[Jeroen]

Originally Posted by ashwinprakas

Unfortunately not the case with motorcycle engines from my observation.

The Gerotor Pump is the first part to give up, I've seen them going bad on motorcycles with odo figures as low as 30k.

I do not know the exact reason why but my assumption is that extending drain intervals affect the clearance and reduces the efficiency of the pump, which goes unnoticed till the motor seizes.

I believe its extended drain intervals as I've to date not seen this happen on an engine with clean internals.

But that is not the case from experience, my understanding is that as the clearance increases, the efficiency goes down until the pump cannot maintain pressure at all.

yes, the mileage/intervals I quoted are for cars, not bikes. Bikes tend to have much lower intervals. That’s what this thread is all about.

I don’t have much experience with bikes, having only owned a 1974 RE Bullet during my Indian years. But most oil pumps on any engine tend to be of the positive displacement type. Be it a gear or otherwise. Those pump tend to deliver a given volume of oil per rotation. In combination with how the oil system is designed, clearances etc that will give a certain oil pressure. When the pump wears, it becomes less efficient. Initially that means less volume per rotation, but at some point it will also not be able to maintain pressure.

I really can’t comment on whether a worn pump is the most likely cause for wear on an engine bike.


Extending drain intervals beyond the manufacturing recommended ones is subject to what I wrote in my earlier post. The difference between car and bike engines being that bike engines, from my little experience seem to subject to more wear and tear compared to car engines (given similar usage and mileage)

So you want to be a bit more cautious. But I would think the same principle applies; mileage is more important than time period.

Short trips mean more wear, water condensing into the oil AND oil dilution caused by fuel contamination:

Whereas the above is certainly true, my main objection is again the lack of measurement. So how real is it? How much noticeable damage does it cause? Probably very little, but again another reason not to idle your engine but drive away and gradually get the engine to warm up in a few minutes.

The amount of water a cubic meter of air can contain under normal atmospheric conditions is minute. Your engine has just a few liters of air in it, so it is not as if one cold start is going to cause a problem.

The fuel problem whilst running rich is correct in theory. But if you have a well maintained engine how much fuel would you think ends up in the oil?

So again, endless video’s on this topics, all very theoretical and very generic. Would be more useful if somebody would actually take some measures. My guess is that on normal maintained cars, water and fuel contamination is really a non issue. Has anybody come across a video of anybody measuring this phenomena?

And again, there is likely to be a tiny amount of water/fuel in your oil. But that is one of the reason you change the oil!!

Jeroen

[mvadg]

Originally Posted by ashwinprakas

.

Originally Posted by ArizonaJim

The engineers who designed the engine know which oils to use in their engines and they know how long it will last before it needs to be changed. They are not in cahoots with the big oil companies trying to make money for them. They want their engines to work well for a long period of time so the customers will remain happy so, they tell owners how often to change the oil and filter. The least we can do is to follow their recommendations.

Originally Posted by srini1785

So whats the point of this thread then?...

a money spinner for the Engine oil companies.

Sorry, the "quote" mechanism on this site seems buggy. I had "quoted" you too above. If you (and almost everyone else) watch the above (and other) videos and read up on lubricating oils (I was lazy, so I just watched the videos) - there are too many factors. When I started reading this thread, I too assumed that with modern oils we could drag our oil change intervals, but after educating myself, reading all the posts here, I intend running to the nearest FNG with the recommended engine oil (and filter as required) to get my scooter and car engine oils changed immediately!

[mvadg]

Originally Posted by Jeroen

Whereas the above is certainly true, my main objection is again the lack of measurement. So how real is it? How much noticeable damage does it cause? Probably very little, but again another reason not to idle your engine but drive away and gradually get the engine to warm up in a few minutes.

The amount of water a cubic meter of air can contain under normal atmospheric conditions is minute. Your engine has just a few liters of air in it, so it is not as if one cold start is going to cause a problem.

The fuel problem whilst running rich is correct in theory. But if you have a well maintained engine how much fuel would you think ends up in the oil?

