These instructions are based on the latest version of the kit, using a 58mm stroke crankshaft with 107mm rod (i.e. standard Lambretta)
The optimum base squish to aim for is 1.3mm, however from 1.2mm to 1.6mm is perfectly acceptable. These are the cold build figures, as on average a gasket will shrink by .1mm when the engine has been heat cycled. So once and engine has been built and run, the figures were are looking for is 1.2 ideal, but within 1.1 to 1.5mm
M8 Main cylinder studs: 20 FT LBS (Use only quality long studs, with thick washers, and long nuts.)
M7 smaller head studs: 12 FTLBS
Reed Manifold counter sunk screws: 7/8 FT LBS
Use a small amount of Loctite Blue 243 on the studs and bolts.
THREE-BOND sealer should be used on all block, cylinder and head faces, as well as the inlet manifold.
Base settings are for standard set ups, and could be different should you machine require it.
Static setting for lower revving expansions such as the JL3 15/16 DEGREES
Variable Timing (Varitronic) 19 /20 at idle
Static setting for Box pipes such as Ancillotti, Clubman etc 16 /17 DEGREES
Variable Timing 21 /21.5 ay idle
Basic carburettor settings - Dellorto 30mm PHBH
Fuel valve 300 minimum, ideally 350
Slide 45 to 50
Pilot 55 / 58
Air Mix 2 turns out from base
Atomiser AV268 for box pipes / AV268 to AV270 for Expansions JL3 etc / AV270 to AV272 for higher revving pipes.
Needle options :-
We use X13 or X2, either need to be on the 2nd groove from the top.
Main jet for box pipes 112 to 120
Main jet for expansion 120 to 130
The above settings are for standard carburettors, we Ideally recommend the use of a variable power jet kits to be fitted.
General Set up advice
Recommended air filter is the Breath Sweet or RamAir, but you can run this open mouthed as well. A fast flow fuel tap is needed, and should be measured at operating height to 550 to 600mls of fuel in one minute or under.Fuel and Oil
We always highly recommend Super unleaded. We have found BP and Esso Supreme to give the best and most constant octane rating results.
Oil should be used at a 3% ratio. This equates to 30ml for one litre of petrol, (150mls per 5 ltrs) Fully synthetic is preferred for the longevity of the engine, piston rings etc, semi synthetic is acceptable.Gearing recommendations
Base calculation is between 5.22 for higher revving expansions, and 4.99 for box pipes and lower revving expansions. (You can visit our downloads page - gearbox details - which lists all gearbox, sprocket and chain combinations with the final drive ratios calculated)
The best option gearbox is Italian Li 150 (early Spanish is the same) using 15/46 sprockets for the 186, and 198 can go to 16/47
A readily available gearbox is the Indian factory SIL GP200 gearbox. Depending on the kit and exhaust, combinations of 18/47 19/47 or 18/46 could be used. Clutch
Five plate is the suggested minimum, six plate would be ideal for longer life or if you use the engine harder. Non synthetic gear oil with a straight 85/90 or 90 grade. Silkolene or Putoline Medium gear oil is ideal.
Normal use NGK BR8ES/BR8EG
Hard Motorway riding BR9ES/BR9EG
When building and engine we always pressure test when built. We highly recommend this with all engines, but more so with kits as air leaks will cause incorrect jetting, poor running, seized or blown pistons. We sell a complete pressure testing kit if you require it, or we can offer a pressure testing service.