Author Topic: 90 Degree V-Twin: Firing Order of 270/450?  (Read 37482 times)

kidneb

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #60 on: May 24, 2017, 01:35:40 PM »
Oh well then-.

BTW -  has anybody checked the treadmill recently, to see if the bearings are properly greased ?  :cheesy:

oldbike54

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #61 on: May 24, 2017, 01:38:39 PM »
Oh well then-.

BTW -  has anybody checked the treadmill recently, to see if the bearings are properly greased ?  :cheesy:

 Is it a Guzzi treadmill ?  :laugh:

 Dusty

kidneb

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #62 on: May 24, 2017, 03:40:20 PM »
Is it a Guzzi treadmill ?  :laugh:

 Dusty

No, it is not. Guzzi has only built motorised devices AFAIK.




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Offline Muzz

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #63 on: May 24, 2017, 03:52:12 PM »
I must admit that my Breva 750 does not have those problems with fixed firing points. I have come up with an ingenious system where the crank pin is actually supported in roller bearings at each end, and these run in eccentric tracks machined in to the flywheel.

Stick with me here. You can probably begin to see that the firing order will not be in the same position each time. To enable this to work I have devised two cunning systems, the Performance Induction Sensor System, or P.I.S.S. to feed the motor at the correct time, and the Continuous Rotating Analogue Potentiometer system to fire it, known as C.R.A.P. You might think that this was a lot of work to find a solution to a non-existant problem, but I can assure you that when P.I.S.S. and C.R.A.P. are tied in with my cunning flywheel arrangement things really hum! :thumb:
Muzz. Cristchurch, New Zealand
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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #64 on: May 24, 2017, 06:38:53 PM »

A 360 degree crank just means a single (common to both rods) crank pin.
So is that the case with a 650 Yamaha twin for example ?

oldbike54

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #65 on: May 24, 2017, 06:47:34 PM »
So is that the case with a 650 Yamaha twin for example ?

 Yes , as well as the 500 CC Hosk from which the Yamaha was developed . The Vert twins from Jolly Olde were 360% also . Technically they don't have to share a crank pin , the two pins simply have to be in alignment .

 Dusty


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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #66 on: May 24, 2017, 10:31:39 PM »
Yes , as well as the 500 CC Hosk from which the Yamaha was developed . The Vert twins from Jolly Olde were 360% also . Technically they don't have to share a crank pin , the two pins simply have to be in alignment .

 Dusty
Yep thanks Dusty.

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #67 on: May 24, 2017, 10:33:44 PM »
Jeepers SS, you really know how to get a conversation started. :popcorn:

Offline redhawk47

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #68 on: May 25, 2017, 12:19:00 AM »
OK,
For you engineering students.

: May 23, 2017 6:43 AM
Left cylinder fires, engine turns to the 270 degree position and #2 fires then engine turns to the 450 degree position and # 1 exhausts and starts intake, engine turns to the 270 degree position # 2 exhaust and starts intake, engine turns to 450 position on compression and fires then engine turns to the 270 degree position and fires.
These two firings are 180 degrees apart,(measured in the direction of rotation), position wise.

In engineering parlance this is what is called a 180 degree firing order.

First semester 101.

Boy, I don't look at this thread for two days and it goes ballistic.
Kirby, your explanation quoted above is not correct. To re-state it:

The left cylinder fires, the crank rotates 270 degrees and the right cylinder fires. The crank rotates an additional 450 degrees and the left cylinder fires and the cycle continues.
(Note: there are 360 degrees in one revolution. Because this is a four stroke engine it takes two revolutions to complete a cycle. 270 + 450 = 720 = 2 revolutions.)
Because the cylinders are 270 degrees apart (measured in the direction of rotation) this is the same as a 270 crank in a parallel twin. The chart of the 270 crank shows the firing sequence of the Moto Guzzi engine.
Dan
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Offline Darren Williams

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #69 on: May 25, 2017, 07:52:28 AM »
George Bernard Shaw said something like "The single greatest problem with communication is the illusion it has taken place". Rodekyll (really enjoyed getting to meet you at CV) wrote something to the effect he got on the interstate at night because "trucks squash the deer into more manageable chunks".  I think this thread has squashed this dead horse into bite sized pieces.   :evil:
The best part of riding a motorcycle is to tilt the horizon and to lift the front coming out of a corner and to drift the back end powering thru loose dirt and to catch a little air topping a hill and... yeah it's all good!

