the clean two-stroke thread

**Norman** · 27th July 2020, 19:58

Originally Posted by Pursang

Well, Ken has already demonstrated a Reverse Uni-flow 2 Stroke running without an external pump.

So, at this point a supercharger is just additional 'complication'. Boost would raise the HP potential, but also increase the likelihood of fresh charge escaping via the exhaust.

Plenty of development opportunity to create a 'clean' burning case transfer RU engine by optimisation of bore/stroke, transfer port area, reed orientation and flex rate, exhaust configuration & duration, etc, etc. (Plenty of scope for TPI too!)

Of course, not all solutions are Mechanical!
If someone develops a smokeless 2 stroke Oil, that smells like fresh cooked donuts And extracts CO2 from the atmosphere we could all be riding Kwaka H1 Mach L's.

Cheers, Daryl.

Triboron two stroke "oil" concentrate/oil injection. Might be an option? I still find that there are more independent test needed. Looking into for example on how it affects engine parts in the long run. But, find it interesting as much of the oil is taken out from the lubrication fluid. It is still too expensive but if used more widespread price should drop. This article gives an introduction by someone else than the company: https://www.zundappveteranenclub.nl/triboron/. However it does not smell fresh donuts

**ken seeber** · 27th July 2020, 20:49

Another top down approach, on the Fazebook "2 stroke R & D thread"

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**Flettner** · 27th July 2020, 20:53

Originally Posted by ken seeber

Another top down approach, on the Fazebook "2 stroke R & D thread"

Interesting concept, mmm, fresh doughnuts.

**Frits Overmars** · 27th July 2020, 23:16

Originally Posted by Pursang

Hi Frits, thanks for your input in this less Racey section. For regular transfer ports, for sure! But, Under Head or Squish Reed transfers are limited to the Squish area. Halving the bore reduces the available area by factor of 4. So, 4 times Stroke for same cc = 4 times transfer velocity. Is this a Good or Bad thing? I don't know, testing required.

You're right about that Daryl, my mind got stuck at 'regular' piston-controlled transfer ports. For Ken's head-mounted transfer flippers, doubling the bore means quadrupling their cross-flow area, same as with the valves in the previous pre-turbo Formula 1 engines, which led to a bore of 98 mm, a stroke of 39,75 mm and a pancake-shaped combustion chamber that required over 50° ignition advance - not the best way to promote thermal efficiency...

Originally Posted by Pursang

If someone develops a smokeless 2 stroke Oil, that smells like fresh cooked donuts And extracts CO2 from the atmosphere we could all be riding Kwaka H1 Mach I's.

Some time ago, when I was 15 years old, I greased my moped petrol with salad oil (freely obtainable when mum wasn't looking) for that lovely racy smell. Since then, smart entrepreneurs marketed two-stroke oil smelling of strawberries, so your donut smell shouldn't be a problem either. But why should it need to extract CO2 from the atmosphere. That's a job for trees, isn't it?

Originally Posted by ken seeber

Another top down approach, on the Fazebook "2 stroke R & D thread"

I haven't visited Fakebook yet today. As always, that will have to wait until I've studied all there is to study on Kiwibiker. But maybe you already took a peek here:
https://www.kiwibiker.co.nz/forums/s...post1131167093
https://www.kiwibiker.co.nz/forums/s...post1131167176

**Pursang** · 28th July 2020, 00:46

Originally Posted by Norman

Triboron two stroke "oil" concentrate/oil injection. Might be an option? I still find that there are more independent test needed. Looking into for example on how it affects engine parts in the long run. But, find it interesting as much of the oil is taken out from the lubrication fluid. It is still too expensive but if used more widespread price should drop. This article gives an introduction by someone else than the company: https://www.zundappveteranenclub.nl/triboron/. However it does not smell fresh donuts

No smell at All! Sounds like a good idea. Has anybody out there had any practical experience with this or other non-oil alternatives?
50 euro/litre seem a bit expensive, but at 100:1 the Premium Petrol is still the major cost.
(Or compare with say, Castrol TTS at half the price, but double+ the mix)
Need a couple of manufacturers, in competition, to get the price down. Perhaps a patent or licensing agreement needs to lapse first!

