Happy New Year!
Mrs A decided it was time I got back in the garage and started work to give us a running Laverda for 2020. The embarrassment of arriving at the LCF rally in June 2019 on a Honda is too much. So the fight back begins…
I’d last been working on a reluctant Atlas #3 with an incurable misfire but with a very stubborn cam cover in which one steel allen bolt had bonded with the alloy cover. I was very patient but it wouldn’t shift so eventually I had to drill the annoying bugger out. I was surprised at how easy this is.
This last round had also ended with me trying to get another engine to work in Atlas #3 but it is knackered so first job was to pull that engine ready for the original to slot back in when it is repaired – as you can see Mrs A lent a hand…
While we had the crane assembled it seemed like a good idea to dig out all the broken engines. The engine from Atlas #1 is still in its frame so that’s a job for next week-end.
With the engines on the floor it was a good time to start opening them up and checking valve clearances. Atlas #2 engine (first engine on the left) has the same problem of a bonded cam cover. Consultation with buddies on the micapeak Laverda list suggest I may have to resort to the drill again but I did read about using a 50/50 acetone/ATF mix as a penetrating agent. I’ve plenty to be getting on with so will be patient and give this a try.
A valve clearance check showed Atlas #3 engine has 6 out of the 8 valve clearances that are too big – the clearances get smaller with wear so I’m thinking the engine must’ve run with wide gaps for some time. There is a closed outside exhaust shim on the primary side which is consistent with the misfire. Before lifting the head I’m going to fit a smaller shim and see if that gives some respite. I say respite because you’d have to think something not so good is going on if just one out of the eight valves is worn.
Checking three other cylinder heads revealed wide clearances in most cases – now despite all the mileage I did I never checked the valves (if it runs why bother…) so perhaps working on a .15/.20 gap is tight – must’ve been happy at around .20/.25 I’d say. Still I’m going to aim to set up all the engines to the former not latter specification.
The shims are the same as fitted to the 500 twins. Slater thought the 2.60 shim I required for the engine was still within spec’ but with OCT this is the smallest shim they supply so this confirms my suspicion that something nasty is going on in the primary nearside exhaust.
Getting to the shims is a pain with all bucket and shim engines in that you have to split the cam chain. The eight valve twins have this bent piece of wire to fasten the split link – I tried bending it straight but in the end the dremmel prevailed.
The cams and associated blocs etc have all been laid out. You can see the white metal cam bearings on the end of the shafts – I have been warned not to mix these up as they wear fit and getting them wrong can lead to seizure on reassembly – something I’m wondering that might have happened to the engine in Atlas #1.
More tales soon.