The heavy duty diesel oil is so cheap at Wal-mart I could change the oil weekly for the same cost as  tank of gas, so what could be a bad thing about this? It's 15W-40 btw. I have it in there currently and it doesn't appear to be causing any problems. Weather permitting, I ride 400 miles a week and most of it is highway so the engine is at 5-7k 90% of the time.

Does anyone see a downside to this?

Quote from: enrgizerbunny on January 26, 2015, 07:50:03 AM
The heavy duty diesel oil is so cheap at Wal-mart I could change the oil weekly for the same cost as  tank of gas, so what could be a bad thing about this? It's 15W-40 btw. I have it in there currently and it doesn't appear to be causing any problems. Weather permitting, I ride 400 miles a week and most of it is highway so the engine is at 5-7k 90% of the time.

Does anyone see a downside to this?

Heck, why not put new tires on every week also    Oh ya......................THERE'S NO NEED TOO!

As to my understanding, car engine oils shouldn't be used in motorcycle engines that use the same oil for engine/clutch/transmision cooling and lubrication.

Don't ask me why, I'm just saying what others have told me.

In motorcycle engines that have separate systems (like some BMWs for example), it shouldn't be (such) a problem.

Just my 2 cents.




Sent from my toilet seat using HTC FartPhone

I know alot of guys running HD diesel engine oil in their bikes. If you take a look at the certifications most HD Diesel oil is rated for JASO-MA. Meaning it meets all the requirements for motorcycle applications where the engine oil is shared with the trans & clutch.
http://www.oilspecifications.org/jaso.php
What people really like is that you can pick up Shell Rotells Full synthetic on sale for about $15/ 5qt jug. Supposed to be pretty good oil for little $

The issue with running other car specific oil (Non JASO MA) is that they usually contain friction modifiers, which doesn't make your clutch pack happy.

By all means, change it every day if you want. It wont be hurting anything except for your pocket book.


And so starts yet another Oil Thread....   

My 02 GS has gone 100k miles on Rotella T 15W-40 heavy duty truck/diesel oil.  Rotella T caries the JASO-MA rating and is suitable for motorcycles that use the same oil for engine, transmission and wet clutch.

bi-weekly can mean twice a week or every 2 weeks according to dictionary, I assume you mean every 2 weeks or approx every 800 miles which is a waste I think.  Viscosity breakdown would be complete at about 1500 miles so once a month changes for your engine/transmission application would still be frequent. 

I changed my Rotella T every 2k miles with a filter change every other oil change for the 100k miles I put on my 02.

Quote from: enrgizerbunny on January 26, 2015, 07:50:03 AM
The heavy duty diesel oil is so cheap at Wal-mart I could change the oil weekly for the same cost as  tank of gas, so what could be a bad thing about this? It's 15W-40 btw. I have it in there currently and it doesn't appear to be causing any problems. Weather permitting, I ride 400 miles a week and most of it is highway so the engine is at 5-7k 90% of the time.

Does anyone see a downside to this?

Apart from  the fact its a monumental waste of time and money........non at all 

Interesting oil note (at least to me)

When I bought my 02 GS (2 years ago) the oil was pretty dirty.  I warmed it up real good and changed the oil and filter.  I put about 100 miles on it, warmed it up good again and changed the oil and filter.  It was so clear after the second change you almost couldn't tell it had oil in it.  Now with just regular 2 to 3000 mile changes it has stayed perfectly clear.

I think it was well worth it to get all the accumulated junk out of the engine.

I use 10W40 oil on mine. It only has 13k miles on it.
I will probably shift to 15W40 around 30-50k miles.
Your bike has an oil filter. Even when using the oil filter and regular oil, your bike should need an oil change every 4 to 5000 miles (not every 1000).

A good way to spot when to change it, is when it's dark brown (usually has a lot of carbon in it).
It needs to be changed before it looks black.

If it still looks yellow, or light brown it's still good to go.