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #70 on: May 25, 2017, 09:50:22 AM »
Kirby, you're subtracting the difference,  incorrect.  You should be adding them to 720.

The firing is NOT 180 between the two fires, it's 270 and then 450.  It's 270 degrees after #2 fires and 450 degree after #1 fires.

Look at your clock,  start at midnite and #1 fires at 9 am (270 degrees later), go around the clock pass noon and go to midnite and #2 fires (450 degrees later).   start again


Also, with straight crank pins there is no way a 90 degree V twin can have a 180 degree firing interval.  Geometry.
« Last Edit: May 25, 2017, 09:52:15 AM by LowRyter »
John L 
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oldbike54

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #71 on: May 25, 2017, 10:03:36 AM »


Keep in mind that we are not talking about ACTUAL firing degrees but the 270/450 nomenclature  refers to engineering architecture only, for classification purposes.

 Yeah , with all due respect to the other participants on this thread , how many of you guys are engineers ? Well , besides Kirby .

 Dusty

Offline Phang

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #72 on: May 25, 2017, 10:07:39 AM »
Yeah , with all due respect to the other participants on this thread , how many of you guys are engineers ? Well , besides Kirby .

 Dusty

Me, I  love mechanical engineering so much till I decided not to make it a career. I chose electrical & electronics engineering in university (college) instead.  :grin:
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oldbike54

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #73 on: May 25, 2017, 10:17:25 AM »
Me, I  love mechanical engineering so much till I decided not to make it a career. I chose electrical & electronics engineering in university (college) instead.  :grin:

 So THAT'S why you keep bringing up sparking plugs , it all makes sense now  :grin:

 Dusty

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #74 on: May 25, 2017, 10:19:26 AM »
Yeah , with all due respect to the other participants on this thread , how many of you guys are engineers ? Well , besides Kirby .

 Dusty

well then, perhaps you can explain the 180 degree firing that many of us here don't understand.  Obviously either someone is wrong, or we have a communication gap. 

I am open to be educated here but haven't a clue what the 180 actually means.  I know it's not the firing interval (9 AM and Midnight) , so what is it?  (Unless it's Kevin Cameron's explanation of making an offset crank)
« Last Edit: May 25, 2017, 10:22:49 AM by LowRyter »
John L 
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oldbike54

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #75 on: May 25, 2017, 10:33:28 AM »
 Kevin Cameron is my go to guy , but Guzzi crankshafts aren't offset . That example doesn't apply in this conversation .

 Dusty

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #76 on: May 25, 2017, 10:35:12 AM »
Kevin Cameron is my go to guy , but Guzzi crankshafts aren't offset . That example doesn't apply in this conversation .

 Dusty

my point exactly. 

So what is the 180?    :smiley:
John L 
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oldbike54

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #77 on: May 25, 2017, 10:42:33 AM »
 Anyone been fishing lately , heard the crappie are biting .

 Dusty

Offline Phang

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #78 on: May 25, 2017, 10:43:04 AM »
Kevin Cameron is my go to guy , but Guzzi crankshafts aren't offset . That example doesn't apply in this conversation .

 Dusty

I like to read his articles too, I keep his book next to my bed  :thumb:




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Offline Phang

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #79 on: May 25, 2017, 11:13:24 AM »

Hey those are familiar!
Used to love to stay at the Raffles! Done all the tourist stuff and just relax.(and food!!!) Being so close to the equator no typhoons?
What's the life expectancy of a new auto these days?

Cheers.

:-)

It's warm , humid and torrential rains, no typhoon  :grin:

It's still 10 years, same for the motorcycle too. My Griso is 7 years old now, it will expire in another 3 years. I have to pay a substantial amount of money if I want to carry on to ride it for  another 10 years  :violent1:
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kirby1923

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #80 on: May 25, 2017, 11:54:36 AM »
Unaware that it included motos!
Cheaper to get a new one? (is there a cc point for the 10 yr rule?

Offline Phang

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #81 on: May 25, 2017, 12:01:24 PM »
Unaware that it included motos!
Cheaper to get a new one? (is there a cc point for the 10 yr rule?

