Beast and the carb

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Andy E
Member
Posts: 32
Joined: Wed Aug 10, 2016 4:26 pm
Location: Wiltshire, UK

Re: Beast and the carb

Post by Andy E »

After a top end rebuild of my 1956 16ms (Long ago converted to 500cc) it was a pig to start, and if it did start, it would often stop after a couple of seconds. I conducted all of the usual checks and tests of carburation and ignition timing, including having the magneto off again to be checked. All checked out ok.

Then the penny dropped. My bike is fitted with an N1-4 magneto as opposed to the SR1 that would have been fitted when new. I had been setting the spark plug gap to the setting for the SR1 as shown in the manual for 1956 models (0.020" to 0.022"). I reset the gap to the spec shown for the earlier models fitted with the N1-4 magneto (0.015" - 0.018") and now it invariably starts first kick whether the engine is hot or cold. Just a thought!
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