Mugello. 125cc converted to 200cc

Part of the upgrade on this scooter will be the very latest innovation from Tino Sacchi.

We are fitting the Brand New Mugello 125 to 200c conversion kit.

This forms only a small part of the upgrade, as we will also be using a larger bore exhaust, better braking, 12volt electricals and a carburetor specifically tuned for the purpose. not only will this scooter be quick, it will stop when required and be ultra reliable.

The new Mugello kit looks like this. Cylinder with added stud holes for a better surface seal when the head is in place, cylinder head, piston, rings, and all fittings.

Super clean surfaces all round with the additional inlet port bridge.

Nicasil barrel lining with additional booster port.

Notice the little lip on the cylinder head. This matches precisely a notch on the barrel so that the two mate perfectly when attached together. We are told that this head and barrel are matched so perfectly, it could be run without a gasket.

The piston in the kit, is so accurately manufactured, it comes with a stamp on it marked "A". If, when you have covered many thousands of miles, you feel your piston is a little on the loose side, then simply remove it and fit the next one up. Marked "B". And so on! Genius!! Your local dealer can advise you changes to the kit.

The piston rings are amazing. A bit like those eye glasses you can twist and turn without breaking them. Exactly the same with these. They are meant to NEVER break. Also notice the clips. they have no ends on, because those are the bits that normally come off and get dragged up and down your barrel causing a seizure and damaging your barrel, head or much, much worse.

 

I'm going to stop drooling now or I might be tempted to just keep the thing.

Engine. Partial strip and full rebuild details

Firstly, in all the years I have been scootering, the one area I have left alone on Lambretta's is the engine. I have never had the need to break open an engine casing as I am lucky enough to have a few of the very best builders in the country on my doorstep.

My best advice, if you are reading this blog in order to assist you to strip a scooter, is that it is likely you won't have the knowledge to strip and re-build a Lambretta engine. That's not to say you can't. Everything is possible. If you have engineering or mechanics skills, then it may not see to be quite a challenge to you.

BUT, you should bear in mind that when you take the engine apart, you will need to know if bearings are worn beyond repair, have the tools for the job and be able to recognise damage to gear cogs, chains, layshafts and so forth. With this in mind, if you are confident, then there will be a link at the end of this section to show you how a professionally built engine is put together. Taking it apart is the same, but in reverse.

What I have done here, is strip the engine casing of most of the parts (where possible) and I am then going to have it professionally re-built. I know it will then be safe for the new owner, have the correct components fitted AND come with a guarantee of workmanship.

Here's what I have done with the engine so far...

This engine appears to have been stood for many, many years. And if this project is anything to go by, taking it apart will fight me every step of the way. Usually, a simple job like removing the rear wheel takes under a minute. Not on this scooter. On your machine, underneath the large nut in the centre of the wheel is a locking plate with 2 or three holes. In one of them, will be a grub screw that goes in to one of the three holes you can see below beneath the washer. On this bike, it is missing and a normal washer has been used. This means that the rear wheel has been overtightened, squashing the washer and almost welding itself to the hub. I simply don't have the correct tools to remove it, so i will simply remove the wheel rim from the hub and leave it in place for the dealer to remove and thus, hopefully prevent any damage I might do attempting the almost impossible.

To take off the cowlings attached to the engine, you need to remove the exhaust unit. First, undo the two large bolts (or studs) at the upper front end of the scooter engine.

Then, look under the engine for a "tab" on the exhaust that is bolted to the block you can see in the picture below.

And finally, the tail of the exhaust should have a ring clip attached to one of the side casing bolts (or
studs). As you can see, the majority of the tail part is missing from this scooter.

Normally, at this point, you should be able to remove the exhaust silencer section from the downpipe attached to the barrel. however, as usual, this one is seized together, so the downpipe will have to be removed with it complete.

So now we will have to remove the cylinder head cowling to get at the exhaust manifold. Take out the spark plug if fitted.

Look at the edge of your cylinder head cowling, it is fixed via 2 bolts to the mag housing and one bolt right in the centre of the cowling. remove all three.

Now you can ease the cowling forward a little, enough to expose the exhaust manifold attached to the barrel. It is attached by bolts on two studs as you can see in the image below.

Removing them can be a bit fiddly, but luckily, these came off OK.

