W/E 18th February 2018

Zimmerman sprag on the right

So the sprag saga continues…it’s becoming a bit tiring now. The fancy ‘Zimmerman’ sprag was fitted to a new starter ring gear. I’d been holding back on using a new ring gear but decided that as I won’t be covering many miles any longer now is the time to start using up these items. The new ring gear enabled the Zimmerman sprag to ‘grab’ but before I could install it the ring gear needed bearings.

I have quite a few ring gears which have their sprag bearing surface worn but the actual bearings that sit on the crankshaft are fine. It’s a bit of a faff to get these bearings out (two) because Laverda put a punch mark on the outer bearing surface to stop the bearings coming out – I’ve seen this technique inside the little Turismo from the 50’s where I thought it was used because ‘Loctite’ didn’t exist back then. I’m guessing that putting three punch marks on the ring gear is simpler in terms of manufacturing than Loctite so that’s what they use. Time spent with a Dremmel soon got rid of the  punch marks and with some heat courtesy of the cooker hob and a couple of sockets the bearings were drifted out and drifted in. I thought the interference fit would be more acute so I used some Loctite on the outer bearing just in case.

I took my time putting the engine back together and the Atlas duly fired up – the sprag seemed good. The test ride proved a success and I was enjoying being back on the road – especially with the clutch working so well. It got a bit late so on came the lights and as a consequence off went the sparks! I pushed the bike the quarter of a mile home…

The second 15 amp fuse has blown – looking at the wiring diagram there’s a problem in the lights somewhere (no shit Sherlock) so it’s gonna be out with the multi-meter. The only good news being it didn’t happen in March riding down to the V6 rally.

In preparation of the V6 rally I decided I need a spare shock. The Hagon unit that’s fitted appears okay but I’m not sure it isn’t a bit ‘wet’. As I don’t have a spare but do have a month before the rally I thought it would be wise to get another ready. The shock shown is a White Power unit. I’m told these were fitted as an option on the Mk 3’s but you can see the lower bracket is slightly bent where it hasn’t been spaced properly and has deformed as the through bolt was tightened.

I have some Falcon Shockabsorbers on my triples and they advertise a repair service for White Power. As I was in their neck of the woods I dropped the shock off and had a chat with Robin. He can fix the shock but was not very complimentary about them saying their damping systems were unconventional (presumably to get round patent restrictions) and in his view didn’t always work that well! He applied this to the newer stuff he’d had in off modern KTM’s.

I commented that I liked the soft damping the shock provided and he said this is most often because of the spring rather than the damping. Most bikes have too hard a spring to cover the range of potential rider weights and whether they take a pillion – he claimed many manufacturers compensated for the too hard spring with a soft saddle! Robin’s final comment was on the bent fork which he didn’t want to bend back in case it broke as that would be very expensive to fix…Hmmm maybe I should have had a go at bending the bracket before getting the rest of it overhauled?

Finally I spent a happy evening in Bromyard – not at Slater Laverda but at the Conquest Theatre listening to a talk given by John Roach and Geoff McGladdery who rode the Trans-America-Trail on a 350 Morini and 500 Triumph. It was a great night – suffice to say the Triumph fell short of the finish line due to a super dooper modern alternator that failed when really put to the test…you’d rely on wires secured by a cable tie inside the primary case! The Morini of course sailed to the end (with just a failed engine final drive sprocket caused by modern chain lube turning sand into grinding paste)…the Triumph owner has now purchased a Morini, which I have to say doesn’t sound like a bad idea!

Nick 🙂

 

 

 

W/E 4th February 2018

So time to go back over the Atlas following the trip to France and see what needs fixing. The sprag clutch was on the way out so that needed investigating, the battery seemed a bit secondhand, the clutch dragged and the chain was dry…oh and the problem with the silencer melting to the sidepanel.

First line was to get at the sprag clutch. First time I’ve done this on an Atlas with the exhaust on the right hand side (Mk 1 and Mk 2 models) and what a pain in the arse it is getting everything apart.

The exhaust system is very secondhand and I decided if I disturbed it then it probably wouldn’t go back together again – or at least not without leaking. I also thought the guard bolts seemed likely the shear if I tried to undo them so the challenge was to get the sprag off without removing the exhausts.

The alternator case just clears the exhaust guard – I was pleased to have the extra long allen keys that fit my impact driver they all came out with little resistance and no distortion of the allen heads 🙂 First issue was I forgot to disconnect the battery so once the alternator rotor touched the windings we had a few sparks!

Case off the next obstacle was the starter motor as I wanted to inspect the alternator. To remove this you have to take off the plastic cover and the cam chain tensioner block and the dip stick to pull the starter out the left hand side of the motor. Fiddly.

The sprag came apart and as usual was pretty beat up. As the picture shows one of the rollers had jammed against the back-plate and this in turn had been cracked. All the plungers are seized in their bores so at the moment that’s looking like scrap!

For the first time however not only was the sprag clutch broken but also the bearings in the ring gear had started to break up – never seen this before.

I have to rummage through the bins to see if I can build a sprag clutch. I have a hardly used Zimmerman sprag but haven’t been able to find a ring gear without wear to make it work. I do have a couple of new ring gears however so maybe now is the time to press them in to action. Time to get the verniers out and do some measuring…

Moving on I spent quite some time adjusting the clutch. The new clutch works well in that it doesn’t slip however the bar adjustment was wound right out to its limit. If it started dragging then I had no adjustment. First step was to pull the cable through which helped but in addition I played around with the small screw that presses on the clutch pushrod – my aim was to get this about half-way in to again provide adjustment. The messing around played off – but as I have no spare cable I must a new one to avoid being stranded at the roadside at some future date.

The battery charged up but I couldn’t recheck the charging because the sprag clutch wouldn’t work – I went over all the connections to the rectifier and so forth and it all looks in good order so fingers crossed when it all goes back together it will be charging…

Nick 🙂