Ok so fuel pump and relay off the bike ....

CF318 relay (fuel cut off) I need to test this and the fuel pump.

I've shorted the pump direct to the battery, it runs but only for a second .. should it run permanently wired like this or does the fact it only runs for a split second imply that those contacts need replacing ? (have found a kit for this)

Relay: How can i test this off the bike?

Thanks

John

 

Pump appears to work properly. It shuts off pumping when bowls are filled.

Test it further by testing actual flow. Disconnect fuel from fuel-rail and aim into measuring cup. Jumper relay and run for 10-sec. How much petrol did you collect.

To test relay off bike, apply power & ground to activation-coil terminals. Then measure for continuity between power input and output terminals.

If you're having starting or running issues, 99.999% of these fuel-related issues is due to dirty clogged carbs. Spray carb "cleaners" no longer work due to removal of chlorinated compounds. Needs complete teardown of carbs to every last nut, bolt & individual component. Lots of scrubbing of secret hidden passages with PEA-based fuel-system cleaner. Ultrasonic soaking for days. Micro soda-blasting to clear out chads. Poking out every bleed hole with soft copper wire of matching diameter. Replacing all rubbers: float valves, pilot-screw O-rings, fuel-rail O-rings, float-bowl seals, even slide diaphragms if needed. Set float height with wet-test and sync carbs.

 

Cheers. It cant be the carbs. It runs on gravity feed perfectly. Its the pump or the relay or maybe a wire in between. Just had it running sweet gravity feed, it started within 3 seconds with empty floats, idling perfect (even cold with little choke). So I plug the pump back in (with its replaced contacts), plug the relay back in ... fu*** wont start or even attempt to fire. Doing my nut in !!! Should the relay get hot .. because it was pretty warm after not much cranking?

 

You say ' pump appears to work properly'. How can you tell? its not connected to the carbs or any part of the bike so it wouldn't know if 'bowls are filled'. I literally wired it direct from the battery to the pump connector lug. It ran for .. i dunno ... half a second then nothing. Im thinking it should just run continually? I've just put new contacts in it .. is there any opther part of this pump that is known to fail or can be serviced, i have no cash for a new one right now.

 

Well, I'm assuming pump's working because it starts and slowly stops? It needs to be connected to fuel-lines to keep it cool.

Can test pump by directly connecting power to it and bypass relay. Does it pump easily for 10-sec into measuring cup? How much volume did you collect.

Relay shouldn't get on hot. Might be sign that pump is drawing too much power? Clicker on bottom of pump should turn off pump by disconnecting it from power.

Basically you want to test pump and relay independently from each other.

Look into doing solid-state conversion for pump. Replaces mechanical clicker on bottom with transistor for more reliable operation.

 

No mate. I've replaced the contacts in the pump but if i wire it direct from a battery it'll move for just a second then stop. Seems like the pump is most likely dead it should run continuously until i break the circuit.) Nothing else to change on the pump so thats that i guess. Straw that broke the camels back

 

Can you move pump plunger smoothly by hand? Sounds like clicker's not working correctly. Usually not worth it to replace only contacts as there many be other issues with clicker. Darn.

Try to find used OEM Mitsubishi pump for carbs from breakers. Way, way better than most brand-new pumps on market. Many are bad right out of box and needs to be tested and confirmed good before using.

 

Ok, so turns out i'm an idiot and the bike is now back to perfect running.

So what was it? ..... it was the contacts in the fuel pump (which i replaced for new ones - bargain at £18)

Why didn't they initially work? ... In short, because it transpires im blind as a bat close up! I hadn't engaged the moving part of the contacts with the cut out on the pumps main shaft. I had screwed the contacts down and the moving part was in fact butted up against the shaft and at a slight angle. This essentially trapped it in place so id hear and feel it try to move for a split second and then give up. Resolution was simple, take it apart, engage the relevant part and put it back together. Should be noted that it is also possible to jam the mechanism with the internal wiring / rubber gromet if you don't get them exactly right .. ask me how i know!

Anyway, long story short. The pumps are generally very reliabe, it is the contacts that fail. Pumps here in the UK retail at (wemoto) £318!!! The contact replacement parts are £18. Quite a simple job as long as you are more careful than i initially was.

Cheers for the replys, I'll mark this one as closed.