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Post by Deleted on Oct 6, 2013 9:03:14 GMT -5
Ok i think my little digital RPM is not setup Correctly. I choose #2 On my RPM i have 2 buttons S1 and S2. For the my motor (139qmb) i don't know wich setup i need to take!? 01- spark plug fires twice per revolution 02- once per revolution 03- every other revolution 04- hours only, will not display RPM Wich setup i need to take for 139qmb motor!  Thank's! |
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Wildfire WFH150-S 10,000+ Chinometer
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Post by ericrockstar on Oct 6, 2013 9:54:48 GMT -5
Once per revolution. Like a 2 stroke.
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Post by Deleted on Oct 6, 2013 12:05:56 GMT -5
Once per revolution. Like a 2 stroke. My motor is a 4 stroke! |
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Post by sailracer on Oct 6, 2013 13:27:43 GMT -5
I have the same tach, Set it on 2 once per revolution.Even though qmb139's are 4 stroke motors, the plug fires on every revolution.
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Post by Deleted on Oct 6, 2013 14:10:20 GMT -5
Ok Thank's a lot!!!  |
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Post by prodigit on Oct 6, 2013 15:24:45 GMT -5
It would be easy to just divide the result in two.
I've read about people who had problems with those tachs, saying they don't update fast enough.
I'd say if that happens, give the tach wjavascript:openSpellCheck();ire a few more winds around the spark plug cable, and it'll work!
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Post by sailracer on Oct 6, 2013 15:35:07 GMT -5
It would be easy to just divide the result in two. I've read about people who had problems with those tachs, saying they don't update fast enough. I'd say if that happens, give the tach wjavascript:openSpellCheck();ire a few more winds around the spark plug cable, and it'll work! I like mine. It's just fine for what it is... an $8.00 test instrument  Tells me what I want to know, when I want to know it  |
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Post by pmatulew on Oct 6, 2013 15:53:37 GMT -5
Mine already has about six turns around and it's still very slow to refresh. Doesn't matter. Works well enough for what we're trying to get out of it.
Actually surprised me when I first hooked it up. I had wrongly assumed that "1800" (anti-smiley quotes) rpm idle seemed high since I was used to bigger motors that idle around 1000. Turns out I had already tuned my scoot by ear to around 2000. Go figure.
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Post by larry001964 on Oct 6, 2013 16:03:20 GMT -5
What your measuring is rpm's rounds per minuet. The 139 uses wasted spark, meaning it fires each revolution, Power, and exhaust, Since your spark plug fires every revolution you want your rpm gauge to register each revolution.
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Post by prodigit on Oct 6, 2013 16:54:07 GMT -5
I also tuned it by ear, incorrectly.
I thought my ATM was going at 1200 RPM, turns out I was 200RPM off, it runs at 1400RPM.
Just like in the high register, I thought my bike did 8k RPM, just by listening to the tone by ear, while it did 8,5k RPM on the meter.
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