Help needed - information on firing order of HD V-Twin motors
Hon. C M S A Summerfield
Hi,
I am a New Zealander who loves British, European and American
motorcycles and I don't really like Jap bikes.
I have this friend who is always slagging Harleys. He has been having
these arguments about Harleys with me, and I'd like to find out the
truth about the Harley V-Twin once and for all.
Can anyone tell me the firing order configuration for the HD V-Twin (I
presume it's the same from the Knuckle right through to the Evo)? Do
both cylinders fire at almost the exact same time, and then the crank
does two revolutions before they both fire again? Or does one
cylinder fire, the crank rotates one turn, then the second cylinder
fire?
Any information given will be gratefully accepted.
Kelly Fitzpatrick
Hon. C M S A Summerfield (fug...@ww.co.nz) wrote:
: Can anyone tell me the firing order configuration for the HD V-Twin (I
: presume it's the same from the Knuckle right through to the Evo)?
One, then the other.
--
Kelly Fitzpatrick
"I read the newspaper avidly. It's my one form
of continuous fiction." -Aneurin Bevan
er...@pacbell.net
In article <54ltfa$8...@lehi.kuentos.guam.net>, kmf...@saba.kuentos.guam.net says...
>
>Hon. C M S A Summerfield (fug...@ww.co.nz) wrote:
>
>: Can anyone tell me the firing order configuration for the HD V-Twin (I
>: presume it's the same from the Knuckle right through to the Evo)?
>
>One, then the other.
Or depending which side you're standing on:
Left-Right or Right-Left.
Eric D.
'97 FLHR
Mark Jenks
Kelly Fitzpatrick (kmf...@saba.kuentos.guam.net) wrote:
: Hon. C M S A Summerfield (fug...@ww.co.nz) wrote:
: : Can anyone tell me the firing order configuration for the HD V-Twin (I
: : presume it's the same from the Knuckle right through to the Evo)?
: One, then the other.
I thought it was the OTHER way around. Must be me..
Fuckin 'Daffy
Crash
Hon. C M S A Summerfield writes:
>Can anyone tell me the firing order configuration for the HD V-Twin (I
>both cylinders fire at almost the exact same time, and then the crank
>does two revolutions before they both fire again? Or does one
>cylinder fire, the crank rotates one turn, then the second cylinder
>fire?
I thought the firing order on a V-Twin was....Front, Rear, Front,Rear..
The cylinders are at a 45 degree offset from one another so they hit
"staggered" thus giving the "Harley Sound"....."da dup, da dup, da
dup".
I know someone is gonna call me on this if I'm wrong, but here it goes...
Front cylinder fires at 0 degrees of rotation, rear cylinder exhausts
at 315 degrees of rotation, front cylinder exhausts at 360 degrees of
rotation, rear cylinder fires at 675 degrees of rotation. Also note
that with a stock single fire ignition, both spark plugs fire at the
same time in both cylinders.
Do not take this as gospel
Crash
79FLH
poo...@msus1.msus.edu
In article <54m362$s...@hummin.sol.net>, mje...@solaria.sol.net (Mark Jenks) writes:
> Kelly Fitzpatrick (kmf...@saba.kuentos.guam.net) wrote:
> : Hon. C M S A Summerfield (fug...@ww.co.nz) wrote:
>
> : : Can anyone tell me the firing order configuration for the HD V-Twin (I
> : : presume it's the same from the Knuckle right through to the Evo)?
>
>
> I thought it was the OTHER way around. Must be me..
po-TAY-TOH, po-TAY-TOH, po-TAY-TOH . . . . .
There, that wasn't so hard, was it?
-pooder th' fired-up bastard
John S. Culp, M.D.
> Front cylinder fires at 0 degrees of rotation, rear cylinder exhausts
> at 315 degrees of rotation, front cylinder exhausts at 360 degrees of
> rotation, rear cylinder fires at 675 degrees of rotation. Also note
> that with a stock single fire ignition, both spark plugs fire at the
> same time in both cylinders.
>
> Do not take this as gospel
>
> Crash
> 79FLH
That's real close, but you're getting me all mixed up with both ignition
and exhaust events. To keep it simple, just think about ignition. if the
front cylinder fires at 0 degrees, the rear cylinder fires 315 degrees
later. The front cylinder fires 405 degrees after the rear. (Because of
the 45 degree angle between the cylinders, with a single crank pin.) For
the original questioner, the cylinders fire on alternate crank rotations.
