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Alkro ByLight

A Mini-Feature by Mark Daniels

Alkro Engineering Constructions logo

Alkro Engineering Constructions - founded in 1989 at Biella, in the northern Italian region of Piemonte - lists varied engineering services, including restoration & sales of old cars, motor cycles, scooters, refitting boats, and interests in rail, aero, and static modelling.

The Alkro ByLight moped is among a family of cycle-based machines deriving from a 12kg biciclette pieghevoli (folding bicycle) design called the ByEtte, and fitted with an engine, this listed as a further range of moped models: ByLight (folding frame with tele forks), ByRigido (non-folding frame with tele forks), and ByCity (non-folding frame with rigid fork, front and rear baskets). A forBy attachment 2-wheel collapsible trailer is also available as a listed accessory.

The ByLight's drive system

Probably the best way to sum up the ByLight is like a motorised folding BMX bike.  The frame looks typically BMX, with a box section tube as the main member, also serving as a petrol tank, and split to fold ahead of the bottom bracket.  The front forks are modern cycle style telescopics, fitted with lightweight, skinny, plastic moulded wheels.

For compact transportation, the pedals unlock with R-clips, release the locking lever to rotate and drop the seat, there's another locking lever to release the handlebars, and again a lever and clamp screw to fold the frame.

Front and rear brakes are lightweight pressed drums set into the plastic wheel hubs.  There's also an uprated front and rear lighting set with electric horn, powered from the motor generator.

In this flimsy lightweight cycle, the 48cc Bernardi engine rated at 1.5bhp, almost hangs like a monster below the bottom bracket, and increases the total weight of the moped version to 20kg.  Carburetion is supplied from a 12mm Dell'orto.  Then look at the rear wheel, and there are gear teeth all round the inside of the rim!  So what's that about? And then the realisation dawns ... it drives the plastic gear teeth from an open plastic pinion on the engine!  Ah, that's not a drive system you see every day!

Alkro ByLight

Maximum speed is given as 45km/h, which converts to some 28mph in groats and firkins, but the prospect of being on such a frail cycle up to these speeds is, to be honest, pretty daunting!  With the old and worn BMX cycle tyres on this example, and that little front wheel, anyone would probably be apprehensive.  Then the broken remains of a bracket by the left hand rear wheel spindle where the sidestand used to be, further seem to serve as some bad omen for the forthcoming ride!

To get ByLight started, click the button on the back of the transmission case to switch from pedal mode to motor engaged, turn on the petrol tap, click down the choke lever, hold on the decompressor lever, and pedal up the road.  It takes a bit of pedalling effort since the drive ratio appears quite low; drop the decompressor lever, and the motor fires up fairly readily.  Blip the throttle to release the choke, and the single-stage centrifugal clutch engages as the revs increase.  Since the cycle is so light, a little kick on the pedals significantly boosts the get-away, and acceleration proves pretty nippy.

The expected cyclic rumbling noises from the plastic gear drive however, won't instil any sense of confidence to even the most mechanically insensitive.  The pilot of our pace bike commented that it 'sounded like something was about to fall apart at any moment', and is apparent enough to distract pedestrians as it clonks by.  Though quite normal and nothing actually wrong, the ByLight grumbles along like a rolling barrel of Lego, and hardly serves to impart any belief to the rider that it might achieve the end of the road, never mind a destination of any distance!

Folded Alkro ByLight

The handling feels light and twitchy.  No problem to steer, but you wouldn't want to let go of those handlebars!  The brakes seem as if they're going to be effective enough under light application, but don't be fooled - pull them on harder and they simply disappear, then as you finally start to slow, produce loud creaking tones just before you stop!  ByLight clocked 22mph on the flat, fading on a shallow gradient to 18mph, and top speed (slight downhill) 27mph - at which the spark plug whiskered, so we clicked back to pedal mode and gratefully cycled home at 15mph.  That's quite enough of that thank you!

It's hard to see the plastic gear and pinion of such a drive system being particularly durable, especially under dusty conditions, where grit would embed itself into the plastic faces and simply grind all the teeth away.  One would probably expect the engine to outlast the drive system, but if the moulded gear wheels were readily available cheaply enough, then it may be serviceable, but basically this appears rather like a 'disposable moped'.  Probably the best way to view the ByLight is a flyweight, easily transportable, compact moped for occasional short-range convenience.  It's really not designed or constructed for regular service use.

Bylight logo

Alkro ByEtte Alkro ByLight Alkro ByCity Alkro ByRigido

This article appeared in the October 2007 Iceni CAM Magazine.

Making the Bylight feature

This came about from Chris Day calling to say he'd picked up this odd-ball folding cycle-ped with a freaky cog-drive.  We'd never heard of it, so did a bit of research, and though there wasn't enough material to justify a full-blown article in itself... maybe a mini feature?  Feeling that Out of the Blue might not have enough volume to carry Edition three on its own, the Alkro was fast tracked as back-up.  It's a worrying prospect to ride such a flimsy machine as this up to its top speed - Chris had far more sense than to even consider it himself, so who wants to volunteer to be a kamikaze pilot?  The Alkro could only be a product of modern age technology, materials and processes, certainly technically interesting and unusual enough to justify an article on it - so the mini-feature was born!  Though probably not likely to be considered as a mainstream machine, the By-Light still has its own little niche in life, and some may look at it and say "That's just what I need".

Alkro say they exported only some 200 machines to the UK, so don't expect to be seeing many about.

Mini-feature, mini price, it only cost £10 to produce the entire article.  We reckon the mini-feature worked OK, so you may expect to see more of them occasionally in the future.

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