I read somewhere even at brown (4k miles), or where most people change their oil, I read that the oil is still 90% good, but just is polluted. They can remove the pollution, and re-use the oil many times over, before it becomes only good for fuel for fire.

So changing oil every 1k miles, means you have only used 2% of it's total lifetime, or something.

Color can be a deceiving metric of remaining engine oil life. When I worked in an oil/tire shop as a teenager, some vehicles (diesels especially) would turn brand new oil dark brown after running for less than a minute. Oil is engineered to suspend all kinds of tiny particulates. When judging engine oil using my raw senses I don't go by color (unless it's borderline black). I let it run over my fingers and rub it in between my thumb and forefinger. If the oil has a gritty feeling, it is loaded and needs to be replaced. The oil can be a medium-to-dark brown and not be anywhere near its capacity for suspending particulates; you can tell because it will feel smooth.

Of course, this is strictly my 2 cents.

Quote from: Leadberry on January 26, 2015, 10:34:01 PM
Color can be a deceiving metric of remaining engine oil life. When I worked in an oil/tire shop as a teenager, some vehicles (diesels especially) would turn brand new oil dark brown after running for less than a minute. Oil is engineered to suspend all kinds of tiny particulates. When judging engine oil using my raw senses I don't go by color (unless it's borderline black). I let it run over my fingers and rub it in between my thumb and forefinger. If the oil has a gritty feeling, it is loaded and needs to be replaced. The oil can be a medium-to-dark brown and not be anywhere near its capacity for suspending particulates; you can tell because it will feel smooth.

Of course, this is strictly my 2 cents.

Shouldn't suspended particulates be caught in either the oil filter or the oil pan filter? There is no reason you should be feeling anything "gritty". If you are, you've got an oil pan to pull apart and an engine to check. In my experience, "time for a change" usually means the oil is thin and doesnt feel...oily anymore.

Quote from: MeeLee on January 26, 2015, 07:57:41 PM
I use 10W40 oil on mine. It only has 13k miles on it.
I will probably shift to 15W40 around 30-50k miles.
Your bike has an oil filter. Even when using the oil filter and regular oil, your bike should need an oil change every 4 to 5000 miles (not every 1000).

A good way to spot when to change it, is when it's dark brown (usually has a lot of carbon in it).
It needs to be changed before it looks black.

If it still looks yellow, or light brown it's still good to go.

I read somewhere even at brown (4k miles), or where most people change their oil, I read that the oil is still 90% good, but just is polluted. They can remove the pollution, and re-use the oil many times over, before it becomes only good for fuel for fire.

So changing oil every 1k miles, means you have only used 2% of it's total lifetime, or something.

Afaik, oil color doesnt tell you anything about the condition of the oil. Just the condition of your filtering system. The viscosity of the oil you pull is what tells you how worn your oil is. Considering the history of the GS engine eating oil, I would change my oil every 3,500 miles just because the GS engine burns it, eats it, and otherwise thrashes good engine oil. It gets worse with age. What you said might be true for newer more modern engines, or older engines that weren't developed by the Suzuki budget-bike division. I definitely wouldn't wait until 5k miles to change my oil on this bike, or any bike that uses a wet clutch.

The oil filter only filters out metal shavings.
It doesn't filter carbon in the oil due to back pressure of the exhaust gasses creeping by the piston rings.

There's lots of oil info to be found online, like in the attachments.

Thicker oil (15W40, 15W50) usually looks darker than thinner oil.

I think Diesel doesn't apply for a GS...

[attachment deleted by admin]

Quote from: Dr.McNinja on January 27, 2015, 12:39:31 AM

Quote from: Leadberry on January 26, 2015, 10:34:01 PM
Color can be a deceiving metric of remaining engine oil life. When I worked in an oil/tire shop as a teenager, some vehicles (diesels especially) would turn brand new oil dark brown after running for less than a minute. Oil is engineered to suspend all kinds of tiny particulates. When judging engine oil using my raw senses I don't go by color (unless it's borderline black). I let it run over my fingers and rub it in between my thumb and forefinger. If the oil has a gritty feeling, it is loaded and needs to be replaced. The oil can be a medium-to-dark brown and not be anywhere near its capacity for suspending particulates; you can tell because it will feel smooth.

