Firing order

[scorpion]

Does anyone know if you can change the firing order on an IL4 so that two pistons fire together at the same time thus having the effect of a double vtwin or a v4. Do they call this a big bang engine?

Just curious!:riding:

[Caddy2000]

Change your crank so that the pistons are working in balanced pairs, change your cams so that the valves open at the new time, and then buy a bespoke ignition system for your bike.......
And if you've got fuel injection get that sorted out as well.

[Mogs]

I think you'd have to change the crank as well, never heard of anyone doing this, it would be interesting

[Mogs]

Snap

[Caddy2000]

crackle!

[Pedrosa]

Plenty of info out there on the "Big Bang" firing sequence.Presently being utilised by both Yamaha and Kawasaki in Moto GP.:cool:

[scorpion]

crackle!
Snap
crackle!
POP!

Is that how it would sound?

[Stu]

Saw the thread title, & thought you were asking for an SV :-dd

[Caddy2000]

Saw the thread title, & thought you were asking for an SV :-dd

1 2 1 2 1 2 1 2?

or is it
2 1 2 1 2 1 2 1?

[rigor]

Or, if you were following Performance Bikes "Project Big Bang" (Started in january issue of this year" then it would go:

Snap
Crackle
BANG!

They were messing around to get a big bang firing order from a normal engine, but their first attempt blew up (Cam bucket shattered and the engine at itself)

[SV225]

1 2 1 2 1 2 1 2?

or is it
2 1 2 1 2 1 2 1?

Unless it's raining, then it's - 2 2 2 2 :D

[scorpion]

If I could get it to work I imagine the sound would be awesome. Ba-dum ba-dum ba-dum ba-dum :D

[Caddy2000]

Unless it's raining, then it's - 2 2 2 2 :D
:winner:

[rigor]

quite similar to a harleys firing order then:

1







2







1







2

[Caddy2000]

BMW's:




1



.................................................. .................................................. ...............................2




1



.................................................. .................................................. ...............................2

[Pedrosa]

this link might be of interest as it gives a very plain explanation of the theory:

http://www.motorcycledaily.com/08april05_bigbang.htm

The Big Bang firing sequence provides more regular power pulses which thus offers more tractability and drive under acceleration.

[rigor]

this link might be of interest as it gives a very plain explanation of the theory:

http://www.motorcycledaily.com/08april05_bigbang.htm

The Big Bang firing sequence provides more regular power pulses which thus offers more tractability and drive under acceleration.

Nope, exactly the wrong way round, Big Bang firing order produces a large "lull" in the power output, which means that the tyre can regain traction. Yamaha's BB firing order was very "irregular".

A conventional firing IL4 is about as regular as you can get.

[Pedrosa]

Rigor..You are totslly correct. Got myself a tadge mixed up there. See below for a better explanation than my own feeble and confused attempt.:p

A typical big bang engine allows two cylinders to fire almost simultaneously, thus giving the rear tyre more time, in terms of crank rotation, between each pulse of power, allowing the tyre time to find grip before the next pulse. In a normal inline four-cylinder engine, where each cylinder fires evenly in succession, the rear wheel is prone to lose grip and not retrieve it until the throttle is eased off, losing forward speed or even high-siding the rider in extreme cases.

Please feel free to totally ignore any comment I have made prior to this particluar post.;)

[haggis]

I think the Yammy R1's Tommy Hill used in BSB last year was a big bang development, sounded awesome. The first couple of laps i was trying to find 'that' Ducati? :confused:...........#-o


I can understand the theory about tyre traction, but isnt a big twin doing the same job? Surely a 1000cc twin weighs less and carries it's weight better than a 1000cc big bang IL4.

[rigor]

I think the Yammy R1's Tommy Hill used in BSB last year was a big bang development, sounded awesome. The first couple of laps i was trying to find 'that' Ducati? :confused:...........#-o


I can understand the theory about tyre traction, but isnt a big twin doing the same job? Surely a 1000cc twin weighs less and carries it's weight better than a 1000cc big bang IL4.

But I think the problem there is that a 1000cc IL4 makes more power than a 1000cc twin. Possibly because they can rev higher. Hence why Ducati want bigger engines.

[toonyank]

Unless it's raining, then it's - 2 2 2 2 :D

Really it's 2 huf 2 huf 2 huf 2 huf ;)

I thought to myself why bother trying to make a IL4 into a twin when you can get a TLR.... yeah baby :smt023

[Tim in Belgium]

Big bang engines will be less well balanced compared with an inline four, likely to lead to reduced service life for crank bearings etc, this is probably one reason we haven't seen it filter down to production bikes, as the rest of the engineering (cams, cranks etc.) is just as easy to engineer from scratch.

[jambo]

OK

Most IL4 engines have the 1st and 4th pistons rising and dropping together and the 3rd and 4th pistons rising together. As you get ignition every other cycle of the piston this gives a 1 , 2 , 4 , 3 Firing order (This is certainly how it is for my 2001 ZX6R)

New cams and ignition could make you fire 1 & 4, then 180 degrees later 3&4, then nothing for 540 degrees (If I'm thinking straight). If you change the crank the firing order is entirely down to you.

I believe this is what the BSB teams did as they (unlike the MotoGP teams) cannot make cranks that have different layouts to the original.


HTH

Jambo

[CB1ROCKET]

OK

Most IL4 engines have the 1st and 4th pistons rising and dropping together and the 3rd and 4th pistons rising together. As you get ignition every other cycle of the piston this gives a 1 , 2 , 4 , 3 Firing order (This is certainly how it is for my 2001 ZX6R)

New cams and ignition could make you fire 1 & 4, then 180 degrees later 3&4, then nothing for 540 degrees (If I'm thinking straight). If you change the crank the firing order is entirely down to you.

I believe this is what the BSB teams did as they (unlike the MotoGP teams) cannot make cranks that have different layouts to the original.


HTH

Jambo


Then the next 180 degrees will be the exhuast for 1 & 4.

Ok its a four stroke but running a bit like a 2 stroke due to having a constant firing pulse on every 180 on alternating pots.

Something like this I belive.

1 & 4 fires, 2 & 3 exhasut

Next 180 dgrees

1 & 4 exhuast, 2 & 3 fires

and so on again back to the top.

Feel free to correct me, but thats how i see it. :rolleyes:

[jambo]

I was just refering to firing order, as you assume the other strokes can be worked out from that. Induction (down), Compression (Up), Combustion (Down), Exhaust (Up), give 720 degrees rotation of the crank per cycle, per cylinder. So for the crank as a whole if you have one pair go, and another pair go 180 degrees later you still have 540 degrees before the first pair have gone through exhaust, induction, compression and are ready to go again.

Jambo

[CB1ROCKET]

Ok i had another thought and really am getting totally mixed up with this 2 stroke concept as in four stroke. oh, oh how about this

1 & 4 fires

next 180

2 & 3 exhuasted

next 180

1 & 4 exhuasted

next 180

2 & 3 fires

then repeat.

So yes there must be blank 360 of no power whatsoever.

I can't see it working as in fire, exhuast, fire, exhuast, fire, exhaust???

[CB1ROCKET]

Just seen your post, so yes thats explain how i see it

[CB1ROCKET]

I can't see it working as in fire, exhuast, fire, exhuast, fire, exhaust???

I could however see this working in a 2 stroke easily as there is ignition every 180........ or per half a revolution