I have an opportunity to install any pump I want on my 1985 K100RT thanks to it having no tank nor accompanying equipment. A decent scan of the info available here turned up the pressure of the of pump should be 65psi, but could theoretically be as low as 36 and shouldn't be above 100. I'm finding all kinds of fuel pumps within those lines. I'm getting hung up a little bit on the flow rate. This page http://k-bike-knowledge.000webhostapp.com/electrical/EFI/bike-wont-start-EN.htm seems to suggest 45lph, but I can't find anything else. I'm not turning anything up with less than twice that. What can I get away with? It'll probably be easiest just to buy oem but I'd like to see what my options are.

A conservative estimate at 100mph for fuel consumption is about 12L/Hr. 

I am basing that on fuel efficiency vs. speed calculations on my bikes.  Getting 35mpg at 100 mph will consume approximately 3 gallons of fuel in one hour.

Most fuel pumps are designed for use in automobiles where mpg can be as low as 8-12mpg.

Add a safety factor of x2 to support hard acceleration and you have a minimum flow requirement of 24L/hr.

Here you are take your choice but the last one Mapco is the pick for the US guys



HOLDEN Commodore VK EFI, VL turbo and non turbo, VN onwards V6 and V8 sedan wagon statesman
HOLDEN Camira JD JE Astra Calibra
FORD Falcon XE XF EFI
FERRARI 412i Coupe
NISSAN Skyline Pintara Pulsar Bluebird
 
ALFA ROMEO 33 Alfetta 75 90 GTV Spider
BMW M3 E30 M5 E28 318i 320i 323i 325e 325i 520i 525e 528i 535i 633Csi 635Csi E23 733i, E23 735i
CITROEN
FIAT Argenta Brava Regata Strada Ritmo X19
JAGUAR XJ6 XJs Sovereign
LANCIA Beta Delta Gamma Prisma Trevi Y10 Turbo
LOTUS Esprit Turbo
MASERATI Bi Turbo
MERCEDES-BENZ
MG Metro Turbo Maestro Montego
MITSUBISHI Colt Turbo Lancer
OPEL Ascona Corse Kadett Manta Monza Omega Rekord Vectra
PEUGEOT 205 309GTi 405 505
RENAULT R5 Turbo R11 Turbo R18 Turbo R19 R21 Turbo R25 Turbo Espace Quadra Fuego
ROVER SD1 Vitesse 3500 Vanden Plas RANGE ROVER LAND ROVER 3.5 & 3.9 EFI
SEAT Ibiza Malaga
VOLKSWAGEN Transporter Caravelle
Mapco 22301

For information porpoises...fits R850 thru R1200C Oilheads, K1100RS/LT, K1200RS/GT and later K75, part number 16 14 1 341 231 fuel pump on eBay US, cheap as chips, made in Japan.

eBay (link)

I did a flow test comparison between my OEM 160,000 K pump and my replacement Chinese pump.
OEM pump 180 ml over 5 sec equals 2.16 litres per min.
New pump  325 ml over 5 sec equals 3.9   litres per min.
It was fitted in July 2017 and so far so good , I researched the Chinese pump as much as I could, and went for a manufacturer. Not all Chinese pumps are created equal. I carry my OEM pump in the tail as a back up, better safe than sorry.
Regards Martin.

Once the top seal has been in the fuel for any length of time it will dry out and leak like a sieve.

RicK G wrote:Once the top seal has been in the fuel for any length of time it will dry out and leak like a sieve.

I cleaned out the pump before storing it in a zip lock bag. Hopefully that will stop it from deteriorating. Although I now might pull it out and see if there is a better way of storing it.
Regards Martin.