As you can see, there may just be a little bit of rust and dirt in the exhaust port.

But with the exhaust removed, you can now take off the cylinder head cowling.

Next, the flywheel cover should be removed. It is normally attached to the flywheel housing via 4 bolts, depending upon your model, there may also be holes for rubber grommets, which assist with anti-vibration. On this scooter, the bolts have all been replaced with oversize screws and will have to be ground off and then professionally removed.

With them all off, the housing can be pulled away.

Removing the cylinder head is simple. Remove all 4 bolts and make a note of the position of the larger one. This is hollow and threaded on both ends to allow the large bolt that holds the cylinder head cowling to be threaded in to it.

This is the position of the larger bolt in configuration with the engine.

With all 4 undone, you can take off the cylinder head. If it is in good condition, it can be re-profiled and the barrel honed or re-bored. So be careful not to damage the fins or join surfaces.

The barrel is locked on solid. The piston is seized inside and is not going to move for me. Another job for the experts. However, I'll press on removing parts that CAN be used again after cleaning.

Remove the two bolts holding the carb manifold.

Remove the two bolts holding the clutch and gear cable adjuster housing. You can also remove the gear linkage, gear selector arm and brake arm. Circlips hold the latter two in position.

Remove the rubber, engine bump stop. Simply pry it out with a screwdriver. Under it, there should be a thick washer. Don't lose this.

 

Remove the circlip from the rear brake arm and pull away.

That's about it for me with the engine. The rear drum is almost welded on, the barrel is seized and the kickstart pedal was missing.

So, because this engine is going to be totally re-furbed with new parts by the dealer, i might as well stop. In any event, it is going to have a brand new 12 volt electrical system, so the flywheel and stator plate are going to be replaced, uprated crank, seals, bearings, chain etc. might as well let the pro's do it.

If you want to continue with yours, scroll down.

Here is an excellent piece, written for the Lambretta Club of Great Britain by Rick huggins.
My sincere thanks to him for putting this together for us. It shows you EXACTLY how to re-build your engine and all the tools required for the job. My advice to you is to get advice before you start. If you can afford it, let the professionals do it, but if you feel good about it, go for it!


http://www.ilambretta.com/engine.html

Wiring Diagram for Mugello 12 Volt Upgrade

As previously mentioned, this scooter is going to be upgraded slightly so that the new owner can enjoy the benefits of some 21st century technology. The first upgrade will be the installation of a 12 volt electronic system to replace the old, unreliable 6 volt points setup.

Cosmetically, this will make no difference whatsoever to the appearance of the scooter but it will mean better starting and smoother running as well as an increased efficiency in lighting.

To carry out this upgrade, the old stator plate within the flywheel will be replaced as well as a new flywheel, regulator, CDI Unit (coil), bulbs and 12 volt wiring.

Here is my own schematic of the upgrade wiring diagram:

Points of interest

I'm always surprised at the things you learn doing jobs like this. Despite how many times you take scooters to bits, you always come across things you either don't know about or have forgotten.

When we removed the legshields from this scooter, we noticed that in front of the rear brake stop bracket attached to the frame, there is a rubber protective cover pointing forward. I don't recall seeing one in this position before but then again, i have never really had to concentrate on the individual items in order to write a blog like this.

So now you know where that part goes to make YOUR anorak restoration just right.

Panel Handles removal

To remove the panel handles from your scooter, undo the bolt on the UNDERSIDE of the handle on the exterior of the panel. Underneath it should be a star washer.

With the bolt removed, slip off the handle and then remove the roller mechanism from the panel from the inside.

The roller mechanism. With the panel handle off, you can pull this section out.

Under each panel handle, on both sides of the scooter, you will see a flat, spacer washer.

If your rollers are damaged, you may need to replace them either as a complete unit or by grinding off the retaining pin and replacing just the roller. All parts need to be cleaned and zinc plated, with the exception of the plastic roller and the handle, which should be polished to a high shine.

All replacement parts are readily available.

Stripdown notes and problems

Before we move on to tackling the engine of this scooter and removing all the tin wear from it, It is worth a few words about the process of stripping down your Lambretta if you are not one of those people who is familiar with the process or do it for a living. There are a lot of posts on this blog, that most good Lambretta dealers or garages take for granted because they carry out this kind of work all the time. This is aimed at helping those who do not!

