Are you a screamer or a banger?

[Peter Henry]

Given the short space of time that nowadays sees race proven technology finding it's way on to road bikes,how long will it be before the screaming IL4's that we all know and love,(?) will be usurped by a Big Bang model? Will Yamaha be the first to the showrooms or kawasaki?
This revolutionary adaptation of firing sequences apparently brings a bike with a whole new feel and sensation to it,let alone sound! The greatest benefits I have read are the ability to enter corners at higher speed and to be able to get on the gas again when cranked over much more safely due to the power pulse delivery.(Evidence of which Rossi being able to outperform Honda's with far superior power and speed on tap)
I have to say that I for one am most intrigued and will be watching developments with great interest. 8)

[kwak zzr]

"the older i get the faster i was"<carl fogarty :!:

[BillyC]

What the hell are you talking about? :?

[Scoobs]

It's like the argument between twins and fours. There is no ideal or optimum configuration otherwise everyone in MotoGP would be using the same. It will be even more difficult for road bikes. GP bikes are focussed machinery designed to do one thing. Road bikes have to be all things to all men.

[Carsick]

Err, I may be talking ********, but don't twins already have a very similar firing pattern to a big-bang 4. I know the number of pulses aren't the same, but the spacing of them is similar, the point being that we're already getting some of the benefits.
Oh, you mean on those IL4 thingies? Not an issue for us, old chap. :wink:

[Scooby Drew]

I think having the power of an IL4 with the delivery of a V2 is the point, it sounds yummy!

[mysteryjimbo]

I think having the power of an IL4 with the delivery of a V2 is the point, it sounds yummy!

Wont it be similar to a huge single? All 4 cylinders firing at once or at least very close.

[Peter Henry]

Scooby Drew is obviously thus far theonly one to have a bit of a knowledge of this theme. :shock:

Scoobs it is very different than optimum configuration. For that a Vee 5 is the one you want usually, but an IL4 configuration allows for a slimmer motor and better handling characteristics.People have been looking everywhere but the firing order of the engine to explain why some bikes handle and grip better than others.
Case in point the RV Honda is at times an absolute pig to control especially at the back wheel. Rossi's M1 though as previously stated, down on power yet is so much more manageable where it matters in the curves. With that in mind how can anyone say it has no baring on real world biking?

This wholoe ball game was started by one of the Yamaha brains who then retired and oh he turned up at Kawasaki Moto Gp team!

By using different cam profiles,crankpin positions and engine management chips a firing order to optimise performance yet one that does not create excessive wear to engine components can be used.

The big bang motor delivers a double combustion pulse by firing two cylinders at a time,followed by a pause,followed by another big bang and so on.

With your regular IL4 motor the firing is spread over 720º of engine rotation with a single combustion stroke every 180º,it is superbly balanced and smooth and can rev very high...but in that lies the problem. Peak power is becoming almost unusable. Firing intervals of this type do not give the rear tyre time to recover grip before the next combustion shock is delivered to the tyre.

The engineers can play and use all manner of crankpin settings in order to maximise the benefits of the B:B:method.

In a nutshell Big Bang gives more torque, more usable drive and better handling characteristics along with an absolutely superb sound!

Now tell me none of that has any use on the roads? :lol: 8)

[Carsick]

Scooby Drew is obviously thus far theonly one to have a bit of a knowledge of this theme. :shock:

The big bang motor delivers a double combustion pulse by firing two cylinders at a time,followed by a pause,followed by another big bang and so on.
I thought I had at least demonstrated that I understood the concept, and I believe Scoobs does as well.
The second part is only true for the most basic incarnations. To the best of anybody outside the teams knowledge, they're not using evenly spaced firings, thus why I said we were getting at least some of the benefits with the V2. On a V2 we having larger but less regularly occuring power pulses, exactly likely the simplest form of big-bang.

As Scooby suggested though, the ideal for the road may be an IL4 or V4 with that kind of firing pattern.

