650/668 - What Went Wrong?

Modified cylinder head made by s.c.f. note new oilway drillings (arrowed ) for Increased cooling. The painted finish is different to the early heads ,being a thin coat with metalic particles,again to reduce heat.

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Early type cylinder head which was prone to overheating causing rapid valve guide wear and valve seat problems.

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Modified(left) and early type(right) heads (comparrison), note thickly painted early head.

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These markings (scf) are what to look for to confirm a modified head is fitted.

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Modified(left) and early(right) barrels (comparrison). Note: modified barrel Markings f. 8. (arrowed) stamped into casting. This again is what to look for to confirm a modified piston barrel kit has been fitted.

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F8 barrel(left) showing oil cooling flow mods around top part of cylinder liner. This greatly improved and controlled temperatures in this area.To date we have had no reports of associated piston/small end seizures after this kit has been fitted! Early type barrel (right) unmodified shown as comparison.

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Modified (left), early type (right) pistons, modified piston is made of different Material and not teflon coated,also note machined groove in between 1st and 2nd rings and +0.30 stamped on crown.

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Modified oil pump gears (left) giving 25% more output than early type (right), again adding to improved engine cooling.

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9 plate uprated clutch kit (left) as opposed to 8 plate unit (right) (comparrison). The 9 plate kit was introduced as early model 8 plate units were prone to slipping. With the 9 plate kit a new deeper cover was introduced, now with a dipstick instead of the early type unit sight glass. One point to watch for on the dipstick itself is that the metal level rod is arraldited to the plastic top, it can drop offand fall into the engine!.

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Balance shaft as fitted to all models.can suffer from stress fractures leading to eventual snapping at these points (arrowed). If your engine becomes noisy with increased vibration,this can often be the problem. Caused by exessive high engine revs (9000-9200). Early type eprom chips allowed the revs to 9200 before the limiter came in,later type eproms limited revs to 8800 in an atempt to relieve the stress levels.

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Overpressure relief valves, modified (left), early type (right). If your bike has the early type fitted ,change it immediatley! It opened far to early, robbing the top end of oil with disastrous consequences. This was a factory recall so all u.k bikes should have this mod but do check it.

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Ignition spinners, late type (left) which suffers badly from corrosion. This type has a woodruff key fitting to the crankshaft. Early type (right) is aluminium with steel adjustable pins and has a ball bearing fitment to the crankshaft.

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Another factory recall on these components. The early type castelated nuts (right) were replaced with full nuts (left). These were fitted to the alternator, clutch centre and balance shaft. Again all u.k bikes should have these mods but do check!

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Early type(8 plate) clutch cover showing sight glass for oil level check,its not unknown for the sight glass to fall out!

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This early type spacer which is made of aluminium sits behind the starter gear. It was replaced by a modified steel unit as the early type was prone to crushing causing damage to the alternator, again something to check!

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Although this was not a factory recall, it is advised that the later crossover exhaust pipes be fitted (see picture below). With the crossover pipes came an uprated eprom chip, this less restrictive kit gave much better midrange power.

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Early type Handlebars (Right) snap at this point (Arrowed). Laverda addressed the problem by Bracing this area (Arrowed) If you have the early type fitted, change them immediately for the Modified units.

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This is the weak point (arrowed) on sub frame Seat Bridge. The crack can eventually Worsen, with the bridge breaking off completely! check yours before it happens.