Tuesday, April 13, 2010

Bird Caught In BMW Gas Tank

A glance at the odometer told me how much gas was in the tank. It read “63 miles,” which was how far I had ridden since topping off on my way back from my last run. In theory, this meant I had approximately three and a half gallons at my disposal, which at a reasonable 70 mph, translated into a 147-mile range. This should have been more than enough for the ride of last Thursday, April 8, 2010.


I have been riding this bike for a little more than 2 years now and can pretty much predict how it will behave under most conditions, including the extent of its thirst. It gets between 42 and 45 miles per gallon — unless I really twist on the throttle. “Fireballs” starts to hit the bottle heavily when the speedo gets above 90 mph, especially as its 71 horses dig in their hooves to move my ponderous ass. I am delighted to report that even at 7 grand in 5th gear, the machine responds “enthusiastically” to throttle inputs. But this spirit gulps 94 octane with reckless abandon.

Though the 1995 BMW K75 has a gas warning light, the meaning of this glowing red omen has become a subject of contention (at least for me). The factory preset position would trigger the advisory when there is still slightly more than two gallons of gas available (90 to 100 miles of range), which made me nuts. I can’t really explain why it made me nuts, other than I was always afraid I’d forget how long I may have been riding on it, or how fast I’d been going during these intervals.

An adjustment of the tank float by my mechanic appears to have lowered this margin to a gallon of gas, or a mere 40 miles — which is what I wanted. That way, I am compelled to get gas as soon as the damn thing lights up. And perhaps that should have been the end of my gas tank drama. Yet nothing is ever that simple.

The bike has a fuel pump in the gas tank that seldom makes a sound no louder than a low hum. This can become a chirping as the gas light goes on, and the fuel level drops in the tank. I have been told that this is a routine development as the pump works harder to suck the gas off the bottom. I have also been told that the gas in the tank serves to cool the fuel pump as it labors. And finally, I have been told that in 99 and 44/100ths percent of the time, any increase in the sound of the fuel pump means a blockage in the fuel filter, which is also located in the gas tank.

I have been told these things by BMW riders whose collective ages go back to the signing of the Magna Carta, and whose aggregate mileage is equal to three times the distance between the Earth and Saturn. They are Dr. Albert Hissingaz, Wilhelm Peltzer, and Heinrich K. Schmidt. (It is rumored that the K75 derives its alphabetic designation from Schmidt’s middle initial.)These statements cannot be contested.

Those not familiar with the unusual characteristics of the K75 will be surprised to learn that the gas tank gets as warm as a hot water heater in normal summertime operation. It was blistering hot on the day of The Great Slider Run. Temperatures were more appropriate for early July, as opposed to late March. And there was still three gallons of gas in the tank when my fuel pump started to make the “chirping” sound.

“What fucking fresh hell is this?” I asked in my most analytical tone. By the time I got to the White Castle in Toms River, the chirping of the fuel pump was quite audible over the running of the engine.

“That sounds like a blockage in the fuel filter,” said BMW sage Don Eilenberger. “It is easily fixed by replacing the fuel filter.”

By the time I got home, the chirping could be heard over a drive-by shooting... And it was constant, regardless of the gas level in the tank, though by this time the gas level warning light was glowing like a fresh rivet.

Which brings us back to last Thursday’s ride. The fuel pump was quiet for a few miles, than started in with the chirping noise again. Those of you with a strong sense of mechanical appreciation are now thinking, “Mechanical issues don’t heal like a flesh wound, stupid.” Well, there’s always a first time.

We stopped on the shoulder of the expressway for me to put my feet down. Hearing the sound, Dick Bregstein said, “You need a new fuel filter. But it’s easily fixed.”

(Above) The mighty Conowingo Dam is the largest structure of its kind in the universe. The angler in the water is actually a statue 324 feet high. Photo from Wikipedia.

Our destination was the Union Hotel (Tavern and Restaurant), in Port Deposit, Maryland. This was a short run (about 110 miles roundtrip) that would bring us to the shoulders of the Conowingo Dam. Turning left at the heavily wooded banks of the Susquehanna River, the road plunges beneath arches of oaks and maples whose roots have felt the marching feet of blue-coated troops heading off to the Civil War. This short stretch of a few miles provides the rider with glimpses of impressive stone railroad bridges in the woods, and the soothing sensation of pockets of cool air, where streams pass under the pavement before splashing into the bucolic Susquehanna. The road runs into historic Port Deposit, which is about three quarters of a mile long, and two blocks wide. Many of the buildings in this little town, are built from stone, hand-cut from cliffs towering over the main street.

