Tacho jumping around

Old 05-11-2019, 08:02 AM
Junior Member
Thread Starter
Join Date: May 2019
Posts: 2
Unhappy Tacho jumping around

Hi all, I was out riding today and my bike suddenly was struggling to start, we checked and the charging system was only charging at 12,07 volts with the bike running, putting the brights on reduced it to 11.98 volts. suspect the regulator/rectifier. No problem, I have one in the mail

However my rev counter is now jumping around sporadically. No constant values, has a mind of its own.

Any idea if this some sort of diagnostic signal the bike is trying to give me? Might this have any link to the charging system?

Earlier in the day it was indicating about 9k rpm, then it jumped up to 14k, now it does whatever it wants to.

Any help would be greatly appreciated

Old 05-11-2019, 08:27 AM
CaBaRet's Avatar
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Join Date: Oct 2016
Location: Lancs ,UK
Posts: 2,519

Think I read somewhere that the Peak voltage should be 10.5v for the Tacho , maybe the problem your having with the Rec/Reg points to that, any associated fault codes,and wouldn't advise riding to far from home

Last edited by CaBaRet; 05-11-2019 at 09:19 AM.
Old 05-11-2019, 09:24 AM
74demon's Avatar
Administrator and MVN, March 2012/Oct 2013 ROTM
Join Date: Sep 2011
Location: socal 949/951
Posts: 7,953

Voltage supply issues will cause all kinds of wacky electrical stuff to happen. That's why most diagnostic procedures start with making sure the voltage is up to par before going further.

Get your charging system sorted out and see if things right themselves.
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