Legendary Lambretta kit manufacturer AF Rayspeed have started to work closely with Spanish exhaust specialists Tecnigas on a new range of Lambretta performance exhausts. SLUK have just dyno-tested the latest model for the RB kit range.
What is it for?
The Tornado plugs a gap in AF’s exhaust range left by the retirement of their previous exhaust manufacturer.
The high-performance RB kit is unique in its swept-back exhaust port outlet and stud positions meaning that needs a specific exhaust design; those intended for TS1 or cast barrels will not fit.
Ray and Ben Kemp were looking for a high-revving exhaust that would extend the useful working rpm of the engine and particularly suit tuned RBs running with large carburettors.
What Tecnigas have made
The resultant exhaust looks like a work of art with a very smooth sweep to the cone layout. Our example is lacquered so you can see all the welds but production exhausts are likely to come painted in high-temperature black paint for improved protection in the harsh environment under a Lambretta.
The fitting method follows the previous NK exhaust’s somewhat unconventional mounting strategy of solid connections between the chamber and engine with no rubber or plastic parts to absorb vibration. I’ve used previous NK exhausts with this system and despite my initial suspicion of solid-mounting, they proved surprisingly durable. Only time will tell about the durability of the Tecnigas exhaust.
The unusual part of the Tornado’s fitting system is that the main ‘sharks’ fin’ exhaust bracket to the engine fits over the top of the main chamber and not underneath as per almost every other expansion on the market. This makes it even fiddlier to fasten the supplied nuts in the tight gap between the exhaust and the cylinder cowling.
However, by discarding the supplied M8 Allen bolts and replacing them with M8 Hexagon-head bolts fitted from the reverse, it makes fitting considerably easier as you can now fit the nuts from the outside and hold the bolt-heads on the rear steady with a spanner.
At the rear the handsome muffler is supported by a bracket that attaches to two of the lower chaincase threads using long M6 Allen screws. I’ve never been a fan of this fitting method because those threads need to be perfect for the support system to work. In my opinion, brackets with connections to three or four of the chaincase studs are preferable for long term durability.
The rear muffler support bracket is slotted and jointed to allow for adjustability of cylinder position, as is the shark’s fin bracket, just in case you fancy a long-stroke RB 244 or 252.
How it compares
We tested the Tecnigas Tornado on a stock RB22 kit fitted with a 30mm PHBH carburettor and fixed 18-degree ignition timing using a special static version of the Casatronic Ducati electronic ignition.
The test engine was mounted in the lightweight ‘dyno donkey’ rig build especially for testing for the forthcoming Complete Spanners Lambretta Kit Book.
Also tested were the old NK Road exhaust and the Franspeed RB exhaust which is the specified exhaust for the BSSO Production Class series.
What you can notice from the graph is that there is a delay in RPM before the Tornado kicks in, but once it does the power output is higher than the Franspeed but it also hangs on to power longer at higher revs.
The approximate 500rpm delay in getting in to the power equates to the Tornado producing slightly less peak torque than either the NK or the Franspeed.
This sort of exhaust is likely to show even more benefit in the upper rev range when combined with a 34mm or 35mm carburettor.
Ground Clearance & Noise
Since we only dyno tested using the Donkey we’ve not had a chance to try the Tornado on the road; however, Ben from AF Rayspeed says that clearance is better than it looks, particularly on the flywheel side.
How does it sound?
The Tornado uses a similar muffler design to the old NK. It’s not the loudest exhaust on the market, nor would you call it quiet. The thin-wall of the chamber and the high-revving nature of the RB make for a real motocross-style exhaust note once in the power. Have a look (and listen) at the video above…
The clear-coated version of the Tecnigas Tornado is already in stock at AF Rayspeed for a retail price of £330. Hopefully, it will soon be listed on their website too.
For the moment if you want one then the best option will be to call 01944 710693 and let them know you saw it on SLUK.
Words and images: Sticky
Additional images: AF Rayspeed
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