Hey all
So I'm getting on with bringing this k100rs special edition back to life. So far I've stripped and cleaned the tank, found the fuel pump wires rotted out with the positive line just floating! I've replaced the spark plugs and it tested OK on cranking as all 4 had a bright spark. 

I'm now onto the injectors, I've took them out and faced them away from the bike on the rail and tested them on cranking. After a few minutes with a combination of carb cleaner and redex via a pressurised syringe I restored the squirt so they were all the same. I've just fetched fresh orings and I'm about to refit them.

I want to test to se if it will fire from an external tank and pump before I put everything back together again. There were two pipes connected to the tank on the left side toward the front, one pipe goes directly to the tank (toward the front) and the other one goes down behind the airbox/gubbins?

Which one do I feed from my external pump and should I expect petrol to come out of the other one as the return?

Thanks for the help.
Mark

Front tube is the return line to the tank, rear tube is the feed line from the pump.
Caution: do not use standard fuel lines into the tank; in immersion they must have a double layer, inside and outside the hose. They are rated NBR/NBR. 
Standard fuel hose will leak quickly.

jbt wrote:do not use standard fuel lines into the tank; in immersion they must have a double layer, inside and outside the hose. They are rated NBR/NBR. 
Standard fuel hose will leak quickly.

I think he means don't use standard fuel line inside of the tank. Regular fuel line is not submersible.

The gas tank front pipe is the return line from the fuel pressure regulator. The rear pipe is from the fuel pump to the rear pipe on the fuel rail.

The exterior fuel hose to use is CR/CMD/NBR or SAEJ30R9. Fuel-submersible hoses used outside the tank will break down from heat, oil and ozone exposure.

duck wrote:

jbt wrote:do not use standard fuel lines into the tank; in immersion they must have a double layer, inside and outside the hose. They are rated NBR/NBR. 
Standard fuel hose will leak quickly.

I think he means don't use standard fuel line inside of the tank 

Sorry, I see no difference between "into the tank" and "inside of the tank"?
But english is not my mother tongue. Can someone explain me so I won't do this mistake again? (And could be arrogant to my daughter who is studying english!  )

I figured that it was because English is not your first language.

into is a preposition implying movement (going into a house)

inside is a noun that refers to the location of something (being inside of the house)

You can ride your Brick into the barn through its door so it can be inside the barn out of the weather, but you should open the door first.

Thanks guys , I had the input back to front and was pumping fuel backwards around the circuit. I had a quick try the right way round but my battery was depleted so we will carry on the battle tomorrow.
The cheap clicker pump didn't have enough beans to drive the injectors for it to idle smoothly but had enough psi for a face wash on disconnection. I have a subaru high pressure pump I will swap out and try again tomorrow.

So far it feels like its just the fuel pressure that's lacking. Great bike to work on so far.

Careful with the fuel pump. The bike's pressure regulator is capped at around 30psi idle and up to approx 36-38psi flat out. The pump is rated at 68psi, so don't go much higher than that (70psi maybe).

The clicker pump only makes 6psi so it couldn't keep up, hopefully the submersible will make atleast 30 psi.

Another update.
It's up and running and starts on the button. So far the bike is connected to portable batterypack, I've placed the subaru submersible pump into a small container full of petrol and attached a smaller battery to this pump.' I connected the pump and had a strong return flow back into the same container.
I put the choke on and it fired straight up, I let it run for 5 minutes and turned the choke off and to my surprise it idled perfectly smooth. There is a little smoke but after 15 minutes it improved considerably so I think it will fine after a shakedown ride.
I also tested the charge circuit and the original fuel pump power wires and great news both were functional. So I don't think it wil be long before the k100rs is back on the road for good.

Thank you everyone for your inputs, I'm now have my eyes peeled for something to mount onto the sidecar chassis.

good job!

bad boy wrote: good job!

You should have seen what was going on under the tank!
Someone had took the sender connector out of that square steel piece under the tank and wedged a bit of 10mm petrol hose into that 8.8mm hole where the sender was. Then the pump wires were fed up this pipe which was cable tied at the top of the tank to the internal metal pipes.

The entire pipe had melted and left just the fabric weave inside, before I drained for cleaning I saw the ancient petrol leaking from the dissolved pipe. I'm surprised it didn't go bang and catch fire between the bodgers legs!

Craziest bodge I've seen yet on a bike.