I am about the acquire a older Honda 750 Nighthawk. This is just a basic DOHC inline 4. Does anybody have any experience with these and what oil can I run? I am not one to pay the outrageous prices at dealerships and wondering if I can get by with Rotella 15w 40 since its 13/gallon at my China mart. This is a shared sump design. Thanks for any advice.
What oil for 750 HOnda Nighthawk?
- Thread starter nomochevys
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Rotella 15w40 will work fine.
Having said that, Honda gn4 is not a bad oil and an honest dealer will sell it to you at 4.25-5.50 a quart, not a terrible amount more.
Having said that, Honda gn4 is not a bad oil and an honest dealer will sell it to you at 4.25-5.50 a quart, not a terrible amount more.
Yes if you get the Honda 4T bike oil (or any bike oil) for a decent price that's the way to go.
Failing that Rotella 5W-40 is pretty cheap and is a better lubricant to their 15W-40 dino.
Failing that Rotella 5W-40 is pretty cheap and is a better lubricant to their 15W-40 dino.
Rotella is better than almost all the old 10w40 moto oils that were around when that bike was new.
If you are going to drive it when the cold start is below 15 Fahrenheit, then you want to go with the 5W-40 Rotella T6. If the coldest cold start is for sure always going to be greater than 15 Fahrenheit, then the lower cost 15W-40 Rotella will be OK and cost less.
I've got that bike right now. I've been using conventional rotella in it for years Its worked very well thus far
Originally Posted By: Clevy
I've got that bike right now. I've been using conventional rotella in it for years Its worked very well thus far
I wont be on it under 40 degree I promise you that.
Clevy, any known issues I need to be aware of? Seems like the tacks fail on these bike but most of it seems pretty bullit proof for the most part. Have you had any issues with yours? I think Rotella is a bargain and glad to hear its working for you.
I've got that bike right now. I've been using conventional rotella in it for years Its worked very well thus far
I wont be on it under 40 degree I promise you that.
They are prone to stator and rectifier failures also. My dad's CB750 DOHC had his go out at 10k. The Hondas are not as bad as the old Suzuki's but they are still known to go out.
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I owned a red and black 1986 CB700SC Honda Hawk and if your owner manual looks like this then
API rating SE SJ SH are now obsolete and do not provide the same level of performance or
protection as the more up to date SL and SM SN specifications... I'm running a API rated SN
SM SL 0 30 Mobil 1 100% synthetic in my 94 Honda because not only does it provide great wear
protection its the lightest viscosity recommended by Honda which frees up the most HP...
API rating SE SJ SH are now obsolete and do not provide the same level of performance or
protection as the more up to date SL and SM SN specifications... I'm running a API rated SN
SM SL 0 30 Mobil 1 100% synthetic in my 94 Honda because not only does it provide great wear
protection its the lightest viscosity recommended by Honda which frees up the most HP...
Of course that 10w30 will shear down and then you are using too light of an oil.
Run the Rotella, then if it shears down to a 30 weight you are still protected. Honda had some cam wear issues in the 80's so you want something with good film strength and good antiwear additive levels. Especially since ya never know what abuse the machine saw in the many years before you came to own it.
I always prefer protection over a small but insignificant gain in performance that may sacrifice that protection.
Run the Rotella, then if it shears down to a 30 weight you are still protected. Honda had some cam wear issues in the 80's so you want something with good film strength and good antiwear additive levels. Especially since ya never know what abuse the machine saw in the many years before you came to own it.
I always prefer protection over a small but insignificant gain in performance that may sacrifice that protection.
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Originally Posted By: Robenstein
Honda had some cam wear issues in the 80's
Mercy Rob... Honda's great camshaft crisis in 84 had nothing to do
with oil and everything to do with Honda's short cut in machining
steps of the cam bearing blocks... they dropped the line bore step and
machined the cam bearing blocks separately... this resulted in mix
match of clearances... in short the cams flopped about... hard coat
damage soon followed... For a cure Honda... in 86... went back to the
more accurate and expensive method of line boring the cam bearing
blocks... You can note the external difference in the head design...
the 84's & 85's rubber valve cover gasket is flat... whereas the 86's
rubber valve cover gasket is half circled covering where it was line
bored...
