Topic: Shift Drum Steel Ball??

[Dr. Frankenstein]

Does anybody have a part number for part # 30 here...? When I took apart my engine and slid the shift drum and the top securing bolt out, I may have lost the 'steel ball' that is supposed to go in there...but I honestly do not remember seeing one or seeing one drop out, and the CSMNL diagram only goes up to part #29! I'm going to go back and scour my bench, but I never saw one of those! About how big is it?

[newday777]

What bike?

[HondaMan]

Did you remove the "bolt"-like shifter detent? It looks like a big bolt-head with a locktab washer on the top of the engine cases, above the shifter drum. These parts all fit into a recess in the upper case there.

[Dr. Frankenstein]

Newday - 1972 CB500 Four;

Hondaman - yes, I did, and like I said, I don't remember seeing a steel ball in there, or seeing one drop out. I went looking for it on the bench, but no luck there, so tried looking up the part (#30) on CSMNL and their list only goes up to 29! 

[bryanj]

The ball is only on VERY early 500 fours, it was modified to the partsi in the small pic

[Little_Phil]

Beat me to it Bryan. Only about the first 19000. Use the inset parts in the box on the right.

[Dr. Frankenstein]

Right - but I have the detent in the shift drum - to my way of thinking, shouldn't there be a ball in there...? And what difference will it/does it make if there isn't one - why isn't it needed anymore? My engine number is 2002777.

[CycleRanger]

Didn't the very early CB500's share some transmission parts with the CB350 twin?
(Which is why the early 500's had transmission issues.)
Anyway, that ball might be the same as the 350 twin.
CB350K PN 96211-10000  ball, steel, #10 5/16 In.
Looks like it was used in a LOT of bikes.

[Dr. Frankenstein]

So should I put one back in...?

[HondaMan]

Yeah, I just looked in my old 'unitized' parts manuals (circa 1998) and they only go up to #29, too!

Maybe try this: if you can guesstimate if a 10mm ball would fit, I could send you an old CB750 Neutral Switch, which has a 10mm ball in it. They can be disassembled by unscrewing (or destroying) the phenolic insulator and the guts pulled out. They internally resemble the 500 parts, but without dimensions I'm not sure if it would fit?

[Dr. Frankenstein]

Maybe I'm worried about nothing - bryan says the drum bolt was modified to not take a ball, as illustrated in the smaller picture - but does anybody know a benefit or detractor from adding it?  5/16" is essentially 8mm...

[bryanj]

DO NOT DO IT

[Dr. Frankenstein]

Do you know why I shouldn't do it...? Honestly, I probably won't but I like to know WHY things are...

[CycleRanger]

Get the CB500K0 parts list here.
https://www.honda4fun.com/dwnload/Part-List/CB500/CB500-K0-Parts-List.pdf

As I suspected it shows that steel ball. Same as the CB350.

You should compare it to the K1-K2 parts list, also available from the same site.

[Dr. Frankenstein]

Right - and mine shows the ball too, but in the inset it also shows the setup I took out of the bike without the ball...bryan says don't do it (and like I said I probably won't because I didn't take one out), but WHY did they modify it and what happens if I put one IN? The detent is there...would it help with shifting? Detract from it?

[CycleRanger]

Right - and mine shows the ball too, but in the inset it also shows the setup I took out of the bike without the ball...bryan says don't do it (and like I said I probably won't because I didn't take one out), but WHY did they modify it and what happens if I put one IN?

Check the K1-K2 parts list. They may have serial numbers that indicate at what number that ball was removed.
If Honda omitted it from later bikes they did so for a good reason.

[Dr. Frankenstein]

I'll check it, but I'm just going to put it back in the way I found it. The interesting thing to see though is I have another 1971 CB500/4 K0 right behind this one that's waiting to be refurb'd. It'll be interesting to see if there's one in there. In a related topic, the manual calls for that 'steel ball' 96211-10000 ball, steel, #10 5/16 In...just ONE of those 'OEM' ones is about $10 - while a whole metric assortment of steel balls (including twenty 8mm steel balls) is $10 on Amazon...just sayin'...

[bryanj]

The modifications were on the clutch plates, push rod, neutral and gear detents behind the clutch and clutch cover plus some odd bits.
If you go to the uk site and look in Ashs dropbox you will find the relevant bulletin about it.
As to putting the ball in you would need all the relevant parts to make it work

[bryanj]

Go to technical and look up sb04 under 500, open the list from the three lines top right corner

[CycleRanger]

I'll check it, but I'm just going to put it back in the way I found it. The interesting thing to see though is I have another 1971 CB500/4 K0 right behind this one that's waiting to be refurb'd. It'll be interesting to see if there's one in there. In a related topic, the manual calls for that 'steel ball' 96211-10000 ball, steel, #10 5/16 In...just ONE of those 'OEM' ones is about $10 - while a whole metric assortment of steel balls (including twenty 8mm steel balls) is $10 on Amazon...just sayin'...

Not all steel balls are created the same..
The OEM part is made of a certain type of steel and properly heated treated.
Not that the cheaper balls aren't, just saying.

[HondaMan]

The modifications were on the clutch plates, push rod, neutral and gear detents behind the clutch and clutch cover plus some odd bits.
If you go to the uk site and look in Ashs dropbox you will find the relevant bulletin about it.
As to putting the ball in you would need all the relevant parts to make it work

Bryan: how do I find Ash's Drop Box on the UK forum?

[bryanj]

Mark, see screen shot below, bulletins also in Manuals and Technical document on this site but you have to look under the 3 lines at top rh corner

EDIT bulletins may be in Alladins Cave