Dear all, have just changed the engines oil, (with Penright 20W60 Diesel, which I have used before, several times) replaced the oil filter with a Ryco Z418 (first time!, have always used HiFlo or OEM filters.) Replaced the gear box oil and FD oil, and lubed the rear end of the spline. Fitted two new tyres. Got the old girl going eventually and went for a jolly around the block to see if everything worked.

Started OK. but soon after, at idle or a bit above, a "knocking" type noise started emanating from the bowels under the tank. It was irregular, and it doesn't sound like a big end on its way out (Wishful thinking??). Also, whilst straddling it, I can feel fairly substantial puffs of air, at random intervals, against my left leg, through the slats of the lower fairing cover (its an LT, still with full fairing)

I'm programmed to go for a ride this coming weekend, and am in a bit of a sweat about it. The thing seems to go OK, but I'd like to get to the bottom of this. Would it be the Ryco oil filter? Throttle body rubbers? Failing engine?

Any suggestions will be GREATLY appreciated.

Rickmeister.

Funny noise and you aren't laughing?  
The oil filter would not have anything to do with it.
Remove the lower inner part of the fairing and see if you can narrow it down as to where is coming from.  Hold a piece of white paper in front of the air stream and see if anything collects on it, stick your nose down there and smell it.
Does it go away when you open the throttle and bring the revs up to 3000?  Does the engine sound like it has a rough idle?
Does the Prime Minister tell lies.  Sorry Unnecessary question there.  How much money have you got. Can I fix your bike

PS Check the breather tube from the crankcase to the airbox, it's right down there near your left ankle behind and a bit above the coils and at idle could quite easily be puffing air.

wonder if its a ignition lead combined with a rubber that has now busted .....the induction system often blows back a little uli ..and I wonder if by chance you have a broken induction rubber (maybe even injector seal ?) which is blowing out of the induction system  as a periodic and cyclic type thing ....happens as it leans off then catches up ...this in itself shakes the bejesus out of the crank cycle and makes all those nice sewing machine noises in to farts and clunks
or you have a fluffy ignition lead that misfires every now and then  ...

don't know what happens when a plug over the vacuum adjuster points fly off ..... could this be the thing ?

just first thoughts mate ...you have checked that the breather tube from the plenum to crankcase is still sealed up ?

I guess left side lower fairing off to investigate ...(crikey you left it late to notice this weird thang ...the trip is just days away ol mate )


good luck .....im sure others will be along soon to join in

Thanx! I replaced the breather hose ("S" shaped, more or less) between the crankcase and the air box about 12 months ago. Will grapple with the lower LHS fairing tomorow and have a bo-peep.

Hmmm the noise isn't the oil filter tool left on the oil filter? with the different filter it could be rattling this time. 

Why use a high flow filter when the oil that you use is so thick that it will take many revolutions after a start before it fills the oil system and will flow very slowly. Your 20W60 oil will probably take 5 times longer to circulate than my 5W40 does. The K engine does not suffer by having 5W40 in it but with a 20W60 the wear on each start up will be huge.
The reason a doctor will treat high blood pressure is the strain on the pump (heart) but the blood does not drain into the sump when at rest.

Re: Oil...I've used the 20W60 for lots of miles now with no adverse effects (to my knowledge). What you say makes sense.  I think that the manual suggests, for our ambient temperatures here in Aus, that the 20W60 is the correct "weight".

Anyway, be that is it may, I followed the Aus guru's (Charlie and Rick) suggestion and lo' and behold, a small hose (wrapped in a steel coil) at the rear of the fuel rail thing, but on the head, had come off. Re-attached, albeit v.loose, wrapped a small cable tie to hold it into place, kicked it in the slats and it seemed to idle OK, with no hilarious noises.

I'm v.negative about these sorts of things, and always think the worse. Much, much more often than not it turns out something simple. C'est la vie!!

Thanks all for the prompt replies.

Rickmeister.

