ffkiwi

I regard the Irvine carb and tank assembly as the best of the lot-the tank suimply unscrews for cleaning, degunging, or changing the fuel tube. A pity Irvine spares were so expensive when the engines were around. The Doonside is a pain because you have to chase the circlip out of its groove and prise it up and out to remove the tank-very positive retention-but hard to remove for cleaning, whereas the Indians and originals just retain the tank with the two bent tabs-eventually these break off-and your tank won't stay put. Here's a few more pics adding to the info pool-the first is the underside of the Russian Mills showing the serial location (the Russian Elfin replicas are marked similarly in the same location) -note that while the prop driver appears to have a centre spigot, this isn't actually the case the case-what appears to be an integral spigot is a separate bush for centre-ing the prop-necessary because of the small diameter of the 3mm stud. Worth it-you'll never break a shaft on one of these! Next a view of the Boddo series 1 carb and tank-which like the Irvine, screws in. [I've called it a series 1, to avoid calling it a Mk1-which might cause confusion. There WAS a Mk1 Mills 75 made in 1949-it looked very similar to the 1.3 in appearance, with a machined, not cast crankcase. The giveway was the acorn shaped tank. Expensive to manufacture it was quickly replaced-in 1950-by the classic Mills 75, which technically is the Mk2!) Note the solid metal tube fuel line-a nice touch. Finally a closeup of the Mk2 Doonside showing the serial # location on the lower right front of the crankcase-I assume the Mk1 Doonsides would have been similarly marked. This shot also shows a nice view of the prop driver properly seated on the crankshaft flats. For the record, only 1000 Doonsides were produced (give or take a few assembled later from remaining stocks of component by Ivor F.)-there were 250 Mk1's-which were exact copies of the original english one-black crankcases, plain silver head, sharp corners on the mounting lugs and no webs on the main bearing. These were available only to the original 250 subscribers who put up the money to fund the project (ca 1973)-which was initiated by Ivor F-who assembled tested and sold the engines. The actual components were manufactured by Gordon Burford, of Taipan engine fame-which accounts for the stamped backplate-see final pic. The wording reads 'TAIPAN.AUST.'After 250 had been produced the crankcase die was modified to produce the Mk2 crankcase-complete with bearing webs, and bevelled corners on the lugs. You could have your choice of plain, gold, red, green. blue or black cylinder head fins.
Finally (and someone is bound to ask eventually)-why 'Doonside' Mills? Well Doonside is a suburb of NW Sydney, Australia, close to Blacktown, and Doonside is where Ivor F lives.

ChrisM
'ffkiwi'