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Tacho reading double

Posted: Mon Oct 29, 2007 11:29 am
by Cront
Hi guys,

I recently got a ZXR 400 H model and I've been having a lot of fun. My problem is the tacho is reading double. Now I know this has come up before and the answer is probably the battery but I don't have any trouble starting the bike at all so I find it a little weird. I originally thought it was a loose ground but that didn't seem to fix it. Could it be anything else?

Cheers,

Cront

Re: Tacho reading double

Posted: Mon Oct 29, 2007 11:36 am
by RedexRobB
Well thats what the others had as far as i know, the bike was starting and running fine just the tacho was messing about. Changed the battery and all was hunky dory.

Re: Tacho reading double

Posted: Thu Nov 08, 2007 9:49 am
by Cront
So...changed the battery and same problem. What would be the next thing to check?

Re: Tacho reading double

Posted: Thu Nov 08, 2007 9:51 am
by zxr_oli
Maybe it is just reading in KM?

Re: Tacho reading double

Posted: Thu Nov 08, 2007 12:00 pm
by Cront
I'm in Australia so yes my SPEEDO is reading in KM but the issue here is actually with my tacho reading double :smt002

Re: Tacho reading double

Posted: Thu Nov 08, 2007 12:04 pm
by RedexRobB
zxr_oli wrote:Maybe it is just reading in KM?
its the rev counter not the speedo :smt001

Have you checked the wiring? Theres a black wire that goes from the tacho to one of the coils and also to the ECU. Check the contact blocks make sure theres no corrsion.

Feel i must apologise because you may have bought that battery for nothing, sorry. :oops:

Re: Tacho reading double

Posted: Thu Nov 08, 2007 12:11 pm
by zxr_oli
Ahh, now i feel like an idiot.......... :smt005

Re: Tacho reading double

Posted: Thu Nov 08, 2007 12:30 pm
by masterofinsanity
RobB wrote:
Feel i must apologise because you may have bought that battery for nothing, sorry. :oops:
how can you buy something for nothing? if you buy something you have to pay a price, if its nothing then its free so you can't buy it. :smt019

Re: Tacho reading double

Posted: Thu Nov 08, 2007 12:39 pm
by RedexRobB
sarcy bugger :smt016

Re: Tacho reading double

Posted: Thu Nov 08, 2007 11:33 pm
by Cront
Yeah I'm going to check all the wiring again, could it perhaps be the coil? I have to admit I've got nfi when it comes to motorcycle mechanics so bear with me here. The first point of contact after the battery is the starter motor right? There seems to be a bit or corrosion on the wires that contact there. Also sometimes, although not very often, it sorts itself out and starts reading true which was what made me think there was a loose ground wire going to the tacho. Could this be caused by anything else?

PS don't worry about the battery it was the only way to rule it out.

Re: Tacho reading double

Posted: Fri Nov 09, 2007 12:32 am
by Cront
I've also spoken to a shop around here and their first suggestion was just to stick another tacho on, unfortunately they didn't have one and it seems a bit strange to me if it is a busted tacho that it would read true every now and then.

Re: Tacho reading double

Posted: Sat Nov 10, 2007 10:22 am
by Cront
Can anyone tell me where all the wires coming from the tacho go? Is it one or 2 to one of the coils? And is that all? This tacho is doing my head in.

Re: Tacho reading double

Posted: Sat Nov 10, 2007 10:58 am
by Northern ANdy
brown is a 12v feed, fused and switched

black / yellow is earth

black does the actual sensing of the rpm, and meets up with the coil wire and fuel pump relay

Re: Tacho reading double

Posted: Sat Mar 22, 2008 1:35 pm
by Cront
If anyone is interest I ended up fixing this by cleaning up the contacts in the plug from the tacho to the loom

Re: Tacho reading double

Posted: Sat Mar 22, 2008 5:22 pm
by MillaMeter
I had the same problem here viewtopic.php?f=7&t=5540

Turns out that hitting the toad out of the counter actually works! lol