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Stéphane

Big (enough) Bang Engine?

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I know most of you probably have your copy of RiDE Magazine, Sept. 06 with the special on VFR.

After reading the post from "air horns" and reading my manual, then the magazine, it downed on me that we might have a variation of the Big Bang motor that made its debut in an RC30. Before I put the article down here, try to remember that:Firing order is 1-3-2-4. Then look at this: #4 and #1 firing within 90˚, while #1 and #3 is 180˚ and #3 and #2 is 270˚!!!!!!!

Ok, here's what RiDE has to say ". . . It' was because the tiny V-four motor[of the RC30] . . . had a secret. The ignition timing meant you got one big bang and then a relatively long gap before it fired again. The theory goes that this helps the rear tyre recover between pulses and improves grip and traction. The RC30 was the first 'big bang' sports bike." RiDE, Sept, 2006, p.72

Mind you the 90˚ interval is followed by the 180˚ then by the 270˚. Still, I think it's only a variation.

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Guest buddie hackett

Dear Stephanie

I asked Al Ludington(Miguel Duhamel's and Erik Bostroms mechanic) about that and I believe his answer was no they didn't use the big bang in the RC-45 and I believe the RC 30 has the same firing order. Honda used the big bang on their two stroke 500 GP. I could be totally wrong.

gallery_3888_786_380207.jpg

Who's that? None other than Miguel Duhamel on a VFR

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I'm pretty sure that the 83-85 VFs, the VF1000Rs, the RC-30, and the RC-45 are the only ones that use the "big-bang" firing order. The difference is generally called the 180 vs 360 degree crank. I couldn't tell you which is which, but the modern VFR has the one that is not as effective, but has a more V-8 like rumble. That rumble is the exact reason that it is used, afaik. Yamaha put it in the V-Max and people raved about the sound, Honda jumped ship and the VFR has been steadily gone down-hill since. :rolleyes:

The sound on my bike is less VFR like and kind of droaney. I think it's a sexy combination of and inline and a V with a torque curve that is boring to look at.

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The 360 degree engines are the Big Bang engines.

MTB

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i had no idea this was old tech, because they talked about the fact that the v4 motogp bikes will implement this technology using feedback on the wheels to allow the ecu to know the position and vary the firing of the cylinders to maximize grip along with GPS units that will change the 'maps' in the ignition to match race track conditions....

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The sound on my bike is less VFR like and kind of droaney. I think it's a sexy combination

:rolleyes:

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360 crank motors (RC30/45 et al) are not really a "Big Bang" motor...but they do have a much lumpier profile than a 180 cranked VFR... :thumbsup:

CBR - I4

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1----------------2----------------4-----------------3----------------1-

VFR - 90Deg V

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1-----------------3------------------------2----------------4--------1-

RC30 - 90Deg V

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1--------4------------------------3--------2-----------------------1-

Nice one Baketech, that's probably the most effective presentation of how the 180-vs-360 firing order works that I've seen :thumbsup: Interesting to see th I4 pattern against the V4s as well.

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Easy to see why they called it the "Big Bang" eh?

Holy crap! It's a Quad Twingle :idea3:

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360 crank motors (RC30/45 et al) are not really a "Big Bang" motor...but they do have a much lumpier profile than a 180 cranked VFR... :thumbsup:

CBR - I4

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1----------------2----------------4-----------------3----------------1-

VFR - 90Deg V

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1-----------------3------------------------2----------------4--------1-

RC30 - 90Deg V

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1--------4------------------------3--------2-----------------------1-

It really shows why our bikes have a distinctive burble at idle... :thumbsup:

Just for fun, here's the original Big Bang...keep in mind these only show one crank rev, as they are 2-strokes...

V4 2-Stroke (90 degree motor)

000----090----180----270----360

-1-------3--------2-------4-------1-

Screamer - V4 2-Stroke (180 degree motor)

000----090----180----270----360

1&3------------2&4------------1&3

Big Bang - V4 2-Stroke

000----090----180----270----360

-1-3-2-4---------------------1-3-2-4

Easy to see why they called it the "Big Bang" eh? :goofy:

Thanks for the easy to understand lay out. I guess I was a bit mistaken. Having said that, it's because of the Big Bang engine that they probably came out with this for the street. My understanding of the Big Bang was the engine fired 2 cylinders within 70˚, then a long pause. I didn't realized that it was all 4 within 70˚ then a very long pause! That's why the RC30 doesn't really qualify as the big bang, but as a variation leading to it.

Thanks again for shading some light!