We weren’t going that far.

The Union Hotel sits on a little bluff halfway between the dam and Port Deposit. I am not chagrined to let the gentle reader know that the tavern part of the Union Hotel is well-known to Harley riders in the region. The bar is typically surrounded by hundreds of Harleys — both stock and exotic —on any Saturday or Sunday. A piece of Wonder bread will be toasted to a crisp in seconds, if exposed to the sunlight refracted from that sea of parked chrome. I am an open-minded man, however, and will drink with the devil when I am hot. My objective was to snort a beer cold enough to shrivel my iguana on its way out.

(Above) US-1 crossing the Conowingo Dam. The pavement is wide enough for a 747 to land on. Photo from Wikipedia.

The parking lot was empty when we turned in. We were greeted by signs which advised that no rider wearing club colors would be admitted to the premises. These were repeated on the door of the bar — which was closed. But the restaurant (in a separate building) was open. And it was here we got the surprise of our lives. The Union Hotel was built of hand-hewn logs in 1790. The structure remains authentic inside and out. It is like dining in a museum of Americana. Our server, Heather, was dressed in period costume and presented us with menus, which include rabbit, venison, bear, and alligator tail, in the appropriate seasons. We ate light. Gerry Cavanaugh and Dick Bregstein had Maryland crab chowder, which they rated as “very good.” I had an open-faced pepper steak sandwich that was excellent. This restaurant was the kind of place you’d take a woman you really wanted to impress. We were there about 90 minutes.

(Above) The restaurant building for the Union Hotel (Tavern and Restaurant). Photo from the internet.

The chirping resumed as soon as I hit the starter button. Gerry looked at the gas tank in amazement, and said, “You got a blocked fuel filter, but it’s easily replaced.”

The ride home was fast, but not as fast as I had envisioned, nor quite as uneventful as the run down. The lack of municipal funding has the cops out in force. They were everywhere, and the stretches of pavement on which Dick and I have had some fun in the past were crisscrossed by radar beams. The attention of the authorities was warranted on at least one curve, however. Traffic was stopped as cops and fireman dealt with a pickup truck that was against the embankment — on its roof. Two young gentlemen, both in handcuffs, were cooling their heels in the back of a police car.

While there was never any hesitation nor lack of power from my bike, the chirping from the gas tank became a constant shrilling. It sounded like a song bird caught in wringer. My thought was that the electric fuel pump would draw more current as it worked against added resistance of a clogged fuel filter, either blowing a fuse or frying a relay. I had no idea if this was even a possibility, but not knowing inspired me to utter a fervent, “Shit, I just want to get home.”

I did.

I switched out the fuel filter and changed the oil (that filter too) on Sunday. Actually, Clyde Jacobs changed them while I made him a hot dog and poured a cold beer. My intentions were good though. I told Clyde I wanted to watch the process, but he asked, “to what purpose,” and I had no good answer. The bad news is that the fuel filter did not seem substantially clogged. We ran the bike for ten minutes but there was no chirping. I will be very surprised if a $600 fuel pump does not sacrifice its life for a $29 fuel filter.

Actually, the fuel pump for a K75 is not $600... It is $19,289.

Anybody want to bet me it’s not the fuel filter?

©Copyright Jack Riepe 2010
AKA The Lindbergh Baby (Mac Pac)
AKA Vindak8r (Motorcycle Views)
AKA The Chamberlain -- PS (With A Shrug)


RichardM said...

Not willing to take that bet. If the fuel pump was running hot for a while due to insufficient coolant (fuel flow), it's life may be shortened. If you had a simpler bike (i.e. one of the ancient BMWs without a proper cooling system) then no fuel pump and you wouldn't have to think about this.

Enjoyed the post and the pictures.

Nikos said...

The fuel not only cools it provides lubrication to the pump bearings. Possible also that the bearings are heating slightly and starting to complain. I suspect that the pump will probably go on for another 5,000 miles (although not a betting man I predicted the winner of the Grand National horse race last Saturday).
Did you receive my email Jack?

As ever, all the best from England. N

Jack Riepe said...

