car377@drutx.UUCP (RogersCA) (09/11/86)
My recently purchased (used) 1982 Yamaha XJ1100J Maxim
does a disturbing thing: When I accelerate VERY hard
(warp factor 8) for more than a few seconds (RPM = 4500 to
8000 through 1st and 2nd gears, 0-50 mph) the WARNING light
begins flashing and the LCD display says "OIL", implying,
I suppose, that the engine is experiencing oil starvation
(the engine oil level is correct with the engine turned off). If
I maintain constant velocity (i.e., stop accelerating, but hold
constant throttle position) the light seems to stay on
indefinitely, and it goes off only if I drop RPMs back down to idle.
(1) Does anyone out there know if this is a normal response for
this engine (1100cc DOHC in-line four)?
(2) Does Yamaha position the sump intake in a location where
hard acceleration will move all the oil away from it?
(3) Is the oil warning system based on oil pressure or does it
just indicate crankcase oil level?
I tried two different Yamaha shops and got pretty unconvincing
responses. (e.g., "Yup, maybe it'll do that, sometimes!, or "Wow, I don't
know!") I have previously talked to the "technical" support people at
Yamaha's USA headquarters. While they were friendly and tried to be
helpful, they had difficulty answering (or maybe comprehending) technical
questions. (I am still waiting for a response to, "What is the
published engine horsepower for my bike?"). I get the feeling that
they do have a few gurus around, but they save them for the
racers and consulting with magazine writers.
If anyone out there knows of a really competent Yamaha mechanic or
shop, I really would appreciate a name or phone number.
Thanks in advance!
Chuck Rogers @ ATT-ISL, Denveranimal@ihlpa.UUCP (D. Starr) (09/12/86)
> My recently purchased (used) 1982 Yamaha XJ1100J Maxim > does a disturbing thing: When I accelerate VERY hard > (warp factor 8) for more than a few seconds (RPM = 4500 to > 8000 through 1st and 2nd gears, 0-50 mph) the WARNING light > begins flashing and the LCD display says "OIL", implying, > I suppose, that the engine is experiencing oil starvation > (the engine oil level is correct with the engine turned off). If > I maintain constant velocity (i.e., stop accelerating, but hold > constant throttle position) the light seems to stay on > indefinitely, and it goes off only if I drop RPMs back down to idle. > > (1) Does anyone out there know if this is a normal response for > this engine (1100cc DOHC in-line four)? Can't answer for sure about the Yammie, but it was SOP for the Kowie Z-1 and its descendants. > > (2) Does Yamaha position the sump intake in a location where > hard acceleration will move all the oil away from it? Probably. The Z-1 had the oil pump in the front of the pan, and hard acceleration shoved all the oil to the rear. There were two solutions; one of them might work for you. (1) Oil pump snorkels, which extended from the existing pickup to the back of the pan, were sold by aftermarket performance houses. (2) The Z-1 had a narrow spot in the pan about 1/3 of the way back. Some people put a little swinging trapdoor there so that oil couldn't slosh back under acceleration. Both approaches worked pretty well. You might also be able to reduce the effect somewhat by stiffening up the rear suspension. Rear-end squat under acceleration does make a significant contribution to this problem. > > (3) Is the oil warning system based on oil pressure or does it > just indicate crankcase oil level? Almost certainly pressure. Nearly all four-cylinder Japanese engines use plain crank bearings (like a car) and therefore require rather high oil pressures. The only Japanese four-stroke engine I know of with an oil-level light is the Yamaha V-twin, which is all roller bearings and can't maintain more than two or three pounds of pressure. > > I tried two different Yamaha shops and got pretty unconvincing > responses. (e.g., "Yup, maybe it'll do that, sometimes!, or "Wow, I don't > know!") I have previously talked to the "technical" support people at > Yamaha's USA headquarters. While they were friendly and tried to be > helpful, they had difficulty answering (or maybe comprehending) technical > questions. (I am still waiting for a response to, "What is the > published engine horsepower for my bike?"). I get the feeling that > they do have a few gurus around, but they save them for the > racers and consulting with magazine writers. > > If anyone out there knows of a really competent Yamaha mechanic or > shop, I really would appreciate a name or phone number. > > Thanks in advance! > > Chuck Rogers @ ATT-ISL, Denver
stuart@rochester.ARPA (Stuart Friedberg) (09/14/86)
