Motorcycle Forum banner
1 - 20 of 35 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I have an '05 M50. I noticed my motorcycle was having a hard time getting enough fuel to start sometimes so I replaced the fuel pump with an upgraded new pump. After hooking it up to the bike I wasn't getting any fuel so my bike wasn't starting at all. I have now replaced the fuel relay, all of the fuses, the fuel pump, and checked most of the wiring. Does anyone have any suggestions on what else it could be or what I might have overlooked?
 

·
Registered
Joined
·
7,198 Posts
Kinked fuel line....tank vacuum...faulty fuel valve...if fitted....faulty fuel valve vacuum...if fitted...all easy and cheap fixes. If your new pump has reduced the fuel flow to zero you may have dislodged a vacuum line. Also check your injector fuse if it has one and all injector connections are good and tight.

One other thing when you turn on the ignition do the gauges run through the start up sweep and can you hear the pump prime?
 

·
Registered
Joined
·
41 Posts
Is the fuel pump in the tank or apart from it ? .

If it's outside the tank check the in tank fuel debris screen before anything else as you must have an unrestricted flow of fuel to the pump for it to work... -Nate
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #6 ·
You need to TEST components before you replace them based on a wild guess.
A multi-meter is a required tool.
A shop manual might help too.
I have a voltmeter. I just don't know what wires should be putting out what and I also wish I could find the correct colouring on the connecting wires soni can check that
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #8 ·
Kinked fuel line....tank vacuum...faulty fuel valve...if fitted....faulty fuel valve vacuum...if fitted...all easy and cheap fixes. If your new pump has reduced the fuel flow to zero you may have dislodged a vacuum line. Also check your injector fuse if it has one and all injector connections are good and tight.

One other thing when you turn on the ignition do the gauges run through the start up sweep and can you hear the pump prime?
No the fuel pump doesn't prime. That is my big problem right now. I don't hear it pump.
Where is the fuel valve vacuum line?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #9 ·
Is the fuel pump in the tank or apart from it ? .

If it's outside the tank check the in tank fuel debris screen before anything else as you must have an unrestricted flow of fuel to the pump for it to work... -Nate
The debris screen is all good. Does the fuel pump need to be in the fuel tank/with a source of fuel for it to prime correctly? After a while I have been testing the fuel pump by itself because I got tired of putting it together and then taking it back out.
 

·
Registered
Joined
·
41 Posts
A very good question ! .

If the pump is the in tank typ it needs to be submersed .

A short test, like 10 seconds just to see if you can hear it spin is O.K. but NO LONGER ! most modern electric fuel injection pumps are high pressure and use the gasoline to lubricate the inside .

Running and fuel injected engine out of gas almost always ruins the pump even if it takes a while to die .

Maybe someone here will have a wiring diagram for your bike ? .

Often one wire leading to the pump is ground and the other comes live when you cycle the relay .

if the engine doesn't start, the relay should cycle off again after 10 seconds or so, this is so the bike doesn't spray gasoline all over you in a crash then burn you to death.

keep asking ! someone will know ~ I don't in your specific case so I don't want to give you detailed instructions that might be wrong .
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #11 ·
A very good question ! .

If the pump is the in tank typ it needs to be submersed .

A short test, like 10 seconds just to see if you can hear it spin is O.K. but NO LONGER ! most modern electric fuel injection pumps are high pressure and use the gasoline to lubricate the inside .

Running and fuel injected engine out of gas almost always ruins the pump even if it takes a while to die .

Maybe someone here will have a wiring diagram for your bike ? .

Often one wire leading to the pump is ground and the other comes live when you cycle the relay .

if the engine doesn't start, the relay should cycle off again after 10 seconds or so, this is so the bike doesn't spray gasoline all over you in a crash then burn you to death.

keep asking ! someone will know ~ I don't in your specific case so I don't want to give you detailed instructions that might be wrong .
Thank you for the information. That is actually helpful. I figured out how to hook up power to the fuel pump directly to test if the pump went out. It still works so now I need to take another close look at the wires on the bike and test the fuel injectors. If that doesn't work then I don't know what will
 

·
Registered
Joined
·
41 Posts
Well ;

Are you sure there's no fuel reaching the injectors ? .

There must be a replaceable fuel filter in there somewhere, try CMNSL for exploded didgrams, few ever bother to change these and they should be changed annually or ever 10,000 miles .
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #13 ·
Well ;

Are you sure there's no fuel reaching the injectors ? .

There must be a replaceable fuel filter in there somewhere, try CMNSL for exploded didgrams, few ever bother to change these and they should be changed annually or ever 10,000 miles .
I'm not sure if there is fuel getting to the injectors. That is what I need to test. There is not fuel filter except what is on the end of the assembly. The whole assembly is already replaced anyways
 

·
Registered
Joined
·
41 Posts
Okay, more here .

I know you might not want to hear this but this engine has adjustable, mechanical valve tappets and they MUST be checked and adjusted if the bike has more than 8,000 miles on it ~ almost no one ever bothers with this as it's a time consuming and fiddly job but you'd be shocked at how often I've returned a "bad engine" bike to the road with this basic overlooked maintenance item .

It may not be within your scope of knowledge / practice / ability and will require you to buy or have, feeler gauges, cranked spanners and Allen tools, possibly more .

Are you anywhere near Los Angeles ? .

I know a Motocycle repair shop in Eagle Rock (N/E L.A.) that can do this or teach you how .
 

·
Registered
Joined
·
41 Posts
Okey-Dokey then, I had to go to work .

Keep plugging away it it, you'll get there.

Once I was a young and broke kid who knew nothing about how Motocycles work, I bought some old bike and pretty much taught myself, now we have these internet places you can go to...
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #20 ·
Here is the factory shop manual, it's in .PDF format and you can download it free then print the pages you need .

I don't have a printer but we're making forward progress, if it eventually needs to shop they'll want this for reference .

This actually gives me a lot of information about the bike. Thanks!!!
 
1 - 20 of 35 Posts
Top