Stock TRX850 head data *caution LOTS of pics*

[Quan-Time]

"Rotary" valves have been around almost as long as the 2 stroke engine. They can be geared to work as 2 or 4 stroke engines, which is awesome.. gear it one way, its 2 stroke, gear it another way, its now 4 stroke. I believe someone did attempt to make a "variable" setup at one stage, not sure how that worked out tho. Must look into it. Could be an interesting exercise to try and re-produce.

One of the earliest examples of rotary valves i know of is the ""Aspin" rotary valve. There may be earlier ones, cant remember on hand. Heres a pic, and a link..

For a really interesting read, check out http://www.isdm.co.uk/aspin/AspinEssay/essay.htm

I saw someone who built a V-twin motorbike with horizontal rotary valve setups.. It was as big the freakin cylinder.. provided HUGE torque.. didnt idle well, but at full noise it was incredible.
I see dandywarhol linked that PDF, i read that quite a while ago. Ive still got it here on my desktop !.

For my money, the best "currently in mass market" valve setup is the desmo. And ducati are VIOLENTLY opposed to letting anyone license it. Many have tried. Saying that, Ferarri did use it at one stage in some special engine, but id have to double check that. Its just such a graceful setup. You can turn the cam around by hand quite easily, where as valve springs provide quite a hefty lot of resistance.


Another interesting setup is the "radial" setup of MV Agusta. Instead of the valves being aligned with the cam, they are placed of optimum air flow, and as you can see, the stems are NOT parallel to each other, so a tiny cam follower / rocker is used to actuate the valve. Extra mechanical load / weight, BUT the theory is much more sound.


I could talk about this stuff all day.. I love it

[HansJ]

...
Another interesting setup is the "radial" setup of MV Agusta. Instead of the valves being aligned with the cam, they are placed of optimum air flow, and as you can see, the stems are NOT parallel to each other, so a tiny cam follower / rocker is used to actuate the valve. Extra mechanical load / weight, BUT the theory is much more sound.
...

ehrmmm, how was it with the Hemi engines? And I believe even our little precious has offset intake valve stems? Ahh, that's why you consider it sound !

I love this as as well. It's astonishing that we still basically use the same engine that Herr Otto designed long ago. It's all just refinements, but the same theory.

Saw a program about the Sterling engine this week. Apparently it's booming (again ), because it is being used in combination with solar energy, getting the heat need from the sun.

Maybe we should create a new thread, this is going way OT...

[arrivisto]

"Rotary" valves have been around almost as long as the 2 stroke engine.

True; but the great thing about the Bishop rotary valve is that is has had a lot of recent research, it's very suitable for bikes, and it's pretty well available now.

...For my money, the best "currently in mass market" valve setup is the desmo.

Not so sure! OK, desmo is perhaps the optimal mechanical poppet-valve system for safe high revs, but it is still complex and involves additional reciprocating parts.

Bikes can get away with an engine that vibrates (no cars or aircraft would ever use a single-cylinder engine); but if you could have a bike engine that is smooth and compact, then why not? BMW have recently developed a DOHC version of its boxer engine. Imagine how compact the engine could have been with a Bishop cylinder head!

Possibly the smoothest internal-combustion engine available at the moment it the Wankel; but the advantages of smoothness, lightness, compactness and high power-to-weight ratio are arguably best suited to light aircraft such as this MidWest rotary-engined ARV super2: http://www.caa.co.uk/application.aspx?c ... gmark=ORIX

[Quan-Time]

the "Quasiturbine" is considered to be the smoothest internal motor ever made. All you hear is noise, and its SUPER smooth. Its been developed for chainsaws and whipper snippers, etc. Anything you hold in your hands, to help reduce arm strain.



The stirling motor is basically for hippies. All the "green energy is good mkay" brigade. Nothing wrong with it, hell its actually good people are experimenting STILL, but the stirling is more.. Its basic, good, but theres only so much the can do with it. Ive seen a stirling motor made out of paper, paper clip, and a thin sheet of plastic, sort of like a garbage bin liner bag. Hold it in your hand, it would work. Only required 7deg difference to actually start pumping.
Sat on top of some dudes computer monitor (old CRT) and it would crank away all day. Quite interesting.

