Thanks for your kind remarks Scottie. This bike garners a lot of interest now, however when I bought it in 1978 it was just an old machine that not many were interested in. I'd like to claim prescient insight but it was just luck. Brian, sorry if we have hi-jacked your thread, you know, boys and toys. As to engine oil, I think it is difficult to buy bad oil now days, so what ever brand you like in a multi-weight should work fine. You have the poorly designed "scissor type" clutch (as do I). At best, this clutch slips until it warms up. I installed the heaviest clutch springs that will fit and used progressively lighter weight oils and found ATF in the chaincase to be the best to alleviate slippage, but it never goes away completely. As far as history of these bikes, I think Rotors response is as accurate as you will find. ERC, beautiful bike. It appears that you have an original Volkes(sp) air cleaner, I have never actually seen one, difficult find. My machine badly needs tires, they should be here this week. I will whine here about my skinned knuckles (w/pics) when the deed is done. This is an actual ad I cut off the bottom of an old MC magazine. At least we know Matchless was selling these in 1961.