Tachometer dropping, missfire and power loss...

[Lvotplay]

My Yamaha XVZ 1200 - 83 has a problem that I can't identify what is causing it.

After warming up and running for 1 hour the tachometer drops out it missfires and power loss until it stops, if I try to start it straight away it feels as if the battery is dead, the tachometer continues to not work and it continues to lose power and I hear all the relays going off,

I wait about 15 to 30 minutes and it goes back to normal.

Can anyone help??

Im form Portugal, Madeira island to be more precise, finding material or parts for this bike is very difficult around here.

 

 

 

[Marcarl]

First thing I would check out is the TCI. It's under the battery floor tucked away and hard to get at.

[Lvotplay]

42 minutes ago, Marcarl said:

First thing I would check out is the TCI. It's under the battery floor tucked away and hard to get at.

 

I've already changed the TCI (I bought it from Carmo electronics), the problem still exists, but thanks for the help.

I simply don't know where to look to resolve this.

[Marcarl]

Next is, check out the coils, I think it's #2 that  governs that part of things, keep in mind that these machine will run very nice on 3 cylinders, so you might not even notice if you drop one.

[Lvotplay]

ok, I'll check the coils, starting with number 2, the loss of power is not exaggerated but here on the island it's all mountain roads, we either go up or down never in a straight line, so I feel the loss a little.

Once again, thank you very much and as soon as I have news I will pass it on.

[Lvotplay]

On 6/11/2024 at 3:23 PM, Marcarl said:

Next is, check out the coils, I think it's #2 that  governs that part of things, keep in mind that these machine will run very nice on 3 cylinders, so you might not even notice if you drop one.

I have already replaced coil #2, the problem persists...

[Marcarl]

Pull the plug wires one by one with the engine running, If all 4 are firing you should hardly notice that you disconnected one. If it starts to stumble you have another cylinder out. While you do this you can also check the spark consistency. It's also a good idea to replace all the ignition wires with new ones, I would go wire wire core rather than carbon core, make sure they are seated well in the coil towers.

[Lvotplay]

On 6/18/2024 at 1:20 PM, Marcarl said:

Pull the plug wires one by one with the engine running, If all 4 are firing you should hardly notice that you disconnected one. If it starts to stumble you have another cylinder out. While you do this you can also check the spark consistency. It's also a good idea to replace all the ignition wires with new ones, I would go wire wire core rather than carbon core, make sure they are seated well in the coil towers.

Hi, I've done all this and it's still the same, I tested the coils and even used a fifth coil and tried it on each of 1 to 4 cylinders.

I now noticed the battery that was placed, btx20hl 18.9ah (20ah), could it be the battery?

[Marcarl]

Next I would look for a loose connection, broken wire, bad ground. Start at the tach and see where it takes you. You can download a wiring diagram from the website here