In article <1848@ihlpa.UUCP>, animal@ihlpa.UUCP (D. Starr) writes: > ... The only Japanese four-stroke engine I know of with an > oil-level light is the Yamaha V-twin, which is all roller bearings and > can't maintain more than two or three pounds of pressure. I have a 1981 Yamaha 550 Seca. It has also has an oil-level warning, rather than a oil-pressure warning. It is a four-stroke in-line four with plain bearings. I am actually rather glad to have the level warning, since it goes off sooner (before actual damage is likely to occur) in the usual case of running low in the sump. I've had this happen twice after/during long distance trips and suffered no damage. It's my impression that when an oil-pressure warning goes off, it's like the chip-detector in a helicopter: You're already getting big time damage; land (pull over) the thing IMMEDIATELY. Anyone care to comment on how long a bike engine lives after oil pressure fails? Stu Friedberg {seismo, allegra}!rochester!stuart stuart@rochester
mjranum@gouldsd.UUCP (Marcus the Ranum) (09/15/86)
> > It's my impression that when an oil-pressure warning goes off, it's > like the chip-detector in a helicopter: You're already getting big > time damage; land (pull over) the thing IMMEDIATELY. Anyone care to > comment on how long a bike engine lives after oil pressure fails? > > Stu Friedberg {seismo, allegra}!rochester!stuart stuart@rochester Depends a lot on how fast you are turning the engine over at the time. Certainly every second you run at low oil pressure is going to put several hundred (thousand?) miles worth of wear on your bike. It all depends on what kind of shape your beaings are in already, and how much of an oil film they retain. There's also the matter of heat, since you might just melt those 'ol bearings right out of there.... I've never ridden very far on a bike with low oil levels. Just far enough to coast to a stop with the bike in neutral and the kill switch punched. I know a guy who routinely logged mega miles on his old Kawasaki 440 with the oil light flashing. Thing still runs, from what I hear. It could be that oil pressure warning lights mean different things on different bikes. On some it could mean you're marginal, and on some it could mean you have 3,000$ of junk between your legs.... Best to avoid it, unless you can talk Honda into giving us a brace of interceptors for some exhaustive testing... :-) Live Free !! mjr -- Moon so bright for love! Outstretched palm at dusk dies With insect-talking
animal@ihlpa.UUCP (D. Starr) (09/16/86)
> In article <1848@ihlpa.UUCP>, animal@ihlpa.UUCP (D. Starr) writes: > > ... The only Japanese four-stroke engine I know of with an > > oil-level light is the Yamaha V-twin, which is all roller bearings and > > can't maintain more than two or three pounds of pressure. > > I have a 1981 Yamaha 550 Seca. It has also has an oil-level warning, > rather than a oil-pressure warning. It is a four-stroke in-line four > with plain bearings. I am actually rather glad to have the level > warning, since it goes off sooner (before actual damage is likely to > occur) in the usual case of running low in the sump. I've had this > happen twice after/during long distance trips and suffered no damage. > > It's my impression that when an oil-pressure warning goes off, it's > like the chip-detector in a helicopter: You're already getting big > time damage; land (pull over) the thing IMMEDIATELY. Anyone care to > comment on how long a bike engine lives after oil pressure fails? > > Stu Friedberg {seismo, allegra}!rochester!stuart stuart@rochester I have two stories to relate on running without oil; one of them is from personal experience, the other is second-hand. The second-hand story concerns a test supposedly performed by Harley mechanics during the development of the Evolution engine. Somebody decided to find out how long this engine would run without oil, so they got a test bike warmed up, drained the oil and took it out for a ride. It went forty-some miles before showing any problems; then they stopped the experiment and dismantled the engine for inspection. They found only minor piston seizure, which could be repaired with fine sandpaper. Similarly, I ran the oil tank and lines on my Suzuki GT750 (two-stroke, water cooled) totally dry somewhere in southwest Missouri one time, and didn't notice until I had stopped for the night in Kansas City. The only symptom was trouble idling (possibly due to the above-mentioned minor piston seizures); I refilled the oil tank, tossed some oil into the gas to cover the line-priming time, and rode the bike another 25,000 miles without engine problems. As far as I can tell, I ran at least 150 miles on the oil that clung to the bearings. It's worth noting that all rotating shafts in *both* of the engines described above are in roller bearings, which is probably why they survived. Plain bearings would probably not last more than a couple minutes without pressurized oil.