Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: davefirestorm on December 18, 2019, 06:32:36 AM
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My new to me 750F came to me with fresh oil and filter,time to change the oil again.Previous owner been running it on 20/50 mineral oil,I don’t have enough 10/40 mineral oil ( find it harder to source these days ) what are your thoughts on grades of oil to use? Apologies for bringing up the subject but it is cold and wet outside😂😂
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20/50 is a bit thick for uk except very high summer.
Try Tesc for their 10/40 (maybe 15/40) mineral DIESEL oil
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As Bryan says there's usually a match in those oils to the spec required.
Have you noticed Bryan though, the supermarkets around here have certainly reduced their oil choices availability. Asda and b+q did quite comprehensive range but all dissapeared over last few years. Huge Tesco here has absolutely minimum choice now, Eurocarparts locally still have decent choices.
From the viscosity point of view, Honda's own data states that 20w can be used from 0 degree C ambient upwards. Historically I've used 20/50 alot in these 750s and never had any issues. It's pretty low risk choice, oil condition having far more impact if not changed.
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All oils have changed over the years. Haven't seen anyone since I was a kid lighting a fire under the tank on a truck :o
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I always use 10/40 except for one time in an emergency when I had to put in 20/50. The engine seized a piston so I never did that again. Opie Oil have a good selection and often do club discounts.
https://www.opieoils.co.uk/c-782-10w40-motorcycle-engine-oil.aspx
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I usually use Morrison Lubricants (Not the Supermarket). Their website recommends:
1st Choice Race 4 TT 10W-40 - Part No. FTT.
2nd Choice Race Sport 4 - Part No. SSF.
I usually buy mine in advance at motorcycle shows and autojumbles like Kempton Park but they do sell their oil on-line and have a technical desk if you have any questions.
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All oils have changed over the years. Haven't seen anyone since I was a kid lighting a fire under the tank on a truck :o
;D ;D ;D That used to be every winter at 6AM on the pit stack to get the graders and dozers running for the day.
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I read that mineral oil is best to 'run in' an engine after rebuild. So since mine was rebuilt, it's been running on 'gamma 10W40 mineral motorcycle oil' by ROCK OIL.
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I use 10/40 now but can't comment on what affect it has on my engines as the bike is used in good conditions and engine totally rebuilt - so I refer back to when I used bikes in all weathers all year round and I used the likes of Duckhams 20/50 on all my Fours (Honda SOHC, ZI and Suzuki 1000's) over 150,000 plus and never had one mechanical issue (can't even remember changing clutch plates - but that might be my memory).
Point is, in my opinion, its about changing with quality oil and filters at the stated service intervals rather than the small differences in grades - and warming bike properly before ragging it.
Just my view
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Not going to use it through winter so will change oil/filter now put last of my 10/40 in my Superdream I’m off to Newark show January so hope to get some 10/40 there.Thanks for all opinions on subject :D
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Back in the olden days I always used Duckhams 20:50 on all of my bikes, never had a problem and I used the bike all year round, I did not start driving cars until I was 28 so the bike was used in all weathers, was fun in the snow.
Cheers
Dennis
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The Duckhams Oil Company were the inventors of the 20W50 multigrade oil which meant that motorist now didn't have to use a different oils according to the temperature or time of the year. This blend of oils was a revelation to the British automotive industry as it went a good deal of the way to compensate for the less than exact engineering tolerences and practices of the day. Your average 15 year old Morris Minor or brand new Triumph now sounded quieter for longer. (Still leaked though!) Then along came the Japanese with their clever metric measuring stuff and brand new machinery that didn't require Old Harrys' skills to compensate for clapped out 60 year old bits of kit. New machine tools meant the Japanese could consistantly work to tighter tolerences which naturally allowed for the use of thinner lubricants, hence the switch to grades such as 10W40. A thinner oil equals faster warm up and so less wear from cold start up; less stiction in moving parts so they can be made to move faster and lighter and cheaper. Thicker engine oil was no longer the way to go so the evocative odour of Castrol R became a faded memory where bikers gathered, and a jolly good thing that was too for any motorcycle engine rebuilder.
All this is just my version of the oil question as I hadn't previously come across anyone regularly using or advocating the use of 20W50 oil in any Japanese bike since the 1970's. Obviously there are some that did and still do and if that works for them, excellent, do what works best for you, I say. :D
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In the winter my Velo single wouldn’t start so I’d have to change to a thinner grade oil also had to drain sump if left more than couple days because would you believe it it would wetsump it also leaked a lot of oil ;D
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Thicker engine oil was no longer the way to go so the evocative odour of Castrol R became a faded memory where bikers gathered, and a jolly good thing that was too for any motorcycle engine rebuilder.
I can well remember putting some Cassie R in the petrol tank of my BSA A65 to get that nice smell.
Cheers
Dennis
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Still have about a litre of R for adding to fuel. Confuses people when I turn up on the 500
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The Duckhams Oil Company were the inventors of the 20W50 multigrade oil which meant that motorist now didn't have to use a different oils according to the temperature or time of the year. This blend of oils was a revelation to the British automotive industry as it went a good deal of the way to compensate for the less than exact engineering tolerences and practices of the day. Your average 15 year old Morris Minor or brand new Triumph now sounded quieter for longer. (Still leaked though!) Then along came the Japanese with their clever metric measuring stuff and brand new machinery that didn't require Old Harrys' skills to compensate for clapped out 60 year old bits of kit. New machine tools meant the Japanese could consistantly work to tighter tolerences which naturally allowed for the use of thinner lubricants, hence the switch to grades such as 10W40. A thinner oil equals faster warm up and so less wear from cold start up; less stiction in moving parts so they can be made to move faster and lighter and cheaper. Thicker engine oil was no longer the way to go so the evocative odour of Castrol R became a faded memory where bikers gathered, and a jolly good thing that was too for any motorcycle engine rebuilder.
All this is just my version of the oil question as I hadn't previously come across anyone regularly using or advocating the use of 20W50 oil in any Japanese bike since the 1970's. Obviously there are some that did and still do and if that works for them, excellent, do what works best for you, I say. :D
Well put! A logical and pragmatic appraisal of the evolution of oil and bikes. On Jap bikes, the key is having good oil in the sump as opposed to the slight differences in grades. Modern semi or fully synthetic oil are the only issue that can affect the clutch plates due to the improved reduction in friction.
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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?
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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?
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.
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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?
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.
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
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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?
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.
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
Not a tight wad Dave.... just sensible by the sounds of it 😊😊😊
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Never synthetic.
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.
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Never synthetic.
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.
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.
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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.