Time for an update . . . .
Just to remind you, this is what turned up:
It was very difficult to push about as the box wasn't running free in Neutral, this was accompanied by horrible 'clunking' noises.
Pretty soon it was a sorry little Rat Bike
:
Taking it apart wasn't difficult. The tank was held on by the single fuel pipe and the airbox only had one bolt - which was very loose. The seat was clinging on with two nuts that were just started on their threads
.
The air filter is a scrapper
.
Anyway, the box was soon on the bench:
The Output Flange nut came off OK, but the taper was very tight (a good sign).
The box was very dirty around the clutch end. The clutch lever was very stiff so I was expecting trouble there.
The magnetic drain plug didn't look too bad - which surprised me as I was expecting more swarf than this:
Soon the box was apart to reveal . . Swarf everywhere
.
I can't show it in stills, but the rear bearing on the output shaft was the worst I've ever seen - its almost possible to remove the outer track from what's left of the balls and cage. The other bearings are shot as well - but are not as bad.
The output shaft has been pulled back from the front bearing. There shouldn't be any discernible space between the bearing and the fifth gear pinion. This is why we fit circlips to the front of the inner bearing.
The swarf has contaminated the oil and has worn the two bearing sleeves that the first and second gear pinions run on - The plain sleeve for First Gear:
The First Gear pinion has a plain thrust washer on each side. The inner one has been pressed into the Third Gear sliding pinion - its supposed to be flat. This has further damaged the bearing sleeve that did the damage to it.
The (expensive) roller Bearing on the front of the Input Shaft is usually OK, however, this one is jammed solid and the rollers won't turn so I guess its full of swarf.
I think the box has run low on oil at some point in its life (there was oil in it when I drained it) as the Input and Output shafts have been 'blued' with heat where the bearings have been choked with swarf:
I'm not intending to replace them as the bearing sleeves will be renewed. I can't see them going soft (or brittle) with the heat treatment.
Some of the retaining washers and circlips on the Output Shaft are damaged and will be replaced. One circlip has been reduced to almost half its circumference, yet I didn't find any broken pieces
.
The 'clunking' noise heard when the bike was being wheeled about came from the Drive shaft. The rear bearing on the Output Shaft was so worn that the Drive Flange was hitting the outer sleeve on the rear gearbox cover - where the 'boot' attaches. This movement allowed the Worm Drive on the Flange to chew-up the Speedometer Drive gear - you can see how the spline teeth are now tapered towards the lower end. I have ordered a 'Good used' one from Motorworks.
Worse, the Drive Flange has cracked the rear cover. Its not critical and I'll put a touch of Epoxy adhesive on it. A 'Good Used' rear cover is £110 from Motorworks.
The good news:
There is some. The selector forks are fine with just one tip showing signs of heat. They will go back in OK.
The complete Selector Mechanism is also A-OK. I'll replace the springs and Indexing Roller as a matter of course but this is actually better than some I've seen
.
The cam faces on the Input Shaft Shock Absorber are also very good.
The Clutch:
The Clutch assembly looked well past its sell-by date and I wasn't very hopeful about saving all of it.
I removed the six 'hold down' bolts and expected the outer retaining ring to fall off and the Friction Plate to fall out . . . not a bit of it, the thing was welded together and nothing would shift it.
I soaked the three locating pegs in Penetrating Oil and left it for a couple of days - still no movement. So with a gas torch and a hammer and cold chisel (to use as a wedge) I eventually got the bits separated.
The Friction Plate is just down to the rivets and the rest is rusty and seized. I'll save what I can but I have ordered three new parts from Moto-Bins today.
The problem then was that all the components were contaminated with very fine metal swarf and I didn't want to put anything back in that state. Washing the Gear Pinions in Kerosene didn't remove the swarf so I dug out my 27 litre Ultrasonic Cleaner
.
"Hubble-Bubble".
After two 20-minute sessions, the cleaning fluid was a dark brown colour.
When the fluid was drained the bottom was coated in particles - mostly steel swarf. I cleaned the tank out with a large clump of paper towel which came out covered in sparkly bits.
As the gear pinions and so on were now thoroughly de-greased I carefully re-oiled everything and set it aside ready for assembly.
I have a couple of (large) orders outstanding with Moto-Bins and Motorworks so assembly will have to wait until the shiny new bits have arrived.
To be continued.
Bob.
