Just two days back in work so the VFR carries on…this is getting to be a habit.
I think this week has been the lowest point of the year so far. Lots of distractions and pressure outside of ‘Laverda land’ makes it difficult to drag myself down to the garage and do some fettling. However part of keeping going is forward planning so I set to and got the 100 cylinder head and Atlas idler gear down to the local engineers for some work.
I fitted the new battery but this didn’t result in better starting – the engine still struggled to turn over. I tried installing a starter off the RGS which didn’t improve matters – infact it showed that this particular starter has a ‘dead spot’ which will need fixing before the RGS takes to the road again…
I also investigated the starter relay as a source of power drain. The connections were corroded but the sluggish starting remained despite them being cleaned up.
I haven’t fitted the matching Zane idler gear for the updated Zane sprag clutch and new from calculations that if I did I would improve the starter ratio i.e. make the gearing shorter and thus spin the engine quicker on start up. I couldn’t fit the idler gear because it needed to be countersunk by a further 6mm – I could cut some of the alternator case away but preferred to get the gear changed.
Getting the gear back should have meant the starter gearing could be improved but I then found out that the bore of the Zane idler has to be taken out to 21mm from its current 19mm – back to the engineering shop…
Still the upside is that I am getting closer to fixing the Atlas. I had wondered how the larger standard idler worked with the larger Zane ring gear but they did for a while but now I find they actually jam. Why this should suddenly be a problem I don’t know – perhaps I am burning out the starter and it has got to the point of saying ‘no more’! Anyways fiddling around showed that I can get the Atlas to start with the original setup (albeit with the improved Swiss sprag) so hopefully it will last for a week by which time I will be able to fit the full Zane kit and hopefully it will be sorted!
Further to the sprag I made enquiries about a replacement mainshaft and got the bad news that OCT only has mainshafts with gears for sale at close on £300. They have 3 left and as they say Atlas parts are rare – when these are gone that’s it!
The 100 bought better news. I removed the cylinder head (without having to take off the tank let alone take the engine out of the frame a la the triples) to sort out the exhaust studs I’d damaged during the National Rally.
The threads were in a poor state – funnily enough the thread on the side where the stud had come out were better than the right hand side where the stud stayed in place but wobbled under pressure. I could’ve just fixed the right hand thread but decided to get both helicoiled. The investigation prompted the idea that rather than put in new studs I’d go for M6 allen bolts to secure the exhaust. The M6 head fitted in the tight fit to the exhaust which meant an end to finding unusual nuts that had to have a smaller than standard head size for the bore.
The helicoiled exhaust studs took M6 allen bolts and the exhaust was secured. The helicoils ought to be stronger than the original thread cut into the alloy so I am hoping the M6 allen bolts are a permanent fix. The only downside is that allen bolts weren’t around in 1958 so if you know what you are looking at you will know it is not standard (I won’t tell if you don’t).
I also took the time to fit new washers under the cylinder head securing nuts. The existing ones were too tight on the studs and caught which could’ve led to a leaking head gasket. Finding M7 washers isn’t easy so I’d got some quarter inch items which with a small seeing to with a rats tail file opened up nicely. Finally I had been running the engine with 10 thou’ valve clearances – I followed advice from Cor Dees and closed these to 6 thou.
When I removed the cylinder head I noticed that the inlet track is a bit scored. I did wonder about smoothing this out but in the end forgot and once the head was back on couldn’t be bothered to remove it. However maybe there is a some ‘development’ potential in smoothing out the inlet port?
A 20 km ride in the Oxfordshire countryside confirmed the 100 now runs okay – it even showed 46 MPH on the straight so hopefully the poor turn of speed on during the National Rally was solely down to the leaking exhaust?
Nick 🙂
Bent screwdrivers, big hammers and old Laverdas 