I would wait until it up and running but that horizontal rubber bobbin does look vulnerable if the vibration is in the vertical plane, you could change it to a bolt and spacer and the oil tank will still be isolated from any direct contact with the frame. All depends on the vibration and the resonances you get from your typical riding style on which will work best.

Thanks for the input, you're right, even if the bracket is solid bolted to the frame there would still be a degree of vibration isolation for the tank as the bracket is attached above the rubber mounts on the through bolts. However, the purpose of the bobbin is only to restrain the top of the tank from pivoting from below, where the through bolts intersect the tank support platform. I expect that this movement would be more as a result of the dynamic forces from the bike accelerating and decelerating with a tank containing hot oil, rather than from vibration, although this would also likely be factor. I am not too concerned about vibration in the vertical plane causing a problem for the bobbin as the rubber isolators in the tank tubes are held in adjustable compression by the through bolts. The rocking movement of the top of the tank will result in primarily an axial load on the bobbin, for which it is designed. But, as you suggest, I'll wait and see what really happens when it's running.

…I installed the larger, M8, vibration isolation bobbins to the silencers. After setting the final positions and alignment, I tack welded the outlet stub sockets in place.

…to install the Morgo oil filter unit, I made a bracket from stainless steel flat bar that bolts to the inside of the gearbox plates, below the oil tank.

That's quite a contraption, just for an oil filter.

There are ones that bolt straight to the engine plate.

Thanks, that's the type of oil filter unit I use on my Bonneville. I did consider using this type on the Triton also, but the Morgo one is physically much smaller (probably around half the size) and fits much better in the area behind the gearbox.

As the mounting clevis swivels through 90deg, I could have mounted the Morgo one directly to the gearbox plate, but I wanted it inboard of the plates for the hose routing I am planning, and that would mean that the top of the unit would be hidden. As I am quite impressed by the detail and finish on the top of the Morgo unit, I wanted it to be visible when installed, hence the need for the fabricated "contraption".

Keep the hoses short, so that if the bracket breaks or fasteners fall out, the filter doesn't hit the road.

Of course, it's possible your bike will vibrate less than mine!

...in preparation for painting, I leak tested the fuel tank.

The tank had been pressure tested by the manufacturer but I just wanted to make a verification, with the limited equipment I have, for any obvious leaks.

I sealed off the vent in the Monza filler by closing the cap onto a nitrile glove and connected fittings to the fuel outlets on the bottom. One had a valve and airline connection the other had a modelling balloon over it; I actually used two balloons, one inside the other.

Using a very low pressure from the regulator on my compressor, I pressurised the tank until the balloons inflated and isolated the tank by closing the valve and disconnecting the compressor. I then went over the seams using leak detection fluid, examining for any bubbles. The tank was found to be leak free, using this method. I also left it overnight with the balloon inflated, and my shed heater thermostat set, in the morning the ballon was still inflated.

Although not a totally conclusive test, it's better than nothing and I didn't really want to use any higher pressure.

"Better than average"

…getting the final parts of the “black build” done before strip down for welding and painting.

I eventually found a brake light switch that fitted and looked right After trying various Lucas, miller and even a land rover switch, I settled on a 1970’s Harley item. This one was small enough to fit behind the lever by fabricating a small bracket and actuating stop.

While I had the welder set up for stainless for the stop switch bracket, I welded the stub sockets onto the exhausts then blended and polished the welds.

Very nice work.

…after disassembling I completed the welding of parts that had been tacked in place during fit up.

Some of the redundant, damaged and oversized holes in the frame gusset plates were filled by first reaming them out to a clean circle then turning plugs from bar that were an interference fit in the holes and welded on the backside.

I also decided to profile the rear brake torque stay, mainly for aesthetics but will also save a few grams of unsprung weight.

Parts are ready to be sent out for painting and powder coating, so now I’ll make a start on the engine and gearbox final assembly.

My goodness, that's awfully nice.

…I got a start made on the engine build. Checked the crankcase face for mounting the barrels was parallel with the crank by mounting between centers on the lathe and orientating level then verifying with a machinists level. This was found to be OK - within the accuracy of the level - and the face was flat with no discernible step between the two sides.

The sump plate mounting face did however have a small step between the two sides so was skimmed with a mill end cutter to true it up.

…with the old main bearings removed I scrubbed the crankcases in soapy water by hand then put them in the dishwasher for a cycle.

The camshaft bearings were OK but the timed breather was removed as it will be replaced with an external reed valve, therefore the camshaft bearing in front of the timed breather was replaced.

The new Morgo tappet blocks were fitted to the barrels and aligned using a straight edge and measured against the cylinders with a vernier.

The new camshafts were dry assembled in the crankcase and the timing gears fitted. The tappets were blued and checked for contact with the cam faces. The contact area was good and as there was very little wear and no grooving on the tappets they were just dressed on a sheet of 800 grit wet and dry on a glass plate in the direction of cam rotation. They were then checked again with blue.

I haven't seen this build before Bry, sorry. To say I'm impressed would be a massive understatement. Well done!
Having seen through all your posts it's obvious to me that I needn't have answered your questions on the Triumph board as I did, of course you would centralize the crank and check out the axial clearance, wouldn't you! And deck the crankcases of course.
I wish I had the skills, and not least the patience. Brilliant!

