TUNING UP YOUR LAMBRETTA So you've got yourself a vintage Lambretta, and you are simply unimpressed with its performance. Its no wonder, our beloved steeds were designed 30+ years ago to cope with the traffic of that time. Motorscooters were originally made to be transport within crowed European cities for short distances, a mandate that did not really require speed. Later on, in the 1960's, competition between Piaggio and Innocenti, and more importantly, the demand for fast scooters in the English market, pushed innovation towards faster scooters. Nevertheless, a scooter designed for the 1960's or 1970's market could stand some improvements to cope with 1990's road conditions. Luckily for us, there are many performance improvements that are available to help your Lambretta take you into the next millennium. Below is a list of some of the more common things you can do to help your LI/TV/SX Lambretta...
One thing to keep in mind; in scooters, as well as in life - try to keep a balance. If you want your tuned scooter to run well, all things have to be balanced out. A big increase in cc's requires more gas flow and exhaust output to match. This is even more important in 2-stroke motors, since the motor is lubricated through the gasoline. If there is too little gas getting to your motor, then too little oil is also getting to your motor, and you stand a risk of seizure.
You should also decide what you want your scooter to do before you begin to buy expensive parts to tune it. If you just want to reliably cruise around town, then keep the tuning to a minimum. On the other hand if you want a fire-breathing monster that will haul-ass, but needs to be repaired every week, then go for the TS-1 kit that is ported to look like swiss cheese. Just remember - the more you tune, the lower your reliability and the more it will cost you, both initially, and later for repairs
So you've got yourself a vintage Lambretta, and you are simply unimpressed with its performance. Its no wonder, our beloved steeds were designed 30+ years ago to cope with the traffic of that time. Motorscooters were originally made to be transport within crowed European cities for short distances, a mandate that did not really require speed. Later on, in the 1960's, competition between Piaggio and Innocenti, and more importantly, the demand for fast scooters in the English market, pushed innovation towards faster scooters. Nevertheless, a scooter designed for the 1960's or 1970's market could stand some improvements to cope with 1990's road conditions. Luckily for us, there are many performance improvements that are available to help your Lambretta take you into the next millennium. Below is a list of some of the more common things you can do to help your LI/TV/SX Lambretta...
One thing to keep in mind; in scooters, as well as in life - try to keep a balance. If you want your tuned scooter to run well, all things have to be balanced out. A big increase in cc's requires more gas flow and exhaust output to match. This is even more important in 2-stroke motors, since the motor is lubricated through the gasoline. If there is too little gas getting to your motor, then too little oil is also getting to your motor, and you stand a risk of seizure.
You should also decide what you want your scooter to do before you begin to buy expensive parts to tune it. If you just want to reliably cruise around town, then keep the tuning to a minimum. On the other hand if you want a fire-breathing monster that will haul-ass, but needs to be repaired every week, then go for the TS-1 kit that is ported to look like swiss cheese. Just remember - the more you tune, the lower your reliability and the more it will cost you, both initially, and later for repairs
Porting: You can get a decent increase in the performance of you scooter by simply opening up the size of the intake, transfer, and exhaust ports of your existing barrel. This can be done to any barrel, and is measured in "stages." The first stage is simply matching the intake manifold to the intake port, and the exhaust manifold to the exhaust port, and the degree of cutting goes up from there. Only trust an experienced shop to carry out these modifications, it would be a shame to end up with a ruined barrel due to a cut rate hack job. This is the cheapest way to go, because you don't need to buy any new components, except maybe new jets for your carburetor. 175 Conversion: This is perhaps the best conversion for all 125-150cc Lambrettas. It is very reliable, relatively cheap, and will give you more power and top speed. Expect a top speed of around 60-65 mph, and more power all around. To carry out this modification, you can re-bore your existing barrel to take the new piston, or better yet, buy a conversion barrel and piston and just slap it on. The advantage of the conversion barrel is that it comes with better porting to take advantage of the bigger piston. The head will need to be reprofiled to match the new larger bore of the barrel no matter which way you go. You will also need to replace your carb with at least a 20mm item to make use of the extra cc's. A new exhaust is not necessary, but can give a bit more power.
Cost: Piston alone - $60-75
Rebore to fit above piston - $40-60
Barrel and Piston Kit - $200-250
Head Reprofile to match bore - $30-60
Carb and Manifold - $200+ Gearing: One thing that makes Lambrettas very interesting to tune is the almost endless possibilities of gear combinations. You can change the size of the primary gear from 15 to 19 teeth (located on the end of crank), the secondary gear from 46 to 48 teeth (located behind the clutch), and all of the gears in the gearbox. When altering the primary or secondary gear, usually you will need to get a longer duplex chain to fit the new gears. Normally changing the primary and secondary gears won't be necessary, and is only done to really customize a motor to one's personal taste. The only time it is useful is if you are tuning an LI 125 or 150 motor. Major improvements in power require lower gearing to make use of them, and a 125 gearbox is not very useful on a highly tuned motor. When building a tuned motor, always ask the shop where you are buying your parts if a different gearbox might be necessary.
