Author Topic: Knackered lower crankcase thread  (Read 1712 times)

Offline burchy75

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Knackered lower crankcase thread
« on: December 11, 2013, 10:04:13 AM »
Right, been having a bit of a go at the K0 engine I bought recently with a clean rag and found one of the lower engine mounts snapped off  :'(

I have a spare lower case but have heard that the upper and lower crankcases are mated at the factory?  Would it be possible to machine another lower to fit the K0 upper crankcase I have here?

Sorry for the noob question :)

Offline hairygit

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Re: Knackered lower crankcase thread
« Reply #1 on: December 11, 2013, 11:35:38 AM »
Strictly speaking, NO. If you still have the broken of art it can be welded back by a VERY competent alloy welder. The crankcase halves are line bored as one unit for the main bearings, the only way it could be done is by getting another crankcase half and getting it line bored again, but that is seriously expensive, and would involve having main bearing shells made specially to meet the new dimensions, and you are talking telephone numbers for prices :(
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Offline RGP750

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Re: Knackered lower crankcase thread
« Reply #2 on: December 12, 2013, 07:42:13 PM »
There is a very good specialist welder down here in Kent.
If you are really stuck if you can take some photos and send them to me
i can go and see them for their comments.
Rich :)
1972 500/4
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1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline burchy75

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Re: Knackered lower crankcase thread
« Reply #3 on: December 19, 2013, 04:01:41 PM »
Cheers both, I think it's ok for now as the K0 engine is not going to be used in the bike rebuild itself, so I'm going to leave it for now I think.  From looking at it, it looks as though there is enough thread there to provide decent enough grip for the bolt itself so I'm going to file it away for now and come back to it at a later date.

Offline burchy75

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Re: Knackered lower crankcase thread
« Reply #4 on: December 19, 2013, 04:07:36 PM »
Strictly speaking, NO. If you still have the broken of art it can be welded back by a VERY competent alloy welder. The crankcase halves are line bored as one unit for the main bearings, the only way it could be done is by getting another crankcase half and getting it line bored again, but that is seriously expensive, and would involve having main bearing shells made specially to meet the new dimensions, and you are talking telephone numbers for prices :(

Hi Hairy Git, I'm assuming if there are two complete 'original' (i.e. from one bike) crankcases, both upper and lower, that any internal engine components will fit straight in there no bother.  I ask as I have a K1 upper and lower crankcase in pretty decent nick, which lacks the internals (I have plenty of spares here though).  I'm assuming they will slide straight in and that your comments above were only relating to two seperate crankcases from two separate bikes?

Offline hairygit

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Re: Knackered lower crankcase thread
« Reply #5 on: December 19, 2013, 06:21:58 PM »
Yes, swapping the internals would be okay, but obviously you would need new main bearing shells to suit the crankshaft and crankcase markings, but they are standard Honda items so not diffucult to get^-^

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Offline burchy75

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Re: Knackered lower crankcase thread
« Reply #6 on: December 19, 2013, 09:04:17 PM »
Cheers Hairygit, thought as much, have a funny feeling David Silver is going to be rinsing me of a fair few quid over the coming months :-)

 

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