Big bang engines

[mfzx6r]

I see the big bang engine is all the go in motoGP but SBK has banned it from being used in SBK superbike racing.
What I find strange is that after watching BSB the other night the Virgin yamaha team over there is running a big band engine in their R1's
Whats the go over here and the US ???? anyone know ? Phil or Tim ??


mario

[Smitty]

Marz
thought the big bang engines were a no-no (anywhere cept MotoGP)
unless available in a street model

[Ment]

or is that just a prediction on Yamaha build quality?

[mfzx6r]

Ian
During last weeks sbk races foxtel ran British superbike races from Brands[the short indy] track and Thruxton track.
The comentators spoke about the virgin yamaha team over there were running a bigbang engine config in the R1's .


mario

[Smitty]

Ian
During last weeks sbk races foxtel ran British superbike races from Brands[the short indy] track and Thruxton track.
The comentators spoke about the virgin yamaha team over there were running a bigbang engine config in the R1's .

mario

thanks mate
a portent of the future? big bang engines in street bikes

[javaman]

What is big bang engine? Last time I heard this was when mick Doohan dominates on his honda... but that's 2 stroke !

[Smitty]

What is big bang engine? Last time I heard this was when mick Doohan dominates on his honda... but that's 2 stroke !

Andy
a big bang engine applies to any internal combustion engine....
(4 stroke 2 stroke or diesel ) of 2 cylinders or more where the cylinder firing order is changed so that 2 or more cylinders are ignited and produce a power stroke at the SAME time
(produce a BIG BANG is the terminology)

Most normal engines fire off 1 cylinder at a time
( in a firing order like 1-2-4-3 (4 cyl bike) or 1-2-7-8-4-5-6-3 (Holden V8 )
a big bang engine can go-
1-2&4(same time)-3 .. or even ALL cylinders at the same time

and the reason?
is to give the rear tyre time to reclaim or get better grip
that is, there are no constant power strokes from the engine which will produce more rear tyre slip compared to where there is a gap between engine power strokes...

hth

cheers

[Smitty]

a bit more of an update....
from here-
http://www.crash.net/uk/en/news_view.as ... nid=108031


Following the release of the Virgin Yamaha 'Big-Bang' R1 in British Superbikes, FGSport - the organisers of the World Superbike Championship - have announced plans to stop such engines appearing in their championship.

Presently the rules allow a standard four-cylinder Superbike engine to be turned into a 'Big-bang' engine - where the cylinders fire in two sets of two or, as with the Virgin Yamaha machine, fire in a one-two-one arrangement - to be entered into the WSBK championship.

However, Marco Della Monica, an FGSport spokesperson, has confirmed to Crash.net that they will change the rules to stop such engines from racing in their series, with a full announcement planned to be made by the FIM in the coming weeks.

hth

cheers

[mfzx6r]

Thanks Ian.
So Virgin Yamaha are still running it
I wonder about Aust and the US if anyone tried it



mario

[Steve_TLS]

Reliability is an issue. There's a lot of stress on the valve train when you're opening 8 inlet valves then 8 exhaust valves together. Then you add the extra stress on the crank and gearbox when it's got two pots firing as one. But the Yamaha team in the BSB rounds seemed to have their bikes working OK.

[mattyv74]

[a big bang engine applies to any internal combustion engine....where the cylinder firing order is changed so that 2 or more cylinders are ignited and produce a power stroke at the SAME time
(produce a BIG BANG is the terminology)

Otherwise known as a flat plane crank.

If my memory as a 5yo is correct, Colin Bond ran one in his torana in the late 70's, till it too was banned.

[Smitty]

....otherwise known as a flat plane crank.

If my memory as a 5yo is correct, Colin Bond ran one in his torana in the late 70's, till it too was banned.

pretty good memory Matt...

Both CBond and PBrock drove a ModSports Torana that had a Lucas FI Holden V8 engine in it with a flat plane crank...I saw it a cupla times at Sandown and it sounded like no other Holden V8 you have ever heard....

and from my collection, I have a press photo of it

cheers

[diesel]

my straight six ford has the firing order 1&6, 2&5, 3&4.
i thought this was the norm and the new trend was to run two cylinders with a slight lag of one behind the other.
not at the exact same time.
then that would lengthen the power.

but then again i am just little whipper snapper hey smitty:)

[Smitty]

my straight six ford has the firing order 1&6, 2&5, 3&4.
i thought this was the norm and the new trend was to run two cylinders with a slight lag of one behind the other.
not at the exact same time.
then that would lengthen the power.
but then again i am just little whipper snapper hey smitty:)

Vince
I think you will find the firing order is....
1 then 6 then 2 then 5 then 3 then 4, not as you said 1 AND 6...
and
the interval between the power stroke (when the plug fires the air/fuel mixture)on each cylinder will be the same (assuming revs are not changing)

make sense? mate


cheers

[diesel]

oh yeah it makes sense.

its just that i've got this image in my head of when when i replaced the head gasket that the pistons were grouped in pairs.