Author Topic: 1975 Honda CB750F Breather Hose Routing  (Read 1699 times)

0 Members and 1 Guest are viewing this topic.

Offline RodSOHC750

  • Full Member
  • *
  • Posts: 94
  • Restoring Vintage Honda Motorcycles
1975 Honda CB750F Breather Hose Routing
« on: July 31, 2018, 07:20:38 PM »
Trying to reassemble my Super Sport.  The breather that mounts underneath the battery tray has several hoses leading to it.  I sketched how I think the hoses could be routed.  Please confirm for me.  I can't find anything in the Parts fiche or manuals.   

Also, where exactly do the 4 carburetor bowl overflow drain hoses route to the hose bracket on the swing arm?  Do they go between the swing arm and gearbox or around the gearbox end?

Thanks.
1979 Honda CB750L Limited Edition
1975 Honda CB750F Super Sport
1972 Honda CL450
1970 Honda CT70

Offline scottly

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 16,274
  • Humboldt, AZ
Re: 1975 Honda CB750F Breather Hose Routing
« Reply #1 on: July 31, 2018, 07:38:14 PM »
The spigot on the rear of the crankcase connects to a spigot the same size on the oil tank; it's not part of the breather plumbing.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,911
  • Bought her new 4/75
Re: 1975 Honda CB750F Breather Hose Routing
« Reply #2 on: July 31, 2018, 07:54:26 PM »
Text pics tomorrow.

On the rear of the cases where they fit together there should be an "overflow guide" that is held in place by a 8 X 56 case bolt. Kinda an elongated loop type thingy that holds the carb overflow tubes. See the crankcase parts page. It shows like it's in front but it isn't.

I don't have a stock air cleaner on either bike so I'll have to look but the bottom nipple is for a drain tube which is not available. HOWEVER try ordering part 17335-323-000 tube assembly breather instead. It is for a 78 550K. Just a little longer and you can trim the end off.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline RodSOHC750

  • Full Member
  • *
  • Posts: 94
  • Restoring Vintage Honda Motorcycles
Re: 1975 Honda CB750F Breather Hose Routing
« Reply #3 on: July 31, 2018, 11:59:40 PM »
When you say the bottom tube, do you mean on the breather or the oil tank.
1979 Honda CB750L Limited Edition
1975 Honda CB750F Super Sport
1972 Honda CL450
1970 Honda CT70

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,911
  • Bought her new 4/75
Re: 1975 Honda CB750F Breather Hose Routing
« Reply #4 on: August 01, 2018, 11:11:03 AM »
Forget the oil tank with what we are doing now. The bottom fitting/tube on the breather assembly is for a drain.

Now, the oil tank fitting attaches to the rear case breather tube.

We have 2 posts going and I don't want to confuse things.   
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline RodSOHC750

  • Full Member
  • *
  • Posts: 94
  • Restoring Vintage Honda Motorcycles
Re: 1975 Honda CB750F Breather Hose Routing
« Reply #5 on: August 02, 2018, 12:57:01 AM »
Understood.  Thanks.  The bottom connection on the oil tank has an internal standpipe and appears to be a vent/overflow. It connects to the rear side of the gearbox. 
1979 Honda CB750L Limited Edition
1975 Honda CB750F Super Sport
1972 Honda CL450
1970 Honda CT70