Kit name: SS225 X7 (large block)
Manufacturer/Supplier: Casa Performance
RRP: £662
Year launched: 2017
Average estimated power output: 30bhp
Bore: 70mm
Stroke: 58mm
Capacity: 223cc
Induction Type: Reed valve Standard Port timings: Exhaust 190° – Transfer 124°
Overview: The SS225 kit is based on the cylinder used on the CASA race-winning scooters from the 2015 ESC and 2016 BSSO race series and features all the port layout features you would expect to see on an item
of this quality. The kit is made from a high-pressure aluminium casting with a Nicasil liner and the induction is through a huge six-petal reed valve which mates into a large inlet port, with single boost and Boyesen side transfer feeds. The main exhaust port runs a central bridge and has good width. The carburettor exits on the kick-start side of the engine and there are a range of inlet manifolds available and thus, depending on which size is used, a decent choice of carb set-ups. Pistons are available in both 30mm and 39mm compression height variants, giving good choices for con-rod lengths. The standard cylinder head is a heavy duty, centre squish, side plug unit which comes with a 10.5:1 comp ratio off the shelf, when using a 58mm stroke. This may alter if you use longer stroke cranks, and may need to be adjusted. Overall, this is a high-performance unit, straight off the shelf, but needs careful thought when setting up, making sure all performance metrics are set optimally if maximum power is to be attained from the word go.
Tuning suggestions: Claiming to be the most powerful kit out of the box for the 200cc Lambretta casing and offering ‘at least 30bhp' with the right set-up, it is already impressive with its performance. What extra power can be extracted from it remains to be seen, but as ever… we scooter owners love to add more power! Certainly for the road, we are now seeing 30+hp scooters becoming more common, with reliability too, and on the track… 40+hp seems to be the goal. The Casa website now also lists the X7e version of the kit, which is the latest update to the cylinder, and features enlarged transfer ports, inlet port and boost port, as well as increased gasket face surface area.