Last updated 09/07/13

Thank you for purchasing your new cylinder performance kit from the Imola/Monza/Mugello range of kits.

The kit should consist of the following parts:

1 x Alloy Barrel (Mugello/Imola/Monza, as appropriate).
1 x Machined cylinder head
1 x Piston
1 x Gudgeon pin
2 x Piston circlips
2 x Exhaust studs, nuts, gasket
3 x Base gaskets - differing thickness for squish clearance
And for the reed-valve type kits, 1 x Inlet manifold assembly with studs and gaskets

Other parts available from us for the benefit and ease of fitting of these kits include:

A range of Mugello inlet manifolds to enable easy fitting of Dell'Orto SH (& Jetex), PHBL & PHBH carburettors.
Dellorto PHBL & PHBH (including power jet types) Carburettors
Longer throttle cables
High flow air filter options for both standard (Dellorto SH type) and larger bodied carburettors
Fast-flow fuel tap; also our exclusive version with low-level warning light
High specification crankshafts
High load engine bearings
'Rolf' brand oil seals
High load bearings
Clutch kits
The technically unrivalled Varitronic Electronic Ignition kits
'JL' type expansion exhaust pipes
Ancillotti and Gori exhausts
And a full spares back up for all of the above!

These instructions are intended to assist you in the fitting of your kit to give added performance and reliability to your Lambretta, (but are not necessarily an exhaustive list of instructions and we cannot be held responsible for damage to you or your machine through following these instructions!). They do not cover subjects such as gearing and individual machine jetting, which are subjects on their own. If you are in any doubt about fitting the kit, please follow the instructions of a detailed manual or seek the assistance of an experienced engine builder and/or as a customer of The Cambridge Lambretta Workshop, please feel free to contact us and we will endeavour to help you. Please take your time with the fitting and set-up of your kit, it will pay dividends in producing a reliable and quick engine. Ensure that the tools and other hardware (including other components of your Lambretta!) used are not prone to 'bodging' the job and do it all with the safety of yourself and those around you in mind.

Food for Thought:
This assembly is intended as a 'bolt-on' kit, but it is only sensible to follow the advice in the following paragraphs; It is imperative that on fitting the performance kit of your choice to your engine the 'bottom-end' of the engine (crankshaft and bearings) is in a strong state, as must be the clutch, gearbox and transmission. Remember; your engine is only as strong as the weakest link! Please bear in mind that a standard Lambretta engine is fairly low powered by modern standards and if you are planning to extract more power from this engine then it may be that the basic engine and transmission unit will need upgrading to cope with a significant increase in power, i.e. an engine that was a 6 brake horsepower unit having it's power raised perhaps to over double this may not cope with such an increase without an overhaul to complete engine. If you are in any doubt about the strength of the unit, then it is only sensible to strip and check it as necessary, or seek professional advice to confirm the soundness of the unit or components.

Points worth considering in the base unit at this stage include:
Crankshaft. The use of a good GP-type crankshaft, which are generally of stronger construction than a basic Li/SX unit or a crankshaft of dubious condition. Also, if a TV-type crankshaft is fitted, this will only match a TV style piston.
Bearings and oil seals. When were these last thoroughly checked or replaced? Race-type bearings are available at reasonable cost.
Ignition system. Any higher revving engine will struggle with a standard points system, which tend not to cope with the demands of the extra speeds the engine works at.
Clutch. What state might this be in? Will it cope with any extra power? Standard clutch units in top condition using 'Surflex' B-type clutch corks, steels in good condition and up rated springs are generally sufficient to cope with these kits in a mild tune stage. Heavy use, e.g., further tuning, riding hard and mainly '2-up' may require further upgrades.
Gearbox. Whichever gearbox you are using it should be in good condition. The final drive ratios can usually be altered to one near to that of your requirements by changing the primary sprockets. The gear selector dog, which operates on the layshaft, must be in top condition so as not to allow the engine to jump out of gear.
Fuel system. The use of a fast-flow fuel tap is advisable with any performance kit Engine casing. The casing should be clean, (internally at least) free of grit and grime. The threads on the casing should all be sound and crack free, as should the dowel holes. Most damaged threads can be repaired, but the amount of work required to do so does vary.
Also, Last but definitely not least! Are your brakes and suspension in top condition? Good sense says these should be. With the increased performance that these kits will bring, this must be reiterated. Upgrades from standard are available

The Strip of the 'top-end'
It may be that you already have the engine unit out of the machine, which makes the fitting easier, but let us assume that you are fitting the kit with the engine in-situ. Preparation to fit the performance kit
By this stage you will have decided whether or not you need to strip any more of the engine for your upgrade. These instructions will not cover further 'bottom end' engine and gearbox work and will assume that you are ready to prepare for the 'top end' rebuild.

Fitting the top-end
Jetting and Timing
For further information for jetting and timing refer to the spec sheet with your kit, or read our "How to jet a carburettor guide" if you have purchased the kit from another supplier.

Some guidelines for start up and early 'running-in'