Sunday, 25 August 2013

Forks on!

It feels like a little progress is being made! It was a bit of a tedious
task but the forks are now installed. It started with re-spraying the cowls
as there was a dent in each that I wanted to remove. Then I discovered the
station sliders were threaded at the bottom ends and the bolts had a
shoulder that need to pass through this 'thread'. The securing nut on one
fork - the one that secures the lower bronze bush - was not threaded
correctly but fortunately I had a spare. The drain plug holes were
completely gummed up and the bores had a very difficult to remove sediment
in the bottom (I used carb cleaner to loosen the rubbish). All in all it
probably took me the best part of a day to sort out all of these issues
(whilst trying to sort out the engine cranks....)

Friday, 23 August 2013

Engine bits!


I never realised how complex it could become when I decided to rebuild the crank part of the engine on the 3T.

I must have around 6 engines and all mostly dismantled. Together with spares and suchlike, collected over the years, I have many cranks, rods and flywheels. So you you would think it a simple matter selecting the better components, fitting together and then voila, the bottom end is complete. If only! Most of the parts are of differing diameters and were either ordered as oversize options or have been machined to take up wear! The first engine has ended up with new old stock cranks and rods fitted to a matching flywheel. The second will have the same and the third will have refurbished cranks/rods with new white metal bearings etc. I would have used the flywheel assembly for the first engine but it was kindly pointed out to me that the assembly may not have ever been balanced. Once assembled I may end up getting the flywheel balanced.

So, the engine (lower end) should be together this weekend and I will post a celebratory photo!

Monday, 19 August 2013

Engine update...

I needed to see how the engine would fit together and test the new cam bushes with the camshafts. One was binding completely. So a strip down and a refit and bolt up had the same effect. The only answer would be to get an 13/16" reamer, make a bush and sort the blighter out!

Today I returned to my bench strewn with parts how I left it yesterday in disgust and reassembled it all again – both cams are free! What was that all about? The weather is the same. Maybe there was some dirt in the bushes but I doubt it. Anyway, on to the flywheel now.

I have now, I think, selected the best set of rods and crank arms that have the least wear (excluding ones I have had restored and a complete new assembly) I have had to use one new old stock con rod, a good arm, one new old stock crank (timing side) and a decent con rod. Play is minimal and I only need to check the small rod end of the used con rod before I assemble.

As a point of interest, the NOS crank assembly I have has no balancing drill holes on it, so I suspect this will need balancing if ever used.



Monday, 12 August 2013

Engine progression!

Today saw the timing side crankcases receive their new bushes. (As you can see, the cases have been vapour blasted)
The white metal bearing was replaced (new old stock) together with the cam bushes. There were two tricks I used here. The procedure was as follows:

  • Mark the cam bushes on the edge with a marker pen to indicate where the oil hole is.
  • Do the same on the crank case
  • This makes it easy to line up the bushes when fitting
  • Put the cam bushes and crank bush into the freezer for half an hour.
  • Put the crankcase into the oven for half an hour at 135degC
  • When ready remove and place on a couple of blocks.
  • Fit crank bush – this should only need minimal force to fit – I use a large wooden block as a drift.
  • Fit can bushes – alighning the marks previously made. To drift in, I use an old camshaft as a tool. Again not too much force is required. Make sure all bushes are fully home.
  • Make a final check that the oilways line up.
  • Same principle was done for the other crankcase – the bearing almost dropped in!

Job done!

Now to fit the camshafts, flywheel and cranks…

Friday, 2 August 2013


The only stantions that are available (at a sensible price) are those for later bikes 3TA etc The only difference with these is the 2BA threaded hole near the top. What I did here was to insert a grub screw (hex socket) and fix it in place with Loctite. These are covered by tubes and so will not be visible.

Thursday, 1 August 2013

Engine casing repairs!

I may not have mentioned it but last year, whilst cleaning up my workshop I knocked off the shelf the casings for the 1st engine rebuild – aarrgghh! Anyway what we did was to fill the hole with plaster of Paris (actually it was a moulding material used by dental technicians) and then clamped the timing cover on and held all the bits together. The 3 bits were chamfered first so that the welder could weld up the aluminium better. The main problem in welding old castings is that they can be porous and contain oil. This makes welding a nightmare. The guy I used is very good and the end result looks good. I will post a photo of the casings later now that they are vapour blasted.
The above photos are not in order, but they will give you an idea of waht was entailed. The red paint was an accident at the same time!! (I had a bad day!)

New exhausts 'v' old

I have original exhausts that I believe are from a 3T (one has ‘Triumph’ stamped in it) As you can see from the photos, they are slightly different but all should be OK. These silencers and down pipes are from Armours.