My 2" mini riser mounted tac upon start up jumps to around 3500-4000 before coming back to high idle speed. At speed around 2000 it will repeat this erratic reading ever so often. It's obvious that the engine rpm is not changing. Its a typical 3 wire system. Ground, positive 12 volt and pickup to #3 on back of speedometer head. Connections appear fine. Been working fine for years. Is this what the tac does when wearing out or is it the connections? It's a rather distracting quick jerky bounce and I sure would like to have a cheap easy fix. It's ridding time now but it's so distracting for an anneal mind. I wear a full helmet and use tac for my speedometer is why I want it. Thanks for the help.

 

-----Original Message-----
From: grf00
Sent: Monday, September 12, 2011 9:25 AM
To: Customer Service
Subject: CobraUSA Customer Service Inquiry
Date Sent: 2011-09-12 11:25:08


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I presently have two of your mini tacs (riser mounted 05 Yamaha 1100 VStar and Harley 04 Deuce.. Both over 3 years old and never missed a beat till lately the Harley one is making an odd quick 3-4K jerky swing at start up before it settles to the normal high idle of 1200 or so. It also appears to hang on return some times at around 2K or slight less. If I go up thru the gears between 2400-3000 it gets a few quick erattic 1000 rpm jumps. Has the motor drive just worn out? It actually still appears to work. Just these odd quirks obivious not normal and it's obivious the engine is not doing what it's doing. I figured I would check the three wires but I did a good solidered instulation and I do not believe this is what it is. Any ideas? Thanks for the Help


Cobra Catalog: NO





First Name: grf00
Last Name: Deuce
Company Name:

Answer:
The tachs are sealed and there is no way to get inside to fix them. The tach is out of warranty but if you want to just purchase a new tach head it is $134.95. Give me a call at 714-692-8180 if you decide to buy the tach head. Thanks for asking Cobra, ride safe.




I changed plugs and the tac appears fine????? Had 10K on the NKG set
Son thinks the plugs were misfiring maybe just a few times per minute and the pulse was affecting tac?