Have a look and see what BMW really recommend, this is taken directly from the rider manual

Rick , that hose on my old RT used to dislodge itself quite frequently , never with the same effect as you have suggested , but good to see you have found the culprit.
I'm inclined to use the 20-50 for the broader temp range. I'm only a short distance from Rick, and as is with a lot of eastern Oz members , our bikes are operating year round in daytime conditions ranging from 10 - 35 degrees.

RicK G wrote:

Have a look and see what BMW really recommend, this is taken directly from the rider manual

Yes Rick the perfect starting point. What that does not take into account is modern oils produced after that manual was printed.

Hope all is well Rickmiester, have you fitted that staintune yet? had it in mind to buy a flexible holden power steering hose from a vn commodore and cut it where the bendy bits were a match to our hose and use it to replace the airbox to engine hose. Will have to grab one next time I'm in Cessnock, can anyone see an issue from such a bodge? I've always used 20weight oil but would love to know what everyone else here in Oz is using, with 26 to 30 degrees in winter and 40 to 45 in summer 20 weight seems right even considering winter mornings are -4 at dawn at worst, what would you all be willing to go down to???? I know most times we dont even roll out of our swags before plus figures but it would be good to know.

Ulrich_Grabau wrote:Anyway, be that is it may, I followed the Aus guru's (Charlie and Rick) suggestion and lo' and behold, a small hose (wrapped in a steel coil) at the rear of the fuel rail thing, but on the head, had come off. Re-attached, albeit v.loose, wrapped a small cable tie to hold it into place, kicked it in the slats and it seemed to idle OK, with no hilarious noises...
Rickmeister.

The vacuum hose for the number four TB is wound with a spring coil and disappears into the bowels at the centre of the motorbike towards the fuel pressure regulator. Was it also idling poorly? That'd be your 'rattle.' If the fit is loose cut just a few mm's off the end and re-attach.

I use 15W40 diesel oil in my K100RS, and am now using it in my K1200GT (the K12's P.O. used BMW's 20W50 exclusively according to the records - in Alaska, WA & OR), and 15W50 full synthetic in my R1150RT & R100 all year round.

Man 20w60 sounds crazy.  I used 20w50 in my k100 for about 6 months, and every time I started it up I felt a little uneasy with the noise it would make for a half second.  I've always ridden classic bikes that needed the heavier stuff, so I used it out of instinct and habit.  I then realized that the tolerances in this engine are much better than 60 years ago, so moved down to 10w40.  

And wow!  

It's a clean start-up every time, AND the engine feels much much freer.  It feels as if it rotates more freely, revs more freely, runs smoother and more freely.  I'd try a lighter weight, below 20w50.

It is the 20 bit that harms engines because that is the viscosity (thickness) of the oil on start up. A 10 or a 5 will circulate much quicker. If you were to measure oil pressures then you would find that they are high with a thick oil, that puts strain on the oil pump and delays the time that the oil takes to get around the whole engine on startup. Doctors treat high blood pressure for the same reason, to save damage to the pump (heart).
If I were offered 2 five year old cars at the same price then I would choose the higher mileage. The reason is that an engines life can be measured in the number of start ups, when the oil has not circulated and is causing wear, then you get the 10 mile run after that when the oil is not quite hot enough to get rid of the water that tends to get in it. That bit causes the mayonnaise that you see in the oil system and that is not a good lubricant so causes more wear. 
I have no evidence, but I would bet that more wear happens in an engine on start up than driving 500 miles in a single trip.

I was under the impression that the 20 bit was only in freezing temperatures.  That may very well be true for you where you are, but where I am, it rarely gets below 50 deg F, so I would only be concerned with the 60 bit.  BUT, I could be totally wrong, and don't remember where or how long ago I heard that.

bikerboy wrote:

RicK G wrote:

Have a look and see what BMW really recommend, this is taken directly from the rider manual

Yes Rick the perfect starting point. What that does not take into account is modern oils produced after that manual was printed.

Viscosity remains viscosity and is still measured the same way as it was 50 years ago. The lubrication qualities may have improved a lot but that chart remains as relevant as when it was printed.

people with big $$$ classic cars and big $$$ to spend use external electric oil pumps.
the theory is to get the oil circlulating and lubricating the whole pile before starting.
in my younger years i did a lot of motorcycle engine re building.
after a rebuild, even though i assembled everything sloppy wet with oil, i would turn over the engine with no ignition until the oil light went out. then let it fire up.
i been using 20-50 in all my bikes for a kazillion yrs...

