Author Topic: Breather hose specs?  (Read 3802 times)

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Offline edwardmorris

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Breather hose specs?
« on: July 14, 2014, 02:24:38 PM »
Anyone know the ID and OD for the Breather Tube C?? #8 here http://www.cmsnl.com/honda-cb750k2-four-usa_model14362/partslist/E01.html#results

I can't find it anywhere except Yamiya, who wants an insane amount for a repop. I'm assuming a standard hose from the auto shop will do just fine, but I can't for the life of me find my old one. If anyone knows the specs, please share..

Offline harisuluv

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Re: Breather hose specs?
« Reply #1 on: July 14, 2014, 07:02:36 PM »
Pretty readily available from a dealer online.  That part number is some kind of cmsnl internal part number.  Go to a real dealer page and look it up.  I have bought that hose within the last six months.

Offline edwardmorris

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Re: Breather hose specs?
« Reply #2 on: July 14, 2014, 09:24:53 PM »
Pretty readily available from a dealer online.  That part number is some kind of cmsnl internal part number.  Go to a real dealer page and look it up.  I have bought that hose within the last six months.
I've tried several, and even called a boatload of dealerships all over. Believe it or not, I found a set of NOS Oil hoses but not this one. This is the part number from the fische 15763-300-303. If you have the same one, can you please let me know which dealer is still carrying them? Thanks!

Offline david 750f

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Re: Breather hose specs?
« Reply #3 on: July 14, 2014, 09:27:39 PM »
1976 CB 750F

Offline Dream750

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Re: Breather hose specs?
« Reply #4 on: July 14, 2014, 10:38:07 PM »
Another option is using auto hose with a 12 mm or 1/2” ID as this will fit the 750 K. Usually found under fuel, emission, heater and transmission hose. Much thicker OD due to the reinforced construction than the OEM hose/tube and it will work just fine. The 750 K6 re-routed the breather tube away from the rear tire, which some earlier K owners can take advantage of. 

Offline evanphi

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Re: Breather hose specs?
« Reply #5 on: July 15, 2014, 06:23:42 AM »
PO replaced mine with similar hose to what Dream750 describes. They routed it straight back and it stops just short of the upper shock bolt.
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

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CB750 Shop Manual (all years), searchable text PDF
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Offline edwardmorris

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Re: Breather hose specs?
« Reply #6 on: July 15, 2014, 09:00:54 AM »
Another option is using auto hose with a 12 mm or 1/2” ID as this will fit the 750 K. Usually found under fuel, emission, heater and transmission hose. Much thicker OD due to the reinforced construction than the OEM hose/tube and it will work just fine. The 750 K6 re-routed the breather tube away from the rear tire, which some earlier K owners can take advantage of.
Thanks for that info Dream750! I'll give finding the OEM one a last try if I hear back from Harisuluv, otherwise, I'll grab the 12mm ID like you've suggested.

Offline KayOne

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Re: Breather hose specs?
« Reply #7 on: July 15, 2014, 01:16:04 PM »
Hey Edward. I get all my thin wall, non reinforced black hose of various diameters off Japanese cars at the auto wreckers. Toyota, Honda and particularly Nissan. It is amazing how well the rubber has held up under  hood.

Hope this helps
CB750 K1 restored
1979 CB750Fz - original except for exhaust, 14000km
1984 VF45F Interceptor - all original, 12000 km
1968 S90 - all original, 2100 miles
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Offline bjbuchanan

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Re: Breather hose specs?
« Reply #8 on: July 15, 2014, 01:38:07 PM »
You can get generic parts hose, you gotta ask for emissions or vacuum hose. That stuff won't be reinforced. The multipurpose, fuel or tranny/steering is big
The dirty girl-1976 cb750k, Ebay 836, Tracy bodykit
Round top carbs w/ 38 pilots, middle needle position, airscrew 7/8ths out, 122 main jet
Stock airbox w/ drop in K&N, Hooker 4-1

Don't trust me alone with a claw hammer and some pliers

Offline bjbuchanan

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Re: Breather hose specs?
« Reply #9 on: September 19, 2014, 10:03:21 AM »
I bought a later model airbox to recirculate the fumes instead of going to the atmosphere. EPA loves it lol.

Peace of mind knowing it isn't spitting in to the wind
The dirty girl-1976 cb750k, Ebay 836, Tracy bodykit
Round top carbs w/ 38 pilots, middle needle position, airscrew 7/8ths out, 122 main jet
Stock airbox w/ drop in K&N, Hooker 4-1

Don't trust me alone with a claw hammer and some pliers

Offline mcswny

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Re: Breather hose specs?
« Reply #10 on: September 19, 2014, 10:09:12 AM »
Here you go, $10 for a meter. Could be enough for your crank case to oil tank and your valve train breather

https://www.belmetric.com/rh75hp-smooth-high-pressure-p-958.html?zenid=4ch4d2obms5fo4g3ad60kuvqs5&cPath=14_139
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