Oddball engines and prototypes

[WilDun]

Yes, well, that could not possibly happen because there wouldn't be a two stroke to steal in the first place and if there was, the thieving dickheads wouldn't bother stealing it anyway!

[WilDun]

Such is the state of affairs in regard to two strokes today!............. (BTW I'm away from home at the moment so, reduced to using my phone - we have just been released from house arrest!).

[husaberg]

Gordon Blair did a lot of research for Yamaha etc. and as well as his two stroke work he also did a lot of research on four stroke cylinder head design - eg the Toyota 4 valve heads (which were I believe made by Yamaha).

Dr Blair was a big fan of the two stroke and dedicated to improving the existing Schneurle system but significantly, he didn't forget the four stroke (his main bread and butter!).
(BTW he lived and worked only a few miles from where I grew up).

When I said that the Schneurle system has done its dash, I meant that, although commercially viable and reasonably successful for quite a while, the whole design needs to be replaced by something which almost eliminates a fresh, oil laden charge from coming into contact with the outgoing charge either in the cylinder or in the exhaust pipe - that really was the cause of its demise on the road going machinery.
The two main things which can save it are its power to weight ratio, a clean exhaust and the possibility of simplicity, that is the only chance it will ever have in making it back on the roads. - The opposed piston is a distinct possibility here - as for combustion chamber shape, could HCCI take care of that concern? and at the same time get rid of all our 'squish' woes (doesn't really matter about the shape anymore)?

Here I go again! Gordon Blair would turn in his grave if he heard me! - so I'll shut up and if someone steps up and proves me wrong, then, so be it!

I did a reply to you the other day but it was lost
my understanding was Yamaha designed the TOyota GT2000 head even theough they had not made a bike bigger then a 350 2 stroke
it want that well they copied it back to do the XS650 a few years later
they went on to collaborate more with Yamaha and likely still do
the lead guy on the GT2000 and XS650 was the lead on the 5 valve and deltabox.
Yamaha it turns out never had a computer so they used to use the computer the Yamaha piano/Organ section had at night.
http://www.xs650.fi/pohja_files/en/truestory.htm
https://global.yamaha-motor.com/abou...ries/0012.html
https://global.yamaha-motor.com/abou...tory/from1965/

[WilDun]

I believe that G Blair did work for Yamaha when they were producing the four valve TX 500 twin and Toyota were developing the four cylinder1600 four valve head imodels in the mid eighties - this was well after the 6 cylinder models.

[ken seeber]

A 2 stroke...….no smoke and no expansion chamber


https://www.facebook.com/StrangeDeve...7816313608614/

[WilDun]

A 2 stroke...….no smoke and no expansion chamber
https://www.facebook.com/StrangeDeve...7816313608614/

Ken,
The video doesn't tell you much of course, but I guess they are on the right track, especially if the expansion chambers are not there mixing fresh charge and exhaust gas!
So as I see it, I may have been on the right track after all!
However before jumping with joy, we haven't as yet seen the result of the tests or know if we are getting adequate power or economy for the everyday two stroke!
It'll be interesting to see what transpires (hopefully soon), because it is getting towards the last chance for the two stroke to regain it's place on the roads!

[Frits Overmars]

A 2 stroke...….no smoke and no expansion chamber
https://www.facebook.com/StrangeDeve...7816313608614/

Ken, The video doesn't tell you much of course, but I guess they are on the right track, especially if the expansion chambers are not there mixing fresh charge and exhaust gas! So as I see it, I may have been on the right track after all! However before jumping with joy, we haven't as yet seen the result of the tests or know if we are getting adequate power or economy for the everyday two stroke! It'll be interesting to see what transpires (hopefully soon), because it is getting towards the last chance for the two stroke to regain it's place on the roads!

It took some digging because the 'info' mainly consists of boasting, but I found out that they use four-stroke-like cases and crankshaft, a mechanical blower, piston-controlled exhaust and transfer ports and a rotary exhaust valve that turns the symmetrical exhaust timing into asymmetrical, giving the supercharger a chance to supercharge the cylinder. Claim for their 600 cc parallel-twin is 200 hp, which I think is feasible with asymmetrical exhaust timing and supercharging.
It reminds me of a similar project, started by my mate Roland Holzner, a couple of years ago.
Don't let the 'Turbo'-text on the engine fool you. It's a crankshaft-driven centrifugal supercharger, but as Roland said: "If it doesn't say Turbo, it won't sell".

[Grumph]

I believe that G Blair did work for Yamaha when they were producing the four valve TX 500 twin and Toyota were developing the four cylinder1600 four valve head imodels in the mid eighties - this was well after the 6 cylinder models.

I don't think he was involved in the early 4V heads - but he was certainly involved with the 5 valve ones.

He gave a talk here in ChCh for the NZ Engine Reconditioners assn - they liked to have a feature speaker for the annual conference.
He was on his way home to the UK from Japan where he'd been showing Toyota/Yamaha and Nissan current thoughts on 4v design.
I'm pretty sure that it was while he was there Yamaha decided to let the 5v engines run their time and concentrate on the next gen of 4V ones.

I got to ask one question - related to the advance curve for the 5v engines - which is just plain weird.
He confirmed it was a turbulence problem - and dropped a pretty plain hint the 5V days were numbered
Incidentally, as I've said before elsewhere, the only bike guys there were the Britten team - and me.

Frits - good to see you posting - hope all's well.
That blown engine could well be a minefield when it comes to cooling. Everything would need to be water jacketed at that power level. Blower, manifolding, driver's gonads....

