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G'day all,
As well as giving the Goldie a new crank assembly ,while we're down there,we're also renewing the main bearings..
My friend Neil was surprised to see that the Drive Side Roller bearing (part #65-1388) wasn't a lipped bearing...should it be ?
The outer part (shell?) of this bearing has a slightly worn surface where the rollers run..
I've also read that this bearing is pretty hard to get ..Would any one know of a supplier of the correct bearing please ?
Cheers for now ...

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Hi Charlie, This bearing is easily obtained, I will get the details for you when at the workshop.

Buy the bearing from an authorised bearing dealer, a lot of the brit bike spares sellers are selling cheap Chinese copies,

MIKE


Mike.



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Cheers Mike.. thanks mate ..

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Just got some information from a friend ... Both roller bearings on the Engine are Lipped bearing types .
Originally Hoffman R325 L for the Drive side .. Hoffman RM9L for the Timing side ... The outer ball bearing is Hoffman BB.H125 ..

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That's odd. The section view in the BMS book shows only the timing side bearing having a lip. The maintenance Manual MC950-2 1/2-1 1/2, reprinted January 1959 by BSA has the same section view.
The drive side outer bearing is retained by a 65-1397 plate.
Huuuuummmm?
My lower end is still apart, and I will check and see if I can see any numbers. I know the timing side outer race number is hidden in the case, and I would guess the drive side number is hidden by the retaining plate. But with the inner race numbers, the bearing number should be deduced.

JR

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Originally Posted by Charlieboy
Just got some information from a friend ... Originally Hoffman R325 L for the Drive side
You need better friends. The engines on either side of the DB, i.e. the CB and DBD, both used part no. 65-1388 for that bearing, which Service Sheet 703 says is a Hoffman RSM11.

addendum:
Originally Posted by Charlieboy
The outer ball bearing is Hoffman BB.H125 ..
I didn't check any further than the DBD parts list and Service Sheet 703 but they have that bearing as simply Hoffman 125, i.e. without the 'BB.H'. I'd have to look in the Hoffman catalog to see what the significance is of that prefix.

Last edited by Magnetoman; 09/16/17 3:55 pm. Reason: addendum
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I believe the original drive side roller should be a Hoffman MRJ 1 1/8, timing side MRJA 7/8. The "A" in the timing side part number indicated a lip. A MRJA 1 1/8 lipped roller was used in Triumphs and can be used on a Gold Star provided you install the outer race in a manner that when the crank is pulled to the timing side by the compensating spring nut the rollers don't foul the lip. The Gold Star crank and mainshafts flex quite a bit and using the lipped roller on the drive side is a bit of chance taking to say the least.


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The numbers on the outer timing side bearing that I replaced are Hoffman RMS 9 LV3. I assume the L denotes lipped.
The drive side is RMS 11 V3.
This is out of a '56 DB, which I am pretty sure has not had other than OEM bearings in it.

Possible sources;

http://www.hoffmannbearings.co.uk/hoffmannballbearings.html

http://www.hoffmann-bearings-hb.com/Stock%203.htm

http://www.hoffmannrollerbearings.co.uk/hoffmann-standard-bearing-symbols.pdf


JR

Last edited by Jerry Roy; 09/17/17 2:59 am.
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Now I'm confused (sob,weep)..
The Drive side roller that was in the Bike has NO lip...Timing side HAS a lip ... outer bearing on the drive side is a BALL type..Is this the correct set up ?
BSA/Gold Star man here in Australia ,Mike Reilly ,Is supplying a new/old stock Drive side Roller Bearing I look forward to seeing it ..
Thanks for your input men ...

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Charlie, I don't have access to my manufactures bearing book at the moment for the numbers, but the set up you have is correct.


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And on the outer race of the timing side bearing, contrary to standard practice of putting it with the number showing, it is installed with the numbers to the outside of the case, hidden in the bore. The lip keeps it from coming out and hitting the flywheel. Here again, a good look at the section view in the RMS book will show the proper arrangement.

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The lip also keep the crank centred, in the event of the drive side shaft nut becoming loose.

Last edited by DBDBrian; 09/17/17 3:40 pm.

