Well ... I have to admit it's not directly a Speedway or Dirttrack bike, but that Jawa engine most certainly is - or at least was!!.
John Blackburn came across this following article that he thought might be of interest, and I for one certainly thought it worth an airing here in the "Workshop" Pages.
Big single fan David Witt made such a good job of his BSA-Jawa that it looks like a factory built bike. David used parts around him to
build up his project which spanned over a couple of years.
The Jawa engine was bought in 1968 by his former speedway racing brother, Alan. The BSA A7SS frame and cycle parts are from a 1961 model.
Engine compression was reduced from 14 to 9:1, and the speedo showed that around 75mph was about top whack. The forks were somewhat less than ideal, but the note from the matt black Goldie silencer seemed to more than make up for it.
Indeed, Dave was the first to admit the bike was far from perfect. He built it as a Budget special for less than £500, but at the time of writing, David planned to make further improvements now that the basic work had been completed.
Aligning the chain proved to be one of the biggest headaches. He used an A10 rear wheel, Honda 250 sprocket, 650 pre-unit Triumph clutch with single row chain primary drive, and a BSA four speed gearbox.
The motor is fired by a BTH competition magnets with no advance or retard and fed by a 40mm Amal Concentric. Lights are powered by a dynamo driven by a sprocket off the back of the clutch drum.
Speedway fans will know that the all alloy pushrod Jawa engines are run on a total loss oil system. David has beaten this problem for road use by mounting an A10 oil pump on the outside of a locally made timing cover.
Certainly a most intriguing story ... which leaves me to wonder if the machine
still exists and if anyone knows of its whereabouts today .....
willowfieldcaravan at gmail.com
David Witt Jawa
Hi the Jawa BSA is still owned by me ! it laid in my workshop being robbed for other projects. The bike has now been rebuilt with a lot of different parts and can be found on Youtube under the heading Jawa speedway engine in a road bike with my name David Witt, ok. Have a look ?