The weakest part of a Lambretta engine is between the transfer port on the mag housing side. It’s common to see a fine crack – these cracks leak especially when the engine warms up and needs welding to repair them.

I’ve lost count how many of these I’ve done! 

30 years ago I joked in the future I would be repairing more Indian casings than Italian ones and guess what – Oh yes I’m repairing these bloody SIL engines over and over again.

Not only is the weak link the transfer area the next weak link is the quality of Alloy that the Indians used, but don’t think Italian casings are much better some are near impossible to weld.

This was another one of those casings, you can tell by the finish of the weld. And check out the casing where its been machined you can see little holes all over, not just in the welded area, the casing is like Swiss cheese. Probably not one to leak through the casing but this is why you need petrol resistant gasket sealer on every face.

As this is the weak area I use stronger welding rods than the casing and build up more to add strength after machining.

Any casing welded will distort. In fact a normal casings set up correctly on a miller will find some the faces move and distort – even worse if your welding on the gasket faces or adding a bump stop or replacing an engine mount.

Check out the machining you can see there are areas not cleaned up as its set up and machined to get the casing back to true.

If you or your welder hasn’t got the correct machinery and you don’t know how to use them – then you’re in trouble! Ask, if the answer is vague – sing ‘stop right now’!

All in a days work!  


Leave A Comment