ALL NEW LAMBRETTA CASING

[warts]

They do say in their blurb the motor mounts can be different sizes, perhaps enough to avoid any head/under frame kissing?
There seems lots of ways to build a motor with little change from £k than we'd prefer. We sorta suspected it wouldn't be cheap.
So I guess no one has seen one?
Is it going to be years rather than months?

[shocky]

They do say in their blurb the motor mounts can be different sizes, perhaps enough to avoid any head/under frame kissing?
There seems lots of ways to build a motor with little change from £k than we'd prefer. We sorta suspected it wouldn't be cheap.
So I guess no one has seen one?
Is it going to be years rather than months?

yea read that i dont know how far back you could push the engine thou as the suspension geometry would change and the rear wheel would get close to the rear of the frame then theres the kick start boss not lining up with the cut out on the panel

[GP240]

a cheaper version of a twin would be nice.

[Adam_Winstone]

My Euro Lambretta GP is 72mm bore by something like 64.5mm stroke (should be 65 as 62mm webs + MB eccentric pin) which works out just over 260cc. This does fit a standard frame and doesn't need anything other than standard engine mounts. If you want to go much longer then you need to start looking at what the DAK (?) guys have done.

The DAK guys decided to change the alignment of the barrel/piston so that it points downwards, which clears the barrel and head away from the frame tube... a very simple and good way of overcoming the issue. If you consider that you've got 360 degrees of rotation to play with then their small angle change is nothing, even if compared to the 90 degrees vertical rotation that Luna and J motors employ. If you are going to seriously reconfigure the casing to take such a large stroke, different cylinder, different web crank (saves pin welding, crank twisting and future rebuild headaches), etc, then changing the angle of the barrel is pretty routine. Indeed, I'm playing with ideas at the moment.... and the DAK casing, crank and mag housing would be a great place to start.

If Steve Rowe still lived closer to me I'd have got him to weld/machine me a bigger engine casing by now

I know that MB offer a 64mm stroke crank but I'd love to hear from anyone else that can better that. Obviously, web diameters are the real restriction and any increase in these will need casing increase to suit. What is out there?

Cheers for now,

Adam

[warts]

Re lengthening the stroke, is there any reason not to move the gudgen pin higher in the piston? High performance 4t's have it as high as possible to have the ring pack as comapct as possible. I see some 2t's have windows to various ports "up there" and use the bottom edge of the skirt too, is this then running foul of the laws of unintended consequences? ie making room available in the cylinder to avoid these difficulties, you decide on crankcase induction. Then you end up with something else entirely and a shed load of other compromises.
The YZ250 crank at 69mm is only 5mm longer stroke, while a std type head and cowl may become an interference fit if moved that amount, is it beyond the imagination of a determined scooterist to resolve?
I think its great that someone is continuing to develop the Lammy concept. I hope sufficient people support it, to make it worthwhile and economic to produce.

[red]

They do say in their blurb the motor mounts can be different sizes, perhaps enough to avoid any head/under frame kissing?
There seems lots of ways to build a motor with little change from £k than we'd prefer. We sorta suspected it wouldn't be cheap.
So I guess no one has seen one?
Is it going to be years rather than months?

yea read that i dont know how far back you could push the engine thou as the suspension geometry would change and the rear wheel would get close to the rear of the frame then theres the kick start boss not lining up with the cut out on the panel

Easily solved buy cutting back end off and chucking panels in the bin :biggrin: :biggrin:

[rosscla]

I think I remember seeing one for sale on flea bay recently where the engine mounts had been moved back a bit and the rear end lengthened to accommodate. Supposed to have been done by MB

[a.lo.v2]

i seem to remember this casing being announced a couple of years ago with crankcase induction, i,m sure i saw a CAD rendering with a casting between the mounting lugs. not sure there is really room for a manifold.

[RICSPEED]

http://www.granturismo.pwp.blueyonder.co.uk/monster.htm

[Rich_T]

This is a real tricky one. there was no competition to Tino's twin but this casing will always, wrongly IMO, get economically compared to SIL casings. With the Indians changing their minds with the weather it would be a risk to cast and machine a run of parts only to have a delivery of SIL products touch down and effectively torpedo your market.

The problem I had with my casing was getting a reliable source of case inducted cylinders, heads, pistons and cranks. This is now fixed as I have tooling for a 275cc water cooled cylinder that uses JS550 jetski pistons on a 60 stroke. Maybe back end of 2013 I'll have a play with the billet case drawings again and see what happens.