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 1.4mm, however from 1.4mm 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 1.3 ideal, but within 1.3 to 1.5mm. The figures are based on cylinder heads with 9.4mm band)
Notes for Engine cases
Although predominately on Indian cases, but can also be on other cases where the top side has been bored high, you should check carefully the seal from the case to the cylinder on the top transfer port. Stock gaskets supplied in the kit can occasionally not give you enough sealing area. The PT Ultimate cases will help overcome this, but we suggest using a 0.50mm packing plate, bonded both sides with Threebond to overcome this. No gasket is needed.Assembly Notes
TAKE CARE FITTING THE PISTON AND CYLINDER-BE SURE TO BUILD WITH THE REED AND MANIFOLD OFF SO YOU CAN CAREFULLY HELP LOCATE THE PISTON RINGS OPEN PART AT PEGS AS THEY CAN CATCH ON THE LEFT AND RIGHT OF THE TOP OF THE INTAKE PORT USE A SMALL BLUNT SCREWDRIVER ON THE RING TO HELP GUIDE TO THE BORE -NEVER FORCE ANY PARTS -Torque settings
Recommended air filter is the Breath Sweet or RamAir. 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, this is a must for longer journeys, hard riding or when the scooter is fitted with any expansion type exhaust 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 4.99. (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 16/47 sprockets.
A readily available gearbox is the Indian factory SIL GP200 gearbox. Depending on the kit and exhaust, combinations of 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.Spark Plug
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.