Originally Posted by Frits Overmars

Some time ago, when I was 15 years old, I greased my moped petrol with salad oil (freely obtainable when mum wasn't looking) for that lovely racy smell. Since then, smart entrepreneurs marketed two-stroke oil smelling of strawberries, so your donut smell shouldn't be a problem either. But why should it need to extract CO2 from the atmosphere. That's a job for trees, isn't it?

Yes Frits, CO2 consumption is a job for trees. If only we would let them grow faster than we cut & bulldoze them down.

I just like the idea of getting a 'green grant' and being subsidised to save the world by riding big, old, 2 stokers about! Win Win

Cheers, Daryl.

**Niels Abildgaard** · 28th July 2020, 04:10

Originally Posted by ken seeber

Another top down approach, on the Fazebook "2 stroke R & D thread"

It is a Schliha scavenge system used in motorbikes 1929 and an aircraft 1935 (Erla6)
It had the eternal two stroke problem of using piston for controling exhaust,but in this case it is at least symmetrical around cylinder.
The only two-strokes still being best for job today has one exhaust valve per cylinder.

**WilDun** · 28th July 2020, 09:07

I'm told that the Chainsaw wielding lumberjacks in Oregon, Canada etc. actually use cooking oil exclusively in their chainsaws - can't remember for sure what kind (might've been Canola) - someone here will know! (possibly only for chainbar lubrication though!).

Update:- Ok. have a look here anyway, this guy seems sensible - Scroll forward to 25 or so and get to the Canola (Rapeseed oil) part.
https://www.youtube.com/watch?v=UqbjQ2DOlIo

But ..... burnt oil, (vegetable or whatever!), is pollution!

**Norman** · 28th July 2020, 10:00

Nice new retro street legal two stroke bike on the market. EURO 4 emission approval..just in time.!?
The injectors are positioned right in the center of the reed valves. The 250cc Vins engine.

https://langenmotorcycles.co.uk/the2stroke/

**WilDun** · 28th July 2020, 10:51

Originally Posted by Norman

Nice new retro street legal two stroke bike on the market. EURO 4 emission approval..just in time.!?
The injectors are positioned right in the center of the reed valves. The 250cc Vins engine.

https://langenmotorcycles.co.uk/the2stroke/

Looks good! - and it is a two stroke!! - seems like one step in the right direction.
If it's as good as the website, it is good! - and now, how good is the price?
Should be cheaper than a four stroke, shouldn't it?? - (much more simple and cheaper to make ??)..... well, no maybe not ..... "cool" ...."sports".

How about a nice little commuter version based on that and sell them (X 10)? and re-establish the two stroke on the roads! (all in the interest of keeping 2T bucket racing on the track and consequently ESE thread of course)!!!

**Pursang** · 28th July 2020, 11:05

Nice Spec, I would ride that......Except I'm obviously Way Not Cool enough!

I just cant possibly bring myself to ride without my helmet fastened.

Cheers Daryl.

**Pursang** · 28th July 2020, 11:57

Originally Posted by WilDun

Update:- Ok. have a look here anyway, this guy seems sensible - Scroll forward to 25 or so and get to the Canola (Rapeseed oil) part.
https://www.youtube.com/watch?v=UqbjQ2DOlIo

But ..... burnt oil, (vegetable or whatever!), is pollution!

That saw was certainly working hard. It would be interesting to see some long term testing of 2 strokes on Canola.
Of course, at Au$2.40/L ( that's like 2c US or EU 0 ), there is no money in it for any real business to bother with.

Burnt oil is pollution, but you get lots of 'Green Points' for burning renewables and not dinosaurs. Bio Diesel, Biogas, Bio 2-stroke!

Cheers, Daryl.

**Flettner** · 28th July 2020, 12:00

Cylinder bolted up to the old set of cases.
Yes it going to be a tall engine alright, but it will fit in the YZF 250 frame. Good enough to be a technology demonstrator. Next one will lay much flatter with the gearbox and clutch wrapped around the cylinder.