Topic: Oil line diameter

[durrango]

I was told by a mechanic that my oil lines are too small and I am starving the engine for oil.  Note that I am running a 836 set up.  What size hose is everyone running from the oil tank to the engine inlet and outlet, thanks...

[PeWe]

Add an oil pressure gauge and check the pressure.
A good add-on anyway. Pressure when cold 70-80PSI, when warm cruising 4000-5000rpm ca 40-60PSI.

As long as oil tank has oil and will be refilled in time it must be good.

[newday777]

I was told by a mechanic that my oil lines are too small and I am starving the engine for oil.  Note that I am running a 836 set up.  What size hose is everyone running from the oil tank to the engine inlet and outlet, thanks...

Do you have the stock hoses and oil tank on your bike?
Or do you have a custom oil tank and oil lines?

[69cb750]

Original lines id=.450" all you need.

[cfairweather]

I make my hoses out of AN10 braided hose and they look like the originals.  The inside and outside diameters are  very close to the original hoses. 

[newday777]

I was told by a mechanic that my oil lines are too small and I am starving the engine for oil.  Note that I am running a 836 set up.  What size hose is everyone running from the oil tank to the engine inlet and outlet, thanks...

Do you have the stock hoses and oil tank on your bike?
Or do you have a custom oil tank and oil lines?

The reason I ask is you didn't include enough information why he thinks you have too small oil line diameter.
 I'm wondering if you have oil starved head damage?? Did your mechanic build your motor and have a failure?

[BenelliSEI]

Check the I.D. (Inside diameter) of the aluminum (stock) fitting at both end of the hoses. If your hose is equal to, or greater than those restricted areas, they are fine. More importantly, are the hoses designed for this application (HOT oil, low pressure). The suction line (oil tank supply to pump) needs to be straight and never to collapse when hot.

[MauiK3]

yes, and if you are using stock oil lines that isn't the problem unless they are collapsing or blocked somehow.

[HondaMan]

I was told by a mechanic that my oil lines are too small and I am starving the engine for oil.  Note that I am running a 836 set up.  What size hose is everyone running from the oil tank to the engine inlet and outlet, thanks...

If you are IN Durango...I think your mechanic might be too high?

The OEM-sized oil system on this particular engine is the largest oversized system ever built by anyone in this industry. Honda was scared to death of a very public failure of the CB750, so the oil pump is 125% (pressure side) flow capable, so that at 50k miles (this was the rumored original design life of these engines) the wear in the crank bearings would still allow for full oil pressure and flow at clearances of less than 0.0032". In real life, the bearing clearances approach half that by around 80k miles while the pumps are still 110% capable with that mileage and clearance.

The only thing I have seen cause troubles with the (OEM) oil lines was/is age, or them being kinked by the owners' removing and abusing them. In extremely rare situations (after such treatment, in both cases) the liners of the aged hoses have come loose and partially blocked a couple of intake lines (the rear one with the bend), which caused the engines to wear their crank bearings (rods were OK) during high-speed touring for thousands of miles. Their only clue was a flickering oil light when they pulled off the freeway to a stoplight.

BUT...here's another question: is your oil light flickering? If so, you may well have the wrong oil type in the bike.

The CB750 requires 20w50 oil with zinc (ZDDP) and NO DETERGENT. If you are using normal car-engine oil, this is causing many troubles, including oil foaming and likely a flickering oil light. That's due to low oil PSI, which will cause bearing damage soon in the crankshaft. Use NON-DETERGENT OIL, 20w50 or at the very least 15w40 weight, with zinc. You can get zinc here:
https://www.ebay.com/itm/183908056251?epid=1632536415&hash=item2ad1c63cbb:g:5PEAAOSwTF1dRKxS&amdata=enc%3AAQAHAAAAoFUM2kd9Gn30OnZAs7DTfTQjfcwKwPLTjNgctEFgHTm4SpraUvS0GDyK2GHWwP1Usm6iT9R%2FeXRSNfFzRvmgL4xLoQmfRupIiDQomR8Avumh6Ji9xriCItb57ux5CREqrbWfSLP7FW5OIUbTYvTvuFsgxlfz34dRuw552YiKeCRqcNXPxL%2Bbs9bn9mvmi%2FeB%2BIEJuanPPXZVKVM6%2FtZSdK0%3D%7Ctkp%3ABk9SR5auidWWYQ

If you use the commonly-available Castrol 4T Motorcycle oil found in most auto parts stores (20w50 weight), add 1/2 of one of these little bottles for the right amount of ZDDP in an oil change.

DO NOT use the Rislone brand of ZDDP additive, as it contains lots of detergent: detergent oil is death to the crankshaft bearings in these engines by way of foaming at engine speeds over 3000 RPM or so. If you are using (or wish to use) synthetic oil. your best bet is the Golden Spectrol 20w50 oil (NOT the one for V-twin engines, it has detergent) made just for these type engines. AMSOIL also makes an excellent one, but is hard to find.