I can vouch for Andy's timing chains, TOG has done 40,000 miles (twice at least) on one of them (well two) I have only known Andy about 12 years in the 35 years that I have owned the bike, I met him through Dave Laker and I bought a timing chain, which I thought I needed, and it was a quarter of the price being asked by mainstream Laverda dealers from mid Eastern England, who (funnily enough) only had the very last genuine one that was available in the entire known world. On inspection of the old mega mileage chain, there was very little if any evidence for renewing it, but I did none the less, 40,000 miles later with a very tatty and overworked (pre-restoration) bike still doing mega mileage, I changed again, this time I measured stretch and wear against the new one, by placing both chains in a parallel loop around two bars turned to about 50mm diameter, the bars were "pumped" apart by a pair of cheapo scissor jacks, near to each chain, just to apply a little bit of tension, those bar were about 300mm long and with one chain on one side and the other opposite the two bars remained parallel, so it was needless, but none the less it gives you confidence, think about it, that chain is in an ideal environment, inside a closed cell and getting drenched in oil at all times, so they should last well.
Conversely My semi un-adopted son (Murphy) blew his engine on his Kawasaki 400, the other sons removed the engine and deposited it on my bench for a rebuild, the top end was quickly removed to reveal a broken rod, a tiny little thing ;like something out of a clock, as the piston had tangled with the valves (again tiny little drawing pin headed things and four per pot) and the collision was too much to bear, the rod was snapped off about mid point and the flailing end had rotated and punched a very neat little "I" shape in the crankcase top, further inspection revealed that the automatic cam chain adjuster had popped out, it is a ratchet type of adjuster controlled buy a spring, as the chain wears the adjuster clicks out under spring pressure, but this had gone way past the level of acceptability and the square shaped rack had popped out of its slot, that caused an error in cam timing and hence the collision, but the chain ( a hyvo type) had not broken, that engine had done about 45,000 miles, and although it was very well thrashed it had been maintained, if there had been a way of viewing the adjuster before hand at service intervals it might not have happened, Apparently Stan Stevens developed a way of changing the timing chain without dismantling the engine (his son had one), but for all intentions and purposes, it is a split the cases job.
That bike was not scrapped, but a replacement engine was very hard to find, so after many mods and much crowbarring a ZXR600 engine was fitted and once the gearing was corrected, that became a VERY VERY fast little bike, obscenely fast in fact (at least 150MPH) bearing in mind the cost, we still have it, it now no longer has lights etc as it is now a track day only bike.
CLEM