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360 crank motors (RC30/45 et al) are not really a "Big Bang" motor...but they do have a much lumpier profile than a 180 cranked VFR... :thumbsup:

CBR - I4

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1----------------2----------------4-----------------3----------------1-

VFR - 90Deg V

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1-----------------3------------------------2----------------4--------1-

RC30 - 90Deg V

000----090----180----270----360----090----180----270----360

000----090----180----270----360----450----540----630----720

-1--------4------------------------3--------2-----------------------1-

It really shows why our bikes have a distinctive burble at idle... :thumbsup:

Just for fun, here's the original Big Bang...keep in mind these only show one crank rev, as they are 2-strokes...

V4 2-Stroke (90 degree motor)

000----090----180----270----360

-1-------3--------2-------4-------1-

Screamer - V4 2-Stroke (180 degree motor)

000----090----180----270----360

1&3------------2&4------------1&3

Big Bang - V4 2-Stroke

000----090----180----270----360

-1-3-2-4---------------------1-3-2-4

Easy to see why they called it the "Big Bang" eh? :idea3:

Thanks for the easy to understand lay out. I guess I was a bit mistaken. Having said that, it's because of the Big Bang engine that they probably came out with this for the street. My understanding of the Big Bang was the engine fired 2 cylinders within 70˚, then a long pause. I didn't realized that it was all 4 within 70˚ then a very long pause! That's why the RC30 doesn't really qualify as the big bang, but as a variation leading to it.

Thanks again for shading some light!

apparantly, everyone else is too. i have read 4 articles on this and they all keep saying big bang = 2 cylinders together like this:

"The 'Big-Bang' Superbike engine is nothing new but, although extensively tested, it has never previously been raced due to the problems caused by the two big power pulses produced. These two 'Big-Bang' pulses, within a four-cylinder engine, create a tremendous amount of stress, often leading to failure within 30 minutes."

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Firing cylinders together is generally known as a "Screamer" configuration....not Big Bang.... :twocents:

Thanks for all that info. I have to go back and re-read my manual. I am suddenly completely unaware of what is going on as I thought I knew and had probably re-read. I thought I had a screamer, but ohh jeeze. Knowledge never killed anyone, it just makes it hard to do homework when there are other, more interesting, things to learn about.

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"The 'Big-Bang' Superbike engine is nothing new but, although extensively tested, it has never previously been raced due to the problems caused by the two big power pulses produced. These two 'Big-Bang' pulses, within a four-cylinder engine, create a tremendous amount of stress, often leading to failure within 30 minutes."

There's an R1 racing in Australia which has been modified to use a 'big bang' firing order - they did a cut and shut on the cams, rotating one half of the cam 180 degrees to change the firing order. It now fires two cylinders at once, then the other two (sorry I'm not sure which ones are paired). It puts out similar power to other comparable R1 engines (it's not modified all that much apart from the cams) but is apparently far easier to ride hard. I think it's hanging together ok, but it's not racing at the top level so is only making 150rwhp. If they went for 180+ it would probably lunch itself.

The BSB Virgin Yamaha team did it too, but in a slightly different way in order to alleviate stresses:

http://www.crash.net/feature_view~t~Exclus...~18~id~6850.htm

BTW you can easily change the firing order of 3rd/4th Gen VFRs by lifting the front cam, spinning it laterally 180 degrees, and dropping it back in... which creates the Twin Twingle [TM] :thumbsup:

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Firing cylinders together is generally known as a "Screamer" configuration....not Big Bang.... :twocents:

The screamer is an even firing order engine. Google Doohan and Screamer.

V4 2-Stroke (90 degree motor)

000----090----180----270----360

-1-------3--------2-------4-------1-

All cylinders fired within 90 degrees is now called the 'long bang'.

Long Bang - I4 or V4 4-Stroke

000----090----180----270----360

-1-3-2-4---------------------1-3-2-4

Edited by rhubarb

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If memory serves, They learned about this idea from the Harley dirt track program. In the early eighties, and late seventies, the Japanese manufacturers wanted some of the American flat track scene. They couldn't figure out why the ancient Vs were waxing the twins and later the new Japanese V motors. Better Horsepower didn't seem to matter!

When they analyzed what H-D had going, they saw essentially an inline twin with a huge hole in the power delivery. H-D motors were run for years with the ignition firing in both cylinders simultaneously. One was early and one was late. This lumpy delivery allowed the tire to regain traction in between power pulses. A handy feature on dirt!

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As I understand it the Japanese domestic market NC30 and NC35 400cc VFRs also sport 360 degree firing order.

