March 15, 2025 Coming March 19, 2025. I sold a 1974 Triumph Trident for a Norton
MKIII Commando partly rebuilt basket case and a little cash. That Trident is documented here.
March 19, 2025 The MKIII arrived today. It has lots of new and restored parts and seems complete. I haven't spent much time looking it over yet. The gearbox needs to be built and I'll do that first. The bottom end of the engine is built and in the frame. The cylinders are bored - haven't looked yet if they need to be painted.
It is a black, matching numbers Roadster.
Started on the gearbox. Other than a couple of studs and nuts everything is there
and in good shape. However, the shell looks "rider good" and when I rebuild
a bike I want all cases to look new. So, I've stripped it and have started my
beautification process. Normally, that would only take me an hour but working one-armed
really slows things down!
March 20, 2025
It's always interesting and always different when you start onb a bike. Besides
the actual beautification process, I makes sure that every threaded hole is open
clean and the stud, bolt, or item that screws into each hole will go in with
fingers only. Since I had studs keeping the holes clear for the seven studs
that hole the inner case to the shell, an old drain plug in the drain
hole, and an old neutral switch in the neutral switch hole, those holes were
easy. That only left the index plunger housing, selector fork shaft, and some
checking:
- Index Plunger Housing. That hole was easily cleared with a bottle
brush.
- Selector Fork Shaft - see the first picture. the four on the left are correct,
the one on the right came with this bike and was poorly hack sawed off. It did
not want to start in the hole and would not start from the outside either. So, I
used on of the other ones I had. Rough starting from the inside but started
easily from the outside. Used it to cleanup the first couple of threads on the
inside. Now all four of the good ones start and thread in without problem from
the inside and the ones that came with this bike is in the metal recycle bin. I
have no idea why someone shortened it!
- The second picture shows the other issue I encountered. At some time in it's
life, the nuts were overtightened and raised a lip around the stud (orange
circle). Also, there were scratches in a few places across the mating surface
(orange oval). Finally, with the location studs removed (PITA), there was a
.002" gap between the shell and my surface plate. A few seconds with 120 grit
paper, about one minute with 220 grit paper, and about two minutes with 320 grit
paper and all is resolved. With a good gasket, it probably would have sealed but
now I know it will.
- Now I'm stuck for little while. The camplate switch "button" is
badly scored and I'm out of stock on them so I have to wait for my next AN order
to be able to assemble the gearbox. I have quite a few used camplates but none with
the MKIII neutral switch "button" in usable shape.
March 27, 2025 I've had a lot of medical stuff going on for my knee replacement
on April 1st. It's still not confirmed that it will happen – PITA! I've
been rebuilding the gearbox as I've had time.
The quadrant "button" for the neutral switch was badly damaged and I didn't
have one, so I order one. That is now installed. The neutral switch that came with
the gearbox was missing one terminal, so it had to be replaced. I stock the Lucas
switches, but they do not work "out of the box". I learned/fought that
on the last MKIII gearbox rebuild. This time I was stuck. The original switch plunger
sticks out of the switch body about 3/16". The Lucas one sticks out about 3/8".
With it adjusted so it just closes, it will catch on the "button" and
prevent you entering neutral. It took two tried, but I cut the plunger in half and
used a Dremel and fine sandpaper to put a smooth ball shape on the remaining plunger.
The first try came out too short and the switch would not close. On the second try
I got it perfect. Now with the switch adjusted so if just closes when on the "button",
it does not touch the quadrant on other gears and hits the "button" part
way up so no binding. With the plunger as supplied the binding between the plunger
and switch body was way too much.
Next problem. The bike came with three main shafts. One is clearly used and form
the middle to the two ends is off by 0.040". the next looked nearly new but
was off 0.020" The third is new from Andover Norton and perfectly straight.
Another problem. The bike came with two layshafts. Both are in perfect shape except
that someone turned the bearing end down slightly – probably to make the slip into
the original ball bearing. The inner race for the layshaft roller bearing would
slip on easily. They probably would have worked and with bearing set they certainly
would work, but I didn't want to wait a day for that to set up. So, I got a
layshaft from stock and used that.
March 28, 2025, Got a call today, the surgery is on for Tuesday. Of course, I was
told that the scheduler would call in the afternoon today and let me know what time
to be there – didn't happen!
More gearbox troubles. See the video below. I really need a phone stand! Anyway,
the kickstart shaft and its bushing that came with the bike are not usable. The
shaft OD measures 1.121" in one direction and 1.123 in the other. The bushing
ID measures 1.128" and is round. Also, the pawl is the most worn I've ever
seen!
I checked a new shaft, and it is 1.122". I went though my bushings and found
a good one with an ID of 1.126". I found a good used shaft in my gearbox parts
that is 1.122" and it has a like new pawl.
OK, time to check/correct the layshaft end play. It has .055" so too much.
Of course, I can't find my collection of shims, so I ordered more from McMaster
Carr and the gearbox is on hold for now unless I find my shims before Monday.
Next problem. The sealing surface of the inner cover was worse than the shell, so
I corrected that and went about checking the screw holes used to hold on the outer
cover. Two holes were fine, one had to be chased since the screw would only go in
about 3/16", I thought I would have to HELICOIL the others as the first part
of the threads was bad, but once chased the more internal threads are fine so it
will be OK.
March 30, 2025 Since I'm stuck on the gearbox until shims arrive, I started on the engine yesterday.
I expected the bottom end to be ready to go but when I uncovered it, not so much. Basically, greasy grimy gopher guts! With basically no right arm and a hurt left arm, getting it out of the frame was not fun but I did it. I was able to do it because my steroid shot from Thursday morning had not worn off yet; but, of course I hurt both arms more in the process.
Next was getting the timing side apart. What a nightmare! The camshaft nut would not come loose with my longest breaker bar, even with a fork tube to extend it. Then I tried heat - no help. Then my air wrench - no help. So, it was time for the big electric driver capable or 450 ft. lbs. I have never found anything to resist it and this was no exception. It came right off. OK, now onto the the drive worm gear on the crankshaft - the big gun was needed for it as well. OK, home free? Nope! I had three pinion pullers when I started. My very old Triumph one that I modified to work on Triumph and Norton - it broke. Then I had
a Norton one that I modified to actually work (the "legs" are too thick), it broke. OK, last try. I had a new Norton puller I got when I bought someone out. Of course,
it was too thick to work so after a bunch of grinding I finally got it to grab and thankfully it pulled the pinion without breaking! Another interesting thing is that the
outer camshaft bushing was very loose in the case - I'll have to figure that out!
Whenever I'm rebuilding a Norton other than 72/73 750s, I send the cases to Colorado Norton Works for their breather upgrade. To save time and accomplish something while in the hospital, I'm going to have them do the case cleanup as well. So, I stripped everything from the cases today and they are box and ready to ship tomorrow.
The insides of the engine are so grimy that I assume the crank needs to be cleaned out so that will be the next step when I'm able. The first picture below is after I got the parts out and cleaned up a lot of the grime!
May 4, 2025 Before my knee replacement surgery I did take the crank apart and
cleaned/inspected it. It’s I good shape. I couldn’t put it back together because
I didn’t have the stud/nut set. Those parts came in the day after my surgery.
I’ve only been to the shop a couple of times before today to get things. Today
was the first day I worked on something there. The gearbox is assembled except
the outer cover. The gear rachet plate is missing (or I haven’t found it) and
the outer cover is not only ugly, but someone drilled out the location pin
holes. Those two parts are expensive, so I’ll check options before ordering new.
So, I can walk, get in the car, and drive. Everyone says I'm doing great. I hoped to be a lot further along at this point!
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