Simon Yates said:
It was a good thing that I could not time the ignition.
I shall renew the primary chains and locknut tab washer but was surprised to find that the nut was loose and held in position by the tab washer.
There may be at least following reasons why did the nut was loose. A correct torque value is not mentioned at all on twin factory manual, but at least RGS manual states it should be 70-80 Nm, that is a low value. People have stated here that it must be 160 Nm for example, that is similar than many other engines have on similar constructions with threads of some similar size. I have also found a post-production tab washer that seemed to be far softer material than the originals or Phils tab washers. I can recommend the tab washers from Phil, those seemed to be very good ones (Thanks Phil, forgot to say this). This may be quite unnecessary, but I have thought to take hardness tests out from the tab washers, I may have an opportunity to do this without a money payment. One good thing can be also to turn the sprocket/crank (when tightening the nut) that way the rotational clearance is towards engine braking. Then the clearance will not turn to the other direction when you take more power out from the engine at the first time after reassembling. To lock the crank for 160 Nm may also be a harder thing than to lock it for 70-80 Nm, it should not be a problem at all with original or similar locking tool. Every kind of other locking methods have been used, all of these can not be recommended.
That tab washer looks on you picture if its corners were bent with screwdriver and mallet. Bits from it may crack and drop to the sump which may lead to other disasters before they get caugh in the separators.
I'm not sure if I'm "poking once a wasp nest" (not sure if this is also some sort of finglish) when I'm saying this one, but I'm quite unsure if there is some 100% correct "right or wrong" simple answer can the tab washer be used more than once or not. Also Laverda factory manuals doesn't actually say anything to it. At least same corner can not be used more than once.
A company that I think is half of the Finland's automotive industry have stated that tab washers of this very exact type can be used up to six times (every corner once) on every brands of road vehicles generally speaking, but of course this requires there is absolutely no any defects on it and if it is assembled and disassembled correct way every time, no matter if it is inside the sump or not. Of course it is safe if the washer is replaced every time. Just an interesting approach IMHO, I'm not making a recommendation.
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