As regards the XS 650 breather valve we discussed, on testing I found my set-up less than ideal. I'll try to explain in case others would be interested:
The original timed breather was beyond repair. To mitigate this I fixed an XS reed type breather behind and just below the cylinder flange, over the existing breather outlet. The crankcase air is expelled through the cam and pipe as per original, goes through a looped plastic pipe and up into the valve. From there it's led through a 10mm ID rubber hose to the rear of the machine.
At first it worked really well but some times after sitting over night, aerated oil would form a snotty foam that seemed to plug the loop between the crank outlet and the valve. It would take some time, and heat, to shift this plug, though it eventually did dissolve. Experiments with a shorter hose from the valve to the gearbox sprocket seemed to work better, but it was messy.
If there's a next time (the bike is back with the owner) I'd rather tap the timing cover somewhere, as done on Norton's. This would get rid of the troublesome loop.
The residual oil level is lower in a Triumph timing chest I believe, so it should work at least as well as on the Norton's I think.

Hope this is of some use.
Stein Roger

Thanks for the information Stein Roger.

…an earlier check of crank axial clearance with the old main bearings fitted indicated that the crank needed to move 0.010” (0.020” measured difference) towards the timing side to center the connecting rods in the bores. With new bearings fitted this was found still to be the case and the axial clearance was measured at 0.005”. With the rods secured with cable ties and a tool ground to match the existing fillet radius, 0.010” was skimmed of the face of the shoulder that the timing side bearing is clamped against. Reassembly confirmed that the rods are now centered and the axial clearance is 0.015”.

…with the new main bearings fitted and the crank positioned correctly, it was time to attach the drive side oil seal holder that I previously made. The holder was turned from aluminium and positioned using a bushing machined from steel bar. After cleaning the area with methylated spirit, the holder’s face that is in contact with crankcase was brushed lightly with Permatex grey moto seal 1 then a fillet of JB Weld Original applied around the outer edge.

…the intermediate timing wheel bush was replaced and bored to size.

Chalk the following comment up to "information to ignore," but Vincent supplied half-time pinions in increments of 0.002" in order to get the backlash at the correct value for their engines. While Triumph owners don't have the luxury of having a selection of gears to choose from, you do have a 4-jaw chuck. The runout of your 3-jaw chuck at any given, arbitrary diameter is very unlikely to be less than a few thou., which means your gear will oscillate toward and away from the cam and engine gears, changing the backlash on every rotation.

Bushes are cheap and you don't have a lot of time invested in sizing the current one so little would be lost redoing it. But, feel free to ignore this since the engine will be just fine with the current bush (but it could be finer-er.).

MM thanks for the comment. The run out on this 3-jaw is pretty good, especially with the external jaws fitted as they don't get much use. Using a 4-jaw chuck would of course allow clocking in, but from where? I don't have a DTI slider to use on the OD of the teeth, leaving the only option to use the bearing bore as a reference before the bush is pressed in. Certainly possible if the bush is removed, the gear wheel then set up in the chuck and the chuck removed with the gear wheel in it to press the bearing in, then refitting the chuck; or on such a small bush you could probably get away with using the tail stock to press it in. I'm happy enough with the results achieved with the 3-jaw and it's still probably more accurate than reaming.

I'd be interested to hear of any other methods that you know of to clock this in using a 4-jaw as a similar operation is required for Velocette gearbox gear wheels, where the backlash tolerance is more critical?

Splitting a hair that is already split results in diminishing marginal utility!

When I've needed to do similar things to high accuracy I've made "soft jaws" or their equivalent. One of my 3-jaw chucks has replaceable jaws, allowing actual Al soft jaws to be fit. These would work, although would require more effort then what is described below, because the final machining of them to make them ready would require clamping a bar of Al of somewhat larger than the OD of the gear and simultaneously machining that bar and the Al jaws away to precisely the OD of the gear, to at least the depth of the gear. At that point the gear would be clamped directly in the soft jaws. Although the scrolls in 3-jaw chucks aren't precise for all diameters, they do repeat to better than a thou. at each given diameter. So, you could insert and remove the gear at will. This isn't an advantage when doing just one, but clearly would be if doing multiple gears.

However, for a gear like yours I would turn the ID and OD of a piece of large dia. Al, making its ID the same as the OD of the gear. This could be done in a 3-jaw chuck since as long as both operations are conducted without removing the Al the ID and OD would be Concentric. Then slit the Al lengthwise, clamp the gear between them, and use the outer surface to adjust the 4-jaw.

The Al could be split all the way, leaving a small step that would jog the indicator, which would be fine. Or, if I thought I would be using the fixture more than a few times, and if the Al had a large enough OD, split it only part way and drill and tap for cap screw to clamp it (or, short of that, a hose clamp).

For completeness, I'll mention that if the gear were smaller I would use a "step collet." I have a number of these, made of soft steel or Al, that have been machined for various holding purposes. The idea is to loosely clamp such a collet in the lathe, machine it with the necessary diameter, then place the part in the stepped recess and clamp the collet firmly. These collets are especially useful for mounting thinner pieces that need to be drilled or machined precisely on-axis.

This isn't splitting hairs. The proper backlash of the gears is the thickness of a piece of paper so if the bush is off by a few thou., which is the precision of any 3-jaw chuck, it will move the gear in and out by that much, which will change the backlash by that much. You certainly can get away with that, using the wrong clearance crankshaft bearings, not decking the crankcases to be perpendicular to the crankshaft axis, etc. It's just that if you do things right (i.e. not the way most people do it) the engine will work better and last longer. In the case of the gear in question, doing it right really doesn't take much longer than just doing it. Given how much pride and effort Bry is putting into this build I thought it worth mentioning.

I was being a bit facetious, you are right.