Oval Pistons?

I notice that the FIM penalise oval pistons with a higher minimum weight for
a given number of cylinders compared to normal pistons.

What advantages do oval pistons give that they are trying to negate?

 

Tell you what, you buy me one of them ... hang on <racks memory> ... Honda
NR750s and I'll ride it round for a while and do you a full report on the
advantages.

OK?

I'm in all day tomorrow, if you're organising delivery.

--
AndrewR, D.Bot (Celeritas)
Kawasaki ZX-6R J1
BOTAFOT#2,ITJWTFO#6,UKRMRM#1/13a,MCT#1,DFV#2,SKoGA#0 (and KotL)
BotToS#5,SBS#25,IbW#34, TEAR#3 (and KotL), DS#5, Keeper of the TFSTR#
The speccy Geordie twat.

 

Erm, yeah, maybe. But I'm fairly sure I remember reading something
somewhere that this was initially tried many years before by one of
the early british bike manufacturers. 'course they failed but their
problem was materials technology. Not sure what their initial
motivations were behind the design were, though.
Possibly there's a BOF or some such other ageing old fart out there
than can either confirm or deny my suspicions.

--
Alex
BMW R1150GS
DIAABTCOD#3 MSWF#4 UKRMFBC#6 Ibw#35 BOB#8
http://www.team-ukrm.co.uk
Windy's "little soldier"

 

You are Tallbloke and ICMFF ShiteOldBritBikes.

ISTR reading about some old Brit experimental machine too. AJS or
Ariel.....

 

Wow!

I guess racing really does improve the breed, or at least makes it more
interesting.

Was it competitive at all or an over-complicated mistake?

Thanks for the very detailed explanation.

 

Definitely the latter. It made intermittent appearance from 1979 to
1981 - it's last outing was at the British GP at Silverstone in 1981,
when it broke down. Honda were so humiliated they built the NS500
two-stroke triple 500, and Freddie Spencer got 3rd in the championship
in its debut season in 1982, and won it the following year. Having
accepted that a four stroke couldn't be competetive, they decided to
dominate with two strokes. Which, with Doohan, they eventually did.

 

<snip>

Fascinating. Every day's a school day.

 

So how come the pendulum has swung back in favour of 4-strokes? Is it not
possible to build a competitive 500cc 2-stroke anymore?

 

As I understand it, emission restrictions have sounded the death knell
for the 2-stroke as we know it, plus advances in 4-stroke technology
(materials especially) have made them a better proposition.

 

They changed the rules 1000CC 4-strokes 500CC 2-strokes

 

You've missed the fact that the new MotoGP bikes have very nearly
twice the capacity (990cc). They did this to make *sure* that they
were faster - the factories were fed up of building racing bikes that
were bugger all use, in terms of technology advancement and marketing,
for their road bike production.

Had they set the MotGP limit at, say, 750cc, I reckon the strokers
would still be faster.

 

Is this it: http://www.timskelton.com/valkyrie/photos/psycho_bike.jpg

 

[snip hugely informative and not too technical explanation]

I like it when you're bored.
--
| Wik -UKRMHRC#10- 2003 R1150GSA -DC#1 -'FOT#0 'FOF #39 - BOD#12 BOB#12
|# You don't believe me | "Experience is the worst teacher.
|That the scenery | It always gives the test first
|Could be a cold-blooded killer. | and the instruction afterward."
***** human response from wik at blueyonder dot co dot uk *****

 

[big snip]

Splendid - that was an explanation of engine technology that a
mechanical numpty like me can understand. Thank you.

That's so good it should go on ukrm.net. Just think - you could author
a whole series of "how bikes work" articles ;-)

 

Well the 2T prototypes that they were building had no real world
spin-off, so the rules were changed to make 4T motors more
competetive.

Consider that, apart from the frame, just about no components on a 2T
motogp bike were transferable to a production bike (with emmision regs
going the way they are).

In fact, now, the mighty Honda sprots bikes are starting to look like
the motogp bikes. A v5 street machine can't be far off, IMO.

 

AOL.

heers Champ.

Erm, isn't it obvious? Well, I think it is anywsay!

 

Supercharged, surely?

 

So do I.

 

[/QUOTE]

Indeed. Interesting, factual, not boring. Well writted.

Me too - has to go further in the same time - so has to go faster,
innit.

 

This is ukrm. Going the extra parsec often isn't enough for some people.