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Brian ... It's imperative the timing side rollers Never come in contact of the lip on the timing side bearing race as this can cause serious damage to both possibly cracking the case in the bearing area with the crank banging to/fro and damaging the rollers and bearing. This is also why when assembling the GS engine it's a must to check for roller clearance by checking the crank end play for 10-20 thou Before the drive side nut is tightened that will pull the crank assembly against the outer ball bearing for zero end play.

A 'word to the wise'. Some years ago a GSr friend had difficulty fitting a belt drive pulley with overly tight splines. Attempting to drive on the pulley he cracked the timing side case. aargh. Since his problems I've used 'dycom' bluing and jewelers files for a good snug fit. Fiddly but ..

BTW, I've used my last OEM timing side bearing and understand they are difficult to find. I do have a (good?) used bearing, but ... Any help finding one would be much appreciated. Phil Pearson has been using a MM bearing substitute with adapters that I may need to use on the current engine I'm gathering pieces for now including a Pearson crank.

Something else to consider would be fitting a outer ball bearing with a outboard seal. With proper crank case breathing this prevents engine oil from being blown into the primary. I and many others have been doing this for years. The result of this is proven with no sign of oil in a dry belt drive primary. Nice.

Another good idea in this area is to fit a modern 'eyelet' type snap ring securing the ball bearing vs the difficult to deal with @#$% OEM snap ring. I've sourced these from a local bearing supplier and I believe Pearson also carries them.

Last edited by dave - NV; 09/17/17 10:10 pm.

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My experience, many years ago, was with ZB 33/31, and one thing I was always told that when rebuilding was to particularly check the condition of the spacer between the two drive side main inners. The GS 500 p/n for this is 65-1396( engine shaft distance collar, outer ). Wear here could be caused by insufficient tightening of the engine shock absorber nut. The importance of paying attention here is mentioned in all rebuild articles.
I'm not sure of the factory dimensions of this part, but it would / should prevent the rollers being in hard contact with the single lip on the outer race. Would be difficult to check without trial assembly. I never had any trouble here with my hotted up "cooking " engine! The ignorance of youth, perhaps !

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Thanks to DBD Brian for putting me straight about what bearings should be in my Bike
To Dave NV .. I was able to source both of the Roller bearings for my DB Goldie from www.MikesClassicCycleSpares.com .. here in Australia ..
Thanks everyone ...

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Originally Posted by DBDBrian
The lip also keep the crank centred, in the event of the drive side shaft nut becoming loose.


Hi Dave, I totally take on board your comment re the crank end float.I was not suggesting for one moment the crank should be installed with zero end float.I was just expanding on Jerry's comment re the reasons for the lipped bearing. As said if the drive side nut becomes loose, (not an uncommon event as the inside of many a primary cover bear witness) the lipped bearing contains the crank within the parameters of it's installed end float (I usually aim for min 5 max 10 thou when using a standard lipped bearing) preventing movement into the timing chest.

I run my own crank with a needle roller on the timing side, this bearing has a dedicated oil feed from the exhaust cam spindle. With this arrangement it is imperative the drive nut remains tight,as there is no lip to contain the end float.
I disband the lock tab, and use Loctite on the drive nut.Todate this has been a satisfactory arrangement.

Last edited by DBDBrian; 09/19/17 5:08 am.

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A bit late seeing this but don't forget Modak in Melbourne for parts, I got a NOS Hoffman bearing from there a while ago. the word is he is having a hard time competing, rent is expensive in the city and may be closing his doors


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Not intending to muddy the waters.... :-)
Many years ago I bought a bottom end that turned out to have an un-lipped drive side inner bearing. It appeared to have been run like this. Correct me if I'm wrong but if the spacer is correctly located between the inner & outer brg. & the inner rollers are aligned centrally on their outer track, not on either edge, then the set up will work OK. ? It is all pulled over to the drive side outer brg. when the nut is done up so if everything else is good, centrality of rod in bore etc, then Why not?
That said, at the time I was pretty ignorant as to the set up on these engines & replaced it with the correct numbered lipped brg., doing it "by the book" as I wasn't very sure of the unlipped one.
If I was having to do a rebuild miles from anywhere & only had an unlipped one, I would use it. My feeling is it would be fine.


na

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