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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Technical Documents/Reference >> quick audio tach /cgi-bin/YaBB.pl?num=1303712067 Message started by surtees on 04/24/11 at 23:14:27 |
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Title: quick audio tach Post by surtees on 04/24/11 at 23:14:27 I got a little worried about my idle after reading that below 1k would starve the top end from oil so decided to do a quick check. I loaded a good free recording app on my laptop called Audacity http://audacity.sourceforge.net/ and recorded a short bit. Shows up like this: http://i1137.photobucket.com/albums/n506/bruce_nali/idle1080rpm.jpg Counted 45 cycles/5 sec= 540/min X 2 (for spark every other cycle)= 1080 rpm...its all good. (I couldn't figure how to easily get an mp3 file linked here or else I would have included it - it there a way?). just something to check until my tach arrives surtees |
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Title: Re: quick audio tach Post by Gyrobob on 05/17/11 at 04:12:34 There are smartphone apps for this, as well. (droid, iphone, etc.) http://www.androidzoom.com/android_applications/sports/heliheadspeed_fzff.html |
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Title: Re: quick audio tach Post by mpescatori on 09/01/11 at 08:18:47 Surtees, You claim "45 cycles in 5 secs", do you mean "45 thumps in 5 secs" ? As in "45 power strokes" ? Because a common mistake people make is to count the number of spark plug pulses and multiply by two, whereas the Savage will have one pulse every upstroke (like in a 2-stroke)... On the other hand, if you actually had 450 rpm at idle you'd sound like a fast-firing howitzer... ;) |
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Title: Re: quick audio tach Post by verslagen1 on 09/01/11 at 10:02:00 6C7164726260756E7368010 wrote:
True, ol' sparky fires every time around (wasted spark, quite common in 4 strokers) Once a few degrees in advance of TDC on the compression stroke. And again simily advanced of TDC on the exhaust stroke. Unlike a 2 stroke, there's nothing to burn. So no ringa ding ding. So number of pulse times 2 is correct. |
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Title: Re: quick audio tach Post by surtees on 09/15/11 at 22:00:50 thanks Verslagen for stepping in. Had not checked this for a while. The spin twice pop once threw me for a sec as well. |
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Title: Re: quick audio tach Post by denistheruski on 01/05/13 at 18:35:53 Nice little trick! I tried this today but got a pretty noisy signal. Any pointers on where to position a (crappy) cell phone microphone to get something I can easily count? |
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Title: Re: quick audio tach Post by verslagen1 on 05/10/14 at 09:16:39 746865666D64000 wrote:
yup |
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Title: Re: quick audio tach Post by koehlerrk on 12/09/14 at 11:05:59 Just downloaded a new app to my phone... Got it off Google Play, it's called "RC Tachometer - True RPM" Lots of settings for RC planes and such, but also for car/motorcycle engines. You set the min and max RPM range, # of strokes (2 or 4) and enter the number of cylinders and press start. It does the rest, and it's accurate! The best part... it doesn't require 1,000 different permissions to operate, just the camera/mic on your phone. ;D |
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Title: Re: quick audio tach Post by TC on 03/20/15 at 16:45:18 As Gyrobob stated there are apps that can be used for this sort of thing, however they are not the easiest thing to figure out. I spent loads of time trying to find an iOS app that worked for measuring rpm to no avail. Then after reading through this thread again the whole metronome thing dawned on me. As verslagen stated a click track at 500 bpm emulates 1000rpm. Enter FREE metronome app for iPhones. It's called Metronome: https://itunes.apple.com/us/app/pro-metronome-tempo-keeping/id477960671?mt=8 You have to set the time signature to 16/32 and tempo to 500 bpm and BOOM you have 1000 rpms to listen to. I just checked the consistency with the link verslagen posted as well. Complete click track harmony. Now you just have to whip out your phone to check your idle rather than go to youtube or whatever else we band of hoodlums have tried. 8-) |
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Title: Re: quick audio tach Post by Sonny on 07/06/15 at 17:46:14 If you have a guitar, keyboard or other musical instrument, 1000hz is very close to a B. 500hz is B an octave below. You can hear the B when you are at the right spot. 1000rpm is a steady, smooth, alert-sounding idle. It's well above any uneven thumpin-and-bumpin. Idle rpm knob: yet another way to "tune" yr. engine. ;-' |
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Title: Re: quick audio tach Post by Kruzader on 05/26/16 at 22:35:23 Can running with an inappropriate idle damage the bike? |
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Title: Re: quick audio tach Post by Sonny on 05/27/16 at 03:25:58 Consensus here is, too low an idle speed produces bad oiling and top end wear. Worse when the bike is leaning on the side stand. You don't want an uneven Harley potato-potato sound on yr. Savage. |
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Title: Re: quick audio tach Post by Kris01 on 05/27/16 at 06:59:23 I don't worry too much about knowing the actual idle speed. You can hear it when it's right. It's just a smooth putt-putt-putt... Too high of an idle won't hurt anything as long as you don't idle at 3000 or something. Too low and you will destroy your engine. Speaking of a high idle... My throttle cable got stuck at the carb and wouldn't return to the normal idle setting. I couldn't get my fingers in there to fix it so I just rode home with the bike idling extremely high. I had to sacrifice the clutch a little at red lights to keep the idle down enough to not blow up the engine. When the light turned green I would just ease off the clutch without giving her any gas. I could get to 35 mph or more without ever touching the throttle. Luckily I only had to ride about 3 miles this way. I got her home and loosened the jammed cable with some pliers. |
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Title: Re: quick audio tach Post by Banzai310 on 06/23/18 at 20:30:51 TC, That was a touchdown! I spent hours looking for an audio tach for the iPhone until I came across your post. Thanks! |
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Title: Re: quick audio tach Post by HAPPYDAN on 06/24/18 at 07:34:43 6A76777A7675190 wrote:
Being a musician, guitar player, and S40 owner myself, I don't quite follow how 1,000 cycles per second (aka Hertz) equates to 1,000 revolutions per minute. Please elaborate. |
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Title: Re: quick audio tach Post by verslagen1 on 06/24/18 at 11:35:57 4B766D7A7B4B68767C7A1F0 wrote:
Being a musician, guitar player, and S40 owner myself, I don't quite follow how 1,000 cycles per second (aka Hertz) equates to 1,000 revolutions per minute. Please elaborate. [/quote] You misread him, 1000 hz is a B, not rpm. 500 hz is an octave below, also B. |
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Title: Re: quick audio tach Post by Spamcan on 08/02/18 at 15:24:43 For those of you with O'scopes "handy", one can wrap a few turns of wire around the spark plug wire, inductively picking up the pulse. Some more modern 'scopes will read out the frequency in Hertz, directly, or, if yours is not capable, you may calculate the frequency by taking the reciprocal of the pulse period. Then again, look up tiny-tach on e-bay and they'll work just fine. I own two of 'em, one for my Suzuki VL1500 W and one for my 1984 Rabbit diesel. |
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Title: Re: quick audio tach Post by Spamcan on 09/06/18 at 11:13:10 Here's how I did it with my Oscilloscope. What ! You don't have an Oscilloscope ? https://youtu.be/dSzlnW5Psms |
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Title: Re: quick audio tach Post by Hiko on 09/09/18 at 13:46:28 If you google 500 drum beats per minute you get a good loud audio of 1000 rpm for our savage |
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Title: Re: quick audio tach Post by Spamcan on 09/11/18 at 12:17:54 True, Mr. Hiko.... 500 beats per minute would synchronize with the Savage's 1000 RPM exhaust (power pulse) note. The engine "wastes" a spark pulse every other revolution. |
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