Jeroen

Thanks Jeroen, for your inputs. Much of what you have stated applies to "normal" wear and tear, which is generally running the engine for an extended period of time under optimum conditions. I have experienced the water contamination on my motorbike quite spectacularly. This was a 400 cc bike that was mostly used within the city for extremely short trips of less than 5 KMs for months together. I decided to undertake a highway trip on a weekend, checked tyre pressures and the oil level on the glass window and off I went. After riding for an hour or so, I decided to take a break and stopped my bike. Out of curiosity, I took a look at the oil level - it had fallen to the lowest permissible level! For whatever reason, I had read up on taking long highway trips on motorcycles and had been warned to carry engine oil! I had to empty the whole can (approx 1 litre) into the bike to bring it back to normal.

Especially on a scooter, in India, we tend to take short trips - many less than 2 KMs, so I suspect this would fall under "severe" service. Again, humidity is quite high in most regions here. Frequent starts are a norm, meaning more fuel contamination. Also, small scooter engines are considered disposable in developed countries (I assume these scooters were designed for such markets initially) and lack many useful and engine wear conserving features (mine does not even have an oil filter or a centrifugal separator!), so all the more reason for us to be conservative!

[Jeroen]

Originally Posted by mvadg

TI have experienced the water contamination on my motorbike quite spectacularly.

I took a look at the oil level - it had fallen to the lowest permissible level! !

Thanks for sharing your experience. Not sure how this was a water contamination experience though? Sounds like a low oil level experience to me?

Oil consumption tends to be very predicatable or rather consistent on any engine as long as you keep using it in a similar fashion. So if your car or bike uses x amount of oil over y kilometers that tends to stay the same within reasonable time and mileage constraints. If all of a sudden your engine appears to be using a lot more oil than before, whilst your driving is similar as before, it could be an indication something is amiss.

Lots of short trips never do any engine any good. To what the actual wear is noticeable differs, but I am pretty sure on bikes it will be easier/earlier.

Mixing two different oils can have remarkable effects on oil usage as well. If you’re low on oil and far away you might not have much choice. But it is preferable to top up with identical oil. Not just specification, but identical in brand/type.

Although in theory two identical spec-ed oils should mix, I have had several odd experiences with them. Leading to almost immediately increased oil consumption. Particular some valve seals on the Alfa are prone to this effect.

Not quite sure what causes it.

Jeroen

[mvadg]

Originally Posted by Jeroen

Thanks for sharing your experience. Not sure how this was a water contamination experience though? Sounds like a low oil level experience to me?

The oil level was at the 'high' mark when I started the long trip. Short trips within the city meant that the bike never reached very high temperatures (normal operating temperatures?). When I rode it for over an hour, the accumulated water / fuel evaporated due to the engine reaching high temperatures, leaving behind only oil. Since there was no oil leak, I assume this was the reason.

[Jeroen]

Originally Posted by mvadg

The oil level was at the 'high' mark when I started the long trip. Short trips within the city meant that the bike never reached very high temperatures (normal operating temperatures?). When I rode it for over an hour, the accumulated water / fuel evaporated due to the engine reaching high temperatures, leaving behind only oil. Since there was no oil leak, I assume this was the reason.

I doubt that very very much.

Once water is in the oil, it hardly gets out, it mixes. No amount of temperature is going to get water out of oil once mixed. But as I said before, the amount of water that can be trapped in air is absolutely minute. Whereas some fuel components might evaporate, again the amount of fuel you would find in lub oil, if the engine has been working normally is minute. So neither water or fuel is likely to have caused this

This is just a case of a lot of oil consumption in a relative short space. You were probably driving at higher speeds and therefor considerable higher RPMs than your regular city driving? Maybe some hills too?

Jeroen

[mvadg]

Originally Posted by Jeroen

This is just a case of a lot of oil consumption in a relative short space. You were probably driving at higher speeds and therefor considerable higher RPMs than your regular city driving? Maybe some hills too?

