Aftermarket tuning options
Vespa cylinder kits for small-block engines
There has never been a better time to source aftermarket tuning options for your Vespa or Lambretta scooter. In this series, we take a look at some of the most popular choices, and see what each has to offer…
Last month we looked at cylinder kit options for the 200cc Vespa engine; we now turn our attention to the largeframe, small-block 125/150 casings. Over the years the choice has been huge, and kits are still being introduced regularly. Those that have been around a few years are often subjected to upgrades so choosing the right one can be a bit of a minefield. For that reason, we have picked out the most popular choices which are currently available.
Kit name: Piaggio 125cc cast iron
RRP: £199
Average estimated power output: 6-7bhp Bore: 52.5mm
Stroke: 57mm
Capacity: 123.5cc
Compatibility: 125 GTR, PX125
For those that still wish to have their engine remain standard but need to replace an old worn-out cylinder, Piaggio offers a replacement. Availability isn’t always guaranteed but stock from shops such as SIP, SCK and VE does turn up. The dimensions are the same as the original so there are no fitment issues and the 150cc variant is available also. The cylinder comes complete with its piston but no cylinder head. This is a straightforward ‘plug and play’ replacement for a standard machine.
Kit name: DR 177cc RRP: £175
Average estimated power output: 10-12bhp Bore: 63mm
Stroke: 57mm Capacity: 177cc Compatibility: 125 GTR, 150 Sprint, PX125/PE 150, Cosa 125/150
The DR 177cc kit is down at the budget end of the market and is reflected as such in its price. Even so, the cast iron seven-port barrel delivers a good upgrade in power over the standard factory cylinder. The cylinder kit comes complete with a piston, cylinder head and gaskets and is simple enough to fit. It is a lower performance kit in the otherwise competitive tuning market, but its low price means it is good value for money. The surprising thing about this kit is that the port layout is actually quite well designed and could provide decent performance if set up properly. However, the budget price of the kit explains the rougher casting edges and the not-so-performance-friendly ‘thick’ piston rings. So, if performance is the end goal, this kit is best left alone, but it will provide a welcome performance boost on an otherwise standard machine, and at a marginally lower price than a standard Piaggio 125 factory replacement item too.