By making sure that as a Lambretta owner, you take an active interest in finding your local scooter clubs, local dealers and actively participate by joining the LCGB, you will be better able to make informed decisions about the tasks you undertake and know your limits. Take time to find out who your local dealers are, talk to a wide range of people who will all have differing opinions about which is best and why. And then visit them too and make your own mind up. All of them are there to help you and do the best job they can, because after all, they depend on YOU for a living.

During the strip down of your Lambretta, TAKE YOUR TIME.

Make sure you have a clean and tidy environment and have all the tools you need at hand and put them away after each session. As you remove items from your scooter, sort them into boxes. One for parts that need to be blasted and painted, one for parts that require polishing, one for scrap parts.

This way, you can go through your parts to ensure you have references for everything you need to replace. If it helps, put nuts and bolts etc that you take off in separate bags and label them so you know you have ordered the right number of replacements. Make a list of things you need to finish your project as you go along. If you do it in an organised fashion like this, you will find it moves along much more quickly and smoothly.

When you encounter a problem, ask if you can. Call a dealer, a mate or use the LCGB forums so the guys there can advise. They have probably dealt with your issue a thousand times.

Do NOT struggle with things and do NOT worry when something breaks. During the strip down of this scooter, I have sheared countless bolts. Most don't matter, but some for example, are still stuck in the horncasting and they need to be removed. I do all this kind of job at the end. I will use whatever stub to try to get them out with grips, but failing that, they need to be ground back, centre punched and drilled out and re-tapped. It's not the end  of the world if this happens and you don't fancy risking it. You can box them all up and your local dealer will be happy to sort them all for you.

On machines this old, it is NOT your fault if a good number of the nuts and bolts are seized solid and end up breaking. But there are a few jobs where it is critical that you don't get too heavy handed and start damaging things. Better to walk away and try later. Leave seized things soaking in petrol or use a little heat to try to free them. And always use decent tools. At the risk of sounding like a health and safety officer, use protective clothing when required. It might be macho to not bother, but trust me, it is no fun having to be driven to hospital at midnight to have a surgeon remove a shard of metal that flew in to your eye while you ground off a 30 year old bolt.



In the pictures below, you can see the main engine bolt that no matter how much heat, lube and time we put in to it, would not budge. Because of this, hitting it hard with a 5lb lump hammer meant running the risk of breaking off one or both of the engine mounts on the engine casing itself. That more or less means a VERY expensive repair or a scrap engine and start again. I want this engine casing because the numbers stamped on it match the frame.


My only course of action was to take it to a dealer and have it professionally removed. It is pretty much the same system i would have used, but these guys know what they are doing. With plenty of lubricant and grinding off the damaged ends of the bolt, they were able to get it to move. Finally, after quite a lot of persuasion, it came out. but oddly, it would only go in one direction.


Half an hour of work to remove one bolt. but think what it saved if I had damaged the engine casing!

 

 

 



 

 





















































































Whatever you break can be fixed, but try to keep it to a minimum. Don't risk breaking a £100 part to get off a 5p bolt. And if, like me, you will be upgrading the machine with modern electronics, don't forget, you might be able to recoup a little of your outlay selling on the original parts. Someone always has a use for them.

Restoring a Lambretta of any kind is NOT cheap. By the time you have finished, not counting labour, you will probably have ended up spending more to complete it than it's immediate re-sale value. But your scooter is an investment. It WILL increase in value. And the better you carry out your restoration, the more valuable it will be. But only you will know just what amount of effort went in to it.

Stick at it during the frustrating periods, THINK about what you are doing and work methodically. You WILL get there in the end.

And one last thing...

Do not, under any circumstances, discuss the financing of this project with your partner.

:-)

Paul Slack
LCGB Webmaster
webmaster@ilambretta.com


A word of thanks.
My interest in all things mechanical started way before my interest in scooters. I was lucky enough to be invited to hold the torch whenever my father was underneath one of his cars, way back when I was in school. I loved watching him do that kind of stuff and he always (as far as I recall) managed to complete the job. I'm still fortunate, in that whilst stripping down this scooter, he has shown up to help me and his hands and feet appear in many of the pictures used on this blog. It is possible to strip a scooter alone, but it's much easier with another good pair of hands.

Thanks dad!