SuzukiSavage.com - tachometer question

DrunkenDwarf Senior Member Offline Morning Zombie Posts: 325 Seattle, WA Gender:	tachometer question 09/12/10 at 21:40:35 I've got one of these Harbor Freight Multimeter with Tachometer. I haven't used it yet because I haven't figured out a good way to fit the pickup for the tach under the tank. Does any know know if I could rig up my own pickup? -D. Dwarf
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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: tachometer question Reply #1 - 09/12/10 at 21:50:36 I guess an induction tach would work sort of - seems to me it would show 2x the rpm because of the savages wasted spark ign - see it sparks every time the piston goes up make your own what? induction pickup?
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thumperclone

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Re: tachometer question
Reply #2 - 09/13/10 at 06:42:32

Reelthing wrote on 09/12/10 at 21:50:36:

I guess an induction tach would work sort of - seems to me it would show 2x the rpm because of the savages wasted spark ign -

if it was single fire coil would read half rpms
we have dual fire coil
1 fire per rev
4 stokes per 2 revs

the clamp goes over the plug wire looks kinda big to fit for permanent install ok for garage work,idle set carb tweakin etc

my tach pu is just wire that wraps around plug wire

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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: tachometer question Reply #3 - 09/13/10 at 07:15:09 yes, tachs are set for a single fire 4-stroke, unless they have a 2-stroke switch seems to me by default it takes the spark count and doubles it for an rpm count - which isn't correct for dual fire or a 2-stroke. are we saying the same thing?
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DrunkenDwarf

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Re: tachometer question
Reply #4 - 09/13/10 at 08:24:54

thumperclone wrote on 09/13/10 at 06:42:32:

the clamp goes over the plug wire looks kinda big to fit for permanent install ok for garage work,idle set carb tweakin etc

my tach pu is just wire that wraps around plug wire

This.

The camp is big and awkward. To use it I have to prop up the tank. It'd be nice if I could wrap a wire around the plug wire and tuck it away until I needed to set the idle or whatever.

Alternatively, I could buy one of these.

-D. Dwarf

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thumperclone Serious Thumper Alliance Member Offline PGR rider riding with respect Posts: 6121 Grand Junction Colorado Gender:	Re: tachometer question Reply #5 - 09/13/10 at 12:52:27 my tach looks like the enm one draw backs:not back lit. small digits hard to read at hwy speeds.. RT think i know what your sayin 1 REV is 360* of crank rotation 2 stroke fires evey time our dual fire fires every time(only has compressed fuel/air mix half the time) single fire four stroke fires every other time
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Tiefighterpilot Senior Member Offline Daily Rider Posts: 346 San Francisco	Re: tachometer question Reply #6 - 09/13/10 at 18:25:05 so Just to clarify... Savage is dual fire per revolution?
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28890 L.A. California Gender:	Re: tachometer question Reply #7 - 09/13/10 at 18:33:28 Tiefighterpilot wrote on 09/13/10 at 18:25:05: so Just to clarify... Savage is dual fire per revolution? how many power strokes per revolution? how many strokes per revolution?
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28890 L.A. California Gender:	Re: tachometer question Reply #8 - 09/13/10 at 20:12:58 verslagen1 wrote on 09/13/10 at 18:33:28: Tiefighterpilot wrote on 09/13/10 at 18:25:05: so Just to clarify... Savage is dual fire per revolution? how many power strokes per revolution? how many strokes per revolution? one power stroke every 2 revolutions 2 strokes for every revolution bang blow suck squeeze
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: tachometer question Reply #9 - 09/14/10 at 04:46:51 The crank creates a pulse every time it comes around. The plug fires at the top of the exhaust stroke & compression stroke. How that affects a tach reading, IDK,, Im sure it does, I just dont know exactly what it does in terms of making a tach report the RPM accurately.
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thumperclone

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Re: tachometer question
Reply #10 - 09/14/10 at 06:12:43

justin_o_guy2 wrote on 09/14/10 at 04:46:51:

The crank creates a pulse every time it comes around. The plug fires at the top of the exhaust stroke & compression stroke.
How that affects a tach reading, IDK,, Im sure it does, I just dont know exactly what it does in terms of making a tach report the RPM accurately.

1 pulse(fire) per "every time it comes around"= 1 rev
tach sees the plug firing

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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: tachometer question Reply #11 - 09/15/10 at 03:02:04 Yea, I know the tach sees the pulse & reads it as a plug firing, but what I dont know is what tachs report, via the needle. Some tachs are designed to work with a wasted spark iggy.
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feelinjunky Full Member Offline No Comment Posts: 238 NJ	Re: tachometer question Reply #12 - 09/15/10 at 10:00:51 Guys, THINK! This is an automobile tachometer. Do automobiles dual fire (2 sparks per 4 strokes)? They would have to, if this tach were to work with our Savage, as you clamp this tool on one wire. If they fire once every 4 strokes, this tach would show 2x the actual revs. in our Savage.
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justin_o_guy2

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Re: tachometer question
Reply #13 - 09/15/10 at 18:53:31

feelinjunky wrote on 09/15/10 at 10:00:51:

Guys, THINK! This is an automobile tachometer.

Do automobiles dual fire (2 sparks per 4 strokes)? They would have to, if this tach were to work with our Savage, as you clamp this tool on one wire. If they fire once every 4 strokes, this tach would show 2x the actual revs. in our Savage.

Duuuhhhh,,thats what Im tawkin bout here Willis..

Yea, I know the tach sees the pulse & reads it as a plug firing, but what I dont know is what tachs report, via the needle. Some tachs are designed to work with a wasted spark igg

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Re: tachometer question
Reply #14 - 09/15/10 at 19:42:13

Reelthing wrote on 09/12/10 at 21:50:36:

I guess an induction tach would work sort of - seems to me it would show 2x the rpm because of the savages wasted spark ign - see it sparks every time the piston goes up

make your own what? induction pickup?

If they can measure the revs from the battery does that mean the engine needs the battery after it has started for the next spark?

The screw going to the negative side of my battery had come off a few days ago, and it started to backfired like crazy at all speeds yesterday even after changing it to prime/ reserve, but after I realized there was no screw today, and took it for a test ride I didn't have a problem. When I go to work tomorrow I will see if this was problem.
It wasn't out of gas because I drove it another 10 miles today.

What Ah battery is recommended?

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