Nonsense Found Building Bikes

GraemeH said:

I'm about to start wiring a Commando - what fuses and holders should I use? I just bought a couple of these blue things above
I am thinking I need a 15amp main fuse, then a 5amp specifically for the electronic ignition.

Click to expand...

Use inline fuses that look something like this.

concours said:

Lol, better than a Scotchlok piggyback with NO fuse

Click to expand...

And to be fair, the wiring ( when done properly) and the fuse, are held pretty securely.

marshg246 said:

Yesterday I was taking a Combat engine apart to rebuild for a customer. While doing that I inspect things to see what I need to buy, service, or fix. This engine has over 78k miles and was apart once when almost new for a bad piston and never since.

When I took the oil pump off it turned very freely, already means worn, but then I noticed that when I looked into the return port turned the drive gear, it appeared that the gear was not turning and was broken. Took the pump apart and it turned out that the gears were all turning and there were no broken teeth but there was a chunk of metal stuck in that port that looked like the end of a Woodruff key. Also, the gear nearest it had small marks from hitting that metal.

Since the oil pump bolts were not staked and there was nothing to tell me otherwise, I assume it left the factory with that metal in that port. The metal blocked about 60-70% of the passage so the pump could work. The metal came out easily by pushing inward once the gears were out of the way.

It is clear that the metal could not go through the pump, so it was in the pump when the pump was assembled.

Click to expand...

My brother bought a new Trident sometime in the early 1970s. When the gearbox failed after 1000 km he pulled it apart to find machining swarf in the box. There was definitely industrial sabotage taking place in the industry at that time.

Rode my Commando for a couple years before rebuilding and discovered this when I removed the oil pump - a bit of piston ring must have been in the sump as the rings were all intact. A small piece was forge welded to the pump gears from passing between the gears . I could not turn the pumps past this spot by hand yet it apparently was no problem for the engine to do. I have no idea how long it had this condition. What’s more how did that piece of ring get through a couple of 90 degree turns in the oil way ?

Richard Tool said:

Rode my Commando for a couple years before rebuilding and discovered this when I removed the oil pump - a bit of piston ring must have been in the sump as the rings were all intact. A small piece was forge welded to the pump gears from passing between the gears . I could not turn the pumps past this spot by hand yet it apparently was no problem for the engine to do. I have no idea how long it had this condition. What’s more how did that piece of ring get through a couple of 90 degree turns in the oil way ?
View attachment 122925
View attachment 122926

Click to expand...

And another thing is the crack in the crankcase around the main bearing....

dobba99 said:

And another thing is the crack in the crankcase around the main bearing....

Click to expand...

....where a prybar was used instead of a pinion gear puller.

dobba99 said:

And another thing is the crack in the crankcase around the main bearing....

Click to expand...

Looks like a crack but it was a chip on surface.

Richard Tool said:

Looks like a crack but it was a chip on surface.

Click to expand...

Yeah right... I think you need glasses mate

I'm rebuilding a Combat engine and gearbox for a guy. When I did the first phase on my cleaning process on the drive side crankcase, I could not get it to like that they usually do at that point. Today, I did the timing side, which was very dirty, but it came out looking exactly as expected easily like normal. So, I redid the drive side. It came out a little better (I have put in new glass abrasive for the timing side). In the end, it will look fine as very little of the drive side shows when in the frame and he primary is installed.

I think the issue is a slightly different alloy mix at the foundry. They are a matching pair but that matching I'm sure happened long after the sides were cast. For one thing, a quick glance and you would think the drive side is a 1974 850 case it is so porous in places. The timing side it more porous than is usually for 1972 cases but no where near as porous as the drive side. Also, the color is slightly different between the sides. I'm sure once I've finished with the final bead blasting and cleaning the will look the same if you don't look too hard. I've done lots of Norton, Triumph, and BSA cases and while these started out nowhere near as bad as some, the drive side has been a real challenge.