Replacing inlet manifold gasket

The most frustrating thing about replacing the inlet manifold gasket on a Lambretta (or mine at least) is that you have to drop the engine off its mount in order to take the manifold off its studs. Another 5mm and we'd be clear. Alas, this lack of space makes what could be a 15 minute job into at least an hour job fraught with potential complications.

On the bright side, we don't need much of a drop so there's no need to disconnect any cables or electrics. Once my engine was removed my engine still sat happily in place and could be cajoled most easily by dragging the scooter from side to side by grabbing the footboard mount. When pulling the frame this way toward the carb side it makes the engine drop enough so that the manifold can just be squeezed over the longer stud.

During all this I did have a trolley jack placed just beneath the cowl in case it decided to drop some more. This was also going to help me move the engine back into place when finished.

I scraped the old gasket off the manifold and the cylinder, being very careful indeed not to drop anything into the cylinder. With the new one in place I squeezed the manifold back over its studs. Previously I'd been using spring washers but after some reading and observation I figured that a crinkle (wavy) washer would be better due to limited space on the studs protruding above the manifold. I didn't have the right size crinkle washer so I made my own! I just took a normal washer and hammered it while held in a vice. Not pretty, but effective.

Inlet manifold worked loose, gasket fail

So I've been using the scoot happily for a long time now with little bother, typically once a week getting to work in Bristol. It must be over two years of reliable starting and riding in all weathers - hot, cold, wet and dry. The only thing I've been having to stay on top of is a very slow loss of air from the rear wheel and regular disintegration of my air hose regardless of whether I buy Indian or Italian. Regular oil checks have revealed no noticeable oil loss through leak or burn. MOT's have gone without a hitch.

All good then, until a few weeks ago when midway through my journey home from work it started running rough - not idling without throttle, and low on power. A test ride the next day revealed that the engine would race frighteningly fast with choke on, and die without it. This is symptomatic of air getting into the cylinder not via the carb.

Then it went cold. Then it snowed:

Finally today the snow has gone and basking in 8 degrees warmth I was able to take a look at what's going on. The inlet manifold has become loose and part of the gasket disintegrated, allowing air ingress. With the choke on this had the effect of a wide open throttle.

So now I need to drop the engine by a few cm's (again) to get the manifold off, replace the gasket, and fit it back with some nylock nuts and wavy washers. Tight. And hopefully this time it'll stay on!