Author Topic: Crankcase main bearing letters - doubting myself!  (Read 845 times)

Offline philward

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Crankcase main bearing letters - doubting myself!
« on: January 21, 2021, 10:50:27 PM »
Looking for reassurance! I know about how hard it is to find the numbers on the crankacases but need to put my mind at rest before spending £250 on mains/big end shells. Have done this a few times on 750's but doubting my eyes when trying to see letters on my 500 crankcases.
Seen a thread recently but can I find it now!
Am I right in thinking the letters do not look identical from crank web to crank web? They look as though they have been written by a child? I can see 'B's' - but my wife cant see any letters - wife say they just look like part of the general marks on the cases. Marks on crank and rods look like they have been printed and are consistant and easily read
Do they look like I've described or am I seeing things?
I've got all B's on cases and 4 x 2's and a 1 on crank - does that sound about right
Thanks
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #1 on: January 22, 2021, 11:02:42 AM »
I note from a post by Trigger on another thread (closed by Steve) that Silvers has put up his prices as a result of the subject of that post (not trying to resurrect that post Steve!) - is this right? If so, it is ruthless!
I was looking to buy a full set of mains/big end shells and wondered why they were so much dearer than CMSL.
I've just gone on the DS USA site and each shell is about £3.40 cheaper than the UK site - (pre tax/VAT, so direct comparison), which is approx 30% more for loyal UK customers!
When I finish this bike, I'm done with resto's - it appears we are here to get ripped off.
DS has helped the classic Honda enthusiasts a lot over the years but if the above is correct, it really is time for me to stop lining a ruthless outfits pockets
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #2 on: January 22, 2021, 11:09:52 AM »
Just rang local dealer and these are still available - and the price is identical to DS UK - so, it seems with still available Honda parts, DS isn't ripping me off!
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #3 on: January 22, 2021, 11:13:49 AM »
So Phil don’t quite understand what the problem is here. The crankcase letters are always the easiest to read, stamped into the back of the lower casing. Very very easy to read. The crank markings can be quite difficult to read, is that the problem?
So I'm looking in the wrong place? When you say 'the back of the lower casing', can you be more specific Ken. I assumed it was the same as the 750 which was (from memory) on the inner casing.
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #4 on: January 22, 2021, 11:22:34 AM »
Thanks Ken - I'll look later. Crank numbers are quite clear luckily
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #5 on: January 22, 2021, 12:03:14 PM »
Got it Ken - thanks again. Just got to pay for the bludy things now! £15 each shell!
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #6 on: January 22, 2021, 12:20:48 PM »
They are all B's - same as I seem to see scrawled on the inside of cases - oo-incidence?
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #7 on: January 22, 2021, 04:26:45 PM »
Fig 144 on page 49 Phil
I've got all B's on crankcase and 1,2,3 & 5 crankshaft journals are '2's' and no 4 journal is a '1' - is it normal to have an odd size amongst the other consistant sizes. Sorry to labour the pont, but want to make sure I'm not misreading the crank numbers leading to wrong bearing sizes.
Hence, I think from the manual, I need 4 Browns and 1 Green.
Cheers
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline Winterfield

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Re: Crankcase main bearing letters - doubting myself!
« Reply #8 on: January 22, 2021, 08:33:11 PM »
This is a timely thread, I'll be doing this shortly for my 400.

One thing that's bothering me: is it a safe assumption that the crank case stamped measurements are still accurate? Or is it better to measure?
What about the crankshaft - is safe to assume it's the same as it was stamped too?

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #9 on: January 22, 2021, 08:52:47 PM »
Experts will be along shortly but in my opinion, the measuring tolerences and diferences between the different bearings are that small (.01mm), that I personally don't feel confident with the micrometers/calipers I have to get accurate readings. (to decide on the bearing size)
I have only build 6 (4 x750 and 2 x 900) engines and always used the case/crankshaft letters/numbers with good results and no longer term issues. I think most people use this method if completely changing shells (as opposed to measuring for wear to decide to change shells)
Over to the ex Honda mechanics!
« Last Edit: January 22, 2021, 08:55:07 PM by philward »
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #10 on: January 23, 2021, 07:10:23 PM »
Unless for some reason the shells have spun in the crankcase it’s fairly safe to assume they’ll remain the same diameter. Again with the crank, if it looks ok it most likely is the same.


Fairly common to see different numbers on the crank Phil
Thanks Ken - I'll arrange for another £285 to be deposited in DS's back pocket then!
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline philward

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Re: Crankcase main bearing letters - doubting myself!
« Reply #11 on: January 23, 2021, 09:32:43 PM »
Big ends as well Ken - probably get away with not replacing the mains/big ends as slight wear only, pondered over replacing but as its apart.....
Good thing is inside really clean, top end is mint and centre selector has no wear. All bottom end bearing good. So putting mains/big ends/rings and hone/primary chain/cush drive rubber/starter clutch/ oil pump overall/oil switchcam chain/guides/seals/gaskets/clutch pushrod - thats expensive enough!
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

 

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