:-)
John Culp
'85 FLTC
Mark Jenks
poo...@msus1.msus.edu wrote:
: -pooder th' fired-up bastard
And all this time, I thought it was: po-TAY-TOHe, po-TAY-TOHe, po-TAY-TOHe.
Fuckin 'Daffy
66FLH
Merrell Wasson
fug...@ww.co.nz (Hon. C M S A Summerfield) wrote:
>
>Can anyone tell me the firing order configuration for the HD V-Twin (I
>both cylinders fire at almost the exact same time, and then the crank
>does two revolutions before they both fire again? Or does one
>cylinder fire, the crank rotates one turn, then the second cylinder
>fire?
yes. no. yes. and tell your friend to bugger off.
the big easy, mr information.
Asshole #39
Karl Fengler
Allen wrote:
> fug...@ww.co.nz (Hon. C M S A Summerfield) wrote:
> >Hi,
> >I am a New Zealander who loves British, European and American
> >motorcycles and I don't really like Jap bikes.
> >Can anyone tell me the firing order configuration for the HD V-Twin (I
> >presume it's the same from the Knuckle right through to the Evo)? Do
> >both cylinders fire at almost the exact same time, and then the crank
> >does two revolutions before they both fire again? Or does one
> >cylinder fire, the crank rotates one turn, then the second cylinder
> >fire?
> It's a four stroke motor, (intake, compression, combustion/power,
> exhaust). Harleys with *stock* ignition send spark to both cylinders
> at the same time, so as one cylinder receives a spark on the power
> stroke, the other is receiving it just at the beginning of it's intake
> stroke. This is known as a "wasted spark" system, (well that's one
> name for it anyway). There are various aftermarket ignitions
> available, that are "dual-fire", IE, they fire the cylinders
> separately. There have been multiple discussions here regarding the
> effectiveness/usefullness of these ignition systems. I *personally*
> favor the dual-fire system, I installed one from Dyna about 7 years
> ago and haven't had any problems with it.
Isn't this called "Single" fire ignition? "dual-fire" being
when both cylinders get spark!
--
-Karl Fengler---------------- BRONCO*351 - FXDWG -
---------------------- ka...@hpb18162.boi.hp.com -
-!! You Have Strayed Upon The Motorway To HELL !!-
Kelly Fitzpatrick
: poo...@msus1.msus.edu wrote:
: : In article <54m362$s...@hummin.sol.net>, mje...@solaria.sol.net (Mark Jenks) writes:
: : So much confusion over such a simple thing. Repeat after me:
: : po-TAY-TOH, po-TAY-TOH, po-TAY-TOH . . . . .
: And all this time, I thought it was: po-TAY-TOHe, po-TAY-TOHe, po-TAY-TOHe.
Naah. It's po-TAH-toe, po-TAH-toe, poh_TAH-toe.
Now, shall we discuss Tomatoes, or should we leave the wenches outta this?
Cuan Coulter
pooder wrote:
>
> In article <54osju$g...@News.IDT.NET>, al...@pcix.com (Allen) wrote:
> >x-no-archive: yes
> >On Thu, 24 Oct 1996 13:32:12 -0600,
> >Karl Fengler <ka...@hpb18162.boi.hp.com> wrote:
> ><snip>
> >>Isn't this called "Single" fire ignition? "dual-fire" being
> >>when both cylinders get spark!
> >"triggers", and fires each cylinder separately. But -- have heard
> >this question before, and recall a thread here on just that point as
> >the naming convention is confusing. "Wasted spark" is less confusing,
> >but still engenders looks of "Huh??".
>
> OK, I get it. What about "dual plugs", though??
>
> [RUN AWAY, RUN AWAY!!]
>
> -pooder th' fleein' bastard
>
> AH #46--a chronologically enhanced, anally enabled citizen
Dual Plugs refer to a set-up whereby owners have modified the cylinder
head to accept a second spark-plug. This is to enable more efficient
burning of fuel in the combustion chamber, although conventional wisdom
is that an evo head is afficient enough not to need such modifications.
Old shovelhead owners who were interested in hotting up their motors
regularly performed this mod. If you are considering it just remember
the value of using a reliable machine shop.
Doug Hahn
Allen wrote:
: Nope. Single-fire fires both same time. Dual-fire has two
: "triggers", and fires each cylinder separately. But -- have heard
: this question before, and recall a thread here on just that point as
: the naming convention is confusing. "Wasted spark" is less confusing,
: but still engenders looks of "Huh??".
