I've been doing a bit of research on finding the original spark plug Rotomo's were released with and found some info some of you may find interesting. A copy of VICTA CUTTINGS for March of '57, includes this:
For some time now we have been talking about the exhaustive tests that our Research Department has been conducting on spark plugs.
We are now pleased to advise that as of this date all future Victa mowers will be fitted with the world famous Bosche plug (No. 175/T2).
Highly regarded by the automotive industry for over 50 years and used as standard equipment in Mercedes Benz and Holden cars, we feel sure that the Bosch plug is an improvement that all agents will welcome.
Attention is drawn to the fact that the gap for the Bosche plug is .025" NOT .035" as for the previous Pyrox plug. The retail price remains unaltered at 8/3d. and the discount is the same also.
So I'd always used the Champion N21, but according to this the Bosch 175/T2 was used before the Champion. Reading back, it looks like any plastic wheeled Rotomos (75,000 onwards) should have the Bosch. Any before 75,000 should have the Pyrox plug, no idea which number though if anyone wants to chime in!
I'd never heard Pyrox before, so did a little reading, and it turns out that they were an Australian company based in Melbourne. In 1955 Pyrox and Bosch formed a joint venture manufacturing plugs at a factory in Clayton. In 1958, Bosch took over Pyrox completely.
I'm now on the hunt for the correct Pyrox plug number for the 125cc. Anyone?
