Oh that gearbox ?

rx7171 said:

More on the ball bearing Mick Hemmings recommends from a couple of sources. Seems the deep groove feature is a plus along with the phenolic cage.


6203-TB-FAG - DEEP GROOVE BALL BEARINGS
In a deep-groove radial bearing, the race dimensions are close to the dimensions of the balls that run in it. Deep-groove bearings have higher load ratings for their size than shallow-groove, but are also less tolerant of misalignment of the inner and out.

FAG 6205TB.P63 phenolic cages ball bearings
FAG single row deep groove ball bearings usually without a cage suffix have a sheet steel cage. The suffix TB behind the bearing NO. means phenolic cages, it has very high mechanical strength, good resistance to corrosion, rust and heat resistance, as well as lubricity. In addition, they are with light weight, high strength characteristics.


The technical data sheet for FAG bearing 6205 TB.P63
Type: single row deep groove ball bearing, with phenolic cages
Dimension: 25mm x 52mm x 15mm
Weight: 0.133 KGS/PC
Radial dynamic load: 14900 N
Radial static load: 7800 N
Limited speed: 9000 1/min

Click to expand...

I hope you meant to copy and paste the 6203 TB P63 info and not the 6205 tb p63.

Anyhow, we know what it is, the issue now is where I can get it and get it for less than weeks pay.

The challenge is to validate current availability and price. I have been working on this for a few weeks. I now put it to the forum. This appears tobe not as easy as it may seem.

pete.v said:

rx7171 said:

More on the ball bearing Mick Hemmings recommends from a couple of sources. Seems the deep groove feature is a plus along with the phenolic cage.


6203-TB-FAG - DEEP GROOVE BALL BEARINGS
In a deep-groove radial bearing, the race dimensions are close to the dimensions of the balls that run in it. Deep-groove bearings have higher load ratings for their size than shallow-groove, but are also less tolerant of misalignment of the inner and out.

FAG 6205TB.P63 phenolic cages ball bearings
FAG single row deep groove ball bearings usually without a cage suffix have a sheet steel cage. The suffix TB behind the bearing NO. means phenolic cages, it has very high mechanical strength, good resistance to corrosion, rust and heat resistance, as well as lubricity. In addition, they are with light weight, high strength characteristics.


The technical data sheet for FAG bearing 6205 TB.P63
Type: single row deep groove ball bearing, with phenolic cages
Dimension: 25mm x 52mm x 15mm
Weight: 0.133 KGS/PC
Radial dynamic load: 14900 N
Radial static load: 7800 N
Limited speed: 9000 1/min

Click to expand...

I hope you meant to copy and paste the 6203 TB P63 info and not the 6205 tb p63.

Anyhow, we know what it is, the issue now is where I can get it and get it for less than weeks pay.

The challenge is to validate current availability and price. I have been working on this for a few weeks. I now put it to the forum. This appears tobe not as easy as it may seem.

Click to expand...

Ouch.
Good catch on the 6205TB.P63 mis cut and paste.

A big thanks to all who have put so much time and effort into replying to my gearbox bearing question...

Can I ask another favor: does anyone know of a link to perhaps a "you tube" video or even the availability of a dvd on how to go about doing this bearing replacement with gearbox still in place.. I have never tackled a job such as this before and am not quite sure where to start.. I have stripped and assembled many of my English bikes over the years but have not been inside a gearbox, I am sure I am able to tackle the job with the right kind of information..

Cheers
Paul

nznorton said:

A big thanks to all who have put so much time and effort into replying to my gearbox bearing question...

Can I ask another favor: does anyone know of a link to perhaps a "you tube" video or even the availability of a dvd on how to go about doing this bearing replacement with gearbox still in place.. I have never tackled a job such as this before and am not quite sure where to start.. I have stripped and assembled many of my English bikes over the years but have not been inside a gearbox, I am sure I am able to tackle the job with the right kind of information..

Cheers
Paul

Click to expand...

