The rebirth of Lazarus

[Oddjob]

Lots of pics coming up so may split the reply.

Gearchange shaft, the one I found today I gave up on. The end that goes in the clutch case was perfect, lovely condition, the shaft though was really rusty and I was concerned the it would bugger up the oil seal. That saying where the seal sat looked ok but the rest of the shaft has to pass through the seal before it gets fully into place. So whilst I haven't binned it I looked for the other one. That was the opposite, shaft really nice, bit of corrosion but nothing too bad. The other end though was rusty as hell. Took me a couple of hours to get it to look nice again. Checked everything and can find no faults. Splines for gear lever are great, tested with a lever I'm currently working on and it just slid on and even without a pinch bolt it wouldn't slip. The large spring is still soaking but is good, so I'll refit that as soon as I've cleaned it.







Next item. No 12 or 23491-286-030. Removed it from the shaft, really starting to hate those odd circlips, even with decent Snap On circlip pliers as soon as you expand the clip it twists round and won't come off. The gear wasn't too bad, fair amount of rust but surface type in general. Cleaned and inspected, cannot find any fault with it, all teeth good, no chips, dogs in good nick. Came out pretty good as well. Looks almost new.

[Laverdaroo]

You're a top man Ken

[Oddjob]

Next item. Here's where it starts to get complicated, sorry.

No 10 gear or 23471-286-010. I found 2 of those but gave up on 1 as it was a little too rusty and it wasn't worth the effort to clean it as I suspected it may fail after a few years of use. It was marginal and if the part was really really rare and unobtainable I'd have used it but it's not so in the bin it goes. The other wasn't anywhere near as bad to start with and after cleaning and inspecting I can find no faults. All gear teeth ok, no chips or signs of uneven wear, Both sets of dogs are good.







So those are the 3 items you want BUT as Bryan says gear No 10 usually comes supplied with gear No 5 as No 5 was changed after the K0. Here's the complicated bit. I found 2 No 5 gears 23420-323-010 or so I thought. One still had the bronze bush inside it, the other didn't. They look identical but on closer inspection and only because I'm a perfectionist did I spot this. After cleaning them both up I was wondering which to offer you, both came out great, no damage. However the one with the bronze bush still installed was bugging me as it wasn't fully driven home. Tried to move it, nope. Stuck hard. Got the old Mapp gas torch out and heated it up. Tried to tap it out, nope. So using the other one as a test sample I found a socket to drive the bush out, wasn't a great fit but it would do. Took it back to the vice and strangely the socket is now too big, odd. Another smaller socket found and more heat and out she popped, promptly rolled off across the garage and hid itself whilst gently steaming at the same time. Went to pick it up, forgot it was mad hot and burnt my fingers, suitable swear words later and back to the vice it goes. Only when this bush is removed does it become apparent the 2 gears are very slightly different. Out with my NOS gear complete with part label and it's clear the one I've just removed the bush from is not 23420-323-010 but 23420-323-000. So it's from a K0 engine, most likely the same engine as the cases are that your having. This is really odd as to my knowledge I have never broken a K0 and there weren't that many around to break anyway, yet I have 2 sets of engine cases both beginning with a 1 not a 2 like the K1. I did buy a few spare engines back in the day and acquired a few more when my family was also buying 500 engines for their bikes.

So here's what they look like. 000 first. You can see a small lip on the central boss.



010. No lip, smooth straight through hole.



The other bush is like a top hat on 010, I used the bush out of my NOS one to show the difference.





So to put this simply, you need to find out which of the 2 types you currently have. Does it have a top hat bush which comes out easily and is therefore a 010 or a pressed home bush like 000. It's the large gear next to the needle roller on the countershaft.

Oh 1 last thing, the little dots etc you can see on the gears are not rust spots or pits, they are just the way they are cast, it's not a smooth surface by any means.

[mickwinf]

thanks for all your efforts Ken, i will have a look over weekend and see what i have

[mickwinf]

Hi Ken i have just had a closer look at my gearbox and have found some more issues. Firstly the gears you have are perfect, numbers 10 and 12. My gear no 10 has the top hat style bush and seems in good nick. Bad news is the countershaft has some corrosion on the part that the oil seal rides on and not sure how well it will clean up. Also the c/s main bearing is noisy and rough, as are the two needle roller bearings on both shafts. Mainshaft seems ok all gears are sound as is the bearing. I agree with you about the circlips, awkward little beggars, will try to get new ones.

[Oddjob]

You mean the large collar on the end of the shaft Mick? I actually removed that the other day from the countershaft I removed the gear from. Just mucking about. I removed the bearing as it's a very hard to find part, this one seemed fine, span it in a container of brake cleaner and it sounded ok so I removed it from the shaft, spotted the little O-Ring that sits behind the bearing so thought I'd remove that to. Then noticed the way the shaft was machined, which meant that the collar had to be removable, which it turned out to be. Only the very inner part contacts the seal, common to see damage on the outside of the collar. Mine has some damage.