Edited by Hornhonker

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Mick Doohan and the Big Bang connection from the pages of MCI

magazine:

Developments of the 91 NSR 500 focused around Doohan testing a number

of designs as HRC shifted their main push behind the new up and

comer... For some while Doohan had been asking engineers to replicate

the wide power band characteristic of the RVF750 4 stroke endurance

bike, which he and Gardner had used to lead the previous summer's

Suzuka 8 Hours... HRC answer was the 2 stroke equivalent of the the 4

stroke Big Bang... technically speaking all four cylinders fried

within 70 degrees to afford the tire more time to hook up...

Consider and instant success by Gardner "Jesus, this is amazing" but

Doohan was a doubter... the 92 NSR droning big bang had a very flat

exhaust note which made it sound slow to riders... It was only during

HRC's final preseason phase that Doohan began to believe in the Big

Bang... He found little difference in lap times but the close firing

order was easier on tires and set up...

Rainey and company were in for the shock as the season kicked off...

Utilizing the Big Bangs ability to find traction where others could

not... Doohan ran away with the first four races... winning by

anything up to 28 seconds wet or dry... The Big Bang proved such a

giant leap forward that rival factories Cagiva, Suzuki, Yamaha rushed

to build copies... having learned the NRS's secret by playing track

side audio recording against an oscilloscope...

There could be no doubt now... Honda now had the best 500 on the grid

by quite some margin... the big bang NRS proved to be a winner in a

variety of hands... Since the 80 when engine HP dramatically

outstripped tire and chassis performance... GP teams had been hiring

tail sliding dirt trackers form America and Australia because no one

else could wrestle these monsters into submission...

Honda only raced the big bang 360º crank... and every V4 they produced

was big bang... but that all changed in 86 with the 180º V4 crank...

Honda was loosing marketing shares to the inline and they split the

crank throws 180 apart to change the pitch from a drone to a scream...

this move sold more V4s but it also muted the drive out of the

corners... you'd have to compare a your 180 5th Gen VFR with an 360

RC45 to get my point... they are basically the same engine except with

regard to crank throws...

Technically speaking 360 means all 4 crank throws rotate together in

one 360º circle whereas the 180 means the 4 crank throws are split

180º apart... it's independent with regard to the 90º cylinder

angle...

I think Honda should design the next Gen VFR without the silly Vtec

and adopt the visceral 360º big bang crank of their race bred V4s...

RC45 360º big bang crank...

300301472_f10330b1db_o.jpg

VFR 180º little bang crank...

300301473_befa4c04a7_o.jpg

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VFR 180º little bang crank...

300301473_befa4c04a7_o.jpg

I like my widdo bang :biggrin:

good read about the development. the whole theory about allowing the back tire time to rest and "plant" itself before being hit by power is interesting.

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I like my widdo bang :biggrin:

good read about the development. the whole theory about allowing the back tire time to rest and "plant" itself before being hit by power is interesting.

It's interesting to note the difference on an unspecting rider's seat of the pants... like my

friend Andrew who normally rides an S3Triumph Triple...

"It was time to trade bikes! I took off on the Mr.RC45. OMG. The RC45

is amazing. It feels nothing like a VFR motor (Which I don't think is

anything special, anyhow.) The RC45 motor is amazing, smooth, torquey,

not at all lumpy like I think of the VFR. Larry may have converted me to

a V4 aficionado."

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Any idea what is the firing interval of new Honda VFR 1200F engine with 76 deg block and split angle crank?

It's a lot like 2 offset crankpin 750 shadow motors siamesed together. The firing order is modified to 1-2-4-3. The cylinders fire in pairs 28' apart like 2 v-twins. Honda has a great little animation of how it works on one of the V4 hype sutes... can't remember where.

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Guest Baketech

Any idea what is the firing interval of new Honda VFR 1200F engine with 76 deg block and split angle crank?

It's a lot like 2 offset crankpin 750 shadow motors siamesed together. The firing order is modified to 1-2-4-3. The cylinders fire in pairs 28' apart like 2 v-twins. Honda has a great little animation of how it works on one of the V4 hype sutes... can't remember where.

It's actually the journals that are physically 28' apart to achieve primary balance of the 76' V-angle...

The firing sequence is 104-256-104-256.

000----090----180----270----360----090----180----270----360

-1-----------2-----------------------4-----------3----------------------1-

The animation is on the main Honda site... :fing02:

Edited by Baketech

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Guest Baketech

Almost like RC30 interval.

Very similar... :fing02:

It's an elegant solution I think. A more compact engine, with a "gruntier" power delivery profile... :wub:

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