: '85 FXRS
: '86 Sportster, (the project)
Sorry Allen but you've got it backwards...
Single fire uses two coils and each coil fires a single cylinder.
Dual fire uses one coil firing both cylinders at the same time (every 360
degrees) producing an alternating wasted spark.
Doug Hahn
'83 FXWG - Crane single fire ignition system with mechanical advance
pooder
In article <54osju$g...@News.IDT.NET>, al...@pcix.com (Allen) wrote:
>x-no-archive: yes
>On Thu, 24 Oct 1996 13:32:12 -0600,
>Karl Fengler <ka...@hpb18162.boi.hp.com> wrote:
><snip>
>>Isn't this called "Single" fire ignition? "dual-fire" being
>>when both cylinders get spark!
>"triggers", and fires each cylinder separately. But -- have heard
>this question before, and recall a thread here on just that point as
>the naming convention is confusing. "Wasted spark" is less confusing,
>but still engenders looks of "Huh??".
OK, I get it. What about "dual plugs", though??
pooder
In article <54nv6q$3...@hummin.sol.net>,
mje...@solaria.sol.net (Mark Jenks) wrote:
>And all this time, I thought it was: po-TAY-TOHe, po-TAY-TOHe,
>po-TAY-TOHe.
Sure, if the bike in question is . . .
(wait for it)
. . . Smalley's.
-pooder th' chortlin' bastard
Chris Troudt
In article <54p2ln$m...@hawk.inetnebr.com>,
shov...@falcon.inetnebr.com (Doug Hahn ) writes:
|> Dual fire uses one coil firing both cylinders at the same time
|> (every 360 degrees) producing an alternating wasted spark.
|>
|> Doug Hahn
Doug, it's not "every 360 degrees". Remember, the front
cylinder fires at 0 degrees, the rear cylinder fires 315
degrees later, and finally the front cylinder is again
ready to fire 405 degrees later. The crank has now made
two complete revolutions for a total of 720 degrees, and
fired the coil twice. Now the cam shaft turns at exactly
half the rate of the crankshaft, so it has only made one
revolution in this period. The ignition rotor is fixed
to the end of the cam shaft, so it too has only made one
revolution, yet it has managed to fire the coil twice.
There are *two* "trigger" points or "windows" on the rotor,
and a single "pick up" or "sensor". At TDC (0 degrees
crank rotation) one window is lined up with the sensor and
handles the spark for the front cylinder. The other window
is exactly 157.5 degrees around the rotor (half of the 315
degrees crank rotation) and handles the spark for the rear
cylinder. From there, another 202.5 degrees later (half
of the 405 degrees crank rotation), the front window is
again lined up and ready to fire the front cylinder. The
crank is again back at TDC (0 degrees) after making two
revolutions for the rotor's one revolution.
The aftermarket electronic ignition systems take advantage
of the two offset windows in the rotor to independently
control two separate coils. The computer in the module
is "smart" enough to measure the difference in elapsed
time between the trigger points and distinguish between
the 157.5 degree phase and the 202.5 degree phase. This
is why most electronic single fire systems start up in
dual fire mode. They require the motor to be running
smoothly for a couple revolutions in order to sort out
which window is which. After that, they switch over to
single fire mode. (Of course, this does not pertain to
mechanical points type single fire ignitions where two
separate sets of points are used to fire the respective
coils.)
--
Later,
CT
o---------------------------------------------------------o
| Chris Troudt AH #40 ctr...@vnet.ibm.com |
| Do it in the wind! Sunny Arizona - It's a dry heat. |
| 95FXSTC - Urban Missile 95XLH - Spousal Contentment |
| 92XL250R - Coyote Chaser --(sig space for rent)-- |
| Any similarity between my views and the truth is purely |
| coincidental except that neither is endorsed by anyone. |
o---------------------------------------------------------o
Chris Troudt
In article <54osju$g...@News.IDT.NET>,
al...@pcix.com (Allen) writes:
|> x-no-archive: yes
|> On Thu, 24 Oct 1996 13:32:12 -0600,
|> Karl Fengler <ka...@hpb18162.boi.hp.com> wrote:
|>
|> <snip>
|>
|> >Isn't this called "Single" fire ignition? "dual-fire"
|> >being when both cylinders get spark!