FWIW These gearboxes are about as straight forward as they can be. You can do it with the hard copy stuff available. Old Brits has an entire section on this. Just get into some reading and take it one step at a time.
http://www.oldbritts.com/gearbox_d.html
http://www.oldbritts.com/gearbox_a.html
http://www.oldbritts.com/gearbox_info.html

For the benefit of those who are not Kiwis or Aussies and so may not know what OlChris was talking about:

"And sorry for the partial hijack to my fellow ANZAC, just over the "dutch"...."

“ ANZAC” – The Australia New Zealand Army Corp – the two countries' armies acting together in World Wars and in other conflicts; a term generally used when seeking to promote brotherhood between the two nations; unlike the more typical relationship of big brother/little brother more often represented by glee of one and gloom of the other arising out of a sporting victory or defeat (Aussies dominant in cricket; Kiwis dominant in rugby - apart from a memorable few years - Aussies dominant in rugby league (but watch this space…) - and Kiwis not taking part in Aussie Rules).

“dutch” – the Kiwi version; the Aussie version of the same word is “deetch” (if you are not Australian it is easiest to say this if you hold your nostrils shut with your fingers) - slang for the Tasman Sea; the body of water separating the two nations, both derived from the English “ditch”.

In short OlChris was being super polite and courteous.

Finally got around to working on my old Mk3 in the last month. Bike has been in "mothballs" for some time. After a good carb overhaul +new jet needles, a clean-up on all the electric connections, a new AGM battery, chain, pair of new K81's and on my final (almost) road test, the layshaft inner bearing exploded. ( Fortunately shifting out of first, and not at 5000rpm in fourth gear as three minutes before...)
The gearbox shell is pretty wallowed out, and will have to be replaced. Gears look good. Will check shafts for run out when I get a chance.
Now I'm spec'ing my parts list.
So the issue is (again) what's the bestavailable replacement for 067710 layshaft bearing.

Mick Hemmings' "SPECIAL RACING BALL BEARING,THE ANSWER! TX 1366 " which I assume this: FAG 6203 TB P63
and Hemmings' list states: "ROLLER REPLACEMENT FOR ABOVE, (NOT RECOMMENDED) 06 7710"

I can't find a price listing on their 2013 price list; 2005 (for reference only) shows £23.50- no description just the above-

or

Andover Norton's 06.7244 overhaul kit with a "roller bearing with plastic cage."
Keith from AN says "we have never had any issues with it over quite some years."

Anyone have first hand experience with these solutions?
Not eager to repeat that last ride...
Tnx

Allen

allenchev said:

Finally got around to working on my old Mk3 in the last month. Bike has been in "mothballs" for some time. After a good carb overhaul +new jet needles, a clean-up on all the electric connections, a new AGM battery, chain, pair of new K81's and on my final (almost) road test, the layshaft inner bearing exploded. ( Fortunately shifting out of first, and not at 5000rpm in fourth gear as three minutes before...)
The gearbox shell is pretty wallowed out, and will have to be replaced. Gears look good. Will check shafts for run out when I get a chance.
Now I'm spec'ing my parts list.
So the issue is (again) what's the bestavailable replacement for 067710 layshaft bearing.

Mick Hemmings' "SPECIAL RACING BALL BEARING,THE ANSWER! TX 1366 " which I assume this: FAG 6203 TB P63
and Hemmings' list states: "ROLLER REPLACEMENT FOR ABOVE, (NOT RECOMMENDED) 06 7710"

I can't find a price listing on their 2013 price list; 2005 (for reference only) shows £23.50- no description just the above-

or

Andover Norton's 06.7244 overhaul kit with a "roller bearing with plastic cage."
Keith from AN says "we have never had any issues with it over quite some years."

Anyone have first hand experience with these solutions?
Not eager to repeat that last ride...
Tnx

Allen

Click to expand...

Alan, welcome to the forum and glad to hear you came out of that experience with no pain other than financial.

