Front brake housing fitting

Hi all
Been a really slow build due to my ineptitude regarding Luna's & other projects and hobbies.
I'm trying to press on but can't get the front brake housing to clamp to the handlebars, any advice or pointers please?
I've got an Allen bolt that goes in under the housing but can't get this tight and looks like I'm missing a piece to fit in there. Even I did not sure what could go through the small half moon hole to lock it in place.
My only idea is to drill through the screw under the switch housing into the handlebar and screw a longer bolt through but clearly not standard. What should happen as per factory design please?
Thanks
Mike

Hi Mickey, there is a spacer tube that goes into the housing first & then the Allen bolt, so as you tighten the bolt it clamps the housing to the bars. For some strange reason they made the housings with 2 different Allen bolt sizes - 5 or 6mm!.Not sure how easy it is to get hold of the tubes? If not just make your own I guess? If you need to know the length I can un-bolt & measure mine if it would help...Steve

Yes please Steve
That would be ace! Sorry to put you out but I haven't got a clue what size or even material it is, I assume metal but does it collapse / concertina or just slot in & bolt up?
Thanks very much for your help
Mike

Sometimes a picture can help, this is from the parts manual I have


This page names the numbered parts


You might have to zoom in or download and enlarge the scans

And after all that, there's some of the parts like the throttle tube and housing on ebay. The threads where the retaining screw (which I shaped I think) are prone to stripping
http://www.ebay.co.uk/itm/Lambretta-Vega-Cometa-light-switch-housing-and-throttle-tube-/141720465328?pt=LH_DefaultDomain_3&hash=item20ff32afb0
Rimini or scooter resto's are a good place to check for the bits as is Jem Booth. I hope this helps a little

that is a handy picture and shows the tube Steve Trotsky said I'm missing. pretty sure I can fashion something to do the job when I get the dimensions. However I'm still confused as to how the tube will help clamp the housing on - it wont touch the handlebar itself and I don't imagine the housing will compress to clamp the handlebar. hopefully all will become clear and it'll work without me having any
understanding of why! this has approach got me this far through life!

thanks again for your help chaps - I thought I didn't know much about bigger lambrettas but I can actually build these. like a fool I thought this little vega would be easier in comparison!

I'm not doubting your skills at fabrication. I would guess making the throttle tube a challenge, especially with the slots at the end for the worm. Easier to go with a ready made tube I'd have thought

You should doubt my skills at fabricating! I also now doubt my ability to describe my difficulties! I could never make that, luckily I've got all that. I even had the lever housing professionally polished! It was I guess doing this that I lost the little tube thingy to hold the housing on the handlebars.
I now think I know what I need (part 5 on the very helpful diagram) just need the size of it and hope it works despite being clueless as to how it works.

H Mickey, sorry it's taken so long to sort  Hope this helps. Mine is a 5mm bolt, any other stuff you need measuring let me know...Steve

 

Thank you ever so much Steve
That could not be any clearer (even for me), I'm sure I can find / bodge something to suit.
Time to press on with the build now !
Thanks again.
Mike

Hi again
Got side tracked with other projects & finding the tube was more difficult than I imagined. Finally sourced one & it works like a charm, thank you again Steve I would never have figured that out in a million years!