Dear Richard:

Small miracles do happen, and happen to me rather often (despite my negative outlook on life). Due to the nature of my knees, I tend to gas up the bike around 125 - 140 miles. That means the pump is seldom exposed to air in the tank. What I am thinking is that some grit or even something like a tiny piece of paper may be clogging the inlet of the pump.

I can't see the pump inlet even using a flashlight. It was my initial assumption that the fuel filter was the first fuel system element online in the tank. That is not true. It is between the pump and the injectors.

The engine was restarted and run for 15 minutes with very little gas in the tank, on the new filter, and the pump was silent. (What I should have done was run it for 15 minutes on the old filter first to see if the sound continued.)

These fuel filters are suppoosed to go 30,000 miles before needing a replacement. I think there is a 50/50 chance I may have solved the problem. I only have 23,000 miles on the bike in total.

I may find out today.

Fondest regards,
Jack • reep • Toad

Jack Riepe said...

Dear Nikos:

The pump on my other K75 had 20 years and 48,000 miles on it, and didn't chirp like this one. Still, I'm hoping luck is on my side.

I'll go check my other email now.

Fondest regards,
Jack • reep • Toad

Unknown said...


DISCLAIMER: I KNOW NOTHING ABOUT MECHANICS, which makes me an expert on opinion and diagnosis

Stay away from Ethanol. It attacks gaskets and creates havoc with fuel systems and gauges. My gas gauge used to record perfectly, now it registers more than I have. They secretly started to put up to 10% Ethanol in all grades below 94 octane. so last tank I started to use only 94. I am hoping that after a few tanks all will be back to normal. Also some blends use more sulphur, so I am thinking that this is a gas related problem

Wet Coast Scootin

ADK said...

Your pump is screwed. Don't be such a cheap SOB and buy a new one.

Oh BTW, I have it on good authority thar a failed pump in a K75 inevitably results in blown head gaskets, a fried clutch and gritted main bearings.

Come to think of it you should probably just buy a new bike, and spare us all the agony of one breakdown story.

Unknown said...

Dear Jack,

I don't recall saying that - but it is what I would have said if I was thinking about chirping coming from a fuel tank on a K bike.. so good call on that.

There is a "screen" - made of some mesh plastic on the bottom of the fuel pump that should keep debris from getting into the pump. It works well until it deteriorates and bits of it start getting chewed up by the pump.

Brian Currie (aka Curry) has a long dissertation somewhere on the Interwebz on using a current measurement to determine how plugged up your fuel filter is. It's an excellent excuse for really cheap (BC refers to it as "thrifty") people to put off replacing their fuel filter.

That said - replacing a fuel filter by mileage is also not all that accurate. If you have a load of crap (tech-term) gas in your tank, the brand new filter you just installed can be instantly plugged up as soon as you press the starter button and power up the fuel pump. Or - if you never get dirty gas - the fuel filter may well outlast the motorcycle. I think you can check with Brian on how to disassemble the filter, clean it and reassemble it.

Anyway - where were we? I seem to have gotten lost..

Oh - shortened life of the fuel pump? I'd suggest buying a spare and putting it with the rest of the spare parts and step-stools you carry on the bike in your tail-trunk. As long as you carry it with you, you'll never need it. Ditto on a fuel filter. If you'd had a spare on the bike on the slider run - the pump would have stayed mouse quiet.

http://www.eilenberger.net/laws.htm See law #2.

Please say HI from me to your lovely daughter. Tell her it's from the old fat guy in an Aerostich from the slider run. That should narrow it down to 25-30 guys who attended.

Chris said...

Dear Jack, your bike is toast. You best give it to me and buy yourself a new one. It's the only sensible thing to do.

Conchscooter said...

I hate technical posts. We never did get to hear about the cleaveage on the waitress's period costume nor how much the iguana shrivelled. This essay was a waste of time and not worth the cost of reading it.
You sounded great on NPR though.
PS if you want gratuitous useless advice from 1500 miles away from a man who rides a carburetted tachless bike and thinks all pumps should be changed every 15 years if they need it or not, then send me a check. You know where I live (gulp!).

redlegsrides said...


I've felt your pain. I replaced the fuel filter on my 1150RT oilhead on schedule but what a PITA.

