Circa 1934 Harley-Davidson Koslow

Thought you might be interested to know about this HD Koslow, an obscure and very rare OHV conversion of a Harley Flathead. Koslow? Owner Barry Brown gave me the 411 on his bike. When in 1931 Ignaz Schwinn, the owner of Excelsior/Henderson Motorcycle Company in Chicago, decided to shut down the business, one of his engineers named Andrew Koslow, an active hill climber and owner of the closest franchise to the actual factory, had a plan. At the time OHV Excelsior big Bertha hill climbers Gene Rhyne  (Crocker future engineer) and the legendary Joe Petrali utilized a twin port hemi head configuration. So, Andrew Koslow  made up a new set of castings using the Excelsior top end as inspiration,  and converted  the big Flathead VL’s to use in the then popular midget car racing. Andrew Koslow ran his motorcycle shop through the 1930’s up until the early 1950’s but never built a complete bike!

Barry Brown’s HD Koslow was built 10 years ago as a 50’s style Bobber around one of these conversions using all period pieces. He started out with a Koslow OHV conversion of a Flathead squeezed into a VL frame. The engine heads and cylinders were unique, cast by Modern Casting, (same outfit HD used) but used knucklehead rocker arms. Maybe more than what you want to know, follows the list of parts and modifications making this machine so unique (only 3 conversions are known to exist).

The Koslow has an heavily beefed up left side drive case and unlike the 2 other Koslows is running twin carburetors (twin Linkerts on individual manifolds). Stainless push rod covers and oil lines. Twin port exhausts (4 pipes, with the 2 left styled after the Harley 45 European road racer pictured in Wright and Hatfield. Engine displaces 84″ engine and runs a UL full flow oil setup.

Oil tank is an air dryer from a Mack truck! Cast alloy gas tank is heavily modified with period in-dash tachometer. Hand made stainless steel battery box and primary with 2 row chain and tensioner. John Cameron inspired Ford hub cap stainless vented derby. 1936 and up style 4 speed transmission. Modified forward frame mount cop shifter. Flanders bars and risers. Strutted VL forks with double Brough Superior style dampers. Twin front brakes activated by Vincent type balance beam. Star hubs laced to 19″ VL rims. Headlight is a spun brass spot taken off the roof of Barry’s 1936 Ford fire emergency rat rod. Crocker “limp dick” taillight”. Crocker magnesium tool box with custom made tribute plaque to Harry Buck who traded him the Koslow engine for a Militaire one!. Barry did cast the bronze floorboard with the Koslow logo in them. Dan Pugens WR pillion (a work of art made with old HD saddle bag leather)

Recently, Barry Brown went to Chicago to show and start the bike for the Andrew Koslow’s grandchildren who still run a shop, but not about motorcycles, now just Chinese made Schwinn bicycles! The HD Koslow bike deserves a better video than the one below…

8 Responses to “Circa 1934 Harley-Davidson Koslow”

  1. 1 Larry R Dec 17th, 2010 at 11:06 am

    Really great machine and definately before it’s time.

  2. 2 Barry Brown Dec 17th, 2010 at 11:14 am

    Thanks for the comment. It is actually more correctly dated as circa 1934 not 1913!

  3. 3 CHOPMONSTER 66 Dec 17th, 2010 at 12:03 pm

    sweet ride , love to see old machines still in action . have a 48 flatty and 47 my collection and love to ride them the most . …

  4. 4 Seymour Dec 17th, 2010 at 12:34 pm

    Sounds like it looks and looks sharp with the Crocker taillight.

  5. 5 nicker Dec 17th, 2010 at 11:05 pm


    Thanks, what a great bit of scooter history.
    Most of those midget motors were probably recycled by the war effort.

    “…Maybe more than what you want to know…”

    No, not enough.
    In a few more years this stuff will disappear and all that will remain of MC history will be aging post-boomers reminiscing of poker runs and fat-tired production “customs.”

    Not much of a interesting legacy there…… 🙁


  6. 6 martin Twofeather Dec 18th, 2010 at 9:17 am

    Excellent Cryil,great job..

  7. 7 Spot's Cycle Dec 20th, 2010 at 9:09 am

    I think in 1936 H-D made a 96c.i. “WATERCOOLED” Knucklehead for the Midget cars, it was able to compete in the race cars but all V-twin type powerplants lost out to the higher reving, more dependable Offenhiemmer inline 4-cyl race engine.

  8. 8 Pete Apr 7th, 2011 at 7:05 pm

    Yes, it deserves a better video. but it is so interesting as an engineering project. I like it. ! had a H-D 74, vintage 1934, when I was in college in the ’50’s. Ratty though it was, it was my introduction to motorcycling. My student-partners in that venture called it “The Suicycle”. .
    It was pretty much stock but a bit of a rodent. Playing with the spark advancer on a quiet evening got a lot of attention – Blammo!

Comments are currently closed.
Cyril Huze