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Mighty Manfred

R80RT: Oil Light Flickers

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Mighty Manfred

My 1987 R80RT runs with the oil level about 1/8th inch above the low line, which is in line with what I've read in several places. I know that rapid deceleration (I know that is a fictional term) can produce oil pressure light flickers - I've not seen this.

 

What happens with me - started a month or so ago - is that the oil light flickers sometimes when I accelerate quickly.

 

Any ideas?

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notacop

What you have is low oil. When the oil is at the lower side of the prescribed level it can get starved at the pick-up but sudden accel or deceleration.

Used to happen to my R80/7. By the time I'd get to Norman Oklahoma, about 1375 miles, it would have used a quart, putting the level on the dip stick where yours is. When I'd unload the bike and ride it the light would flicker until I put the proper amount back in.

I bought a deep pan for it. It held another quart. Much better that way.

The proper level for your oil is at the top of the checkered area on the stick. Exactly where the operators manual suggests. You listening to someone who knows better than BMW engineers?

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Mighty Manfred

Thanks for your reply. Actually, Snowbum and a couple others who know much more than I about airheads have remarked that these engines have a natural fill level - more oil would burn off or be sucked into the engine, leaving it at the natural level. Mine has been at this level for 18 months - only recently started flickering.

 

I will add some oil before I ride it and see how that does.

 

I've been thinking about a deeper pan - divergent opinions about that as well.

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JimD

Did this start right after an oil change? If so I suggest that you check and make sure the o rings and metal shim on your oil filter are installed properly or do not have a cut in them. Also the oil pressure sending unit on the lower left side of the engine can cause this problem. It can be the sending unit itself or sometimes the connector on the unit has gotten dirty or loose on the sending unit.

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Mighty Manfred

As far as I can recall, it did not start right after an oil change. Don't recall any event at all before this started. My 1987 R80 is much simpler with regards to the o-rings and filter - I installed the filter and o-rings same as was removed.

 

I will take a look at the sender. I pulled the heads and replaced head gaskets and push rod tube seals last year, so that area is much cleaner - making it easier to see the oil sender :-)

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notacop

Just what could be wrong with having an extra quart of oil working for you? I don't remember what brand of deep pan I got. Some were just spacers with cooling tubes in them and others were actually a deeper pan with extenders that lowered the pick-up.

 

Then again, maybe it is just low oil engine death saying hello to you. The engine only holds 2 quarts/liters when full and you cheat it by almost a liter by running it low. I question the collective genius of your advisors.

 

When I swapped the engine in my 80/7 for an R100R motor I was glad to put the deep pan on it and have the oil cooler to boot. More is better.

My R65LS went 217000 miles with a deep pan and never had a light flicker. The 80/7 light never flickered after I got the deeper pan. The 80/7 went away when it was cheaper to buy a replacement engine/trans than do a valve job.

Edited by notacop

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UberXY

I don't know how it works on an oilhead, especially without an external oil cooler, but on an air/oil cooled Porsche, the bulk of the oil capacity is used for engine cooling. Older 911s take a full 11 quarts, but lubrication is not compromised if only 2 quarts are in the engine. Cooling, on the other hand, would not be good.

 

But in your case, the oil sender is the very first thing I would check; in fact, given the age of the bike, I would just replace it and see what happens. BTW, do you have an oil temp dipstick? I have an old Luftmeister one on my R65, and it's been handy, though sometimes scary when stuck in traffic in July.

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Mighty Manfred

UberXY,

 

Funny thing is this behavior is inconsistent. I have tried an oil cooler on my bike and found it to be too much additional pain in the butt, compounded by the full RT fairing.

 

I do not have an oil temp dipstick - don't think I need to be looking down at my left foot while riding :-) I try to avoid traffic jams, having seen how the oil light can flicker while sitting in hot traffic at 1,100 rpm - going out at 1,500.

 

I will look at replacing the oil sender.

 

Many thanks for those who have responded.

Edited by Mighty Manfred

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Mighty Manfred

Before I went out on a 200 or so mile run this morning, I checked the air pressure and added oil - brought it up to the mid-point on the dip stick. No light flicker all day.

 

Many thanks, notacop, for keeping after me.

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notacop

Mighty MAn you are welcome. May all the cures be as simple.

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Paul Mihalka

"brought it up to the mid-point on the dip stick"

 

I still don't get it why not fill it to the top mark on the dipstick. That's what the marking is there for. Oil stays cooler, is also a main coolant, and you can ride a longer time without checking/worrying.

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notacop

Paul, I think Mighty man is getting there 1 small increment at a time. Fill to the top of the mark and fugitaboutit for a thousand miles.

Like the guys with the sight glass that can't decide if it is half full or half empty. Horns of the dilemma.

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Mighty Manfred

What is ya'll's view on deeper oil pans? Mac Performance makes one, but they do not specify how much capacity it adds.

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Paul Mihalka

All the deeper oil pans or oil pan spacers I remember added 1 quart of oil. I had it on all my airheads.

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Mighty Manfred

I just rec'd an email reply from Mac; their deep sump adds 2 quarts to the crankcase. Does this seem like a reasonable addition? No oil cooler on my airhead.

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Paul Mihalka
I just rec'd an email reply from Mac; their deep sump adds 2 quarts to the crankcase. Does this seem like a reasonable addition? No oil cooler on my airhead.

 

YES! But it will hang down. Don't jump curbs with it...

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Mighty Manfred

LOL! I don't jump anything on my airhead. I will ask them for dimensions and see how far down it actually will hang.

 

Thanks!

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Paul Mihalka

Just found this:

 

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=110632768254&crlp=1_263602_304652&ff4=263602_304652&viewitem=&guid=36eb407212b0a0abd234d694ffff0c7d&hlp=false&rvr_id=205927481589&ua=M*F%3F&itemid=110632768254

 

When you assemble it, put a tip of Locktite on the bolts of the oil pickup extension. That getting loose can be catastrophic.

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Mighty Manfred

That's most interesting - same vendor, $5 more on eBay than on their own web site, after adding shipping.

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rich t

Overfilling airhead crankcases can lead to oil use and oil leaks. Oil pickup spouts are held on with two bolts that can come loose, and eventually, the pickup falls into the oilpan. It is possible, however, that there may be a fault in the oil pressure switch.

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Mighty Manfred

Since filling up the pan to near the top fill line, I've not had any oil light flicker :-)

 

My current decision is to not put a deeper pan on my bike. But I reserve the right to change my mind.

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HairyCannonball

For hundreds and hundreds and hundreds of thousands of miles on /5, /6, and /7 airheads, I always filled my oil to the top mark, and never had oil consumption issues. I have no idea where these myths start and how running a quart low is a good idea. Foolishness. Keep the oil at the top mark. Every time that oil light flickered it was telling you that you had low oil pressure on your bearings, bad bad bad. If you have oil consumption issues, it is time for a top end.

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