Author Topic: '75 CB400F exhaust and oil pan work  (Read 1614 times)

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Offline chrisp

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'75 CB400F exhaust and oil pan work
« on: March 10, 2013, 10:20:00 PM »
So I've been working on replacing an oil pan that was damaged on my bike (stripped threads).
There are a few tricky bolts on the oil pan, which made it so I needed to talk off the exhaust....i've been told you can do it without removing the exhaust, but that seemed like playing a game of Operation.

Anyway, I have a new oil pan, and all the parts I need. I've been soaking the oil pan in kerosene for about a day now to degunk it.

I've really only just started doing work on motorcycles so everything I do is a learning experience.

The things I'm stuck on now are around a few parts and anything I might need to do to put them back together.

1) Oil pan gasket. Does that need anything before installing it...or just sandwich it between the two parts?
2) Exhaust gaskets. I've been told I would probably need to replace these once I took off the exhaust. I'm not sure if they are gone or not, but I also have no idea how to get them out. I tried to pry a small awl behind one, but Im mostly concerned about potential damage to the cylinder, so I've not put much pressure on it. (I attached pics of it). I bought these OEM, so hopefully they're all good.
3) Anything to know about putting the gaskets back in once I've gotten the old ones out? I've read about cement...but I doubt I'd need that.


Any help or pointers to more detailed instruction on this sort of thing would be super helpful.

Thanks!




Offline MoMo

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Re: '75 CB400F exhaust and oil pan work
« Reply #1 on: March 11, 2013, 04:22:23 AM »
I either use a pick with  90 degree angle or a cotter pin tool to remove the gaskets, rarely do they need replacement though.  Nothing special for the oil pan gasket, tighten from the middle out, like an x pattern...Larry

Offline chrisp

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Re: '75 CB400F exhaust and oil pan work
« Reply #2 on: March 11, 2013, 09:34:20 AM »
Thanks!
Ya I don't know if the gaskets need to be replaced or not...this is just based on what a mechanic told me.
Typically when would they need to be replaced?

There's nothing I need to do to the new gasket on the oil pan? (I thought I had heard it needed to be coated in oil a bit) I had heard about tightening evenly.





Offline iron_worker

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Re: '75 CB400F exhaust and oil pan work
« Reply #3 on: March 11, 2013, 11:48:19 AM »
The copper gaskets are crush gaskets and are only designed to be used once... however lots of guys use them over and over. When you pull them out you'll see they are flat like a washer but they actually are shaped like an o-ring when new. I would replace them but even if you don't the worst than can happen is you'll get an exhaust leak.

IW

Offline malcolmgb

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Re: '75 CB400F exhaust and oil pan work
« Reply #4 on: March 11, 2013, 12:19:48 PM »
I have re-used the exhaust copper washers without problems, don't bother trying to remove them if that is your plan. The oil pan gasket, I use some grease to hold it in place and help it to seat itself, it also makes it easier to remove next time too.
Malcolm

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1976 XL175 - Sold
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1966 CA78
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Offline chrisp

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Re: '75 CB400F exhaust and oil pan work
« Reply #5 on: March 11, 2013, 06:03:25 PM »
Gaskets: I have new ones I would put in place instead. They seem VERY well seated in there, I'm not sure how to actually get them out without marring the surrounding metal. I thought potentially getting something plastic in behind them would work, but I've not been able to get anything substantial back there. I have a 90 degree pick I've used to clear some space behind it, but it's not moving at all with decent force.

Any other tricks / chemical solutions to help get them out? Maybe it's not worth replacing them?

Glad to see someone using grease, I thought a light coat of oil would be good, but grease is probably even a bit better.



Offline malcolmgb

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Re: '75 CB400F exhaust and oil pan work
« Reply #6 on: March 12, 2013, 09:54:25 AM »
If a metal pick doesn't remove them a plastic one is less likely to, I have used the 90 degree pick before and can be a bit of a job, use the pick to score around the edges of the gasket where the carbon seals it, eventually it will give or collapse in on itself.
Malcolm

Artificial intelligence is no match for natural stupidity.

1977 CB400F
1973 CL175 K7
1976 XL175 - Sold
1964 CL72
1966 CA78
http://forums.sohc4.net/index.php?action=gallery;su=user;u=1988

Offline MoMo

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Re: '75 CB400F exhaust and oil pan work
« Reply #7 on: March 12, 2013, 01:30:14 PM »