Honda had some cam wear issues in the 80's
Mercy Rob... Honda's great camshaft crisis in 84 had nothing to do
with oil and everything to do with Honda's short cut in machining
steps of the cam bearing blocks... they dropped the line bore step and
machined the cam bearing blocks separately... this resulted in mix
match of clearances... in short the cams flopped about... hard coat
damage soon followed... For a cure Honda... in 86... went back to the
more accurate and expensive method of line boring the cam bearing
blocks... You can note the external difference in the head design...
the 84's & 85's rubber valve cover gasket is flat... whereas the 86's
rubber valve cover gasket is half circled covering where it was line
bored...
Originally Posted By: nomochevys
Originally Posted By: Clevy
I've got that bike right now. I've been using conventional rotella in it for years Its worked very well thus far
I wont be on it under 40 degree I promise you that.
Clevy, any known issues I need to be aware of? Seems like the tacks fail on these bike but most of it seems pretty bullit proof for the most part. Have you had any issues with yours? I think Rotella is a bargain and glad to hear its working for you.
I haven't had any problems with mine. Its an 86. The speedo died this season but otherwise the bike had run great. I've put 30000kms on this bike since I've owned it. Not a single issue.
I've tried many different oils in this bike and rotella has been the best one I've used.
Originally Posted By: Clevy
I've got that bike right now. I've been using conventional rotella in it for years Its worked very well thus far
I wont be on it under 40 degree I promise you that.
I haven't had any problems with mine. Its an 86. The speedo died this season but otherwise the bike had run great. I've put 30000kms on this bike since I've owned it. Not a single issue.
I've tried many different oils in this bike and rotella has been the best one I've used.
Originally Posted By: BusyLittleShop
Originally Posted By: Robenstein
Honda had some cam wear issues in the 80's
Mercy Rob... Honda's great camshaft crisis in 84 had nothing to do
with oil and everything to do with Honda's short cut in machining
steps of the cam bearing blocks... they dropped the line bore step and
machined the cam bearing blocks separately... this resulted in mix
match of clearances... in short the cams flopped about... hard coat
damage soon followed... For a cure Honda... in 86... went back to the
more accurate and expensive method of line boring the cam bearing
blocks... You can note the external difference in the head design...
the 84's & 85's rubber valve cover gasket is flat... whereas the 86's
rubber valve cover gasket is half circled covering where it was line
bored...
I did not say it was an oil problem, I said it was a cam wear issue. Just like I have replaced a TON of small block chevy cams that wore even faster with the weaker anti wear additive packages in SM and SL PCMO oils.
Originally Posted By: Robenstein
Honda had some cam wear issues in the 80's
Mercy Rob... Honda's great camshaft crisis in 84 had nothing to do
with oil and everything to do with Honda's short cut in machining
steps of the cam bearing blocks... they dropped the line bore step and
machined the cam bearing blocks separately... this resulted in mix
match of clearances... in short the cams flopped about... hard coat
damage soon followed... For a cure Honda... in 86... went back to the
more accurate and expensive method of line boring the cam bearing
blocks... You can note the external difference in the head design...
the 84's & 85's rubber valve cover gasket is flat... whereas the 86's
rubber valve cover gasket is half circled covering where it was line
bored...
I did not say it was an oil problem, I said it was a cam wear issue. Just like I have replaced a TON of small block chevy cams that wore even faster with the weaker anti wear additive packages in SM and SL PCMO oils.
Originally Posted By: Robenstein
I did not say it was an oil problem, I said it was a cam wear issue. Just like I have replaced a TON of small block chevy cams that wore even faster with the weaker anti wear additive packages in SM and SL PCMO oils.
Thanks for clearing that up Rob... we don't want to give the impression that a 30 grade oil
API rated SM SL would begin Honda's great cam crisis all over again...
I did not say it was an oil problem, I said it was a cam wear issue. Just like I have replaced a TON of small block chevy cams that wore even faster with the weaker anti wear additive packages in SM and SL PCMO oils.
Thanks for clearing that up Rob... we don't want to give the impression that a 30 grade oil
API rated SM SL would begin Honda's great cam crisis all over again...
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Bls. Have you actually ridden the bike in question. If you had you would know that the shifting gets very notchy as the oil shears and by starting with a 30 grade,not weight,you are effectively shortening the oil change interval because once the 30 grade even shears slightly the bike will be a serious pain to shift and ride quality will degrade to the point of not even wanting to ride.
