This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

2003 tuono tacho needle jumps/jerks if connecting battery terminals or on false start

T

Tuonome

Joined Mar 2015
7 Posts | 0+
Ireland
Hi just joined the forum
apart from a fuel small snags I love my tuono
but its irritating to ride the bike n the tacho could be 4000 rpm of actual engine rpm
if you reconnect a new battery the needle goes tick tick tick jerking as it goes n settles approx 1500-2000
Rpm of its last rezt position, in order to get it to go ba k to zero iv to touch one battery terminal on n off the battery till it returns to 0 in a clockwise direction
when I get the bike going etc it will read ok until the event of a misfire! Lets say you slightly touch the starter switch n it doesnt fire up first time the tacho needle goes ape sh! T again anyone have this issue before n possible fix thanks
 
Hi Tuonome,

I haven't come across this specific issue, however I'm sure that someone on the Forum has seen this before.

For what it's worth, it sounds like a trapped/damaged cable - or even a clocks fault - or bad connection to a relay.

This is only my thoughts, but I think it is a good place to start.

Good luck

Gray :thumbup
 
Thanks for your reply I think im gona have to strip her down n chase the wiring but today I notice a sound from under the seat a sound that remind me of an old pc thinking n thinking lol you know that noise of a struggling old pc or laptop but thats for another day
 
Hi, I have had my tuono for 4 weeks now and after 3 days it did the clutch. A 2 week wait for parts and that's fixed, so of for a ride, first fill up dash resets and tacho is reading 4000 rpm low. read the site and I find out that disconnecting the negative from the battery and then tapping the lead on the negative post of the battery will eventually have the needle move to its original position "yeah'. Anyhow I decide that there is enough info on the alternator wiring problems to do a check as the voltage on the battery is only 12.78V when running at 4000rpm. Here is the result, a slightly crispy connector and I can not pull the brown connector at the rectifier on the sub frame apart as it is melted together as well. I am going to fix the wiring tomorrow and I will post how it goes.
Photo090.jpg
 

Attachments

  • Photo092.jpg
    Photo092.jpg
    50.2 KB
Hi, I have replaced all the connectors above and It would still reset occasionally, so I went through all the connections on the bike and found high resistance joints on the earth wire to the frame and motor, the battery and the rectifier mount. The rectifier was obviously damaged by the voltage and current fluctuations caused by the connectors and would collapse it's voltage output when hot. I have then replaced the 20A standard rectifier with a 37A Yamaha one and then increased the wire size to the battery. After all this I am getting a consistent 14.3 volts at the battery at 4000rpm. This has stopped the computer reset and it starts a lot easier. I hope this helps.
 
A final fix for my tacho jump, it happened again on disconnecting the battery due to the needle being loose on the tacho shaft. After realignment I glued the needle into the correct position and even if I disconnect the battery it stays in the correct position.
P.S. I also replaced the starter solenoid that developed a short in the relay windings
 
Having the same problem with my gen 1 and would like to know which Yamaha model reg/rec you have used?

Many thanks
Glen
 
×

Similar threads

K
Rev counter problems
Replies
1
Views
2K
Six5
Six5

New Posts