Tech Torque: Aftermarket tuning options
There’s never been a better time to source aftermarket tuning options for your Vespa or Lambretta. In this series, we take a look at some of the most popular choices, and see what each has to offer.
Since the first aftermarket cylinder kit was launched, and created a revolution in the scooter tuning market, there has been an ongoing development and delivery programme bringing us ever-improving tuning goodies. Scooter owners are no longer reliant on just using cast iron cylinders and a hand file in an attempt to gain more power; the world of purpose-built bolt-on kits became a reality and has made the whole job much easier. Since that time there have been dozens of kits, cranks, carbs and exhausts made available, but when it comes to choosing the right one for your scooter it can be a very daunting and confusing task knowing which option to use. Perhaps there is even now an excess of items? So we at Scootering have been busy putting together a guide to what products are available and what each one offers in performance, breaking down each component category, what the item is and what it has to offer. There is a lot to look forward to in this series, from brakes and suspension, through to kits and carbs… so don’t panic if you don’t see something you like in this edition, it’ll most likely be in another part of the coming series. Over time we will cover both Lambretta and Vespa tuning options, but there is an abundance of stuff to get through, so in this edition we will start with the most popular Lambretta cylinder kits and move forward from there… Words: Stu Owen
Images: www.sip-scootershop.com, MB Scooters, Gori, CamLam & AF Rayspeed
Kit name: RB20/RB22/RB25 Manufacturer: AF Rayspeed
RRP: £450/£535/£595
Year launched: 2010/2007/2008
Average estimated power output: (RB20)21bhp, (RB22) 23bhp, (RB25) 26bhp Bore: (RB20)66mm, (RB25) 70mm, (RB25) 72mm
Stroke/rod: (RB20)58/116, (RB25) 58/107, (RB25) 60/107
Capacity: 198cc, 223cc, 244cc
Standard Port timings:
RB20: Exhaust 187° – Transfer 126°
RB22: Exhaust 186° – Transfer 130°
RB25: Exhaust 187° – Transfer 131° (triple port)
RB25: Exhaust 186° – Transfer 126° (mono port)
Induction Type: All reed-valve
Overview: The first RB to be launched was the 225cc version with triple exhaust port and double boost port, as well as Boyesen transfer ports and a huge W-style reed-block. It was claimed by Ray Kemp “to take the standard Lambretta casing to its potential”. With its big power output, even in the standard form, it gives a race-tuned level of performance, by standards of the day. With tractability low down it can still be used around town but its real potential is that of a fast motorway kit. The RB25 was launched, initially with the same triple exhaust port layout as the RB22, but was also later offered as a monoport version (same as TS1) and this was often preferred by the tuning fraternity, as it allowed more manipulation of the tuning options. It also came with the improved triple boost port. This larger RB25 kit requires the mouth of a 200cc casing to be machined to accept the bigger cylinder spigot. The RB20 was a smaller, carbon copy of the monoport RB250, just presented in a smaller CC format, designed to fit straight on to a small-block casing, and using a crank with a 116mm rod to allow for the use of the Yamaha Blaster piston.
Tuning suggestions: Similar to the TS1 there are many different ways of extracting more power from all three variants. All of the RB variants use their own specific type of exhaust pipes, not compatible with previous kits, due to the nature of the RB’s angle of exhaust port exit. This has led to several manufacturers producing pipes for the kit, the JL race has proven to unleash its potential even without additional porting work, and the German brand of Pipe Design expansion chambers proved almost unbeatable on all-out bhp. With its ‘W’ style layout of the reed block using eight petals, this performs well without requiring any change. The RB25 monoport is the ‘go to’ option for many tuners, as it carries both big cubic capacity which gives a lovely wedge of torque in the mid-range, as well as being simple to port on the main exhaust outlet. The standard transfers and boost port are very healthy in standard trim and rarely require touching at all. The big difference with the RB22, though, is its three-port exhaust layout when compared with a single port on the RB20. Many tuners find it easier to weld the two side ports up on the RB22 and make it into a single port configuration. In the right hands, the potential of the RB20 kit can easily be more than 30bhp, well over 40bhp with the RB22, and in excess of 50bhp with the RB25. In fact, the ‘baby’ RB20 only requires a long-stroke 62mm crank to take it up to 215cc, and with just a minor tweak to the exhaust port, it will touch 30hp very easily when matched with a 34mm carb and race pipe. Though some of these figures are at the extreme end of the spectrum, and usually reserved for race/ sprint scooters. Even in standard trim, the respective RB kits have both solid bhp outputs as well as healthy torque figures. When built with the correct exhaust, carburettor and gearing combos they not only give a high top speed but do so with controllable acceleration through the usable rev range. RB25 & RB20 stand out as the prime picks.