Just to remind you, this is what turned up:
It was very difficult to push about as the box wasn't running free in Neutral, this was accompanied by horrible 'clunking' noises.
Pretty soon it was a sorry little Rat Bike
:
Taking it apart wasn't difficult. The tank was held on by the single fuel pipe and the airbox only had one bolt - which was very loose. The seat was clinging on with two nuts that were just started on their threads
.The air filter is a scrapper
.Anyway, the box was soon on the bench:
The Output Flange nut came off OK, but the taper was very tight (a good sign).
The box was very dirty around the clutch end. The clutch lever was very stiff so I was expecting trouble there.
The magnetic drain plug didn't look too bad - which surprised me as I was expecting more swarf than this:
Soon the box was apart to reveal . . Swarf everywhere
.
I can't show it in stills, but the rear bearing on the output shaft was the worst I've ever seen - its almost possible to remove the outer track from what's left of the balls and cage. The other bearings are shot as well - but are not as bad.
The output shaft has been pulled back from the front bearing. There shouldn't be any discernible space between the bearing and the fifth gear pinion. This is why we fit circlips to the front of the inner bearing
.
The swarf has contaminated the oil and has worn the two bearing sleeves that the first and second gear pinions run on - The plain sleeve for First Gear:
The First Gear pinion has a plain thrust washer on each side. The inner one has been pressed into the Third Gear sliding pinion - its supposed to be flat
. This has further damaged the bearing sleeve that did the damage to it.
The (expensive) roller Bearing on the front of the Input Shaft is usually OK, however, this one is jammed solid and the rollers won't turn so I guess its full of swarf
.
I think the box has run low on oil at some point in its life (there was oil in it when I drained it) as the Input and Output shafts have been 'blued' with heat where the bearings have been choked with swarf:
I'm not intending to replace them as the bearing sleeves will be renewed. I can't see them going soft (or brittle) with the heat treatment.
Some of the retaining washers and circlips on the Output Shaft are damaged and will be replaced. One circlip has been reduced to almost half its circumference, yet I didn't find any broken pieces
.
The 'clunking' noise heard when the bike was being wheeled about came from the Drive shaft. The rear bearing on the Output Shaft was so worn that the Drive Flange was hitting the outer sleeve on the rear gearbox cover - where the 'boot' attaches. This movement allowed the Worm Drive on the Flange to chew-up the Speedometer Drive gear - you can see how the spline teeth are now tapered towards the lower end. I have ordered a 'Good used' one from Motorworks.
Worse, the Drive Flange has cracked the rear cover. Its not critical and I'll put a touch of Epoxy adhesive on it. A 'Good Used' rear cover is £110 from Motorworks
.
The good news:
There is some. The selector forks are fine with just one tip showing signs of heat. They will go back in OK.
The complete Selector Mechanism is also A-OK. I'll replace the springs and Indexing Roller as a matter of course but this is actually better than some I've seen
.
The cam faces on the Input Shaft Shock Absorber are also very good.
The Clutch:
The Clutch assembly looked well past its sell-by date and I wasn't very hopeful about saving all of it.
I removed the six 'hold down' bolts and expected the outer retaining ring to fall off and the Friction Plate to fall out . . . not a bit of it, the thing was welded together and nothing would shift it.
I soaked the three locating pegs in Penetrating Oil and left it for a couple of days - still no movement. So with a gas torch and a hammer and cold chisel (to use as a wedge) I eventually got the bits separated.
The Friction Plate is just down to the rivets and the rest is rusty and seized. I'll save what I can but I have ordered three new parts from Moto-Bins today.
The problem then was that all the components were contaminated with very fine metal swarf and I didn't want to put anything back in that state. Washing the Gear Pinions in Kerosene didn't remove the swarf so I dug out my 27 litre Ultrasonic Cleaner
.
"Hubble-Bubble"
.
After two 20-minute sessions, the cleaning fluid was a dark brown colour.
When the fluid was drained the bottom was coated in particles - mostly steel swarf. I cleaned the tank out with a large clump of paper towel which came out covered in sparkly bits.
As the gear pinions and so on were now thoroughly de-greased I carefully re-oiled everything and set it aside ready for assembly.
I have a couple of (large) orders outstanding with Moto-Bins and Motorworks so assembly will have to wait until the shiny new bits have arrived.
To be continued.
Bob.
.
.
.
. I must be getting old and soft 
.
as ever Bob.