A new one has to pay the same 10 years tax too. It is across the board regardless of the engine capacity.

I would like to tell you more but let's just stay on the topic.

I'll start a new topic about the costs of motorcycle ownership in Singapore  :azn:
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oldbike54

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #82 on: May 25, 2017, 12:03:53 PM »
A new one has to pay the same 10 years tax too. It is across the board regardless of the engine capacity.

I would like to tell you more but let's just stay on the topic.

I'll start a new topic about the costs of motorcycle ownership in Singapore  :azn:

 Weren't we discussing fishing ?

 Dusty

Offline redhawk47

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #83 on: May 25, 2017, 12:16:24 PM »

Thank you for the explanation of the 4 stroke cycle but..

Read it again I was talking about the firing positions of 270/450 which are 180 degrees apart hence the engine is considered to have a 180 degree firing cycle. (response to original question from op)

The 2 positions in degrees that the engine fires in a 720 cycle.

Keep in mind that we are not talking about ACTUAL firing degrees but the 270/450 nomenclature  refers to engineering architecture only, for classification purposes.

OK, I went back and read the original post. The question asked was why is the 270/450 nomenclature used instead of firing position values.

Answer. Because using the degrees between firings the sum adds up to 720. 270 + 450 = 720. This is always true regardless of configuration. Using this method provides a check sum.
If you use the firing position values they may or may not add up to 720. For the Moto Guzzi 90 degree twin the firing positions (relative to zero) are 270 and 720. 270 + 720 = 990. (Or 0 and 270)

PS: I am a Mechanical Engineer, BSME and Registered Professional Engineer

Dan
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Offline Delta425

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #84 on: May 25, 2017, 12:31:31 PM »
WOW!  Sure wouldn't want to see the thread if we were discussing something with a more complicated firing order, like a flat-plane 60 degree V-8.  Or, an 18 cylinder radial.  Or, a 9 cylinder rotary.....

Anyways, I'll take an AR10 over an M14 ANY day!

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #85 on: May 25, 2017, 02:52:50 PM »
OK, I went back and read the original post. The question asked was why is the 270/450 nomenclature used instead of firing position values.

Answer. Because using the degrees between firings the sum adds up to 720. 270 + 450 = 720. This is always true regardless of configuration. Using this method provides a check sum.
If you use the firing position values they may or may not add up to 720. For the Moto Guzzi 90 degree twin the firing positions (relative to zero) are 270 and 720. 270 + 720 = 990. (Or 0 and 270)

PS: I am a Mechanical Engineer, BSME and Registered Professional Engineer

you're kidding, I take it.   


And I am still clueless about the 180 degree interval.
« Last Edit: May 25, 2017, 02:53:56 PM by LowRyter »
John L 
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Rough Edge racing

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #86 on: May 25, 2017, 03:02:58 PM »
WOW!  Sure wouldn't want to see the thread if we were discussing something with a more complicated firing order, like a flat-plane 60 degree V-8.  Or, an 18 cylinder radial.  Or, a 9 cylinder rotary.....

Anyways, I'll take an AR10 over an M14 ANY day!

  This firing order stuff is more or less an abstract problem...I have a hard time with abstract but not looking at real life stuff...Visualizati on of  a P&W R2800 is no problem because I have seen the parts in person...

twowings

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #87 on: May 25, 2017, 03:05:37 PM »



oldbike54

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #88 on: May 25, 2017, 03:06:43 PM »
  This firing order stuff is more or less an abstract problem...I have a hard time with abstract but not looking at real life stuff...Visualizati on of  a P&W R2800 is no problem because I have seen the parts in person...

 How's the fishing in rural N.Y. Tony ?  :rolleyes:

 Dusty

Rough Edge racing

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Re: 90 Degree V-Twin: Firing Order of 270/450?
« Reply #89 on: May 25, 2017, 03:28:23 PM »
How's the fishing in rural N.Y. Tony ?  :rolleyes:

 Dusty

  Well, I live three miles from Lake Ontario...About 40 miles north the Finger lakes, we have a half acre pond on our property with small mouth bass and blue gills, several streams nearby with trout...I have no interest in fishing... :laugh:

 

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