Lambretta crank induction with Malossi MHR 221

[mick1]

Cheers Sean

My original idea is to get it up and running, dyno it............then strip it down and have a play.......i'll be in touch

[mick1]

Ok, so it was all going to plan.....but as we say "if it's all going to plan you've got the wrong plans"

Sure enough i offered the engine into the series 2 frame....(i'd cut the loop away with plans for a removable back section), but......
series 2 frame by mick leaf, on Flickr

It appears the head on Vespa is quite a bit taller than a Lambretta. The head is too close to the frame and the spark plug is not offset and would be impossible to get at.

The options i considered were: Remove fins and cut new hole for plug.
Fit a Lambretta head (probably Avanti)
Alter frame
What i decided to do was:

Ld frame 1958 French by mick leaf, on Flickr

Cut up a 1958 French Ld and put the engine in after removing "surplus" structural frame work. To be fair i'd had the frame for over 10 years with the intention of fitting a Li/GP engine but had never got round to it. Anyway, got the angle grinder out and went to work. I had a rear section of a series 2 frame to hold the engine, so the intention was to graft this into the Ld.

Here was the first attempt at fitting the engine (i don't have a garage and most of the work is done "al fresco"):

QMT Raptor by mick leaf, on Flickr

[holty]

a shorter rear shocker will give the head more space on the first frame you had it in, a center plug head would help too, offset cones might help as well, been through this with my rotax, my barrel is slightly leaning down to give more clearance and I trimmed the head, and a short spark plug, ways and means, keep at it, im sure you will find a solution, good luck.

[mick1]

Hi Holty

The pictures didn't do it the injustice it needed I reckon that the head is nearly 50mm higher than a standard lambretta. I tried it with a 300mm shock in and it was miles away, coupled with the fact that by slightly angling the head down i was pushing the exhaust into serious ground clearance issues. I'm happy with the outcome as the french Ld will be on the road along with the series 2 that i'm currently building an engine for (Avanti steel lined barrel, slightly tweeked).

More to follow

[Grumpy225]

Ok, so it was all going to plan.....but as we say "if it's all going to plan you've got the wrong plans"

Sure enough i offered the engine into the series 2 frame....(i'd cut the loop away with plans for a removable back section), but......
series 2 frame by mick leaf, on Flickr

It appears the head on Vespa is quite a bit taller than a Lambretta. The head is too close to the frame and the spark plug is not offset and would be impossible to get at.

The options i considered were: Remove fins and cut new hole for plug.
Fit a Lambretta head (probably Avanti)
Alter frame
What i decided to do was:

Ld frame 1958 French by mick leaf, on Flickr

Cut up a 1958 French Ld and put the engine in after removing "surplus" structural frame work. To be fair i'd had the frame for over 10 years with the intention of fitting a Li/GP engine but had never got round to it. Anyway, got the angle grinder out and went to work. I had a rear section of a series 2 frame to hold the engine, so the intention was to graft this into the Ld.

Here was the first attempt at fitting the engine (i don't have a garage and most of the work is done "al fresco"):

QMT Raptor by mick leaf, on Flickr

Why not have the cylinder and head turned down to the same diameter as a Lambretta cylinder? I know the exhaust stub will make it tricky but someone with an end mill could make short work of it. As far as the spark plug placement goes just weld up the factory hole and have a new one cut in the correct place. This way it all mounts up at the correct geometry and all the clearances work as per normal.

[mick1]

Fair point Grumpy, I did consider altering the fins to suit but decided not to. I'm guessing they made them that big for a purpose (cooling) and as i don't hear of many seizing, or having the problems we have with Lambrettas i kept it as standard as possible. The cowling is one of my next challenges...The Vespa intake is opposite to the Lambretta, so a few mods needed on this one.

[Steveshipley]

great work and interesting read. good luck Mick

[mick1]

Couple of side issues and slight change of plans:

As i'd originally planned on putting the engine in a series 2 with the GP forks, i had to extended the forks to fit. This was done. When i changed the frame to the Ld i discovered the fork stem on an Ld was longer than a series 2, which meant.....lengthening the forks for a second time. Job done and and fits well.

I'd also originally planned on using a customised headset:
IMG_20190526_111526 by mick leaf, on Flickr
IMG_20190526_111547 by mick leaf, on Flickr
I'd bought this of ebay a few years ago and presumed it was Series 3 gp modified headset. It was bought with no internals and no description.

It fitted reasonably well but caught on the top of the horncasting. I trimmed the horncasting suit and it looked ok.
IMG_20190419_140305 by mick leaf, on Flickr

I then decided to buy the internals....duly bought...but didn't fit

I took the headset up to AF and showed it to Ben and Scot...there was a mixed opinion, the internals were a series 2 but the headset clamp was definitely a series 3 ? It was suggested it could be off a 3 wheeler or it was some sort of hybrid ? either way series 2 internals were needed. I'd also intended fitting a GPS speedo and that would need the headset modifying.

I decided to put this headset to one side and use the original Ld handle bars. This required a new gear change and a Hydraulic brake/throttle. The brake and throttle was simple enough as these are standard motorcycle parts. For the gear change i bought an MB set up.

IMG_20190526_111347 by mick leaf, on Flickr

quite pleased with the result....but....it turns out that the Ld forks are a slightly larger diameter than the GP ones This meant making a thin bush to fit inside the clamp. Another annoying hic-up but got it sorted and fitted.

It seems every little problem has a knock on effect and creates more issues.....still onwards and upwards.

[wrecklessrobbie]

An interesting project Mick.
I have been watching your progress.
How are you lining up the rear and front wheels?
Do you have a jig?

[mick1]

An interesting project Mick.
I have been watching your progress.
How are you lining up the rear and front wheels?
Do you have a jig?

Ah, yes how did i line everything up.........I started of with spirit levels on everything and measuring from what i assumed was a good reference point. My first few attempts didn't look right, with things obviously out of kilter, so after much deliberation i finally settled on doing it by eye

As much as the frame may be straight whose to say if the hub, forks, rims, tyres, etc are 100% Driving behind some scooters it's easy to see that rear wheels don't line up with front ones and some rear wheels are at a quirky angle....yet they still handle ok.

I'm quite happy with how it's going and i think i'm in the ball park (good eyes !!) but i will put it in a jig before it gets it's final weld.