Jeroen

Hmm. Never occurred to me! Yes, full throttle, much of the time, no hills though! And about the moisture levels, you are right again - Arizona is dry, very dry. (As an aside, the trip was from Phoenix to Tuscon, I found the scenery so boring, I actually turned back and went home - never completed that trip to Tuscon by motorcycle ). I guess you've solved this puzzle! Thanks.

[rakesh_r]

Originally Posted by Kosfactor

Is there Semi-Synthetic written verbatim on the user manual alongside an API spec?

Yes Sir, there is, attached a screen shot of the recommendation as mentioned in the Owner's Manual of the BS4 Himalayan.

[Kosfactor]

Originally Posted by rakesh_r

Yes Sir, there is, attached a screen shot of the recommendation as mentioned in the Owner's Manual of the BS4 Himalayan.

My curiosity was based on a report that API itself bailed out on the Synthetic Vs Semi Synthetic Vs Mineral marketing fist fight, so where did RE get a standard that API does not have. Most likely a error in printing.

The manual now looks like this on Page 5 & 8.





You will definitely get the right oil going by the correct API grade, just that the Semi-Synthetic confusion is now over!

[mvadg]

Originally Posted by mvadg

Hmm. Never occurred to me! Yes, full throttle, much of the time, no hills though!..

Actually, I did some reading on this - engine was hot and the oil had been pumped into the engine parts and the sump obviously had less oil. The correct procedure would be to allow the oil time to drain back into the sump and then check. This was the condition before I started trip, when the window showed "high normal". When hot it showed "low normal". So, this topping up with engine oil without using the correct procedure to check the level was a BIG MISTAKE!

[ashwinprakas]

Originally Posted by srini1785

Let me give you my theory : Only the 100 - 200cc mass market motorcycle segment have such recommendation of short oil change intervals as its a money spinner for the Engine oil companies.

Not true.

Oil change interval is determined by;

1. Application
2. Sump Size

You need to consider that lower displacement engines when out on the highway are practically operated at over 80% of their output which literally is competition use i.e when oil is required to be changed after fixed hours of use in contrast to fixed km's.

Next thing to take into account is that most commuters are air cooled, and more than heat what needs to be taken into account is that an air cooled motorcycle is tuned to run Richer than a liquid cooled motorcycle i.e more blow-by contamination. Which is another reason they're referred to as Dirty Engines, cause they consume more fuel and require more frequent oil changes.

Now having considered application we come to the understanding that from use alone the oil is worn down by;

1. Sheer from metal to metal operation.
2. Suspended Friction material from the Wet Clutch.
3. Contamination from Combustion Blow By.

Next in line comes the sump size of about just 1 Liter.

In the earlier days the change interval was around 1500~2000 km's per liter sump size, which served everyone well but in the recent years manufacturers have advertised longer intervals with some recommending up to 5~10k km's interval on the same old 1L sump air cooled engine. Then there are also oil companies that advertise so well that the typical Indian has come to believe that a 1000/- oil changed every 5~6k km's does more good than a 200/- oil changed every 1.5~2k km's.

So simply put we in effect are extending our drain intervals by default without knowing it, either by following latest manufacturer recommendations or by our own ignorance.

Now this is not a conspiracy claim, I've seen the difference first hand with respect to visible gunk on internals and crap caught by the centrifugal filter and gerotor pump strainer on identical motorcycles as mine that were running on Synthetic oils for just double my drain interval i.e 3k km's compared to 1.5k km's on mine running on cheap Diesel oils, manufacturer recommends 5k drain intervals.

Here are a few snaps with my clutch cover off for the very first time since purchase, odo was at around 50k km's;





This was taken after I burnt my clutch clean off during an interstate run when I rode up a rocky trail with a pillion onboard () and then rode 600~700km's back home and then did a week or two of errand runs before sourcing the clutch and replacing it.

In short, maximum possible contamination, yet you can see that the centrifugal filter isn't packed with crap even at 50k on the odo and the gerotor pump's strainer isn't gunked up as well. In the background you can even see the the inside of the clutch cover which doesn't have a tinge of discoloration.