Op. busy here seems to have a good back story however his advice til now has been questionable for the most part and incorrect for the rest.
Trust me when I recommend rotella conventional 15w-40. The syn rotella shears to fast and shift quality degrades so you can't extend the interval to achieve any return on the extra cost buying it.
I've used Amsoil in both the yellow cap powersports version and the 4t flavour. They didn't last as long as rotella did in service and cost double or more. I used M1 4t 10w-40 and the Amsoil lasted longer before shifting was affected. It wasn't even 1500km before the Mobil told me it was time to go.
I used motul in it once in the 15w-50 4t. It was awesome. It lasted over 4000kms in service and was the longest lasting oil I used in that bike but cost vs rotella just didn't add up.
Rotella goes over 3000km in my bike before shifting gets notchy at 10 bucks per oil change or motul at 4000kms at 80 bucks per oil change.
See my point. Synthetic oils are great in a racing situation but in my bike he oil shears to the point of loss of proper shift function long before the oil is even close to being used up,so for that reason I use conventional rotella.
I can drain rotella due to shear at 3000kms or I can dump m1 at 1/3 or that due to shear or I can dump Amsoil at 2/3 of that due to shear.
See where I'm going with this. The engine revs out at 7000 rpm and isn't making any power past that so no point revving past that point.
My bike seems most comfortable from 3000-6000rpm. Anything more than that is wasted gas and lower almost felt like lugging it even though it wasn't. There just isn't alot of torque down low.
I could get 60 mpg out of that bike at 60mph. I suggest using tc-w3 in with the fuel. The bikes from the 80s weren't made for ethanol and the oil in the fuel seems to add some time before needing new rubber parts
Its a great bike. I welded some pegs on the front frame to help stretch my legs but even before the pegs it wasn't too bad.
My girl rides is now to commute on nice days. We keep racking up miles and the bike just keeps eating them up.
As far as coolant I use water wetter and distilled water and no issues thus far
Op. busy here seems to have a good back story however his advice til now has been questionable for the most part and incorrect for the rest.
Trust me when I recommend rotella conventional 15w-40. The syn rotella shears to fast and shift quality degrades so you can't extend the interval to achieve any return on the extra cost buying it.
I've used Amsoil in both the yellow cap powersports version and the 4t flavour. They didn't last as long as rotella did in service and cost double or more. I used M1 4t 10w-40 and the Amsoil lasted longer before shifting was affected. It wasn't even 1500km before the Mobil told me it was time to go.
I used motul in it once in the 15w-50 4t. It was awesome. It lasted over 4000kms in service and was the longest lasting oil I used in that bike but cost vs rotella just didn't add up.
Rotella goes over 3000km in my bike before shifting gets notchy at 10 bucks per oil change or motul at 4000kms at 80 bucks per oil change.
See my point. Synthetic oils are great in a racing situation but in my bike he oil shears to the point of loss of proper shift function long before the oil is even close to being used up,so for that reason I use conventional rotella.
I can drain rotella due to shear at 3000kms or I can dump m1 at 1/3 or that due to shear or I can dump Amsoil at 2/3 of that due to shear.
See where I'm going with this. The engine revs out at 7000 rpm and isn't making any power past that so no point revving past that point.
My bike seems most comfortable from 3000-6000rpm. Anything more than that is wasted gas and lower almost felt like lugging it even though it wasn't. There just isn't alot of torque down low.
I could get 60 mpg out of that bike at 60mph. I suggest using tc-w3 in with the fuel. The bikes from the 80s weren't made for ethanol and the oil in the fuel seems to add some time before needing new rubber parts
Its a great bike. I welded some pegs on the front frame to help stretch my legs but even before the pegs it wasn't too bad.
My girl rides is now to commute on nice days. We keep racking up miles and the bike just keeps eating them up.
As far as coolant I use water wetter and distilled water and no issues thus far
I would recommend some sort of coolant...those impellors catch it rough.
Distilled water is my flush, definitely not my everyday.
Distilled water is my flush, definitely not my everyday.
Originally Posted By: SuzukiGoat
I would recommend some sort of coolant...those impellors catch it rough.
Distilled water is my flush, definitely not my everyday.
