Author Topic: oil lines, oil tank questions....?  (Read 1088 times)

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Offline BrianAdair

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oil lines, oil tank questions....?
« on: September 12, 2010, 07:20:16 PM »
I am building a '77 CB750K Cafe style, I have the stock oil tank, don't like it at all, like the K1 to K6 tank I have one of those also, but it doesn't seem to fit in the frame due to the engine bracket that bolts on the outside of the frame. I modified this tank to fit, but not sure I'm even going to use it now..... ::) If I do my oil lines are too short..... Does anyone know where I could get longer oil lines?
Or can the ends be cut off and re-crimped on new line, at say a hydraulic hose shop?

I'm thinking about just building a custom tank to the style I want, if I do this I will just change the fittings on the tank to standard flare fittings, but the ones on the engine are the problem since they are a machined part.

On the oil tank,
the one that was on my '77 has the feed to the engine, then the return, and one vent tube. The older tank has 2 vent tubes..... why is this?
I can't find anything in my manuals showing detailed pictures or an explanation on the oil tank vent lines.
Since my bike was in pieces when I bought it, I don't know where the lines went to, do these vent tubes go to the crank case breather? or the valve cover breather?
I appreciate any help!

Offline the architect

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Re: oil lines, oil tank questions....?
« Reply #1 on: September 13, 2010, 11:51:32 AM »
I feel your oil tank pain  ;D  I happily travelled down the custom oil tank Road of Madness when doing my cafe build.  If you have time on your hands (and a high-speed connection), you can take a look at it all here:  http://forums.sohc4.net/index.php?topic=63166.0

But the Cliff's Notes version (and answer to your questions) is something like this:

The 2 tank vent tubes:  1 goes to atmosphere (pressure vent/overflow, vented to just ahead of the rear tire - smart  ::) ) and the other goes to the rear crancase vent tube (attaches at the top of the oil tank).  Ask me how I know  ;D


CB750_37 by modern.built, on Flickr

I ended up reusing the stock oil line fittings that connect to the engine.  I carefully cut off the crimp connectors (see below) and used standard, oil-safe hose from the autoparts store for my lines (it's got a decently large I.D, maybe 5/8" or 3/4", off the top of my head).  I secured them will hose clamps of the appropriate diameter.  Presto - now your lines can be any length you like, and no need to get a hydraulic shop involved ;D

A custom tank is a bit of a PITA, but well worth it, IMO.  Here's mine.  There are some other great ones floating around on the forum.  A quick search should turn up a few.  And Benjie has his unique take on it, as well.


CB750_125 by modern.built, on Flickr
Rider no. 83 on the 2013 SOHC/4 Honda World Tour
Rider no. 228 on the 2012 SOHC/4 Honda World Tour
Rider no. 70 on the 2011 SOHC/4 Honda World Tour

my '75 CB750 cafe build photo documentary:  looking for the Lone Stars is like playing Where's Waldo -- enjoy.
http://www.flickr.com/photos/34828040@N05/sets/72157615892537535/

CB350 twin, rigid meat grinder:
http://www.flickr.com/photos/34828040@N05/sets/72157627005176764/

Blip Workshop
http://www.blipworkshop.com
http://www.facebook.com/blipworkshop

Offline BrianAdair

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Re: oil lines, oil tank questions....?
« Reply #2 on: September 13, 2010, 07:59:34 PM »
Thanks for the info man!
Thats what I needed to know, so just regular hose clamps and no leaks?

I found some fancy chrome ones at Cycle X that look like the crimp fittings but are still just a screw clamp, and at $16. ea..... I'm not sure about that..lol

BTW I like your bike!!
I have to make mine for 2 up also, orders from the wife... ;D

Thanks again man

Offline scottly

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Re: oil lines, oil tank questions....?
« Reply #3 on: September 13, 2010, 08:06:54 PM »
I did the same thing as the architect. Just oil-safe hose and hose clamps. No leaks ;D(there is no pressure on those lines)
Don't fix it if it ain't broke!
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Offline the architect

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Re: oil lines, oil tank questions....?
« Reply #4 on: September 14, 2010, 10:09:21 AM »
Thanks for the info man!
Thats what I needed to know, so just regular hose clamps and no leaks?

I found some fancy chrome ones at Cycle X that look like the crimp fittings but are still just a screw clamp, and at $16. ea..... I'm not sure about that..lol

BTW I like your bike!!
I have to make mine for 2 up also, orders from the wife... ;D

Thanks again man

My pleasure, buddy!  No leaks at my fittings.  In fact, the barbs on the oil fittings grip the inside of the hose so well, I be it wouldn't even leak without hose clamps.  When I have to run new hose, I have to cut the old hose off the fittings with a razor blade - they won't pull off, no matter how hard I pull.

I'd pass on the Cycle X clamps, unless you're hard up for some chrome.  And in that case, I've seen those at the regular autoparts stores, even. 

Cheers!
Rider no. 83 on the 2013 SOHC/4 Honda World Tour
Rider no. 228 on the 2012 SOHC/4 Honda World Tour
Rider no. 70 on the 2011 SOHC/4 Honda World Tour

my '75 CB750 cafe build photo documentary:  looking for the Lone Stars is like playing Where's Waldo -- enjoy.
http://www.flickr.com/photos/34828040@N05/sets/72157615892537535/

CB350 twin, rigid meat grinder:
http://www.flickr.com/photos/34828040@N05/sets/72157627005176764/

Blip Workshop
http://www.blipworkshop.com
http://www.facebook.com/blipworkshop