Featured Tiger 90 Rebuild

When the lighting switch is in the LOW or HIGH position there is no continuity between pins 1 and 2 or 2 and 3, as there should be. This means the lights at the front won’t come on.
I will look in to this later, it may be that it needs fixing inside, or reconfigure to use different pins (pins 4 to 7 aren’t used and make an internal connection) or buy a new switch.
Here is a pic of the multimeter showing max ohms resistance, the page from the Triumph workshop manual and the switch with the multimeter probes on it.

 

This is a little bonus - in one of the crates was a new old stock brake light switch.

 

This is definitely the lighting switch, the wires are are all to and from the lights.
The white plastic knob on the front unscrews and can be removed very easily. Maybe in the past someone just replaced the knob with one from an ignition switch?

 

Tested the rectifier in the usual way. 12v battery on pairs of connectors and a multimeter in-line to check the voltage. The Triumph workshop manual gives a clear description of what to do. Anyhow, there’s full voltage getting through where it shouldn’t so this one needs to be replaced.

 

Zener diode on, but not checked, as I will do that when the engine is in and running.
Rectifier, needs replacing.
Brake light switch, on but not wired in. Brake pedal and rod on all right and rear brake working.
Light switch connected up but has one missing contact, ignition switch tested and connected up.

 

This fine pair of hooters was in one of the box of bits that came with the bike, and they still work. The bracket fits the front mounting for the petrol tank, so that’s where they will go.

 

The headlamp shell took a hit at some point in the past and is now egg shaped - very fitting for Easter which was last week. It’s not too bad, so it should be possible to fix it, although the rim is in worse shape and will likely need replacing.

 

While the headlamp is apart it is worth checking the ammeter. Took the back off, carefully blew the dust out and applied a tiny drop of watchmakers oil to the spindle ends. Good for another 50 years.

 

Dismantled the rear light. The two studs that hold it to the number plate both broke off, the internal earth strap is broken, the lens bolts fell off the backing plate and the lens has a corner chipped off. The good news is the bulb works.

 

Well that didn’t take to long to mend. I’m glad that it could be refurbished instead of taking the easy option of replacing the whole unit.

 

Back light and number plate on the bike and testing the brake light circuit.

 

Some minor repairs To the wiring in the headlamp then lots of fettling to get the rim to fit. Now wired up and on the bike, proudly showing its battle scar.

 

More on the electrics..... it turns out that the main lighting switch is all right and the high/low beams, tail light and pilot all work when using the switch. So the duff continuity test was in error.
Moving on.
The handlebar switch for high/low beam is in a twist grip on the left. It’s a period Britax switch but I don’t know if it’s original to Triumph. Here is the switch on the bench in pieces.

 

The dipper switch doesn’t work because of a broken spring that should be keeping the contact under tension. I fashioned a new spring and now the switch works. In the picture below the new spring is in place in the switch and the old broken spring on the bench next to it.

 

The lighting switch is now in place on the handlebars and tested all right. The horn switch is wired in and working too.

 

For a change of scenery I started tinkering about with the engine today. Firstly it cannot be turned over on the kickstart, so it is probably seized. When the timing cover is off I will try turning it over with a spanner but I’m not expecting it to move.
Secondly there was a chain wrapped around the sprocket, but I found a false neutral between third and fourth gear and could take the chain off.