Tuesday, 28 November 2017

A little maintenance

The W/NG, since I'm shaking down and it is at the front of the garage, is my go-to bike at the minute. Since I made this list I've done a few jobs:
  1. Grease the forks & replace the missing nipple - done
  2. Maybe replace the fork bushes - not done
  3. Tighten the brake torque arm anchor or weld it in - done
  4. Make a T-bolt for the exhaust clamp - done
  5. Adjust and lubricate the primary chain - done
  6. Have a look at the clutch - not done
  7. Change the regulator to a V-Reg - done
  8. Fit a couple of transfers - done one...
I had a nice little trip out a couple of days ago to test the exhaust, which was great but the bike is not very fast and I'm not satisfied that I've got it running as well as it could.

I noticed that the carburetter slide was not reaching full travel for some reason, and that the plug was pretty dark. It's also had a bit of an oil leak from the inlet rocker shaft, which as you can see has heavy flat washers fitted over the banjos and the fibre washers. Not surprisingly, the oil leaks down the threads and comes out under the nut.

So what to do? What we always do in these situations - ask an expert, which always means someone in the AOMCC. In this case, a post to the forum yielded lots of useful information including this from Paul Jameson:

The correct assembly is as follows:
  1. Slacken off the screw on the opposite end of the rocker shaft from the banjo.
  2. Fit copper washer, then banjo then copper washer then acorn nut.
  3. Tighten acorn nut.
  4. Tighten screw on the opposite end of the rocker shaft from the banjo.
And this is why. Paul Jameson again:

The rocker shaft has a shoulder which goes against the inside of the rocker box so with the method above you tighten the nut, banjo and washers against the shoulder. The rocker shaft is sealed so that oil cannot emerge under pressure at the screw end. Hence the screw only seals against oil running along the outside of the rocker shaft.

So, undo this screw on the opposite side:

And you can see the end of the rocker shaft. Grip this with a very large screwdriver or a washer in the slot, and tighten down the acorn nut on the other end, against the fibre washers, then replace the large screw and snug it down into the milled recess to seal the rocker box.

Next, have a look up the inlet tract with the throttle fully open. Yes, I know I can see the carb slide:

Something odd here!

Let's have a look at the slide and spring. First off, the needle shouldn't be in that position, which is why my plug is sooty - it should be in the middle slot; secondly, that doesn't look like an Amal spring and fiddling around with it allows the slide to move up fully. Shame it doesn't return properly... It looks like it has its original brass slides though.

We'll have to get a new spring at least.

Turning to the back end, the chain has loosened off a lot. The primary chain is fine, and the chain is easily tightened up using Ariel's handy adjusters; odd spanner size though, the hex appears to be 3BA.

So that is that for today - we need a couple of seals for the rocker shafts, a new carburettor slide return spring and some front wheel bearings for the SQ4.

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