On the way to the Illinois Rally in mid-May, 2003, the electronic fuel injection pump on my 1993 California III i.e. failed to start. These pumps are essentially identical on all fuel injected Guzzi models manufactured from 1993-2003 (after which the pump was installed internal to the fuel tank). Although I didn't know it at the time, I was about to enter "auto parts hell". This is my story.
When that pre-ignition "beautiful buzz" doesn't happen, few owners are prepared, since these pumps seldom fail and are taken for granted; accordingly, the rider is unprepared with knowledge of specifications, parts number, location of installation, or a source for parts. As such, failure can be catastrophic on a trip a long way from home, and more costly than it needs to be.
For the uninitiated, specifications for this pump are essentially the same for all 1993 - 2003 models: nominal voltage is 12 volts, system pressure is 3.0 bar (43.5 psi), delivery quantity is 100 liters per hour (l/h), and power consumption is less than 6 amps at system pressure. Included in the design (and all fuel pumps) is a check valve, and this one has as well an overpressure valve which shot circuits if pressure rises above 5 bar. The pump's inlet nipple is a nominal 12mm and the outlet nipple measures a nominal 7mm; buying a pump with different size inlet/outlet as a stop-gap emergency repair starts a domino-effect of changing fuel line size, thus pressure ...not desirable.
While this information is of absolutely no value to auto parts staff (their parts systems are established only on auto make, year, and part number), it is important for you, as some retailers may unknowingly sell you a replacement pump for "high pressure" systems i.e. 6.5 bar/94.5 psi, which is incompatible with Guzzi fuel system components e.g. regulator, hoses, etc. The auto parts databases do not make such specification distinctions, so you have to be vigilant in understanding the system application.
As your Guzzi is a motorcycle and not an auto, and as such is excluded as a "manufacturer" from auto parts databases, the key to repair is obtaining a part number recognized by the auto industry (be prepared for the ubiquitous question: "What make, model, and year of car?"). On my '93 model, the failed OEM pump was a Weber #PI-121 (2.060 inches diameter, 4.065 body length w/o inlet and outlet; add an additional 1.45 in. length for the inlet nipple and 2.5 in. length for the outlet nipple. [Current pumps are considerably more compact in length than my OEM Weber, and finding a shorter one within specs always eases reinstallation, especially if located under the tank.]
Upon checking the pump's adjacent relay, and finding it good, the pump was removed and its motor found inoperable. The usual suspects were rounded up for parts; a prominent Midwest U.S. Guzzi dealer had none on hand, and could "order one" for $325, with an uncertain delivery date. The local NAPA and other auto parts houses could not cross reference the Weber number to any of their proprietary suppliers, or major auto manufacturer numbers. As it was now Sunday, an interact search was begun, and a speed shop in California pictured a "Redline Weber" pump (Weber # 112) seemingly identical to mine.
A subsequent call on Monday to shop staff revealed that the box for the pump was labeled "Pierburg", with the cost and shipping at approximately $220. As the specifications for the pump were unknown to the staff, and cross-reference to the OEM Weber pump could not be absolutely confirmed by the shop, I declined ordering for the moment.
A subsequent search confirmed that Pierburg, a German firm [well known in Europe but relatively unknown in the U.S.] was in fact producing the Weber pump with the exact specifications I needed (sold currently as the Pierburg #7.21565.70.0 and formerly numbered #7.21565.50.0 and #7.21565.52.0). A call to Pierburg's U.S. importer (Mr. Craig Wolfe, Peachtree, George; 1-770-631-7500) promised the pump's availability from an auto import shop in north Chicago, but a call to that shop revealed they did not have the pump in stock.
By now it was Tuesday, and hoping for a more local (and cheaper) source, other tantalizing clues emerged from the net; Volvo autos (with years and models!) linked to Pierburg numbers were found...and a local Guzzi owner with a '99 EV visited - his pump was mounted on the frame beneath the left side cover and the number was barely visible: Bosch #0580464048. A call next morning to a local Volkswagen shop and the Bosch was ordered with a promised next day delivery (indeed, it arrived on Thursday).
After ordering the Bosch pump, I also called NAPA with the Bosch number in hand, and NAPA was immediately able to cross reference it to their proprietary "Carter/Federal #P72018" for $174.73, and a call to Auto-Zone revealed their proprietary "Master #E7334" (with a lifetime guarantee for $189.99) was also an exact replacement for the Bosch. [Can you say "1991 BMW 318 IC automobile w/1.8 L 4 fuel injected engine"?]
The Bosch pump was installed, and the opportunity also used to replace the 8mm fuel line with fuel injection hose (Gates brand #SAE 30R9) which has a formula much more impervious to effects of heat and gasoline solvent breakdown than standard fuel line; I highly recommend it or a similar spec brand. Fuel line clamps were also used instead of U.S. style standard hose clamps, so as to avert line damage and provide more uniform connections. The gas filter was due for replacement, and was replaced as well (Bosch #F5005; other applicable fuel filters are: NAPA #3564; Car-Quest #86564; and NAPA #3008, which is slightly longer than the NAPA #3564).
The new Bosch pump worked perfectly, and was quieter than the original Weber.
Repairs to my Guzzi were expertly performed by noted Guzzi mechanic and tuner Steve Kames of Kingston, Illinois (815-784-2886), and special thanks to Mark Stohr and Steve for traveling 180 miles each way to pick me and the bike up instead of attending the Illinois Rally.
No particular reason was found for the OEM pump's failure; the fuel filter and lines were found to be clean of dirt and debris. As with all things mechanical, some part finally failed after years of trouble free service. Yours could last forever, or go out tomorrow. If it does fail, you can be prepared by becoming familiar with the function and location of the pump on your model Guzzi (buy and study the applicable fuel injection, factory repair, and parts manuals available from Moto Guzzi).
If replacement is needed, repairs are possible in relatively short order, and can be competently performed by you in absence of a skilled mechanic. And, the final installment of this saga may then be written: I believe a less-expensive ($100-120) external fuel pump applicable to Guzzis is "out there", perhaps through Tractor Supply Company or Fleet-Farm in the Midwest U.S., and with the numbers herein you may find it. The experience of European and other non-U.S. Guzzi owners may also be forthcoming as to sources/prices for pumps in their localities. In any event, you won't be required to take an endless detour through "auto parts hell", and that beautiful buzz will be back!