[Scoobs]

I thought I had at least demonstrated that I understood the concept, and I believe Scoobs does as well.

Thanks Carsick.

I have read a bit and understand the rudimentary principle of big bang. I couldn't design an engine though.

but an IL4 conficuration allows for a slimmer motor and better handling characteristics.

I don't think that is a correct statement either. Viewed from the crank end maybe, but they are generally installed across the frame. This actually makes the bike wider than a "V" configuration (unless you get to 7 cylinders). The bike will have a greater frontal area etc etc.

Keep posting though. This stuff genuinely interests me.

[Peter Henry]

Scoobs what utter and complete tosh I wrote earlier! "slimmer" durrr! I misread a quote from Masao Furasawa the head engineer of the Yamaha Moto Gp team. :oops: (Give me a break it was in a Spanish mag!)he did actually say that an inline motor he felt offered better handling for a bike,however this can be rendered almost useless if the engine is too peaky.
The teams are not showing their card as to what configuration they will use with the smaller 800cc limit in 2007. Although we remember Yamaha having no small success with their 500 Vee two stroke motors?
I am trying to get my head around whether the Big bang doo dar could actually work on a Vee motor? Gut feeling says not? I think it is definitely an inline engine enhancement,wot u think?
Test riders have stated that the bike with the big bang does have more characteristics of a Vee motor and does not need to be howling up the rev range to work.bends can be entered in hiogher gears and yet good positive reponse fely when winding on the gas.

BTW I was not,(Carsick please dont hate me! :? )trying to be defamatory erlier I was trying to provoke folks to chip in! I do think that this Big Bang thing is going to really offer us all a genuine alternative to the motors we all know presently. This will become bigger news as the projects move on and I believe can only offer promise for us mere mortals!

Going off at at a tangent..it will be interesting to se how Honda perform from Brno onwards as theiir motors are set to have another 10/15 horses and another 700 to 800 revs to play with. But then again the extra power hasnt meant a lot thus far this season has it? :shock: 8)

[Ivar]

This "big bang" thing is not new, it was used on the Honda 2-stroke V4 500GP racer , was it 89? Those high-strung 2 strokes were both peaky and difficult to handle , and the big bang configuration seemed to help a lot in getting power to the ground back then.

[Biker Biggles]

As I understand it you can make any engine fire in any way you want but the downside is vibration.Most modern engine types have evolved to produce smoother running,which is better for road bikes and reliability.Hence the traditional big singles and parallel twins were overtaken by IL4s.Ducati made good use of the fact that a 90 V twin also has good balence,with its slight power deficit sorted by the big bang pulses.Honda Kawasaki and Benelli tried the IL6 type for ultimate smoothness,but they were just too wide.
If they want to go for a big bang IL4 they will have to engineer some balence into it that is not naturally present,but will it be worth it?I doubt it,and I think it is better engineering practice to use a naturally balenced configuration.

[sv4me]

Ask Mick Doohan what he thinks of Big Bang engines,dont think he'll be too complimentary :)

The Big Bang engines have been banned from WSB but not BSB. Some reckon its because they want to keep WSB racing to bikes that are more like the ones you see in the shops. Theres always been a question of reliability over big bang engines but I heard that Yamaha were addressing this with the new R1

What makes a Big Bang engine exactly? Is it mainly changing the camshaft to allow different timing configs? :?

Im not very technical minded but love reading about Big Bang engines ever since the NSR500 8)

[Carsick]

As I understand it you can make any engine fire in any way you want but the downside is vibration.
Was my understanding as well.

If they want to go for a big bang IL4 they will have to engineer some balence into it that is not naturally present,but will it be worth it?I doubt it,and I think it is better engineering practice to use a naturally balenced configuration.
Apparently it works quite well in the gp engines without any detectable extra wear or major problems with vibration. Whether this is true in a road engine which would be expected to do 4k miles between oil changes nevermind how many miles between rebuilds, is another matter.