So I take it you have the bike in question,and have put the miles on it I have in the past few years.
My comments are based on experience with this exact bike. Yours are .........
Antifreeze lowers the boiling point of the coolant itself. Antifreeze does exactly as the name implies and surprisingly enough it doesn't dissipate heat as fast as water does.
CORRECTION
Demineralized water not distilled is what I meant.
I would recommend some sort of coolant...those impellors catch it rough.
Distilled water is my flush, definitely not my everyday.
So I take it you have the bike in question,and have put the miles on it I have in the past few years.
My comments are based on experience with this exact bike. Yours are .........
Antifreeze lowers the boiling point of the coolant itself. Antifreeze does exactly as the name implies and surprisingly enough it doesn't dissipate heat as fast as water does.
CORRECTION
Demineralized water not distilled is what I meant.
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My "opinion" is based on the fact that I have separate certifications saying I'm a Honda and Yamaha service tech.
Being a Harley doesn't make your bike a mechanical wonder immune to the effects of poor lubrication for the impeller...nor the chemical reactions that occur when only water is used.
It's your bike, do what you will. Time will prove me right however.
Water wetter and distilled water does produce the lowest temps. But if your bike has a thermostat it negates in benefit of more effienct cooling by keeping the bike at the same temperature no matter what.
Now, if that's a histrung racing app with a stock cooling system struggling to maintain balance, then yes...it can help.
Being a Harley doesn't make your bike a mechanical wonder immune to the effects of poor lubrication for the impeller...nor the chemical reactions that occur when only water is used.
It's your bike, do what you will. Time will prove me right however.
Water wetter and distilled water does produce the lowest temps. But if your bike has a thermostat it negates in benefit of more effienct cooling by keeping the bike at the same temperature no matter what.
Now, if that's a histrung racing app with a stock cooling system struggling to maintain balance, then yes...it can help.
Originally Posted By: Clevy
Bls. Have you actually ridden the bike in question. If you had you would know that the shifting gets very notchy as the oil shears and by starting with a 30 grade,not weight,you are effectively shortening the oil change interval because once the 30 grade even shears slightly the bike will be a serious pain to shift and ride quality will degrade to the point of not even wanting to ride.
Op. busy here seems to have a good back story however his advice til now has been questionable for the most part and incorrect for the rest.
Trust me when I recommend rotella conventional 15w-40. The syn rotella shears to fast and shift quality degrades so you can't extend the interval to achieve any return on the extra cost buying it.
I've used Amsoil in both the yellow cap powersports version and the 4t flavour. They didn't last as long as rotella did in service and cost double or more. I used M1 4t 10w-40 and the Amsoil lasted longer before shifting was affected. It wasn't even 1500km before the Mobil told me it was time to go.
I used motul in it once in the 15w-50 4t. It was awesome. It lasted over 4000kms in service and was the longest lasting oil I used in that bike but cost vs rotella just didn't add up.
Rotella goes over 3000km in my bike before shifting gets notchy at 10 bucks per oil change or motul at 4000kms at 80 bucks per oil change.
See my point. Synthetic oils are great in a racing situation but in my bike he oil shears to the point of loss of proper shift function long before the oil is even close to being used up,so for that reason I use conventional rotella.
I can drain rotella due to shear at 3000kms or I can dump m1 at 1/3 or that due to shear or I can dump Amsoil at 2/3 of that due to shear.
See where I'm going with this.
I agree it's shift quality that determines how light an oil you can run and for how long. In other words run the lightest oil that still allows reasonably smooth shifting when the oil gets hot for the oil change interval your okay with.
I'd still suggest trying Rotella 5W-40 or even some Rotella 10W-30 which is so much lighter on start-up to a 15W-40.
The lighter oil may work for you without your shifting becoming notchy. If not it's a simple maTTER TO DUMP THE OIL
Bls. Have you actually ridden the bike in question. If you had you would know that the shifting gets very notchy as the oil shears and by starting with a 30 grade,not weight,you are effectively shortening the oil change interval because once the 30 grade even shears slightly the bike will be a serious pain to shift and ride quality will degrade to the point of not even wanting to ride.
Op. busy here seems to have a good back story however his advice til now has been questionable for the most part and incorrect for the rest.