Of course, this is strictly my 2 cents.

Shouldn't suspended particulates be caught in either the oil filter or the oil pan filter? There is no reason you should be feeling anything "gritty". If you are, you've got an oil pan to pull apart and an engine to check. In my experience, "time for a change" usually means the oil is thin and doesnt feel...oily anymore.

Quote from: MeeLee on January 26, 2015, 07:57:41 PM
I use 10W40 oil on mine. It only has 13k miles on it.
I will probably shift to 15W40 around 30-50k miles.
Your bike has an oil filter. Even when using the oil filter and regular oil, your bike should need an oil change every 4 to 5000 miles (not every 1000).

A good way to spot when to change it, is when it's dark brown (usually has a lot of carbon in it).
It needs to be changed before it looks black.

If it still looks yellow, or light brown it's still good to go.

I read somewhere even at brown (4k miles), or where most people change their oil, I read that the oil is still 90% good, but just is polluted. They can remove the pollution, and re-use the oil many times over, before it becomes only good for fuel for fire.

So changing oil every 1k miles, means you have only used 2% of it's total lifetime, or something.

Afaik, oil color doesnt tell you anything about the condition of the oil. Just the condition of your filtering system. The viscosity of the oil you pull is what tells you how worn your oil is. Considering the history of the GS engine eating oil, I would change my oil every 3,500 miles just because the GS engine burns it, eats it, and otherwise thrashes good engine oil. It gets worse with age. What you said might be true for newer more modern engines, or older engines that weren't developed by the Suzuki budget-bike division. I definitely wouldn't wait until 5k miles to change my oil on this bike, or any bike that uses a wet clutch.

As MeeLee said, oil filters are engineered to filter particulates over a certain size. There is plenty of crud generated in an engine that is too small to be caught by filters; engine oil is designed to suspend this stuff and keep it from depositing everywhere. The more loaded your oil becomes with particulates, the darker it gets.

It makes sense then that color is an indicator of oil condition, not necessarily of oil filter condition. While color isn't the final word in determining oil life, engine oil can only suspend so much junk effectively. Once the oil becomes loaded, if you don't change it out, you start to get sludge (it would reach an opaque black well before this point).

Note: Perhaps gritty wasn't the right word, but there is certainly a friction in loaded oil that can be felt when rubbed between the fingers.

Yep! .. old diesel oil feels. ... slightly like really thin wet corn starch? Kinda thing.... or slightly fatty maybe?

Quote from: Shepa on January 26, 2015, 09:25:18 AM
As to my understanding, car engine oils shouldn't be used in motorcycle engines that use the same oil for engine/clutch/transmision cooling and lubrication.

Don't ask me why, I'm just saying what others have told me.

In motorcycle engines that have separate systems (like some BMWs for example), it shouldn't be (such) a problem.

Just my 2 cents.




Sent from my toilet seat using HTC FartPhone

you, and your sources are mistaken. it will be fine.

Quote from: enrgizerbunny on January 26, 2015, 07:50:03 AM
The heavy duty diesel oil is so cheap at Wal-mart I could change the oil weekly for the same cost as  tank of gas, so what could be a bad thing about this? It's 15W-40 btw. I have it in there currently and it doesn't appear to be causing any problems. Weather permitting, I ride 400 miles a week and most of it is highway so the engine is at 5-7k 90% of the time.

Does anyone see a downside to this?

it won't cause any problems.

you might wear out the threads for the drain plug if you're not careful. that's a LOT of action for something that really only needs to happen 30 times per 100,000 miles traveled.