[Peter Henry]

Ivar I understand where you are coming from but I am not altogether sure this is correct? I think you are referring to the beast that Doohan was comfortable with but Criville would not sit on! If this concept was with Honda in 1989 would they have not naturally been the first to use it with a 4 stroke motor?

I have read that although the permutations of crank pin settings are many,possibly the ebst setting for best performance and kindnes to engine parts plus one that maintains tyre friendly power drive is as follows:


With a 1 and 4 / 2 and 3 big bang configuration 3 and 4 crankpins could be set at say 50º TDC or thereabouts after pistons 1 and 2. therefore allowing instead of two seperate big bangs, two overlapping bangs whichare just slightly out of sync with each other.

The sound from the M1 Yamaha is so similar to one of the Ducati's it is uncanny! :shock:

[Carsick]

'points out the last discussion we had on big-bang' http://forums.sv650.org/viewtopic.php?t=25152&highlight=bang

[Peter Henry]

Carsick.....My apolagies in full sir after reading indicated previous post! :oops:


SV4me wrote:

Theres always been a question of reliability over big bang engines

Haven't seen Rossi pushing his M1 back to the pits too often over the past two seasons mate? :wink:

I dont really understand why we should expect them to be a whole load of trouble if they hit the dealerships in road bike form? I have every faith that all of the possible question makrs would have been thoroughly addressed before this.

Ivar could be right u know about the NSR Honda? But Doohan was the only rider not scared of it and won lots with it? I think he psyched so many people out before races as they knew what he was riding was an absolute animal! Almost a double kick when it hit the power band! :shock:

[Carsick]

No apologies necessary, just adding in a bunch of other stuff that had already been said.

As for getting everything sorted before it ever reached a road bike, you'd hope so, but we know that isn't true with bikes we're buying now and there are reliability issues with big-bang, it just happens that the yamaha team (for one) seem to have got that sorted for their particular engine that gets rebuilt god knows how often.

[sv4me]

SV4me wrote:

[quote]Theres always been a question of reliability over big bang engines

Haven't seen Rossi pushing his M1 back to the pits too often over the past two seasons mate? :wink:

I meant as a road bike reliabilty wise. Rossi doesnt have to worry about service costs :wink:

His engines not supposed to last that long,where as we want our bikes to run and run for thousands of miles \:D/

Like I say though,Yamaha have been testing the Big Bang engine in their R1 race bikes so you never know,could see in the dealership in the not too distant future?

So what are we talking about here,a bike with the power delivery of an IL4 and the noise of a twin?

[Jp]

So what are we talking about here,a bike with the power delivery of an IL4 and the noise of a twin?

No, its more like, power of an IL4, delivery and noise of a twin, deelish or what?!

Somebody suggested using a V4, this is a good idea, but V4's have a natural imbalance in the engine, and would have extra weight due to it needing, is balance shafts or something, correct me if im wrong?

I would look forward to big bang coming to road bikes, i cant really see what a different firing order would do to the reliability, its still doing the same amount of revs isnt it?

[Ivar]

Was just reading an interesting article about a 4-stroke "bigbang" engine made 30 years ago... :!:
In 1973/74, Some of the engineers at Norton-Villiers-Triumph made a inline 4 by essentially sawing off 1 cylinder on each end of 2 BSA rocket3 engines, and then mating the resulting twins to make a 980cc inline 4. The 2 middle cyls fired in parallell.
Sadly, NVT did not have the funds to develop it further, nor modernising their manufacturing equipment as neccessary to get it into production. And went then went bankrupt... :x :cry:
http://www.teamobsolete.com/QUADRANTNMM.jpg

[Carsick]

i cant really see what a different firing order would do to the reliability, its still doing the same amount of revs isnt it?
Because you can completely change the way that the vibrations and stresses are reinforced or counteracted.