Jack Emmott

Marty · Post by **Marty** » Mon Jul 02, 2012 1:16 pm

I have heard of a Emmott speedway engine here in NZ. It was based on a short stroke motor but had the magneto mounting either welded onto or cast into the crankcase. I know the man who bought it and raced it around '65 or '66 after he had blown up his Jawa and couldn't get a replacement in time to defend his NZ title. His words on its performance were less than complimentary
Marty

ianselva · Post by **ianselva** » Mon Jul 02, 2012 5:22 pm

Anyone wishing to start his or her career in the 500 class however was faced with the prospect of purchasing and maintaining a much more expensive Manx Norton or Matchless G50. It was precisely this state of affairs that prompted two brothers from South Norwood, London - Peter and Philip Green - to manufacture an inexpensive, over-the-counter, clubman's racer. Ex-S E Centre grasstrack racers and proprietors of the engineering firm W A Green & Sons, the duo formed a subsidiary company - Dynamic Balancing Engineers Ltd - to manufacture the 'GB500'.
The GB500 used an overhead-valve Matchless G85CS moto-cross unit tuned by ex-AMC race mechanic Jack Emmott, whose main activity was the building of G85-based engines for speedway and grasstrack. Indeed, the Emmott-tuned Matchless speedway engine was a catalogued item: "Ample spares available at competitive prices," stated AMC's advertising. The Emmott-tuned motor incorporated a forged 9.5:1 piston while retaining the standard 7R-type crankpin, con-rod and flywheels. The magneto was bolted directly to the back of the timing chest, simplifying engine removal, and using an Amal Concentric carburettor and high-level megaphone exhaust system the motor produced a (claimed) 49bhp at 7,000rpm.
Bolted into Dural engine plates, the Matchless G85CS/BSA RRT2 engine/gearbox unit formed a structural member of the frame, which was constructed from aircraft-quality T45 tubing and weighed just 11lbs

Ian

242017 · Post by **242017** » Mon Jul 02, 2012 9:41 pm

Any idea how many Grasstrack bikes or speedway engines that were sold or used?

Marty · Post by **Marty** » Wed Jul 04, 2012 1:00 am

http://www.newcastlespeedwayhistory.co. ... ge%205.htm
Another interesting site with a pic of the Matchmaker speedway bike and information on Jack Emmott. It is almost at the bottom of the page
Marty