Then, the second one (about a year later, maybe more) clogged to the point where it disconnected itself from the fuel lines...rendering the motorcycle unstartable due to lack of fuel. That was costly to fix.

I really hope it's not your fuel pump.

Now that I have carbureted motorcycles, life is simpler. I'm not saying better, or worse, just simpler.

One thing about Airheads, less things to go wrong, I'm starting to really appreciate that these days.

Good luck and I hope it was just the filter.

redlegsrides said...

Oh, and one more thing, I sure don't miss the time and effort it took to remove the tupperware from my 1150RT before getting at its innards.

Woody said...

Chirp this. Ride the fucker and when it dies, have Cutter fix it.

Jack Riepe said...

Dear Bobskoot:

You are the second rider in a week to tell me of the evils of ethanol. This other gent, a Mac Pac rider, described in vivid detail the horrid gunk and crap he found in his "R" bike's (BMW, naturally) fuel lines, filters, and petcock. He attributed the proliferation of this crap to the ethanol in the gas he used.

I was under the impression that all gas in the US, including 93 and 94 octane had ethanol in it. I was told that mixing an ounce of Stabil with a liter of
1995 Krug "Clos Ambonnay" Brut Champagne, and running it through the engine will greatly offset ethanol related problems.

I will try this next, and let you know what happens. Leslie has a bottle of 1995 Krug "Clos Ambonnay" Brut Champagne in the closet, but she is saving it for a special occasion... Like when I fall in the LaBrea Tar pits.

Fondest regards,
Jack • reep • Toad

Jack Riepe said...

Dear ADK (Chris Wolfe):

I've been taking Swedish lessons. "Fucjk Yµ!"

Fondest regards,
Jack • reep • Toad

Jack Riepe said...

Dear Don:

I am certain you diagnosed that squealing fuel pump as the victim of a rogue fuel filter. I was just about to saddle the bike when the guy on my left addressed the fuel pump, while the guy on my right said, "Let's all ride to a cathouse and get banged."

Could you have been the guy on my right? I thought it might have been Gantz, but I had sweated out all my electrolytes by that point and everything is a bit fuzzy.

I am delighted to hear that the screen mesh cover is on the bottom of the pump, hidden from easy inspection. If the chirping persists, and I'm betting it will, that pump will have to be pulled. And my second bet is that the screen on the pump is fused to it by a secret Luftwaffe process that will require replacing the whole unit.

My bike was built by Bomar the elf, who was buried with the high priests who held the secrets to the pump.

Curry told me that he has devised a process by which the pull tabs on soda cans can be re-machined in less than two hours to replace the 36¢ crush washers. He has reconditioned an old washing machine to serve as the grinder. And it still does clothes, if I understand him correctly.

I told Katherine that the really old BMW guy said to say, "Hello." She said, "Give Mr. Bregstein my regards."

as ever,
Jack • reep * Toad
Twisted Roads

Jack Riepe said...

Dear Chris:

You can have the bike... However, there will be a $7,000 shipping and handling fee. Due to the difference in unstable currency rates, payment must be in Krugerrands.

Fondest regards,
Jack • reep • Toad

Jack Riepe said...

Dear Conch:

BMW envy (and penis envy) are apparently rampant in Key West. Though I must say the left-handed endorsement you have given this blog, in inadvertently demanding a stronger focus on cleavage, will be cited many times.

I have yet to give this machine a good workout since the fuel filter has been changed. I don't really expect the pump to stop squealing and rather imagine it will have to be pulled.

This is not a complaint, just the grim eventuality of having to deal with a mechanical reality. An acquaintance of mine,Moto Edde Mendes, rode a vintage K75 around the world and through the Sahara, without having a fuel pump changed. And I expect he was pumping petrol with the consistency of corn syrup in many places.

It is just the luck of the draw.

Fondest regards,
Jack • reep • Toad

Jack Riepe said...

Dear Charlie6 (Dom):

I don't mind the necessity of replacing fuel filters... After all, the purpose of replacing a $29 fuel filter is to avoid replacing injectors or pistons.

But it is enough of a bitch getting at this one in the gas tank, that I wouldn't just try it myself the first time. Watching Clyde work on it provided me with a number of great tips for minimizing this effort for when I do.

The "K" bikes are said to require less of the attention that keeps an "R" bike purring... Yet it cannot be denied that when they do require something, it can be a bit of a challenge to the uninitiated. Officially, I would leave stuff like this to my mechanic. He zips through this crap with his eyes closed.