And yes, this went WAY off topic.. but i dont mind, its about somethin im passionate about.

As for me and the desmo valve, anything that can win GP races is worthy in my opinion. Ferarri wanted it for their F1 car, did a bunch of research on it, but ducati denied it. So fairly much all F1 uses pneumatic valve actuation from what i understand. I remember reading something about the closing arm hitting a "harmonic" at about 15000rpm, so some extensive research had to be done to sort that out, but thats obviously a non-issue now. Any motor you can turn over by hand without big back pressure (take the spark plug out first !) has less mechanical load, which means more power makes it thru to the crank and out to the wheel. This can only be a good thing.
Saying all this, ive always flirted with the idea of getting a 12A rotary, splitting it in half, make it 588cc, mount it inside a bike like norton did back in the day.. Have it spin backwards, could prove to be quite interesting.. One day..

[davamb]

I don't think Ducati has any claims to desmo though, I know Mercedes used them in the 300SLR long before Ducati started using it, and I'm sure there were predecessors to MB as well.

And I always thought the core idea of desmo was to have really wild cam lobe shapes and not worry about the valve being able to follow them - nothing at all to do with energy loss or high rpm.

Happy to be proved wrong on either case of course (or both for that matter) ...

And yes, this went WAY off topic.. but i dont mind, its about somethin im passionate about.

Excellent!

[M.V.]

Mercedes had it before Ducati, but only just, & it had been used before that.

http://en.wikipedia.org/wiki/Desmodromic_valve

[Quan-Time]

please remember that the "Wheel" wasnt patented until 1974.. Goes to show how screwed up the law systems are. Ducati are fairly much the "keeper of the key" in the current desmo development. No one else really uses it mainly for the problems that cams and valves USED to have, they are now a thing of the past.

Desmo-valve is more of a "trade-mark" to some extent rather than technology.

As for other engine styles. Theres HEAPS. Some people have affinity for IL4s, some love the V-twins, others think that theres "harley davidsons, and other crap", its all individual. I know guys who only play with 6cyl cars, and HATE V8s. Others swear by rotary's. Ask 10 different engineers about the best head design, you will get 10 different answers. I guess find what works best for you and stick with it. Look at MotoGP / Wsbk. Each bike is quite different, especially in GP.. But they are all so close in terms of power and speed. Comes down to chassis much of the time now.. Tyres and suspension. etc.. Motors are quite similar in terms of performance.

Ultimate engine ? whats peoples thoughts ? Please try to keep it realistic.. Not "i want a 500hp smooth delivery jet engine, which produces no heat".. Try to be ... realistic.
I have a fairly good idea of what id like.. But whats your opinions ? Displacement, config, head style, rough RPM workin range, gears, efi / carb, turbo / charged / NA, metal type ?.. list a "unlimited budget super machine" style.. Ill list mine after

[M.V.]

Big question Quan Time!

At least 100 hp at 8000 RPM, less than 1000cc displacement, probably a v four for the "best of both worlds", so to speak.

Turbocharged, probably, if turbo lag can be nullified, EFI would be best for performance & it would be nice if it revved to 16K, & 6 gears would be nice.

(More RPM = more power, but is it linear? 16K rpm = 200hp?)

As to materials, that well out of my league! Feel free to tell me what it would require though!

Of course, I probably wouldn't buy it, cos I'd rather have a simple carby bike that was easy to work on...

[Quan-Time]

heh.. "work on".. i work on anything.. Hell, i built my own ECU just so i could control spark and get EFI.. I should really get my head examined.. Anyone else have ideas what they want ?

[davamb]

Fave engine would have to be the Lancia V4 as used on the Fulvia in capacities of 1.4 and 1.6 litre. A clever little bit of kit with a very narrow V angle so that a single block is used with the cylinders interlaced. A twin cam arrangement still used. Very short and very light. Think it won a couple of rallies, before being upstaged by Lancia's own Stratos.