Trust me when I recommend rotella conventional 15w-40. The syn rotella shears to fast and shift quality degrades so you can't extend the interval to achieve any return on the extra cost buying it.
I've used Amsoil in both the yellow cap powersports version and the 4t flavour. They didn't last as long as rotella did in service and cost double or more. I used M1 4t 10w-40 and the Amsoil lasted longer before shifting was affected. It wasn't even 1500km before the Mobil told me it was time to go.
I used motul in it once in the 15w-50 4t. It was awesome. It lasted over 4000kms in service and was the longest lasting oil I used in that bike but cost vs rotella just didn't add up.
Rotella goes over 3000km in my bike before shifting gets notchy at 10 bucks per oil change or motul at 4000kms at 80 bucks per oil change.
See my point. Synthetic oils are great in a racing situation but in my bike he oil shears to the point of loss of proper shift function long before the oil is even close to being used up,so for that reason I use conventional rotella.
I can drain rotella due to shear at 3000kms or I can dump m1 at 1/3 or that due to shear or I can dump Amsoil at 2/3 of that due to shear.
See where I'm going with this.
I agree it's shift quality that determines how light an oil you can run and for how long. In other words run the lightest oil that still allows reasonably smooth shifting when the oil gets hot for the oil change interval your okay with.
I'd still suggest trying Rotella 5W-40 or even some Rotella 10W-30 which is so much lighter on start-up to a 15W-40.
The lighter oil may work for you without your shifting becoming notchy. If not it's a simple maTTER TO DUMP THE OIL
Originally Posted By: Clevy
Bls. Have you actually ridden the bike in question.
Certainly and the shifting did not degrade as miles were covered... Mercy Clev don't fear
the shear... sheared oil just means you're getting more flow and flow is lubrication not
pressure...
Quote 540 RAT Member SAE (Society of Automotive Engineers)
"Thinner oil also flows more at normal operating temperatures. And
oil FLOW is lubrication, but oil pressure is NOT lubrication. Oil
pressure is only a measurement of resistance to flow. Running thicker
oil just to up the oil pressure is the wrong thing to do, because that
only reduces oil flow/lubrication. Oil pressure in and of itself, is
NOT what we are after."
Quote Dr.Haas
"It is time to introduce the concept of lubrication. Most believe that
pressure = lubrication. This is false. Flow = lubrication. If pressure
was the thing that somehow lubricated your engine then we would all be
using 90 weight oil. Lubrication is used to separate moving parts, to
keep them from touching. There is a one to one relationship between
flow and separation. If you double the flow you will double the
separation pressure in a bearing. The pressure at the bearing entrance
is irrelevant."
"In fact the relationship between pressure and flow is in opposition.
If you change your oil to a thicker formula the pressure will go up.
It goes up because the resistance to flow is greater and in fact the
flow must go down in order for the pressure to go up. They are
inversely related. Conversely if you choose a thinner oil then the
pressure will go down. This can only occur if the flow has increased."
Bls. Have you actually ridden the bike in question.
Certainly and the shifting did not degrade as miles were covered... Mercy Clev don't fear
the shear... sheared oil just means you're getting more flow and flow is lubrication not
pressure...
Quote 540 RAT Member SAE (Society of Automotive Engineers)
"Thinner oil also flows more at normal operating temperatures. And
oil FLOW is lubrication, but oil pressure is NOT lubrication. Oil
pressure is only a measurement of resistance to flow. Running thicker
oil just to up the oil pressure is the wrong thing to do, because that
only reduces oil flow/lubrication. Oil pressure in and of itself, is
NOT what we are after."
Quote Dr.Haas
"It is time to introduce the concept of lubrication. Most believe that
pressure = lubrication. This is false. Flow = lubrication. If pressure
was the thing that somehow lubricated your engine then we would all be
using 90 weight oil. Lubrication is used to separate moving parts, to
keep them from touching. There is a one to one relationship between
flow and separation. If you double the flow you will double the
separation pressure in a bearing. The pressure at the bearing entrance
is irrelevant."
"In fact the relationship between pressure and flow is in opposition.
If you change your oil to a thicker formula the pressure will go up.
It goes up because the resistance to flow is greater and in fact the
flow must go down in order for the pressure to go up. They are
inversely related. Conversely if you choose a thinner oil then the
pressure will go down. This can only occur if the flow has increased."
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