Karl is correct. Allen is incorrect (see below).
|> Nope. Single-fire fires both same time. Dual-fire has two
|> "triggers", and fires each cylinder separately. But -- have heard
|> this question before, and recall a thread here on just that point as
|> the naming convention is confusing. "Wasted spark" is less confusing,
|> but still engenders looks of "Huh??".
|>
|> '85 FXRS
|> '86 Sportster, (the project)
NOPE! NOPE! NOPE!
Single-fire fires each cylinder independently.
Dual-fire fires both cylinders simultaneously.
Stock ignitions are dual-fire (or wasted spark).
Aftermarket ignitions are usually single-fire.
Either type must have two "triggers", since each
cylinder gets its designated spark at a different
crankshaft position. In the stock ignition
system each trigger just fires the same coil,
so both plugs spark every time. In aftermarket
electronic ignitions, the module or "brain" is
"smart" enough to figure out which trigger point
is associated with which coil. This is done by
pulse width measurements. There is only one sensor
or pickup, but there are two "windows" in the rotor
which trigger the sensor. Hence, most electronic
systems will operate in dual fire mode during the
cranking and initial startup of the engine. They
need a couple crank revolutions to get things
sorted out before they switch to single fire mode.
This of course does not apply to dual point systems
where two sets of ignition points are used to fire
the respective coils.
--
John C. Armerding
On Wed, 23 Oct 1996 11:17:42 GMT, fug...@ww.co.nz (Hon. C M S A
Summerfield) wrote:
>Hi,
>
>I am a New Zealander who loves British, European and American
>motorcycles and I don't really like Jap bikes.
>
>I have this friend who is always slagging Harleys. He has been having
>these arguments about Harleys with me, and I'd like to find out the
>truth about the Harley V-Twin once and for all.
>
>Can anyone tell me the firing order configuration for the HD V-Twin (I
>presume it's the same from the Knuckle right through to the Evo)? Do
>both cylinders fire at almost the exact same time, and then the crank
>does two revolutions before they both fire again? Or does one
>cylinder fire, the crank rotates one turn, then the second cylinder
>fire?
>
>Any information given will be gratefully accepted.
>
>
>
Stock ignition fires both together. This causes power loss and
vibration. Single fire ignition corrects this problem.
Foo
John C. Armerding wrote:
> Stock ignition fires both together. This causes power loss and
> vibration. Single fire ignition corrects this problem.
Nah! Wrong. The extra "spark" doesn't give that much vibration.(heh
heh) Unless you are useing (and hooked up to) Hoover Dam to fire yer
plugs.
The newer single fire thingamabobs, are *maybe* more accurate in the
timing....maybe. (Please don't start a thread on this)
But the horse power gains derived from one, is insignificant if any.
Vibrations? From a dual? Where is this vibration coming from?
Certainly not the motor unless you or your mechanic can't tune.
(the second (Phantom fire) does not effect the charge.)
(Of course I could be completely wrong.)
Doug Hahn
Chris Troudt wrote:
: Doug, it's not "every 360 degrees". Remember, the front
-snip a very detailed explanation-
I stand corrected, thanks.
Doug Hahn
'83 FXWG
Chris Troudt
In article <3273D6...@foo.foo>,
Foo <F...@foo.foo> writes:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Well of course. That goes without saying.
Merrell Wasson
>In article <3273D6...@foo.foo>,
>Foo <F...@foo.foo> writes:
>
>|> John C. Armerding wrote:
>|>
>|> > Stock ignition fires both together. This causes power loss and
>|> > vibration. Single fire ignition corrects this problem.
>|>
>|>
>|> Nah! Wrong. The extra "spark" doesn't give that much vibration.
(heh
>|> heh) Unless you are useing (and hooked up to) Hoover Dam to fire yer
>|> plugs.
>|> The newer single fire thingamabobs, are *maybe* more accurate in
the
>|> timing....maybe. (Please don't start a thread on this)
>|> But the horse power gains derived from one, is insignificant if any.
>|> Vibrations? From a dual? Where is this vibration coming from?
>|> Certainly not the motor unless you or your mechanic can't tune.
>|> (the second (Phantom fire) does not effect the charge.)
>|>
>|> (Of course I could be completely wrong.)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
of course you could be wrong, dipstick. and you are. the advantages of
single fire are well known to be easier starts, smoother operation, and
accurate timing, plus the option of multiple discharge, and or,
individual cylinder timing on some models. if you have ridden a single
fire igniton bike, there is no doubt that the motor is smoother. none.
the big easy, got one, works like a charm.
Asshole #39