Modern Vespa

I need to install a new exhaust manifold. I've looked at past posts and repair manuals and I'm hoping for clarity on a few things.

1. Liquid gasket or no liquid gasket on the exhaust flange (or any other portion of the manifold). I've read that it's a dry fit and that it's too close to the engine and will burn off. But also, take all precautions to avoid leaks by using liquid gasket.

2. Lambda sensor torque..how is this achieved without damaging the pipe or sensor? In a vice? Miami vice? I have the socket configuration sorted to get the torque, just want to do my homework before making a round pipe oblong because I was impatient.

Thanks as always.

The exhaust manifold gasket is a dry fit copper one, part number 480853.

You'll need to remove the pipe in order to remove the Lambda sensor. I'd secure the pipe in a bench vice in order to remove it.

Hi Touring300, Thank you for this info. I have the old copper gasket out and a new one ready to go. The Lambda sensor is also out of the old manifold.

I had purchased a specialty 22mm deep socket for the Lambda sensor, but the sensor wiring is too long and rigid to allow the socket to get a good hold. I have a 22mm open wrench style that will work with the sensor and torque wrench. I just want to make sure I can get the 40-50Nm of torque on the sensor without damaging the new pipe.

Assuming you performed this task, did you put copper anti-seize on the Lambda threads?

Thanks again. I'm appreciative.

I recall using an open ended wrench because of the wiring issue, and high temperature anti-sieze on the Lambda threads when reassembling and I've never had any issues. I am sure if anyone has any useful tips on this topic they will jump in.

While I won't be starting up the bike for a few days, everything tightened and set up without much issue. I guess we'll see how I did when I start 'er up. Thanks again.

Or clamp the sensor in the vise and rotate the downtube around it.