Cost: Primary Gear - $25-35
Secondary Gear - $60-75
Longer Chain - $40-60
Complete Gearbox - $200-300
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Top End: There are many possibilities to increase the performance of your scooter by altering or changing the top end (i.e. piston, barrel, head). In most cases when you make major performance modifications to increase your power, you need to make sure that all components of your motor are in top shape to handle the increased load. New seals, high quality bearings, and good nylon chainguides are the basic places to start. Then move on to building your more powerful top end. Outlined here are four of the most popular methods for top end modification, as well as their respective costs. 190 Conversion: If you want to unleash the full power potential that is in your 125-175cc Lambretta, then the 190 is the way to go. With this conversion, you replace the original piston with a modern Suzuki motorcycle piston which is much lighter and smaller than the original Innocenti designed item. This is a pretty radical process, especially on 125 and 150 machines. On those bikes, the original barrel must be rebored to fit the new piston size and also cut to allow the port timing to match up with the smaller Suzuki piston. Only the rebore is not necessary on the 175 since it has a shorter rod than the others. This conversion along with a bit of porting work, a bigger carb, and bigger exhaust will give you about 15-18 horsepower and a top speed of around 75 mph. An electronic ignition gives this set-up optimum performance.
Cost: Piston alone - $90
Rebore and modifications - $200
Barrel and Piston kit - $300-350
Head Reprofile to match bore - $30-60
Carb and Manifold - $200+
Performance Exhaust - $250-500
Electronic Ignition - $250-300
TS-1 Kit: This kit is the best way to get your 200cc Lambretta to really move. It consists of a aluminum barrel with nicasil lining, reed valve manifold, and piston. It comes in two versions, a 200cc, and a 225cc and has been proven over many years to be fairly reliable, and very powerful. This kit is made to be used with a GP crank, and so a new crank (and therefore mag flange, flywheel, etc.) will need to be substituted on any TV or SX 200 based motors for this kit to work. You will also need a big carb to feed the fuel hungry cylinder as well as a performance expansion chamber to get rid of the exhaust. An electronic ignition is an absolute must with this kit. Fitting a TS-1 should net your Lambretta somewhere in the neighborhood of 18-20 horsepower, and even more can be achieved with the right porting etc. It is not the cheapest way to go, but man, is it ever fun!
Cost: TS-1 kit - $350-450
Carb - $150+
Performance Exhaust - $250-500
GP crank - $150-250
Mag flange - $200
Electronic Ignition - $250-300 Carburetor: Most Lambrettas came stock with rather small carburetors, and so, there are many options for slightly improving performance by simply replacing the carb. One of the easiest things you can do is swap your original carb out with another, bigger, original carb. You can also get a much larger motorcycle carb and custom manifold to fit on your scooter. Some of the most popular brands to use are Mikuni, Amal, and Del'Orto. The stock Lambretta carbs range up to 22mm, but the with the others, you can fit up to a 35mm.
Cost: Stock Carburetor - $100-150 Motorcycle Carb - $100-150+
Stock Manifold - $40-50 Big Bore Manifold - $50-70
Exhaust: One of the most important parts on a 2-stroke motor which affects your performance is your exhaust. You can easily change your motor's dynamics by fitting a performance expansion chamber to your Lambretta. Honestly, the stock exhaust on a Lambretta is not very good, and you can get a bit more power and a higher top speed by trashing your stock exhaust. There are many companies selling various different types of expansion chambers to fit your Lambretta. When buying a new expansion chamber, think about what you will need on the motor you are building. Prices and added performance vary widely, from a pattern Indian GP exhaust to a hand made British piece of art. Nevertheless, you won't really need a massive free flowing exhaust on a lightly or non-tuned bike, so the GP, Situ, or Clubman exhaust will do just fine. On the other hand, if you are running a TS-1, or highly modified motor with a big carb, you will need the extra flow that comes with a nice fat expansion chamber. The best thing to do is to check with the manufacturers or sellers of several pipes before you buy to see which would be the best for your particular motor. Some give you better bottom end torque, others wide open top speed and rev's, and usually when you get one, you sacrifice some of the other. So do you want to street race from stoplight to stoplight, or go out on the highway at high speed? Decide, and then buy the pipe to fit your needs.
Cost: Indian GP exhaust - $80-100
West Coast Lambretta Works pipe - $250
Handmade English pipes - $300-500
Suspension: The stock Lambretta suspension system is not particularly good, especially on machines that don't have front dampeners. You can vastly improve your machine's ride and handling by fitting decent shocks and dampeners to it. On the back, you can fit a Bitubo gas adjustable shock on your bike to give a much stiffer ride. On the front, there are several options. If your Lambretta did not come with dampeners stock, there is a kit you can fit to your forks to allow you to use them. Once you have the kit, or if your bike came with dampeners, then you have a few choices. A strong adjustable friction dampener (as fitted to motorcycles as steering dampeners), an uprated stock looking dampener, or a stock dampener. Of course, there is a price difference. Generally, the faster you plan to go, the stiffer you want your scooter to ride, so keep that in mind when buying suspension bits.
Cost: Bitubo rear shock - $200-250
Front Dampener fixing kit - $20-40
Motorcycle steering dampeners - $100-125
Uprated dampeners - $60-75
Stock dampeners - $50-60 |
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