Author Topic: Main bearing induction hardened?  (Read 2180 times)

Online KiwiGF

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Main bearing induction hardened?
« on: 02.05. 2011 12:59 »
I need to have a small journal crank reground Big ends to 040 under and main to 030 under and have been advised that the main journal was induction hardened by BSA so if more than 010 is taken off the journal will then wear out quickly

So I'm going to look into getting the journal built up with hard chrome to use a NOS 010 under bush I already have but I thought I'd ask on the forum first if anyone else has experience of building up the main journal? Good or bad?

I'm also a bit concerned about being on my last big end re grind. Can the big ends be built up back to standard? (at a reasonable cost)

Thanks!
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2009 KTM 990 Adventure, cos it’s 100% nuts

Offline bikerbob

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Re: Main bearing induction hardened?
« Reply #1 on: 02.05. 2011 13:32 »
Hi there
Who told you that it was not advisable to go below 0.0010in as BSA in their service sheets say you can have three regirinds down to minus 0.0030in. My own A10 Gold Flash is on minus 0.0030in and has done about 13000 miles.
56 A7 s/a
63 A65

Offline beezalex

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Re: Main bearing induction hardened?
« Reply #2 on: 02.05. 2011 14:52 »
I have not seen any BSA TS journal that was hardened or heard of any credible evidence that they were.  BSA service sheet 208 recommends .030 and .020 as the undersize limits for rod and gear side journals, though if you can get the bearings, I doubt a mild street motor is going to have a problem going to .040 and .030.  Alternatively many shops that will grind cranks will also weld them, which is also acceptable for anything other than a race motor.
Alex

Too many BSA's


Online KiwiGF

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Re: Main bearing induction hardened?
« Reply #3 on: 03.05. 2011 07:38 »
Thanks for your replies, service sheet 207 has the main shaft journal up to 010 am I missing a page of that? Or have I got an out if date version?

Is 208 the engine re assembly sheet?

New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2009 KTM 990 Adventure, cos it’s 100% nuts

Offline bikerbob

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Re: Main bearing induction hardened?
« Reply #4 on: 03.05. 2011 08:25 »
HI there
Yes service sheet 208 is the reassembly sheet it is 8 pages long 209 is the gearbox.
56 A7 s/a
63 A65

Offline Goldy

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Re: Main bearing induction hardened?
« Reply #5 on: 03.05. 2011 11:11 »
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Online KiwiGF

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Re: Main bearing induction hardened?
« Reply #6 on: 04.05. 2011 12:17 »
Thanks everyone I'm now convinced the advice I got was wrong and I can get the main journal ground and only ground the amount to get it round etc then either buy a new bush slightly under what i need and or get one relined with white metal and then get the bush line bored to suit the crank

Reading the "speaking of vibration" posts all the way through helped a lot !

I'm still a bit concerned about being on the last big end grind of 040 though.....But with a bit of luck I'll never wear the new big ends out!
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2009 KTM 990 Adventure, cos it’s 100% nuts

Offline beezalex

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Re: Main bearing induction hardened?
« Reply #7 on: 04.05. 2011 13:59 »
Thanks everyone I'm now convinced the advice I got was wrong and I can get the main journal ground and only ground the amount to get it round etc then either buy a new bush slightly under what i need and or get one relined with white metal and then get the bush line bored to suit the crank

I typically grind just to clean up the main bearing and then machine and align-hone a new bronze bearing insert.  This has worked well for me.
Alex

Too many BSA's


Offline Butch (cb)

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Re: Main bearing induction hardened?
« Reply #8 on: 13.05. 2011 17:33 »
I'm presuming that with 1k oil changes and running a return side paper filter I should get around 30k miles on my recently built motor. Is that sounding conservative?   
Warning - observations made by this member have a 93% unreliability rating.

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'58 S/Arm Iron Head Flash Bitza


Online muskrat

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Re: Main bearing induction hardened?
« Reply #9 on: 13.05. 2011 20:28 »
 Or more I hope as I'm coming up to 30K on the '51's last build. Still sounds sweet.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
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Online KiwiGF

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Re: Main bearing induction hardened?
« Reply #10 on: 14.05. 2011 09:03 »
Beezalex could explain more about yr main bearing method please or what material spec something like LG2 ? And is the honing a home job or does a specialist do it?

I'll have to have the main ground by a specialist along with the big ends, but if I could get a bush made up and then finish it to size myself I would like to do that
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2009 KTM 990 Adventure, cos it’s 100% nuts

Offline beezalex

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Re: Main bearing induction hardened?
« Reply #11 on: 16.05. 2011 13:45 »
KiwiGF.  The honing requires a precision honing machine.  I have Sunnen hone that works great for this, a lot of automotive machine shops will have the machine for rod reconditioning and small engine cylinder honing, but they probably won't have the correct size hone, which isn't cheap. 

That aside, here's the process:
1. Grind crank (done by a trusted specialist) - rod bearings to the appropriate oversize, TS main journal to where it just cleans up.
2. Extract the old TS main bearing.
3. Remove the bearing insert from the sleeve and replace with SAE 660 (high lead, also known as alloy 932) bronze.  Alternatively, you can purchase undersized bearings from various retailers.
4. New insert is pressed with 0.003" interference and sized 0.005" undersize of the journal on the lathe.
5. Bearing assembly is pressed into the case (heat case).
6. Insert guide bushing into drive side bearing (I made one out of steel)
7. Assemble cases and hone bushing to .001" clearance. The hone passes through both the bearing and the guide bushing.  The guide bushing will be honed along with the TS bearing, guaranteeing alignment.

I had some pictures, but, stupidly didn't back them up so they are gone along with my laptop that was stolen a couple of months ago.  I'll be doing an A65 in the next month in the same way and will take some more pics.

Hope that helps.
Alex

Too many BSA's


Online KiwiGF

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Re: Main bearing induction hardened?
« Reply #12 on: 17.05. 2011 07:56 »
Thanks beezalex that helps a lot no honing machine in my shed but I now know what to look for in the way of equipment at the specialist

My t/s case is worn and the bush was a loose fit so I will have to get a one off bush made up

I have an old southbend lathe which is very worn but I might have a go at making one myself if I can find the material

So far I've heard of line boring, line reaming and line honing the bush and I now know what line honing is!
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2009 KTM 990 Adventure, cos it’s 100% nuts

Online Topdad

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Re: Main bearing induction hardened?
« Reply #13 on: 18.05. 2011 14:54 »
Hi kiwigf, re your bike ,if it started off in  liverpool around '55 it was probably sold by Cundles who were main dealers or perhaps Victor Horsman ,they were retail dealers and I worked for both of 'em though much later  '66 -71. re the main question I honesttly don't about case hardening but a call to SRM would sort out queiry they are very helpful and will talk over things like this, regards Bob hebdon.
" rules are made for the guidance of wise men and the blind obediance of fools"
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Online KiwiGF

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Re: Main bearing induction hardened?
« Reply #14 on: 20.05. 2011 09:58 »
Thanks for the info topdad

 when I asked the VMCC to see where bsa sent my bike I needed to find it had been exported to nz as it's much easier to register a bike here if you prove it was registered in nz before- and it's sort of a proof if it was imported here new

So I was hoping to find it had been sent to Liverpool docks!

As it happens the PO found the rego papers so the problem of proving the bike had a number plate before was solved
Having old plates is no use in nz as the government destroyed the registration records during computerization years ago and my bike had not been registered for 30 years
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2009 KTM 990 Adventure, cos it’s 100% nuts