I cleaned up the countershaft, mine also has some corrosion on it, it's marginal as to being reused. The bearing, yep that's ok, cleaned it up, filled it with silicon oil and bagged it up in a sealable plastic bag along with the O-Ring and the collar. Almost certainly got another shaft somewhere, will take a look.

When you say gears are perfect, you mean the ones I posted pics of or the ones you have, wording is confusing me.

Wonder what happened with the gearbox you've got, seems a lot of damage going on it there. I'd inspect the main shaft as well Mick, check all gears etc if a countershaft gear goes it can take the corresponding gear with it.

Make a list of everything you need and I'll trawl through my box of bits and see what I can dig up.

Good news is that I found the top hat bush, I didn't spot it hiding in the bottom of the box, there were 2 mainshafts in the and quite a few of the gears. I looks like there were 2 complete gearboxes in there at one time. Will check the other bin I keep gearbox parts in and see if there is another countershaft in there.

[mickwinf]

Hi Ken, i meant the gears look really good and will be great for me. I have investigated a bit more and the mainshaft looks good all throughout, including the needle roller when i checked it and cleaned it. The countershaft has rust pits on the end that runs in the needle roller (no 24) so might be noisy or wear quickly , and the collar where the oil seal rides is pitted also. I have checked the selector drum and forks, and the centre fork is ok as is the lh one, however the rh one nearest the clutch side does have some wear and is a little tight on the selector drum. I am wondering if that was the cause of the dogs breaking off? so parts i need are the two gears 10 and 12, a countershaft with bearings inc needle roller, a rh selector fork and the gearchange shaft.

[mickwinf]

on even closer inspection i have found some tiny chips off the mainshaft gear, 3rd/2nd so need that also if you have one. have stopped looking now!

[Oddjob]

I may have found the internal needle roller bearing new, I presume then outer casing is still fine?

It cost £5.50 and I ordered 2 so I could test them. Will let you know when it arrives, same make as the Honda one, Koyo.

Checked the other box and nothing of use. It was this box I emptied of most of the gearbox bits as they were getting on my nerves.

The other alternative is to wait for me top split my engine and we'll see what the box is like in that. I'll be fitting my NOS gearbox in it's entirety so that box will be going spare. No idea when I'll get round to breaking then engine but some time this summer I'd imagine.

The mainshaft gear 3/2nd. I presume that's the double sliding gear, if so I spotted 2 of those in the first box. Might have a decent right hand selector, 24211-323-000, will have a look. That's the only part I'm missing for a complete NOS gearbox, I keep spotting them but they are always too dear. I was thinking of going with the Italian alternative where they make new selectors which are supposed to be better than the Honda ones, should have bought them before Br-----T though.

[Oddjob]

No joy on the right hand selector fork, got 3 left ones and remember giving the last right one to Trigger a year or so ago.

[mickwinf]

i think its actually the lh one i need as had the crankcases upside down, i think it is the one at neutral switch end but will check again

[Oddjob]

The left and right look almost identical, the way to spot the difference is that they both have an inward curve on the fork, the outward curve is the difference, on the left it's a nice arch shape, on the right it has a section that dips in right on the crown of the arch.

We are talking about the metal bracket coming off the tube that holds the fork ends BTW.

All my left hand ones are really good.

I contacted the Italian people today asking for a price for all 3 selectors, they are 450 euros for all 3 but they offered me all 3 for 375 a few years ago. I'm seeing if they'll still do the same deal. If they do I'll sell my NOS forks, the middle fork is the rarest and can fetch close to £200 alone, the left hand one is around £100-120. So if I sell those it almost covers the cost of the new ones.

2/3rd gears are soaking in brake cleaner, we'll see what they look like shortly.

I've often wondered why the needle rollers are different on the 2 shafts, one has them captive in a cage and the other has loose rollers yet both are the same size.

[mickwinf]

what you say about the two needle rollers is interesting, both of mine have caged rollers, however one has one roller per gap in the cage and the other has two rollers per gap.

[K2-K6]

"I've often wondered why the needle rollers are different on the 2 shafts, one has them captive in a cage and the other has loose rollers yet both are the same size."

More load and lower speed favours crowded (rollers next to each other) and higher shaft speed ordinarily heads toward single rollers spaced individually in their cage.

Logic would say the clutch shaft has crowded, with the remote shaft using singular rollers. I don't know which orientation they are in this engine.

[Oddjob]

Looks to be the other way round. I took one apart the other day, the cage was rusted into the bearing housing and it had the pushrod hole so it must be the clutch one. As said this was the caged one.

Normally there is one roller bearing where the rollers just fall out when you remove the bearing from the shaft and the other which doesn't. Normally have to use grease on the loose roller type to keep them in.