Wednesday, September 23, 2015

Biketech7 - Holidays And Riding The BSA.

It's been a long time...
Five years in fact since I last swung a leg over this fifties 650 twin. Dad had kept it up together in fairness, with a few little adjustments here and there (which I put back the way I like), but the one thing that wouldn't come good was the charging system.



This bike always seemed to suffer when left for long periods, but a quick reversing of the polarity usually got things going. Not this time however.
For those not in the know, earlier Brit bikes used a 6v positive earth system. Just like it sounds, the live terminal on the battery goes straight to the frame, and everything else is connected via the negative terminal. Exactly the same as what you're used to, but the other way around. Easy.

And because I was desperate for a ride, a few quick checks were needed to diagnose the various components:
  1. Fuse ok (not a standard fitment, but it's peace of mind to have an inline one fitted).
  2. Lights and horn work.
  3. Ammeter deflects when something is turned on (proves the ammeter is still in the circuit).
  4. Try correcting the polarity because sometimes it will reverse itself - remove field and D connections from the dynamo, take a wire from the negative terminal and flash the field "F" terminal on the dynamo. You should get a nice blue spark and everything should now be good to go. Alternatively, hold the cut-in points closed for a couple of seconds.
  5. Remove end cover from dynamo and check it's turning. Also cleaned the commutator while inside.
  6. Connect up both terminals of the dynamo to one side of a 12v test light, and the other to the frame. Run engine and hope the light gets brighter when engine revved. Perfect.
So everything was good... 

Time to check the CVC. 
The Lucas Compensated Voltage Control unit is an amazing bit of kit for its day. It only kicks in when a certain output is received from the dynamo, it regulates that output and charges the battery correctly, and cuts out again when the output is no longer enough so the battery doesn't try to power the dynamo. It also adapts for changing temperatures... but it can be a bugger to set up right (for me at least).
I have to admit that I've never done it strictly by the book. In the past I've set up the point's gaps "somewhere near", got the cut-in points to work "just right" and set up the battery voltage to "near enough". And I've never had a problem, in twenty years, including a lot of night rides, with 6v electrics, and a 30/35w headlight bulb. 
12v lights? You don't know you're bloody born nowadays!



But I digress, this time the cut-in circuit wasn't having any of it. Time to remove the CVC for a better look and, at first glance, it still looks in good condition. With a bit of poking and prodding though, I noticed the earth connection on the backplate was no longer secured by solder. 



I knew this would be hard to solder back on because of the size of the steel backplate - large metal areas take too much heat away from the area you need to solder, rendering the soldering iron useless. Although I could apply more heat using an old fashioned style soldering iron (heated with a blow lamp), I was worried the various windings/coils would get damaged. So, with much messing around with two electric soldering irons, and getting nowhere, I decided to drill and tap the backplate and solder a wire to the loose terminal. Then I could secure the wire with a terminal and a screw. Job jobbed (although in my haste to refit it, I forgot to take a pic!).

With it refitted to the bike, the cut-in points were now working. The charging side wasn't brilliant, but enough to cover the brake light use for daylight riding. And I was off!

It's hard to put into words how good it feels to ride the old Beesa again. Strange how you just slot straight back into righthand gear change. The lack of front brake is ok as long as plenty of room is left between other traffic; the half-width hub is renowned for being one of the best of its time, but I think the shoes are past their best. The handling isn't modern by any means, but just let the frame do its thing, push harder, and it still goes round the corners the same as any other. Almost. And before long the side stand touches the ground and you know it's time to back off a bit and just enjoy.

The Wye Valley.
It's an amazing place to ride. From Monmouth to Chepstow, you follow the river closely, and the tree canopy is immense nowadays, like riding through a tunnel. Scenic doesn't do it justice, and I've forgotten how much history is pummelled into you when you haven't seen it for so long. In the mundane commute to work you forget to look at its beauty, but today my senses are on overload. I miss this a lot.
First through Redbrook, with its two cracking pubs, my fave being The Boat on the other side of the river, just use the old railway bridge to get over there. The food is immense and Guinness is on tap so it'll do for me. 


Then it's on down a few winding miles, across Bigsweir Bridge and into Llandogo. The Sloop is another good pub well worth a visit and does great meals. 


Next stop is Tintern, unless you cross another bridge into Brockweir, but I'm just  sticking to the main road for now. I stopped halfway through the village to get  a pic just above the river. Yeah, it's a nice spot.


Just round the corner at Tintern Abbey and the sun was in the perfect spot. The Abbey's not doing bad considering it was knocked up in 1131, and it might still have its roof if it wasn't for Henry VIII. Yes, it wasn't just his wives, he lopped the tops off monasteries too.


After Tintern it's down to St. Arvans on some proper bends. It's as good as I remember down here and perfect for the Beesa. It still amazes me the pace you can carry through here on a sixty year-old bike, and gets annoying when I get stuck behind the commuters, but hey, it gives you more time to look around. This is living baby! Down to Chepstow Racecourse and I turn back to do it all again. 
The Beesa was faultless and I love the way it just sits there and idles perfectly like it was used everyday. 

That's my mix up of a blog post today. A bit of mechanical, some scenery and a bit of history chucked in too. Needless to say I want to go and do it all again.