Fondest regards,
Jack • reep • Toad

Jack Riepe said...

PS To Charlie6 (Dom):

This K75 is regarded as the "low bike." There is no real Tupperware on this one. In fact, there aren't any knee pads on the tank either. Instead, there is a tank guard that is held in place by a hex bolt. The lower ends secure to the frame with clips. This works, and I have gotten to love its looks. But I miss the knee pads on the tank and the sidecovers of my previous K75 just snapped on and off.

Fondest regards,
Jack • reep • Toad

Jack Riepe said...

Dear Woody:

How I would love to have Cutter go over this bike. The pump was squealing last year when I gave the bike to Cutter, and was as quiet as a dead mother-in-law when I got it back. (This is what leads me to believe it could be the filter.)

Maybe next year, when my finances are hopefully better.

Fondest regards,
Jack • reep • Toad

Unknown said...


I think it's a conspiracy to keep you going back to the dealer for service. Things can always be engineered for ease of service, but they aren't

I've been thinking that there are a lot of aftermarket products designed to make the bike work better and these accessories are not even offered by the manufacturers.

Wet Coast Scootin

Jack Riepe said...

Dear Bobskoot:

This bike does not go back to the dealers. For big jobs, it goes to Cutter — a legendfary mechanic in the BMW community. If the job is not a major pain in the ass, I will ask my friend Brian Curry to take a look at it. Curry is also recognized as a K75 Guru. And by little jobs, I mean he is quite capable of removing something like a Sprint fairing, rewiring it, and reinstalling improved highlight wiring.

There have been millions of words written about substitutes for BMW filters and pumps. I have read a million times that there are auto fuel pumps, made by Bosch that fit in this tank.

Cutter once told me that the design of the bike calls for a certain part and that the engine running specs are based on that part. So I go with what he tells me.

Curry occasionally services parts where others toss them.

There was a huge discussion on oil filter substitutes. One guy had found some for $7. I paid $16 for the OEM oil filter. I'd rather spent the extra $9 than worry about it.

I was pissed about spending $29 for a fucking fuel filter... But that wouldn't break the bank either.

I'll tell you what gets me pissed. I spent about $650 for the PIAA HID lights, and that was not with installation. Then a friend of mine, Gary Christman, found the company that makes them for PIAA and sells them for $175!!!! PIAA adds the name and a wiring harness.

The wiring harness was not worth $475 bucks. I ended up discarding the PIAA switch to use a BMW dash switch anyway. Do I love the lights? Yes. Do I love how they look on the bike? Yes. Would I have gone the route that Gary Christman did (If I had the chance to do it over again)? You bet. Did I get fucked? Yesireeee Bob.

But that's how these things work.

If there is one thing that I am righteously pissed about, it is the horn that BMW and other marques install on these motorcycles. By the way, mine is working properly again. It is a FIAMM sports model, but will be replaced by a Steeble Nautilus compact air horn.
It alwasys good to hear from you.


Chris said...

Jack, sounds good. I'll take delivery now, and I'll pay in 2039 when I've collected enough of the coins.

Jack Riepe said...

Dear Chris Luhman:

Aaaaaaaaaaah.... I knew you've been thinking about my bike. Everybody does. There's a guy in Key West who can barely sleep thinking about it.

Fondest regards,
Jack • reep • Toad

Unknown said...

Mr Jackie "r":

Not only can he not sleep, he walks around all night with his dog, as he has no TV to watch

Wet Coast Scootin

Abby said...

After that ordeal, I think I'll leave my fancy LED gas gauge alone. I've run out of gas after ignoring the red blinking light, because it means I have at least 2 gallons left. Thankfully my baby's carbureted and have reserve for when I've pushed my luck.

Love Don's law #2. I've used that reverse Murphy's law for years. In fact, that's why I carry life insurance even though I have nothing to lose or small children to support. I also knew it was a big mistake when I left home on my cross-country trip without 5/8" and 10mm wrenches, which were the only two tools I needed on the trip.

You're very generous in your subtle "drinking with the devil" comment. Most Euro-snobs aren't so kind. Oops, did I say that out loud?

In response to a comment you left on my blog, I'd love to be linked, and I've done the same for you. I think we need to have a moto-blogger get together some time with the whole lot of us.