Hi all, new in the forum and to the RTs, also not really tech savvy.
To start with, there are a couple of thing I don't quite get on my recently bought RT3.

1. What's that thing on the right side of the frame, under the exhaust? It's a small metallic squared "box" connected with a wire...

2. I see two small levers on the left handle. One of the 2 going to the cylinder head while the other to the front of the cylinder (covered by a round gum). Which one of the 2 is the decompressor? And what's the other?

Thanks

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Can't help with the box attached to the frame . It's nothing originally on the bike .
The lever and cable going to the front of the cylinder , is the stock decompressor valve
for starting .
The other lever and cable going to the head , is an aftermarket compression release ,
sometimes used going downhill , to reduce rear wheel lockup , I believe ,
though I could be corrected , if wrong .
I've seen plenty of the aftermarket decompressor before , but never on a 360 with
the stock decompressor . Quite unusual .

 Was going to say---we 'all' want to know whats in that box now. But then i saw the second pic & expanded it. It's a resistor & i have one like it but not with that cover, I think--bit of a guess--that its to take the place of the headlight with the switch in the park position but running, which leaves headlight off but is still firing full power into the light circuit & had that there so the other lights don;t blow. Think my yamaha V90 early "70's scooter had it so you could run minus the headlight but have tail & park light running. Maybe i got mine off a DT250 come to think. Now all that would be sorted by single wire regulator.

Does yours have an unusual ignition or lighting switch with an extra position. In my post above i'm referring to all lighting running on AC magneto power.

Nixt, welcome to the forum from Andy in U.K.  I can tell from one of your other threads 'Finally got one!' you are pretty excited to be the new owner of a 360, and so you should be as that's one great looking bike, so well done.  I also like that you intend to keep it as original as possible too.  I'm no expert on any bike let alone your specific model but rest assured there are good folk on this forum who will soon be along to help you with your queries.  I stand to be corrected but that 'box' you mentioned attached to the frame looks very much like a dummy resistor load.  In the early days before proper reliable voltage regulators came along it was always a design challenge to carefully balance a bikes electrical loads between lighting cct  (esp when switching the lights on and off) and charging circuit.  The biggest single switchable electrical load on your bike is the headlight (perhaps 25Watts?) which if unattenuated would easily unsettle the electrical balance of the lighting circuit typically causing front bulb(s) and or the rear bulb to blow too.  Yamaha's rather crude (by todays electronic standards) method of limiting the load swing was to use a dummy resistor load of 'similar capacity' to the headlight.  It is wired to switch IN/OUT to offset the impact of switching the headlight on/off.  A much better solution nowadays is to fit a 6V single wire regulator, assuming you plan to keep the bike stock electrics, and ditch the dummy resistor load altogether.  Simply wire the regulator into your lighting circuit from your stator. Hope this helps, Andy. 

Thanks all for the warm welcome and the precious help.
I went down in the garage and you were all right
Attached there's a picture

I've also tried the 2 decompression levers and looks like the aftermarket one (on the cylinder head) works much better than the other. Maybe it was added due to some problem with the original...I'll try and look into it.
Do you know of any common issue with that I should check?

What if I want to get rid of the aftermarket decompressor? How can I close the valve cap then?


One more thing: it looks like the exhaust has been welded to some silencer (pic 2 and 3)?
There were any original silencer back then (them I'd keep it) or can I just cut it to leave the original one?

Ciao

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Whilst previous answers are likely to be correct, I wouldn't totally dismiss that resistor as being a non standard fitment. The reason that I say this is because you probably have a European model, and there a few differences between the Euro and US models. Does it look like it has been spliced into the harness after manufacture, or does it look like it is meant to be there? Also, is there a resistor in front of the coil, with a single red and single white wire going to it?

Your left side switchgear is not the same as US models, in that you have a lights on/off switch fitted there. This is blanked off on the US models and the on/off switch is within the main ignition switch (second turn round for lights).

Personally, I would ditch the aftermarket decompression valve and replace it with either a spark plug or blanking plug (see parts list). 

Have a look to see if the standard decompression valve is being opened by the cable. Maybe remove the valve from the cylinder and check that the hole isn't blocked with carbon. If you need a new cable, then DEET here sells them (This email address is being protected from spambots. You need JavaScript enabled to view it.).

If the bike runs ok with that pipe, then probably leave it for the time being.

It would be great if you could find a Euro specific parts and/or service manual! Fleabay userid bobomoto58 in France is my "go to" supplier for manuals, but he doesn't appear to have anything at the moment.

EDIT - of course I meant rectifier with the red wire and white wire, not resistor!

The aftermarket decompressor is a neat trick, makes some funny noises when in use, and does I suppose help with engine braking in deceleration, but you will end up with black oil all over the cylinder head from use and black oil seepage around the decompressor. As for starting the engine, properly tuned, and timed the aftermarket decompressor isn't needed in my experience, the OE decompressor works just fine. 

Good for scaring pedestrians lol those head decompressors, or stopping stalling in tight situations down hill through the trees. Trials bikes used then in the old days in difficult observe section trials.
Original in the front is a good setup but over many years of rich mixture it can block in the cylinder hole but 'also' the hole leading down to the exhaust port outlet, plus get carboned up in 'itself'. Have mine blanked off & just kick it hard but not ideal.

Hi, the "box" is a resistor. It was standard on a lot of European models. I attached you the pictures and part number of the part list.

Axel