Now compare it with the insides of the same model of motorcycle i.e Bajaj Pulsar P220 with less overall mileage than mine but that was serviced at the ASC as per manufacturer recommended drain intervals i.e 5k km's:



As expected the gerotor pump wasn't pumping well on cold starts and had to be changed.

Compared to this the clutch cover on my P220 that was run on cheap Diesel oil changed at 1.5~2k drain intervals is clean enough to eat rice and dal on.

Hope that clears things up.
A.P.

[Jeroen]

Many diesel oils are equivalent or even superior to motor cycle oils I believe. Like specific motor cycle oil they don’t contain friction modifiers. Which would cause serious problems for your clutch.

I have seen/heard a lot of bike guys shifting to full synthetic diesel oil, which seems to be working very well with them, with substantial longer drain intervals.

Bikers, compared to car owners, have the advantage of picking their engines apart much more and much more easily. So you can get a better feel, even take measurements of one oil over the next.

Gunk is one thing, colour another. I would not judge the effectiveness of a lub oil by how clean the components remain.

Originally Posted by ashwinprakas

As expected the gerotor pump wasn't pumping well on cold starts and had to be changed.

What causes the problem on cold start? how did you notice/measure. Usually positive displacement pumps when worn do better with cold oil than warm oil. Just very noisy, but that in itself does not have to be a problem

Jeroen

[ashwinprakas]

Originally Posted by Jeroen

What causes the problem on cold start? how did you notice/measure. Usually positive displacement pumps when worn do better with cold oil than warm oil. Just very noisy, but that in itself does not have to be a problem

Stating the obvious, these are vertical engines with oil bathed valve trains and when set to rest for extended periods the oil does drain back into the sump through the timing chain well.



So when Starting after a long break the gerotor pump that sits at the base of the crankcase with its mouth feeding immediately above the bottom of the case has to ensure that the valve train is bathed in oil, else you'd get audible distinct clatter that cannot be mistaken for anything else, it is similar to the sewing machine sound you get when you have way too much valve lash, only difference being the sound goes away after a few seconds of idling.

This can be confirmed by removing the exhaust side tappet inspection cover/cap which most of the older motorcycles have in contrast to removing the complete head cover. With the cap off, on a motorcycle with a perfectly working pump as soon as the motor fires up you can see oil splashing out of the inspection window, but with motorcycles where the pump isn't working right you can see that as long as the clatter is audible the tappet would be running dry and only when the head is flooded would the noise subside and the oil would start to splash out of the inspection window.

Over the years I've seen this failure on different models and makes of motorcycles with the same symptom and the only common factor is the visible gunk cause I've owned the same motorcycles and have personally never faced a pump failure to date in spite of clocking decent figures on the odo, though with remarkably cleaner internals.

Hence my association to visible gunk on internals, though in the ZMA I've taken the old pump apart and have not noticed any visual differences to a brand new replacement, maybe the difference is not obvious to the naked eye, I'm not sure, but now I really don't bother to investigate, if at all anyone comes to me with the same concern we directly go ahead and replace the oil pump and that gets the job done.

[Jeroen]

Originally Posted by ashwinprakas

Over the years I've seen this failure on different models and makes of motorcycles with the same symptom and the only common factor is the visible gunk cause I've owned the same motorcycles and have personally never faced a pump failure to date in spite of clocking decent figures on the odo, though with remarkably cleaner internals.

Hence my association to visible gunk on internals, though in the ZMA I've taken the old pump apart and have not noticed any visual differences to a brand new replacement, maybe the difference is not obvious to the naked eye, I'm not sure, but now I really don't bother to investigate, if at all anyone comes to me with the same concern we directly go ahead and replace the oil pump and that gets the job done.

It is really no difference to how oil pumps work on car engines. Problem with many modern cars is, it might take quite a bit of spannering to get the valve cover of so you can check the oil across the valve train.