Rabidchiwawa007 wrote:I was under the impression that the 20 bit was only in freezing temperatures.  That may very well be true for you where you are, but where I am, it rarely gets below 50 deg F, so I would only be concerned with the 60 bit.  BUT, I could be totally wrong, and don't remember where or how long ago I heard that.

The 20 measurement is indeed at 0c (I don't understand f) but at 15c it is still loads thicker than a 5. A 5/40 is still thicker when cold, despite the 5, than the 40 is when at running temperature, therefore the 15/40 is like sludge on start up but the smae as the 5/40 at running temperature. A way around this would be to fit an electric oil pump that you operate before starting the engine, but that adds weight and complexity.
If you want to experiment then get some 20/50 and some 5/40 and put them into two cups. Now get a couple of bits of narrow bleed tube with one end in each cup. Put both bleed tubes in your mouth and suck. You will see that the 5/40 rises the tube much quicker than the 20/50 and so is able to lubricate all of the engine parts much quicker.

RicK G wrote:

bikerboy wrote:

RicK G wrote:

Have a look and see what BMW really recommend, this is taken directly from the rider manual

Yes Rick the perfect starting point. What that does not take into account is modern oils produced after that manual was printed.

Viscosity remains viscosity and is still measured the same way as it was 50 years ago. The lubrication qualities may have improved a lot but that chart remains as relevant as when it was printed.

Of course it does. I'll bet that chart changed from the first '1983 K100 to the last 2000 K1100 though without any changes to the lubrication system.
30 years ago the best way to keep two bits of metal in the engine apart was to use a thick enough oil. These days synthetics with long chain polymers can lubricate just as well with a 30 viscosity as the old oils did with a 50.
Here in Europe light diesel engines have been in cars since the 1960s. Diesels were hard on their oil with a compression ratio of 23 to 1. In the mid 70's a 20/50 was a standard oil for a diesel, now a 5/30 is the standard. Has the engine changed? Not normally, in the case of the 2.5 litre Citroen engine it went from a 20/50 with 3000 mile oil changes in 1975 to a 15/40 with 6000 mile oil changes in the space of 10 years. My modern Hyundai 2 litre Hyundai 140bhp diesel was built in 2006 and the handbook specified a 10/40 semi synthetic oil. Now that has changed to a 5/30 full synthetic. I never though that the day would come when a diesel was using a thin oil like that, but the long chain polymers make it hold the metal bits apart (lubrication). It will even withstand oil temperatures that are 40c higher than a mineral oil.
I am not preaching here, and you use what you want too. One thing is that in all my bikes and the aircraft, I will use the most modern oil that I can buy for a reasonable price.

I don't think it matters all that much with modern oils.  

K bikes are bulletproof.  I've never heard of one suffering from oil-related issues.

I run mine on recycled vegetable oil. The only problem with that is that the exhaust smells like french fries so I'm always hungry.

duck wrote:I don't think it matters all that much with modern oils.  

K bikes are bulletproof.  I've never heard of one suffering from oil-related issues.

I run mine on recycled vegetable oil. The only problem with that is that the exhaust smells like french fries so I'm always hungry.

You might laugh, duck, but I know of a few diesel cars in the UK that run on vegi oil and they do stink!

duck wrote:I don't think it matters all that much with modern oils.  

K bikes are bulletproof.  I've never heard of one suffering from oil-related issues.

I run mine on recycled vegetable oil. The only problem with that is that the exhaust smells like french fries so I'm always hungry.

I wonder if my dietitian would believe that 

on start up isn't everything sloppy with oil from the last run ??
maybe a small problem with a hydraulic lifter in a different engine needing to be pumped up after a long interval between runs. the early oil heads had that problem with the hydraulic upper cam chain tensioner bleeding down over night.
the 1 on the other cylinder was on the bottom so there wasn't a problem.
i believe the lighter weight oil is easier on starter and battery in colder months.