SOHC.co.uk Forums > CB750
20/50
Nurse Julie:
--- Quote from: davefirestorm on December 20, 2019, 02:14:44 PM ---
--- Quote from: Nurse Julie on December 20, 2019, 11:01:54 AM ---
--- Quote from: davefirestorm on December 20, 2019, 10:15:06 AM ---My understanding is that an old engine ( I’m talking old Brit ) has “bits/film†of crud stuck to it’s innards and using modern semi/full synthetic oils can loosen this crud via the additives/detergent in it.Would this apply to our SOHC fours?
--- End quote ---
That's a risk with any old engine that has been poorly maintained regardless of what oil is used. On our SOHC/4's, it is debris going around the engine, coming up the oil ways and blocking the oil restrictor jets that causes oil starvation to the cam and the result is catastrophic and very expensive to repair damage. It is the frequency of oil changes throughout an engines life that contributes towards mechanical and engineering longevity. It doesn't matter what oil it is as long as its changed regularly. Mineral for running in a newly built engine then on to semi synthetic. Never synthetic.
--- End quote ---
Being a lifelong tight wad :D I would never use synthetic oil,did once on a VFR but then used semi synthetic on all modern bikes.I stick religiously to oil change frequency,always have :D
--- End quote ---
Not a tight wad Dave.... just sensible by the sounds of it 😊😊😊
Horace:
--- Quote from: Nurse Julie on December 20, 2019, 11:01:54 AM ---
Never synthetic.
--- End quote ---
May I ask why? A completely rebuilt motor is effectively a new one and unless the various seals are affected by it why not use it?
I was always a Duckams 20/50 user, peer influence probably. Currently I'm using Halfords Classic 20/50 in a cb750 and a cb77.
Nurse Julie:
--- Quote from: Horace on January 05, 2020, 06:39:13 PM ---
--- Quote from: Nurse Julie on December 20, 2019, 11:01:54 AM ---
Never synthetic.
--- End quote ---
May I ask why? A completely rebuilt motor is effectively a new one and unless the various seals are affected by it why not use it?
I was always a Duckams 20/50 user, peer influence probably. Currently I'm using Halfords Classic 20/50 in a cb750 and a cb77.
--- End quote ---
So a 1960's / 70's newly rebuilt engine would never have had fully synthetic used anyway. Also, any bike, in this case Honda SOHC/4' with the wet clutch system, which they all have except the CB750/4's, the clutch will slip more than a slippery thing. Semi synthetic is fine as is mineral.
Rob62:
10w40 semi synthetic motorcycle oil for me, in all my classic bikes. I think 20w50 is too viscous for a bike engine.... no point in using fully synthetic unless you have the latest superbike in which case it will be correctly specified in the service manual.
Navigation
[0] Message Index
[*] Previous page
Go to full version