maybe you could try scamming a 1200 crank and cylinders into the rebuild, for some more cubes. could be fun.

brad

You would have to go aftermarket for the pistons. Stock 1200 units are cast and are not designed for the higher-compression "S" motor.

I think that if the bike tips over to one side, some oil is going to flood the cylinder under the piston, and some will stay trapped in the crankcase, but little or none will be sprayed on the crank bearings or the rings/valves. Haven't heard much about valve damage, I would think they would have gone pretty quick also..

It really brings a tear to my eye to think of an S on it's side like a beached whale, slowly grinding itself into toast! All those expensive alloys, all that technology! A bike designed to go 100K miles self-destructing in 45 seconds.. I would want to reach out over my broken body and hit the kill switch...



[This message has been edited by motoman (edited 07-27-2001).]

If you can't check the oil before rideing perhaps a 2 cycle bike would be better for you. BMW won't pay for a engine run dry, no should they. Best,

No, and I didn't read my owners' manuals, granted, but some pre-flight info on owning a first BMW would have been appreciated. To say "check the oil regularly" does not imply "before each ride" in my book. *Shrug*

Gee thanks Dr. Curve - that reply was so helpful. Love your spelling skills.

Just a thought, but a temp gauge or maybe even a dipstick (no offense, 'Dr' Curvo) might have prevented all this...

I agree with Motoman. BMW should have all its bikes equipped with a sensor that warns of a low oil level BEFORE the engine even starts. The sight glass on a S is hard to see, especially with the lowers in place but you simply must check the oil every time you start out on a S with under 6000 miles on it. Break in very slow and carefully and then they will use no oil later. A internal oil level sensor is the way to go.....that way if the oil is low...... a circuit could refuse to even start the engine. Best,

Well, the jury's still out on break-in techniques... Many believe a hard break-in will seat the rings faster. The manual recommends going up hills to increase engine load to accelerate ring seating. I think they all break in eventually, some faster than others.. Although I have heard that babying the bike is worse than riding it like you stole it!

I do think a sensor is a great idea. Even easier would be to greatly increase the sensitivity of the oil pressure light, so it would go on if you are 1 qt low and stay on... Maybe they can borrow some of the sensitivity of the damned fuel light!



[This message has been edited by motoman (edited 07-30-2001).]

I have had two oilheads and neither was babied during break-in. Neither ever used/uses oil. Every BMW tech I've talked to said oilheads need to be run fairly hard early on to prevent oil use. My buddy's GS was broken in easy and it uses oil still and he has 44,000 miles on it.

Hi,

The oil light is controlled by an oil pressure _switch_. It's either on or off.
A gauge with a range of values wouldn't help either, because oil pressure is not really related to oil level. You either have enough for the sump to suck oil, or, you don't, and it sucks air. I.e. you either get full pressure, or it drops to zilch in a couple seconds.

I think Jim is right in that a level switch that prevents starting with oil level could help. Of course, since these guys are susceptible to the the parking procedure changing oil level, that would have its own problems. You can't use level during running, because the level changes somewhat with rpm and a lot with lean angle. Basically, there's no easy way to prevent engine destruction in a tip-over via monitoring oil level or pressure.

Honda got it close to right with an ignition cutout below lean angle. But, if one is defective/miscalibrated, it can cause a cutout during a corner and cause its own problems. Thus Honda's recall. In general, you won't see an engineer design a safety system that will or could cause as many problems (or false fail indications) as it fixes. They'll instead error on making the basic system more robust.

In short, if any engine (cars too, they're just less susceptible to tipping over) runs on it's side or back, the bearings are going to die. No one, not even F1, has found a good way around this to my knowledge.

If it were me, I'd opt for a very conservatively acting version of what Honda does with the lean angle / ignition cutout.

Btw, the valve damage is not usually mentioned because they are drastically less dependent on oil pressure for surviving.

Another note, oil temp is a pretty indirect indicator and wouldn't have helped here. The damage due to pressure drop will happen far quicker than a temp rise could be registered in the large thermal mass of the system. In general, temperature is not a fast acting indicator.

Bearings (plainshell/babbit) don't just want a trickle of oil, but rather rely on a high pressure supply so that the piece being suspended essentially surfs on that high pressure oil film. (similar to an air bearing, in some ways) The valves and most of the valve train receive oil from the pump, but don't need much more than a trickle except at very high rpms. Just the film and oil present at time of oil pressure failure will keep the valvetrain alive for a while. The valve stems run in bronze which not only traps a fair amount of oil, but is itself 'self lubricating' to an extent, insofar as it doesn't readily gall against steel or ss (titanium is rougher, but still not bad)

blah blah blah enough typing for this kid.

