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914World.com _ 914World Garage _ bouncy tach

Posted by: scott thacher Mar 18 2005, 07:05 PM

title say it, i was wondering how much they charge to stop a tach from bouncing, with the tach working otherwise?

Posted by: trekkor Mar 18 2005, 07:27 PM

I called down there and they quoted $250.

Maybe I misunderstood them...

KT

Posted by: seanery Mar 18 2005, 07:31 PM

Isn't bouncy tach a symptom of a poor ground? If so, check your grounds first. It's cheaper.

Posted by: SirAndy Mar 18 2005, 07:33 PM

QUOTE (seanery @ Mar 18 2005, 05:31 PM)
Isn't bouncy tach a symptom of a poor ground? If so, check your grounds first. It's cheaper.

bouncy tach is usually *not* your tachs fault!

i fixed mine (along with a few other gremlins) by getting a new relay board ...
Andy

Posted by: scott thacher Mar 18 2005, 07:37 PM

well i will let the cat out of the bag

i found something internal that fixes some of the bouncy tach problems. i am just wondering what would be a fair price to charge for the service. i would feel guilty charging over 50 bucks, its not hard just takes some time. i would also calibrate the tach to 3000 rpms or so.

Posted by: Otmar Mar 18 2005, 09:41 PM

Heck, I put a big fat cap on mine and now it's rock solid, except when the ground wire gets loose...

Matter a fact, here's my notes on it:
Sun 04/25/04 06:26 PM
Tachometer bounce getting to be too much,
Added 2650 uF 10V across the coil winding. This helped a lot, no more bounce, reasonable response.

Been great ever since.

Posted by: scott thacher Mar 18 2005, 09:48 PM

i found a mechanical thing inside that is affected by wear ( ie old age ) basicly if you smack you dash and it jumps i can fix it

Posted by: Aaron Cox Mar 18 2005, 09:51 PM

gigure out how to trigger a tach from a mallory cdi.... 12V squar wave at 20 percent duty cycle yada yada

Posted by: scott thacher Mar 18 2005, 09:56 PM

QUOTE (Aaron Cox @ Mar 18 2005, 07:51 PM)
gigure out how to trigger a tach from a mallory cdi.... 12V squar wave at 20 percent duty cycle yada yada

not a problem, 3 parts needed a small capacitor, and transitor and another capacitor

basicly the transistor can trigger to ground when it gets triggered by the cdi box, the capacitors are to level out the spikes

Posted by: Aaron Cox Mar 18 2005, 10:01 PM

QUOTE (scott thacher @ Mar 18 2005, 08:56 PM)

QUOTE (Aaron Cox @ Mar 18 2005, 07:51 PM)
gigure out how to trigger a tach from a mallory cdi.... 12V squar wave at 20 percent duty cycle yada yada

not a problem, 3 parts needed a small capacitor, and transitor and another capacitor

basicly the transistor can trigger to ground when it gets triggered by the cdi box, the capacitors are to level out the spikes

make it happen for me!

tell me what i need to do