Tuesday, 14 June 2016

Laverda 750SF


l was a little worried about buying a bike with 63000 miles on the clock, even if it was an Italian classic. The SF3 stood there glinting in the sun, its engine alloy polished, its chrome gleaming and its paint glowing. it looked the business. The other problem was that the owner would not give me a test ride He had taken me for a quick ride as a pillion which had not particularly impressed me — my feet were still tingling from the vibes.

It was a toss up whether i walked away in disgust or handed over £1500 in used fifties. The problem with motorcycles is once a certain machine gets into your head it's damn hard to shake off the lust. To give me some more time to think, I checked the chassis over, flicked on and off the fairly rudimentary light switches and kicked the tyres. In the end I took a coin out of my pocket, tossed it in the air and asked the owner to call heads or tails. He got it right and l was the proud owner of a 1973 Laverda 750SF3 — a bright Italian red one, naturally!

Ten yards down the road it became immediately apparent why the owner did not want me to test ride the machine. The gearbox was fucked up. First gear engaged with an annoyingly large clunk that made the machine lurch forward half a yard. As soon as l powered away it leapt out of gear. Changing into second produced a nasty graunching noise and with the rev counter barely past 1000rpm the whole machine vibrated like some massive tractor trying to impale itself on a brick wall.

A little more power made the vibes diminish and once 40mph had crept up on the clock there was a tendency towards actually accelerating. With 5000 revs on the clock I opened the throttle, ready to have my arms pulled out of my sockets by the vertical twin grunt. Not much chance of that, as the revs approached 600me the clutch began to slip. Up to third with 80mph on the clock, vibes began to pour in and I quickly put her into fourth and backed off to 70mph.

I had also noticed that it was a heavy bugger to throw about. It's not that it weighs nearly 500lbs, although that would be bad enough, it's also a very top heavy beast. Going into slow but sharp bends, hauling the bike over it had an unnerving tendency to want to drop straight on to the tarmac I had to save my bike and dent my pride with a quick dab down on to the floor with my boot — something I thought I had left behind with my frantic Fantic days.

The ride home took in some sublimely fast A roads, territory I would have thought perfect for Italian machinery. The SF was stable up to 80mph in a straight line, thereafter the gentlest of weaves intruded. When, a few weeks later. I tried for the top speed that gentle weave changed to a violent wobble when the speedo approached 110mph. I say approached because the vibes shook the bars, clocks and my eyeballs so vividly that a clear view of my speed was not possible.

Back to that initial ride (of 95 miles). Long sweeping curves did not suit the chassis at all well. Banked well over on a slightly rough surface the front forks seemed to flutter and when a quick change of direction was necessary, the back end twitched for a few yards after the event. The amount of muscle needed to flick the bike from side to side was incredible.

The engine power characteristics were less than endearing. It seemed to run OK between 70 and 90mph, but higher speeds were blitzed by primary vibes whilst at slower speeds the engine shook in the frame as if there were some engine bolts loose. When I arrived home I tightened them up but it did not stop the shakes. But that was after it ran out of fuel — SFs run out of fuel in a spectacular manner; no warning coughs or anything, the engine stops stone dead. This can be very disturbing if, as happened, you had just finished overtaking an oil tanker only to stop dead in front of its bumper...

Further carnage was in evidence once back at my home. Not only was the engine dropping oil in the fashion of a Royal Enfield twin. when I glanced at my expensive watch I saw that it had stopped ten minutes after I'd picked the bike up. Further use of the gearbox revealed that the only way to take off safely was to use second gear and a lot of clutch abuse....which explained why I had to rip off the side case to replace my clutch plates. Under such abuse I found the clutch would last 4000 miles until it started to slip slightly at speed and 5750 miles before the bike became impossible to ride.

Even second was prone to occasionally jumping out of gear under power and the whole transmission was agricultural and basic at best. The clutch lever was incredibly heavy, so much so that more than ten minutes in town would have the rider screaming in agony. Just to complicate matters, extended town riding caused the engine and clutch to overheat, so as well as clutch slip at high revs there was clutch drag below 2000rpm. The gearchange action felt like it had looked solid, at times. and would have been much better if it had a C50 type change where you can stamp at either end of the lever to change up and down — the gear lever tended to cut through leather shoes at a frightening rate.

If all that wasn't bad enough, it became much worse if you neglected the daily adjustment of the chain... that which came with the bike lasted for only 500 miles until I had to put my hand in my pocket for a new 'un — this lasted for an absurd 4500 milesl

Apart from the chain and clutch, in the first 10,000 miles the engine required little attention or money, which is just as well because I was so pissed off with this classic that if I hadn't got some decent mileage out of it I would have taken a ten pound hammer to the thing.

I soon found. that typical of Italian metal, if you were silly enough to take it out in the rain, the machine reacted with fury. The engine stuttered, the back wheel stepped out of line under the merest hint of throttle abuse, the triple disc brakes took the day off and all that shiny alloy and chrome turned to a disgusting mess of corrosion. Luckily, I bought the bike at the beginning of an unusually long period of sunny weather, so by the time the top end started giving trouble I was rather more enamoured of the machine than it had any right to expect.

The cylinder head layout of a single chain driven camshaft actuating two valves per cylinder will be familiar to any student of sixties Honda twin design — the engine even looks like a dead ringer for a CB72 motor. The problem with mine was that the cam lobes had worn through the hardening, resulting in the need for valve adjustment every 100 miles... l had mine built up with weld, then machined and hardened for a third of the cost of a new cam. After 12000 miles there is no discernible wear on the lobes, I am very happy to report.

Whilst the head was off I took the opportunity to look at the pistons and bores. Some moron had fitted pistons with different shaped heads — unbelievable, no wonder it shook and vibrated so much. A new set of pistons and rings. plus honing of the bores had that back under control. On the road it still wasn’t vibration free but the usable speed band had increased from 45 to 105mph and on occasions I even had the speedo on the 120mph mark.

Even after nearly twenty years the suspension was still rock hard. So much so that the bike tended to twitch violently over rough road surfaces. A set of Konis was the simple and relatively cheap solution to the rear end. The front springs were replaced with a set more relevant to modern civilization and PJ1 fork oil added to make sure it didn’t get out of line. The result was effective up to 85mph, thereafter the weaves and wobbles became much worse.

Overall, despite all the problems, I liked the bike, especially after a proper set of pistons were fitted and various muscles had developed to cope with the heavy action of the controls. However, rapid destruction of consumables, a poor average consumption of 42mpg and an engine that started making some very strange noises with 85000 miles on the clock, began to make me realise I couldn't really afford the indulgence. I got £1800 when I traded it in for an XT350. so I can't really complain.

Dave Coulson

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