[WilDun]

I don't think he was involved in the early 4V heads - but he was certainly involved with the 5 valve ones.

He gave a talk here in ChCh for the NZ Engine Reconditioners assn ..........
I'm pretty sure that it was while he was there Yamaha decided to let the 5v engines run their time and concentrate on the next gen of 4V ones.............
He confirmed it was a turbulence problem - and dropped a pretty plain hint the 5V days were numbered ..........

That blown engine could well be a minefield when it comes to cooling. Everything would need to be water jacketed at that power level. Blower, manifolding, driver's gonads....

Yeah, the 5 valve engines didn't quite get there and I guess by what you are saying, he didn't have his heart in it anymore - but, was it his invention or was he was charged with the task of trying to develop it for Yamaha? (I dunno) - certainly it agrees with Frits's 'KISS' principle!
As for the "gonads" thing - mightn't be a bad idea for some of the clowns riding around the roads - by turning them into "Eunuchs" and save the world from the proliferation of such people in society! ..... me? - I somehow escaped!

FRITS
Thanks for all the digging you have been doing - you obviously are still interested in the future of the two stroke as a viable powerplant for everyone in tomorrow's (post pandemic) world, as opposed to competition only.

As I have been saying, competition is often a spinoff from whatever we are used to driving on the roads and if the interest swings to competing with EV's (and it could if fashion dictates) then where will the two stroke with it's versatility end up ? - in the history books!
I still maintain that a "clean" two stroke has a future in the 'hybrid" scene and there could be a huge market in the underdeveloped - I mean emerging countries - (got to be PC! ) or anyone in the world looking for independent personal transport.

Your old Mate is right, the name needs to titivate the simple minds of the 'dedicated followers of fashion' (these people with their disposable income are everywhere).
The name tag is all important and keeps changing - eg our original (and correct) idea of a "moped" no longer bears any resemblance to what people are calling mopeds today! ..... so maybe we could invent a new name for the supercharger (to keep it separate from a turbocharger) ......... maybe "Grunter" - or something equally ridiculous!

[190mech]

I looked at the Strange vid,,appears to have the spark plug lead attached to the supercharger housing,and a UNI filter bobbing around on the "cylinder head"..How do we know if the electric starter isnt motoring that 'engine' over to make it appear to be running??Seems to 'run' rough also..Perhaps I'm a skeptic,but after the Ryger affair more proof will be needed!

[WilDun]

I looked at the Strange vid,,appears to have the spark plug lead attached to the supercharger housing,and a UNI filter bobbing around on the "cylinder head"..How do we know if the electric starter isnt motoring that 'engine' over to make it appear to be running??Seems to 'run' rough also..Perhaps I'm a skeptic,but after the Ryger affair more proof will be needed!

There is the old English saying, "the proof of the pudding is in the eating"!

[husaberg]

Yeah, the 5 valve engines didn't quite get there and I guess by what you are saying, he didn't have his heart in it anymore - but, was it his invention or was he was charged with the task of trying to develop it for Yamaha? (I dunno) - certainly it agrees with Frits's 'KISS' principle!
As for the "gonads" thing - mightn't be a bad idea for some of the clowns riding around the roads - by turning them into "Eunuchs" and save the world from the proliferation of such people in society! ..... me? - I somehow escaped!

https://www.kiwibiker.co.nz/forums/a...p?albumid=4977

[ceci]

A 2 stroke...….no smoke and no expansion chamber


https://www.facebook.com/StrangeDeve...7816313608614/

This video is a screenshot of the one shown on the creator page.



The other:University Of Idaho Clean Snowmobile Team's Rotary Synchronous Charge Trapping. Valve system blocks exhaust port to prevent fresh intake charge from going into exhaust.

[lohring]

Someone needs to explain to me why these complex new designs are better than the simple, tuned pipe, crankcase scavenged engines. Are they more powerful, easier to maintain, less expensive, or lighter weight? They may be more compact and have a better power band, but I can't think of any compelling reason to chose this new design or any others for small engines.

Lohring Miller

[WilDun]

Someone needs to explain to me why these complex new designs are better than the simple, tuned pipe, crankcase scavenged engines. Are they more powerful, easier to maintain, less expensive, or lighter weight? They may be more compact and have a better power band, but I can't think of any compelling reason to chose this new design or any others for small engines.

Lohring Miller

Lohring,
I agree that the two stroke with it's (inherent) simplicity and great power/weight ratio is being undermined by the need to add on all sorts of attachments in order to make it perform properly all over the rev range (this being very necessary on road machines), the tuned pipe has it's (often huge) advantage in the BHP department but only in within a certain rev band - all the other addons/accessories are there to make up for it's downsides on the roads where the full rev range is important - so we still haven't got any simple answer to making the two stroke useful for commuting or cruising on highways! - but the bloody oily smoky exhaust which has more or less sunk it as far as using it for something other than 'sport' or garden tools etc. is still with us - that alone could cause its demise!

That's my take anyway - we are proposing all these 'new' ideas only because it gives us pleasure to keep trying something new - as you say, no compelling reason!
Then, (to put the boot in), it appears that governments are looking at banning all combustion engines eventually, possibly by as early as 2030!
I'll probably be gone by then - (think I was doomed to live only in the internal combustion era !). - look at the pollution coming out of that thing! - and to think that I lived through that! ......... but, it was a “fun ride” while it lasted!