Kit name: Imola (small block) Manufacturer: Tino Sacchi
RRP: £550
Year launched: 1999
Average estimated power output: 20-21bhp
Bore: 66mm
Stroke: 58mm
Capacity: 198cc
Standard Port timings: Exhaust
186° – Transfer 127° Induction type: Reed-valve
Overview: The Imola is Tino Sacchi’s answer to getting the ultimate performance from the Lambretta small-block casing. This was the first kit he launched more than 20 years ago, and was often referred to by tuners as a ‘baby TS1’. That comparison, in terms of the original 186cc port layout, wasn’t too far off the mark. During its time the kit has gone through several changes, and like the Monza, there became two distinct variants… the ‘original’ and the ‘super’ Imola. The ‘super’ version, in all honesty, is a world apart from the standard kit, and the two are not really comparable. In standard trim, the super bolts on as a far superior item, but the low cost and tunability of the ‘standard’ versions make them far more appealing to the mass market. Like all Tino’s kits, the Imola is made from aluminium with a Nikasil lined bore. Reed-valve induction means the carburettor inlet is on the right-hand side.
Tuning suggestions: The development of the kit over the years has been improved vastly and the 198cc version now available is already in a good state of tune straight out of the box. Though the option to tune it even further is possible, for the road-riding, rally-going scooterist it really isn’t necessary, we just tune… because we can. By using the best race pipes out there, such as CST, AF, JL, Pipe Design etc. and even just a 30mm Dell’Orto carburettor, then 22+bhp is achievable without any additional work. Once you start porting, and adding long-stroke 62mm cranks, then 30bhp is well within grasp.
Kit name: Super Monza (large block) Manufacturer: Tino Sacchi
RRP: £600
Year launched: 2011 Average estimated power output: 29-30bhp
Bore: 70mm
Stroke: 58mm
Capacity: 223cc Induction type: Reed-valve
Variant: Super Monza ‘Ultimate’. This is the version of the Monza kit that was completely redesigned by Charlie Edmonds at Performance Tuning and was originally offered in the UK by Cambridge Lambretta including options for PT full works upgrades.
RRP: £1295+
Overview: Hailed as the ‘complete top end’ fast touring package when it was launched and claiming to be the most powerful ‘off the shelf’ kit at the time. It had many superior tweaks, including short stud fastening at the base of the cylinder, which allowed larger Boyesen feeder ports and correctly angled sub-exhaust ports. All port timings, and angles, were calculated by Charlie Edmonds. In standard form, it requires the Super Monza exhaust which is different from a normal Lambretta exhaust because it has a different manifold angle. This means it’s not just a case of buying the kit and simply bolting it on as it requires other components specifically designed for it. Once you worked through the complete package of kit, crank, carb, ignition, clutch and gearbox options, the price could be eye watering.
Tuning suggestions: The whole ethos of this kit was that it didn’t need tuning, so on this one ‘tuning options’ is a somewhat moot point, though the kit did suffer from bad publicity in its early days and was notoriously difficult/ expensive to set up. When the kit was altered from ‘factory spec’, some UK tuners suggested that the exhaust port exit diameter was too large, thus losing gas velocity, so for anyone wanting to change the original intended purpose of the kit, from fast-road/touring to race, this requires welding and machining to solve. Given the time and cost constraints it can often be easier to start with something cheaper and more compliant/easier to manipulate.
With short stud fixings, Boyesen feeders, triple exhaust ports, and six- petal reed i nduction, this was considered a very exotic i tem upon l aunch.
Kit name: Quattrini 210 (small block) Manufacturer: Max Quattrini RRP: £650 Year launched: 2017 Average estimated power output: 23-25bhp Bore: 68mm Stroke: 58mm Capacity: 210cc Standard Port timings: 180° exhaust – 123° transfer
Induction Type:
Reed valve
Overview: Max Quattrini is well known for his Vespa tuning kits, this being his first entry to the Lambretta tuning market. The kit is for small-block engine casings only but his unique design of the cylinder is what gives it an advantage over other kits. The cylinder spigot is almost done away with, allowing for the bore to be larger, using a 68mm piston and thus giving 210cc on even just a standard 58mm stroke crank, though, like the RB20, a 116mm rod is required. The angle of the exhaust port is similar to that of the RB and also requires a specific expansion pipe to fit. A dedicated expansion is the best option and Chiselspeed produced the first versions in its CST 10/11 road/race versions. In reality, this is a kit intended for those wanting high performance out of their small block rather than just a simple upgrade. Unique feature such as offset cooling fins, O-ring stud seals, central head plug and stud relieved piston shaping make this a tantalising bit of kit.
