Max Alth, and Oil-Injected Motorcycles

All of the flaming crap being thrown around reminds me of a section in Max Alth's book _All About Motorcycles_ on two-stroke engines.

In the section where Alth discusses two-strokes (he mentions split-single engines! Hooray for twingles!), he says that two-strokes are both more polluting and more efficient, but that steps are being taken (in 1981, or whenever this was being written) to develop oil-injection systems that squirt oil _directly onto the sides of a moving two-stroke piston_

What happened to that? Alth seems to have believed that this would have made a two-stroke less polluting, but the only oil injection systems I have heard of are like the one on my Express, or the ones on Tomoses that are supposed to vary the amount of oil based on engine rotation speed.

Why no systems that inject oil only into areas with moving parts? It would require that engines be designed for it, but could be worth it for at least those racing engines that need to be light and powerful.

Also, has anyone else read Max Alth? I have _All About Mopeds_ too, and it's so corny I could cry.

Re: Max Alth, and Oil-Injected Motorcycles

way way back in the 80's Saab was still playing with the ideas and had fantasy's about using compressed air to blow the oil in a fine mist right where it belongs.

I think the main reason that any of this research and othes into improving 2 stroke desighn is the overwealming legislation implending regarding the making of new ones and it not being practical.

Re: Max Alth, and Oil-Injected Motorcycles

You can at this very moment buy two-strokes which have sealed crankcases, and which inject air-fuel mixture into the cylinder. Mercury Outboards is one. This could be improved on by by injecting air into the cylinder as the piston recedes from detonation, this would push the exhuast gasses out, and then on the piston's up stroke fuel could be injected, the air already in the cylinder mixing with the fuel, and detonating every stroke.

Re: Max Alth, and Oil-Injected Motorcycles

I just purchased the vintage "All About Moped" book by Alth on Amazon. Also bought 6 other 1970s era moped books that I'll post reviews of eventually.

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Re: Max Alth, and Oil-Injected Motorcycles

Cool - see, now answers to these types of questions all seem to come from non-motorbike sources - it's always an outboard or a marine diesel or a snowmobile that uses avant-garde two-stroke tech.

Zizz, where does the oil come in to the Mercury outboard though?

Also, if you push air into the cylinder to clear out the exhaust gasses (say, in advance of a squirt of fuel/air mixture) wouldn't you need an exhaust pipe that is just a straight draw? Or, does the squirt of air you're thinking about somehow counter any backpressure from the exhaust?

Even the perfectly straight, baffled exhausts on my '66 Puch (two of them - hooray for twingles again!) do create some backpressure, though I don't think it's really by design.

I think that the air squirt (which would only work with fuel injection, like you mentioned) might benefit cleanliness at the cost of efficiency, and I still wonder about a better way to oil these engines.

Re: Max Alth, and Oil-Injected Motorcycles

Twingle's Response /

Twngle .. 'someone' deleted my post I have no idea why but I'm disguising my response so it might get left on. The oil in the Merc is in the sealed crankcase. I'm not an engineer so I don't know about the exhaust. My son in law is a marine mechanic and he told me about the Merc after he went to a winter workshop. I sent my idea for air injection to Bombardier in Austria, Bombardier makes Puch.

Re: Max Alth, and Oil-Injected Motorcycles

air would be a pain to shoot out of an injector that also did oil but doable

Re: Max Alth, and Oil-Injected Motorcycles

Twingle's Response /

The oil is sealed in the crankcase like a four stroke .. the air and/or air-fuel is injected like diesel fuel.

Re: Max Alth, and Oil-Injected Motorcycles

but to vary witch one was shooting u would have to have switches and valves set up to an air injector and oil injector that came out of the same nozel and the oil probably isn't light enuf to make a mist its to dense

Re: Max Alth, and Oil-Injected Motorcycles

and it would make it crazy lean which = seize city

Re: Max Alth, and Oil-Injected Motorcycles

Zeke's response /

Zeke - there is no need to inject oil .. the oil is sealed in the crankcase as with a four stroke .. there is no need for valves as the engine would work much like a conventional two stroke instead of the upstroke sucking gas, air, oil in the injector would shoot the gas and air in .. that's how diesel fuel injectors work .. they shoot it in. But diesel is four stroke .. this is two stroke .. but it could be made to one stroke .. a detonation at the peak of every upstroke.

Re: Max Alth, and Oil-Injected Motorcycles

Zeke's response /

WHy lean? The injectors would shoot in the precise amounts of air and gas. No problem. Think fuel injection in modern four stroke car engines .. but inject the air also.

Re: Max Alth, and Oil-Injected Motorcycles

How did we go off topic in a sort of off topic post?

The air-injector idea would probably necessitate just that - an air injector. That's possible, as is an oil injector, as is fuel-injection. It seems that what we have concluded is that the suitably-minded engineer can choose to build an anything-injector, and then use the various devices to time every aspect of engine performance. Well... that's kind of a cool idea too.

My favorite line in this topic so far is what I believe is a mis-type: "...but it could be made to one stroke..."

I think that only firearms are "one-stroke."

A detonation at the peak of every "upstroke" is a "two-stroke" engine (there's an upstroke and a downstroke).

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