I assume you've read previous posts this thread but to reiterate Mick Hemmings recommends a ball bearing replacement the 6203-TB fibre-cage and not a roller bearing because the shaft flex in the gearbox, like what happened in the Combat with the crankshaft flexing has the potential to tip rollers onto their edges, causing failure like the original roller bearings in the Combat.
That is the bearing I put in and although I don't beat the snot out of my bike when I ride it has held up just fine.
Mick has a very long history on these bikes and I've never heard a complaint about his knowledge or advice.

It appears the old ball bearing doesn't fail due to the balls themselves going out of round but the metal cage holding them breaking down.
A problem that will not happen with the fiber cage of Micks bearing.

A roller bearing would have more capacity to take a load but like noted above would not like the roller edge loads of a flexing shaft.
Other issue of roller is needed for shimming of shaft end play that is just another chore in its installation.

I suggest you call Mick and ask him to confirm what I've noted above.

rx7171 said:

I suggest you call Mick and ask him to confirm what I've noted above.

Click to expand...

Allen, when and if you do this, please report back on price and availability.
Thanks,
Pete

Called Hemmings on Monday.
Got, I assume, his cheery wife on the answer machine. Not there Mondays! Her voice just made me grin...

Re: Call Hemmings
Will try back tomorrow. I believe Keith at Andover regarding no problems with their roller bearings, but the Hemmings warning caught my attention, especially if I replace the shell with a NEW one. ($400 US)
-My other option is to cannibalize a complete but bent Mk3 I have squirreled aside for a later resto. I'm pretty sure it has not had the original bearing replaced, so if it's still intact, I might overhaul that one.
Here's a thought though:
The bike is completely original.
I seem to recall that the Mk3 frame, engine unit, and gearbox were all serial numbered the same. I wonder if, in a non-concourse restoration, a mis-matched number on the gearbox would significantly decrease the sale value in the future.
Re: sudden stop
No damage done to me, but dodging bullets is not something I want to do too often. I have already experienced this Commando phenomena once before, also at low speed. Also an exploded ls ball bearing...

Allen

850 Mk3
'69 Fastback
'63 Bonneville
'70 Trident
850 Mk2 in box form

A year or two ago I purchased the Hemmings suggested ball bearing from a moped company that had good service, unfortunately they seem to be currently out of stock - still might be worth a call to them.

http://www.treatland.tv/FAG-6203TB-P63- ... -super.htm

lbridges said:

A year or two ago I purchased the Hemmings suggested ball bearing from a moped company that had good service, unfortunately they seem to be currently out of stock - still might be worth a call to them.

http://www.treatland.tv/FAG-6203TB-P63- ... -super.htm

Click to expand...

Yes, they are hoping for December but do not seem to be able to get them either.

Re: Commando layshaft bearing
Had a few minutes today to pull the (EP90 gearoil stinking) clutch to see if I could detect any runout on the mainshaft. Semi-scientific eyeballing it, I could not see any. Will use a dial gauge when completely apart, but I may have dodged one there. Still need to check the layshaft. Gears look ok but the ks bush looks wallowed and I noticed a bushing peeking/crumbling out of the layshaft first gear.

>>suggest you call Mick
>>please report back on price and availability

Spoke with Angie Hemmings today. Very helpful!
Their ball bearing is in stock and currently £32. ($50 US)
I guess there is just a difference of opinion about what works best*. A Roller seems to be a better choice at first glance, but visualizing as best as I can, I see the point about the radial flex stressing roller edges, where a ball would just just roll on. I'd bet both work great; Both outfits are very confident in their solution to the issue. All of this assumes of course that both bearing options have a flexible cage, which is my understanding.
I suspect that either is a good solution, and in the interest of science, I may build my "spare" Mk3 box with the roller, and this one with the ball. That way I can at least eyeball both.
I also will be inspecting and replacing that bearing in the Fastback... someday...

*BTW, in my book what works best is whatever it takes not to duplicate this serious defect, especially at speed. The Treatland.tv site does not look like the kind of vendor I want to trust with my life. Even if they still had the bearing in stock, I don't think I'd feel quite so confident cranking it on hard whilst riding with my buddies on their 21st century versions of "Superbikes" knowing that bearing was from a moped company. probably just getting paranoid in my old age.

Allen