SuzukiSavage.com - Tachometer

thumperclone Serious Thumper Alliance Member Offline PGR rider riding with respect Posts: 6046 Grand Junction Colorado Gender:	Re: Tachometer Reply #15 - 02/27/07 at 14:01:50 im corn fused...i thought 4 stroke = 1 suck,2 compress,3 fire,4 exhaust... SO she fires every other time the piston comes up...?
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smokey02

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Re: Tachometer
Reply #16 - 02/27/07 at 19:18:46

Yes, it's a 4 stroke, she fires every other time the piston comes up,
BUT,
the spark goes off EVERY time the piston comes up.

It would be more expensive and complicated to run the ignition off the
camshaft, (1/2 rpm of crank)
much cheaper and simpler to run the ignition off the crank/flywheel,
so every other spark is 'wasted'.

One goes off at the top of the compression stroke, (squeeze)
one goes off at the top of the exhaust stroke. (blow)

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Salad_Shaker

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Re: Tachometer
Reply #17 - 02/28/07 at 01:38:36

Let's see if I get this now. Def. a 4 stroke: suck-squeeze-bang-blow but has an extra spark on the fourth phase which is "wasted". Right so far? Does this wasted spark actually do anything at all? Is there any sort of afterburner effect on an unburned mixture in the exhaust gasses maybe upping the efficiency a shade and cleaning the emisions too? We should be told!

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LANCER

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Re: Tachometer
Reply #18 - 02/28/07 at 05:43:13

Quote: [We should be told!]

... Men in black suits come to your door in the dead of night and say one thing only ... [glow=red,2,300]"this is on a need to know basis, and you don't need to know", [/glow]then they leave in the black suv they drove up in, and the black helicopter above your home slowly and silently moves back up into the black moonless night sky ...

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smokey02 Full Member Offline Time flies like an arrow, fruit flies like bananas Posts: 233 Alta Loma, California Gender:	Re: Tachometer Reply #19 - 02/28/07 at 14:11:00 I believe that wasted spark goes off just after the exhaust valve closes and just before the intake valve opens, I don't think it has much effect on anything. ...but keep your eye out for black helecopters...
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amcline

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Re: Tachometer
Reply #20 - 03/01/07 at 09:27:24

mind if i chime in with a question, talking about it firing after the exuast valve closes,
would that be the issue behind these bikes having way more backfire and after fire problems than many other bikes? sounds to me once the piston rises on exuat, if it fires to soon it would ignite any leftover fumes and there you go,
what would the fix for this be?
changing cam timing so the exuast closes sooner? or changing the ignition timing? and how do you do that if possible

sorry my post dont have anything to do with a tach, but i would like to get a small one, seen them on ebay for about 30-40 bux.

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smokey02

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Re: Tachometer
Reply #21 - 03/02/07 at 20:39:32

I'm guessing the exhaust valve would already be closed before the wasted spark went off.

Isn't backfiring more related to the lean carb settings to meet EPA regulations?
go to the Technical Documents/Reference and look at:
"Mid-Range Power & the White Spacer (Backfire)"

Getting back to Tachometer.....will a HD (or any V-twin) tach work on our LS650 ? It seems that kind of tach would be calibrated for 2 sparks every 2 revolutions, the same as our 1 spark every 1 revolution?

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Maroon 96, HD turnout, Iridium, TKat brace, Big Crank, seat lift, Narva +50 w/ yellow filter in a XV920 9

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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: Tachometer Reply #22 - 03/03/07 at 05:38:23 most tachs for an hd will - some have an option for a single fire adapter, this you do not need
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mpescatori

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Re: Tachometer
Reply #23 - 03/07/07 at 06:27:28

Hi all, pardon me for this intrusion, but I would like to shed some light on this
"wasted spark" issue.

The so called "wasted spark" is a very cheap and popular solution
for cutting emisisons without having to rehash the entire engine.

1st spark: during compression, as we all know;
2nd spark: during exhaust, ignites and helps burn any unburnt fuel,
thus improving COx and NOx readings.

The 2nd spark will occur before the exhaust valve closes,
but before the intake valve opens

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Maurizio Pescatori, Esq.
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Kropatchek

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Why more than 1
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Re: Tachometer
Reply #24 - 03/07/07 at 07:26:57

mpescatori wrote on 12/31/69 at 16:00:03:

1st spark: during compression, as we all know;
2nd spark: during exhaust, ignites and helps burn any unburnt fuel,
thus improving COx and NOx readings.

The 2nd spark will occur before the exhaust valve closes,
but before the intake valve opens

Sorry!
From the SSM:
Exhaust closes 14 degr. after TDC and inlet opens 22 degr. BEFORE TDC.
That means BOTH are open during that periode.
Ignition takes place 5 degr. before TDC at 2000 RPM and 30 degr. before TDC at 4000 RPM.

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