I have come across the odd problem with oil pumps. As I said, just wear is usually no problem at all. They tend to be over dimensioned any way. Even if takes a few seconds longer to build up pressure and visible oil shows, that does not have to be a problem either. As long as you get the correct pressure it is fine. Measuring oil pressure can be a problem for some workshops. They often just rely on the oil pressure light dimming. (That is if you have one of those of course, )

Would be interesting to see what the oil pressure reads on these pumps. New versus suspected ones. Cold versus warm oil.

The most common problems I have seen with car oil pumps tend to be the drive mechanism. If that gets buggered the pump stops working all together in most cases.

Not sure what the gunk has to do with replacing the pump, or do I misread that part?

Jeroen

[ashwinprakas]

Originally Posted by Jeroen

Measuring oil pressure can be a problem for some workshops. They often just rely on the oil pressure light dimming. (That is if you have one of those of course, )

Same is the case here, in cars the Oil Gauge has been eliminated a long time ago and on motorcycles they weren't really present to begin with.

Very few motorcycles like my P220 rely on oil pressure switches to notify the rider of low oil pressure but they seldom work as intended, mine lights up when it rains heavily.

So the only means to detect insufficient flow is to listen for valve train clatter and confirm by opening the tappet inspection window. Which is quite easy on motorcycles, here's a snap of the cover off on my ZMA;



This is the intake valve, the exhaust valve cover can be taken off without even removing the tank, in fact since the below cavity would be bathed in oil, merely unscrewing the cap would cause oil to drip out indicating flow.



A perfectly running pump means there'd never be clatter even after a month of the motorcycle sitting idle, but with a pump which is on its way out there'd be noise on every cold start, though it might be okay to ignore them on some engines, the same isn't recommended on these motorcycles engines as running the camshaft dry for even a short while can cause serious damage, especially on models that still come with flat tappets.

Now even though the said clatter is distinct most owners simply fail to notice or basically ignore it as a result the engine fails, quoting below an update from another forum that was posted yesterday;

So I took it to mechanic and he says the engine needs work , it ran dry ( without engine oil)
Am not sure how engine ran dry because in last service the oil that was drained was of right amount and I also didn't see any oil leakage at my parking .
Waiting to get the hike towed from Noida to Delhi now

So an update the engine has oil just fine but oil pump failed due to which oil didn't reach the upper part of engine.
Mechanic says that there should have been a different sound from engine but I couldn't make out any change in engine sound .
Anyway have to get the engine rebuilt.
Thanks for the support

Source

Might seem coincidental but this is quite the norm here, people simply fail to notice, plus rarely do anyone bother to keep a motorcycle past the warranty mileage which I believe is the reason for a lackluster interest in motorcycle maintenance.

The most common problems I have seen with car oil pumps tend to be the drive mechanism. If that gets buggered the pump stops working all together in most cases.

Not knowledgeable about car's but on motorcycles the pump is driven by the clutch basket which is driven by the primary gear which is fixed on the crankshaft.

Unless there is a mechanical failure with the pump it wouldn't stop rotating as its connected by hard parts, but the case with oil flow is dependent on clearance of the inner rotor with the outer rotor, which I suspect is being affected by extending drain intervals.

After all since the inner rotor is fixed on the driven gear and the outer rotor rotates inside the well their positions remain fixed even though with respect to each out the surface clearance can change with wear. I hope I'm saying it right.

Basically the apexes of the inner rotor fails to maintain a perfect seal with the outer rotor resulting is oil not being pulled in adequately into the entry chamber as well as not being adequately pushed into the oil galleries as it possibly flows out of the exit chamber due to galleries offering more resistance by virtue of their narrow sizes which aids in increasing oil pressure so that oil quickly flows to all critical parts.

Once again, I have not measured or tested anything, and coming from a non-engineering/science background lack theoretical knowledge, hence this is just my understanding of how the system works from basic reading, common know-hows and amateur wrenching experience. So do feel free to correct me if I've missed anything.

Not sure what the gunk has to do with replacing the pump, or do I misread that part?

I was using the gunk as a relative indicator of poor maintenance or rather extended consumable change intervals, Apologies if I didn't articulate that well enough.

Regards,
A.P.