Bikes, though, a different matter. I'd always thought that a parallel twin should provide the lightest weight (other than a single of course) but I was surprised to find that what is saved in block and head weight is then lost to crank balance weight and the v-twin is actually optimal. This is according to Phil Irving's books which I've just been reading. The TRX might go against this though with balance shafts and 270 degree crank and justify my original thought. (Must the rocking couple of this engine still be considered though?) I still don't know why we don't have carbs at the front of the bike and exhausts at the rear though. Convention?

Whatever the configuration, it has to be a twin. Less is not enough, more is excess.

[M.V.]

I still don't know why we don't have carbs at the front of the bike and exhausts at the rear though. Convention?

I've wondered that for a while, too, had some very long discussions about it as well!

Never come up with a concrete explanation... There's a new Yamaha that is that way, I'll see if I can dig up a link...

http://www.cyclenews.com/articles/new-b ... 010-yz450f

Makes a lot of sense to me!

[dandywarhol]

I'd hazard a guess that its to do with the tuned length of the exhaust system - more scope with the exhausts out the front.

[Quan-Time]

honestly its package.. Theres a nice spot for an airbox under the fuel tank. Thats why every bike (well most) do it like that. Also protects the carbs from damage and big debris. It tends to just bounce off the exhaust and go "ding" rather than "smash"..

[arrivisto]

Big question Quan Time! ... At least 100 hp at 8000 RPM, less than 1000cc displacement, probably a v four for the "best of both worlds", so to speak. ... Turbocharged, probably, if turbo lag can be nullified, EFI would be best for performance & it would be nice if it revved to 16K, & 6 gears would be nice.

M.V.'s wish list does beg the question: if that's what you would really like, why still mess about with a TRX?!

I've had 43 bikes, and the best road machines included a VFR750, an ST1100, a Triumph 900 Sprint Sport (stonking engine; but tall and heavy), an MZ Skorpion (best handling and braking ever) and a lovely BMW R75/5. Also, it would be churlish to omit my BSA A65T Thunderbolt that took me to Sicily and back without missing a beat. I've had V-twins: a Duke ST4, a Hesketh V1000 (interesting, if flawed), a Guzzi Strada 750 (yawn!) and a Ducati 600SS (beautiful, but gutless & crap suspension). V-twins are lovely, but ...

... having had my TRX for nearly two years, I never want to sell it. So what's so great about the TRX?

It looks great. It's "cobby", that is, it looks how a bike should look. The tank shape is brilliant. The 270-crank is a thing of genius; it's not a "pretend V-twin", rather it's the optimum parallel-twin (and the parallel-twin is still arguably the best engine layout for a biggish bike). The power output of some 80bhp is fine; and although 90-95 bhp might be nice, there is a law of diminishing returns. More power requires a stiffer frame, bigger tyres and chains, more weight, more expense. Although physically big, and with an 850cc capacity, the TRX is still almost a middleweight; and that's what makes it fun.

I accept the TRX isn't perfect. I would like to see a MarkII version; but I don't want too many changes, because the TRX needs updating, not reinventing (think VFR!). I'd like a MkII version to be: no more than 900cc, with 95bhp, 10-15kg lighter, better forks, lower exhaust pipes, better lights, easier access to spark plugs and oil filter, a comfier seat and a bit more storage. That's it!

Meanwhile, I'm just very happy with my TRX!

[slow codger]

So what you need is the new Tedium motor, 900 cc, 6 gears, tuned to give better horsepower. R1/R6 forks for adjustability, side radiators as per Honda Vtwins, with the engine angled forward for access to the plugs. 2 into 1 manifold (would save the weight by the 2 into 1 alone), with a short stubby pipe. Any seat other than Yamaha who don't know what padding is, with a larger tail piece for storage!

As said yamaha haven't bothered with the Mk II so I also will stick with the Mk I

Dave E