Tuning suggestions: The kit is already in a high state of tune and will require welding to the casings if the transfers are to be opened any further. Suppliers suggest that Indian and Spanish casings give the best seal/ fit, even on a standard kit, as some Italian casings have less meat and therefore can be a bit hit and miss with fit. With the right expansion pipe added it looks likely that the bhp figure could well get up into the high 20s and certainly further with some additional porting work. With a small carb and CST touring pipe, this is a pleasing ride, with a very rewarding and user-friendly spread of power, straight out of the box and pulls long gearing options very well. Beyond that, race pipes, big carbs and porting bring the usual rewards. Aside from the already mentioned technical specifications, which make this kit stand out from the crowd, in performance terms, it offers a strong midrange performance, which is usually something lacking from the smaller cc items. Further use of 60/62mm cranks will increase capacity to 218/225cc and boost power further.
Kit name: GT 240
Manufacturer: Gran Turismo
RRP: £880
Average estimated power output: 25bhp Bore: 70mm
Stroke: 62mm
Capacity: 238cc
Induction Type: Reed valve
Overview: Following the success of the small-block GT 186 kit, Richard Taylor of Gran Turismo finally ventured into the big-block market with the GT200. Now on offer is this complete top-end package, which even includes the crank… hence the price. Though it is reed-valve induction it benefits from the carburettor sitting on the traditional side. Also, the cylinder is made from cast iron, therefore, it has plenty of oversizes available and the bore can be cleaned up quite easily. This kit works well even from low revs, making it ideal for touring.
Tuning suggestions: Being made from cast iron makes it far easier to work on than Nikasil lined cylinders. The only downside is it’s a much harder material to work on than aluminium, though not a problem for an experienced tuner. There is good potential to be had from the kit and with the right porting and expansion pipe combination 30bhp+ should be achievable, just be cautious of heat dispersion at this level.
Kit name: RT195 (small block) and RT225 (large block)
Manufacturer: MB Scooters/BGM
RRP: £438
Average estimated power output: (RT195) 15-16bhp, (RT225) 19-20bhp
Bore: (RT195) 65mm, (RT225) 70mm Stroke: 58mm
Capacity: 193cc/223cc
Induction Type: Piston ported
Standard Port timings: 170-174 exhaust - 121-125 transfers – 142-146 inlet
Overview: Originally developed by Mark Broadhurst as a kit with ‘wide appeal’ to get most scooterists from A to B quickly and economically. The RT (Race-Tour) kit is a piston-ported, aluminium, Nikasil lined kit which comes with a CNC head. There are just two versions, one for the small block and one for the big block, making it an easy choice when purchasing. They are a midrange power upgrade in terms of performance in their standard set up. Both kits will run on anything from a big-bore Clubman through to a full expansion so you can set up the engine quite easily depending on the type of (race or tour) performance you desire.
Tuning suggestions: There’s a lot of potential to be had from the kit and being piston ported, very easy to tune, a simple light porting job is often all that is needed for most. There is also the appealing option to fit a reed valve; this is a popular conversion offered by MB Scooters, who have also extracted good power from both variants via additional porting work. The competitive price of the full kit means after the work is done the price overall is not too expensive. If you already have this kit set up with a Clubman for touring, and want to improve performance, then Mark at MB is always happy to discuss options, and if he is too busy, then many tuners work well with these kits also. Plus, 60/62/64mm x 110mm crank options offer huge benefits over standard, with minimal work required, these are also offered by MB.
When Scunthorpe-based scooterist John Henderson committed to building his perfect custom scooter there could only be one source of inspiration. “Oasis were a life-changing band,” he began. “They are the greatest rock ‘n’ roll band of a generation. I grew up watching and listening to them at every opportunity.” ‘Growing up’ may be a slight exaggeration as by the time Oasis released their debut album in 1994, John was already old enough to have become infatuated with scooters. “I grew up on the same estate as a lot of the Pathfinders and Road Rats,” explained John. “I’d see them riding around and just knew I had to have a part of it.” His first scooter was a TV175. “Bought for 50 quid,” he laughed. Sadly the Government was set to wipe the smile off young John’s face. After a summer of tinkering to get the old TV roadworthy, a change to licensing regulations meant that legal use was now out of the question. At the same time a girlfriend came along and John concentrated on developing his skills as an electrical technician. The dream of scooter ownership never died but it would be several years before his ambition was realised.
Little by little
First across the threshold was a red GP150, a scooter he still owns and that’s recently commenced its own rebirth. Next came a 1963 Li150, an original-paint machine that had been bought with the intention of using it as a base for an Oasis project. “From the moment I bought the Li, people were persuading me to leave well alone. It was a good, solid scooter with nice panels and original paint. Being honest the whole ‘rusteration’ scene isn’t for me but I finally gave in and sold it to a mate.” With cash in hand the search for another project bike began and as John explained, this GP seemed destined for a home in Scunthorpe. “I saw the GP advertised at a very decent price and although it was up in Scotland I knew it was crying out for me to buy it.” If there’s one thing that matches, perhaps exceeds, John’s love of
Oasis it is Scunthorpe United FC or to fans, ‘The Iron’. “Someone had written ‘Any old iron’ on the GP’s legshield. I took that as a sign!”