February 15, 201016 yr To help with a machine eligiblity issue can anyone state, with confidence, when the Amal Concentric MK1 and MK2 carburettors were first introduced.
February 15, 201016 yr Hi Clive, your question is a bit open as eligibility regarding these carbs differs for Pre65 / twinshock and region to region. Can't give you an exact date of introduction for the MK1 Concentric but it was late 60s, definitely not before 1965. However, it is ok for Pre65 events even though original fitment for pre65 bikes would have been the monobloc. I don't know of anywhere that won't allow it. I don't think the MK1 1/2 is eligible in any of the main Pre65 events. The MK2 was mid to late 70s introduction and definitely not Pre65 eligible. There are no rules on twinshock carbs so a MK2 could be fitted to any twinshock. Hope this helps although you could probably find definitive dates from the Amal website.
February 22, 201016 yr 1968 was the first year that Amal Concentrics were fitted to British road bikes. Triumphs, BSAs and Nortons all had Monoblocs in 1967.
February 22, 201016 yr 1968 was the first year that Amal Concentrics were fitted to British road bikes. Triumphs, BSAs and Nortons all had Monoblocs in 1967. I have an Amal brochure for the 600 and 900 series Concentric carburettors dated March 1967. The Settings list shows concentrics being fitted to BSA MK3 Spitfire in 1967
February 23, 201016 yr I bought a new BSA in '67 with monoblocs and another in '68 that had concentrics. Both were Canadian models. I own a '67 Triumph Bonneville now that originally had monoblocs. Again, Canadian market. UK models may have been different but I rather doubt it, I was buying Brit mags regularly at that time and I think I would have noticed. Amal may have had brochures out earlier but I don't think concentrics made it onto production bikes until '68.
February 23, 201016 yr Trickymicky is correct! I've just been going through my old mags and Motorcycle Mechanics tested a new BSA Sports Bantam in April 1967 which sported the "new" 626 Amal Concentric! I stand corrected!
February 23, 201016 yr The Amal website link is useful, the new adjustable float is long overdue! I thought the float level on the mark 2 on my Montesa was way off and I wasted a lot of time adjusting it by moving the seat and it turned out to be the enricher plunger that was leaking, making it run rich! I poked the seal out of the end and re-installed it upside down and now it's fine!
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