Author Topic: Cracked crankcase (whilst riding?)  (Read 974 times)

Offline GoldenFailure

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Cracked crankcase (whilst riding?)
« on: 17.02. 2012 16:24 »
Thrashed the flash for 100 miles today, only done 300 since I got it due to multiple mechanical intrigues, but it ran brilliantly today (except for one silencer falling off and getting a little bit run over)
But when I ran an oily rag over it 10 mins ago I noticed an inch long Y shaped crack in the crankcase, emerging from the centre front engine mounting bolt and heading for the primary case.
Its rough edged, maybe 0.7mm wide and one edge seems higher than the other.
I'm not 100% positive, but I'm fairly sure it wasn't there before (and with all the road salt Ive been oily ragging it everyday) Do I panic, ignore it, or is there a solution. (Bearing in mind Ive got a 3000 mile trip on this bike in 6 weeks time)

Any advice appreciated!
1955 Plunger Golden Flash (doesn't work)
1967-2005  Enfield Bullet bitsa (evil)
Absence of common sense or car to go with it.

Offline kommando

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Re: Cracked crankcase (whilst riding?)
« Reply #1 on: 17.02. 2012 17:33 »
Quote
but it ran brilliantly today

They always do just before blowing up  *sad*

Sounds like you have crack which can only get worse, its needs aluminium welding by someone good but BSA alloy cases do weld well as the alloy is good quality so it will last. Leave the welder to decide what work to do, he may drill holes at the ends of the cracks and create a valley over the crack so the crack is stopped and he gets good penetration.
No BSA twins just unit singles
Scotland

Offline GoldenFailure

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Re: Cracked crankcase (whilst riding?)
« Reply #2 on: 21.02. 2012 18:20 »
Hi kommando. Cheers for the reply. Do you reckon the engine needs to come to bits, or could it be welded in the frame?
1955 Plunger Golden Flash (doesn't work)
1967-2005  Enfield Bullet bitsa (evil)
Absence of common sense or car to go with it.

Offline muskrat

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Re: Cracked crankcase (whilst riding?)
« Reply #3 on: 21.02. 2012 19:31 »
G'day GF,
             is it leaking from that spot? Is it really a crack? I have seen casting dags that look like a crack.
 If it is a crack "I" would strip it down and repair (weld) from the inside.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline wilko

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Re: Cracked crankcase (whilst riding?)
« Reply #4 on: 21.02. 2012 20:57 »
Close up pic required.

Offline kommando

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Re: Cracked crankcase (whilst riding?)
« Reply #5 on: 22.02. 2012 10:59 »
If its confirmed as a crack then as others have said then its a strip down as it will need to be welded from both sides to ensure a strong weld.

Post a pic.
No BSA twins just unit singles
Scotland