Yes please, do start a thread. I don't know that it matters, but right here in the Lounge would work, or the Garage is appropriate as well going by the description in the index.
Speaking for myself, I'd love to see the entire project.
Posilutely!!!! This is a terrific piece of engineering - very impressive. Can’t wait to hear it run!!
I also really liked that Quadrent build - imagine if the Brits had evolved their traditional twins in the late 1960s (as they certainly should have) and used the key technologies to actually build something like that for production. If they could have contained costs and made it reliable and leak-free, they could have given the Z1 and big CBs some real competition. Ahh well.
Further to the two stroke story: in a recent classic bike magazine, there was a fascinating article about a guy who builds multi-cylinder ring-dings out of Kawasaki triple engine components. If I recall, he has done several 4s, and 5s and even a six and (I think) a seven cylinder bike. I can’t remember if the article said much about the ignition systems or sealing arrangements, but the bikes looked to be well sorted out with nice exhaust systems etc. and were said to be rideable (albeit with rather limited ground clearance for cornering).
When I was a boy, I worked in a MC shop around the time I got into bikes and one of the older guys had an Ariel Square Four (1950s era British touring bike - 1000 cc air-cooled vertical four cylinder engine with two crankshafts geared together - sort of like a Suzuki RG500 racer). The big Ariel ran and rode extremely nicely and I was very taken with it. You still see them at vintage MC rallies and they have a dedicated following. Terry Wolfe in London ON (the same chap RobinC is working with on his ‘78e rebuild) works on Ariel engines.
I’m sure Fred could also tell us a lot more about the Ariel than I can.
Speaking generally, a four-stroke is somewhat easier to deal with than a two-stroke because the crankcase sealing issues aren’t as critical. Rear cylinder cooling in a square engine format could be an issue if you tuned it for too much power, but with liquid cooling, it could be licked and even the air-cooled Ariel seemed to work fine. The Ariel used pushrods and had (I think) only one camshaft running in the block just above the crankshaft synchronizing gears. For induction, it had one fairly big carb behind the cylinder block that fed all four cylinders through a cast-in manifold and it even had the cutest little distributor with four plug wires coming off the top (you see it in the diagram above).
The owner I worked with could actually push down on the kick starter with one hand and easily start the bike from cold. It was the smoothest and quietest running motorcycle engine I’ve ever seen, except perhaps for a Gold Wing.
Later I actually drew-up a set of drawings for an “XS1300” version of the Ariel using two 650 engines in a new crankcase. I suspect it could have been made to work pretty well, if I’d had the money to build it.
At the time I did those drawings I was working in the West African oil patch for Schlumberger Int’l (a French oilfield services company) but when I was leaving on days-off, the drawings were stolen by a Nigerian border official who told me that they were “industrial secrets” and thus, not permitted to leave the country. @sshole. I was too tired and sick from malaria to argue with him and I didn’t have enough cash on me to bribe him...sad.
The beauty of these “square” engines is that they are very compact and have excellent reciprocating balance characteritistics - if you do the math, they run very smoothly with no extra balance shafts. The problems are complexity and cost and simply fitting everything in economicallly.
In any event, they do work. but proved to be just another technological dead end.
Pete