes with a title, everything fits, it can easily be improved/modified and lots of accesories already fit-up nicely.

  5. Giolli Joker says

    Great build!

    I guess there’s a mistake in reporting the USD forks diameter… 58mm is highly unlikely, most likely we’re talking about 48. Commercially available products are no larger than 50mm, surely there are exceptions in racing (e.g. KTM Rally racer has 52mm WP forks, unavailable commercially).

    • says

      58mm is the diameter that goes through the triple clamps. Not a mistake. When making triple clamps, this is the determining dimension.

  6. akaaccount says

    For a tiny little company that the vast majority of riders never cared about there sure are a ton of Buell engines floating around out there. Hopefully they’ll persist for a while yet.

  7. Butch Schultz says

    As the previous owner of 2 Buell Cyclones, I can say that they made pretty decent HP in stock form (84 @ the crank).
    Weighed in around 420 lbs, quelled a lot of vibration due to the way the engine was mounted to the frame, and the bare frame weighed a mere 26 lbs.
    $2500 will get you a good runner.
    Nice build, guys.

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