Damnit, have I just agreed with Jim again?
http://www.pelicanparts.com/ultimate/smile.gif

Hi,

The oil light is controlled by an oil pressure _switch_. It's either on or off.
A gauge with a range of values wouldn't help either, because oil pressure is not really related to oil level. You either have enough for the sump to suck oil, or, you don't, and it sucks air. I.e. you either get full pressure, or it drops to zilch in a couple seconds.

I think Jim is right in that a level switch that prevents starting with oil level could help. Of course, since these guys are susceptible to the the parking procedure changing oil level, that would have its own problems. You can't use level during running, because the level changes somewhat with rpm and a lot with lean angle. Basically, there's no easy way to prevent engine destruction in a tip-over via monitoring oil level or pressure.

Honda got it close to right with an ignition cutout below lean angle. But, if one is defective/miscalibrated, it can cause a cutout during a corner and cause its own problems. Thus Honda's recall. In general, you won't see an engineer design a safety system that will or could cause as many problems (or false fail indications) as it fixes. They'll instead error on making the basic system more robust.

In short, if any engine (cars too, they're just less susceptible to tipping over) runs on it's side or back, the bearings are going to die. No one, not even F1, has found a good way around this to my knowledge.

If it were me, I'd opt for a very conservatively acting version of what Honda does with the lean angle / ignition cutout.

Btw, the valve damage is not usually mentioned because they are drastically less dependent on oil pressure for surviving.

Another note, oil temp is a pretty indirect indicator and wouldn't have helped here. The damage due to pressure drop will happen far quicker than a temp rise could be registered in the large thermal mass of the system. In general, temperature is not a fast acting indicator.

Bearings (plainshell/babbit) don't just want a trickle of oil, but rather rely on a high pressure supply so that the piece being suspended essentially surfs on that high pressure oil film. (similar to an air bearing, in some ways) The valves and most of the valve train receive oil from the pump, but don't need much more than a trickle except at very high rpms. Just the film and oil present at time of oil pressure failure will keep the valvetrain alive for a while. The valve stems run in bronze which not only traps a fair amount of oil, but is itself 'self lubricating' to an extent, insofar as it doesn't readily gall against steel or ss (titanium is rougher, but still not bad)

blah blah blah enough typing for this kid.

Damnit, have I just agreed with Jim again?
http://www.pelicanparts.com/ultimate/smile.gif

I've dropped my Honda XR250 many times with the engine running while the bike was on it's side with no ill effect...It has a *dry sump*, oil-in-frame.

MarkC

I'd like to clarify that the connecting rod and crank in the XR uses roller bearings (I believe) instead of plain shell bearings.

[This message has been edited by MarkC (edited 08-01-2001).]

Back to the strange oil usage. Mine has 20,000 miles. It will go 2k without using, then use half a quart in 150 miles. Same riding style and conditions.

Any ideas?

I check my oil level every time I'm off the bike, a rather paranoid behavior.

Raven, when do you check it? How long does it sit before you check it? Does it sit on the center stand or the side stand?

------------------
Matthew

Stepping back from the bikes to a time that I used to hot-up VW beetles (also a boxer engine), we had recently upgraded the engine capacity to 1916cc.
one night driving home rather fast through the corners we noticed the oil light come on for about 30 seconds, then it went back out.
then about a month later the engine started making lots of noise and we took it back to the place that we built the engine.
turned out all the bearings where shot and that the moment with all the oil in one side of the engine (from the g forces) was all it needed to make a small grove in the bearings. this grove widened until the valves where able to rock side to side and make all the noise.
we ended up having to do a complete re-build (inserting brass sleeves in the bearings). then we installed a PobJoy Sump (a small extender - about 1 to 2 inches tall- in place of the sump drain plug).
this sump prevented the oil totally leaving the oil pickup in fast corners and made the engine live a long and prosperous life.

maybe a sump surge protector like this would be a good idea for the R11S to help prevent loss of oil pickup??

Just an Idea

Saintly

On my wife's $1500 (used) 1992 Yamaha Seca II the oil light comes on when the oil is low. It scared the **** out of me when this first happened, we put in 1/2 quart of oil and went on. I also owned a Mercury a few years back that worked the same way.

Erric whats the word on the bike ?

------------------
In the Piney Woods
Nick

It's looking up, I spoke with my Claim Representatives' Supervisor since no one was calling me back. He heard my story and he told my Insurance Agent that things were going well with my call and he thought that I was on the up-and-up with my story and the events leading up to it.

I'll tell y'all when I get my bike back.

(Bought a 1981 CB750 to wrench on in the meantime *grin*)

For your Honda 750 needs check out www.vintagerider.com
It also has forums for BMWs and other bikes

------------------
In the Piney Woods
Nick