Author Topic: 1975 CB750F with oil leaks.  (Read 1273 times)

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Offline kaptainkid1

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1975 CB750F with oil leaks.
« on: April 13, 2016, 01:23:31 PM »
I have a 1975 Honda CB750F super sport and I have few oil leaks around the bottom end.
Since the bike is stock and more than likely all original parts how often does the Oil line leak?
It seems the oil is leaking from the Oil Lines to sump reservoir.
How often do these lines fail and need to be changed? I know they're 41 years old. Should I just buy ebay used ones? or buy news ones?
I feel the oil can be leaking from other place too. I haven't track them down since the leak is very minor. No appreciable oil  lost during fluid changes.



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« Last Edit: April 13, 2016, 03:30:25 PM by kaptainkid1 »
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Offline flybox1

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Re: 1975 CB750F with oil leaks.
« Reply #1 on: April 13, 2016, 02:21:11 PM »
you can have new braided stainless lines made.  might help, or replace the o-rings where they attach to the case.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 1975 CB750F with oil leaks.
« Reply #2 on: April 13, 2016, 02:26:24 PM »
I'd go for 2 new O-rings at the fitting.  Make sure you're not getting drips from the clutch cover instead or the seal for the kick starter. The part bolted to the engine, not it's chrome cover.
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Offline kaptainkid1

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Re: 1975 CB750F with oil leaks.
« Reply #3 on: April 13, 2016, 03:33:49 PM »
Replace the o-rings first before buying new ss braided lines. Which i've priced at $120 on ebay. Ok I'll do that first.
So these lines are very strong then? It seems they're covered with cloth braid and I"m guessing rubber tube?
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1974 BMW R90S Barn Find
1995 BMW R1100GS Dual Sport Daily
1996 Triumph 900 Adventurer Bobber

Offline HondaMan

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Re: 1975 CB750F with oil leaks.
« Reply #4 on: April 13, 2016, 03:50:31 PM »
When they leak, it is usually caused by someone wrestling them out of the frame - they then leak near the crimp fittings. Sometimes the wrestlers have actually split the hose(s), working them so hard. :(
Where is the oil showing up on the bike?
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Re: 1975 CB750F with oil leaks.
« Reply #5 on: April 20, 2016, 03:13:23 PM »
I had a set start leaking at the crimps. I found a local place that just crimped new stainless braided lines for like $15 after I cut the old crimps off.


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Offline 70CB750

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Re: 1975 CB750F with oil leaks.
« Reply #6 on: April 21, 2016, 04:54:51 AM »
^^^That^^^

With a bit of luck, somebody can cramp new lines on for you, they carry 0 pressure, even clamped on rubber hose would work.
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Offline kaptainkid1

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Re: 1975 CB750F with oil leaks.
« Reply #7 on: April 21, 2016, 10:46:08 PM »
yeah i've decided to put on new braided ss lines.
1975 Honda CB750F Daily Rider      
1974 BMW R90S Barn Find
1995 BMW R1100GS Dual Sport Daily
1996 Triumph 900 Adventurer Bobber

Offline b1jackson

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Re: 1975 CB750F with oil leaks.
« Reply #8 on: June 20, 2016, 05:18:21 PM »
I just bought a bike with a similar leak.  It collects on middle of the swing arm and puddles at the lowest point near the chain tightener on the left.  Any idea what size the o-ring is before I dismantle?  I don't thing mine has ever been off before so I don't expect it's been roughed up.
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