They were designed, priced and made to last to the end of the warranty of the bike which in the 60's was six months, they are made of mazak which is a zinc based pot metal which is unbelieveable soft, the mk2's are made of aluminium.I've had bikes with 40 year old concentric carbs that run just fine.
how many years is "quickly" ?
I need 34mm carbs and the mk1's stop at 32mm , the options are jap carbs or the later brit ones , being a brit bike i would like to keep it all british.I've seen MKII's with flogged out slides too, I don't think the issue was Zinc or pot metal V's Aluminium, making the slide out of the same material as the body was where the wear came from, hence guys making brass/chrome slides
I've had good luck with both types, MKII's are cleaner (no tickler) and have a better choke setup, but they are big and don't look as cool
Just my opinion
Sounds good, It would be cool to keep it all Brit. Smooth bores start at 34mm might be worth the extra cash ?.I need 34mm carbs and the mk1's stop at 32mm , the options are jap carbs or the later brit ones , being a brit bike i would like to keep it all british.