Problem with starting the engine after bike assembling

[S0nic]

Hey, everyone!
I've finally painted the entire bike matte black (except the engine), but that is not the problem.
The whole bike, except the engine was disassembled to go get painted. At last, yesterday I've assembled it back and tried to start the engine. It starts very-very hardly and gains about 800 rpm and even can hold them for about 5-7 seconds. After that the rpm rate falls down and the engine stops. All four cylinders work fine according to the sound. Trying to twist the throttle leads to loosing rpm and engine stopping. The engine itself was not disassembled, so the problem is not inside. All wires have been connected properly. Only the neutral sensor wire has bad contact, but I've solved that problem.
Has anyone faced something like this? Where should I dig to find what's wrong?
Thanks a lot and sorry for my bad English.

 

[Kenward]

Is something blocking airflow going into the airbox, or the TB's themselves? I've seen a couple instances where tape or a rag is stuffed in to keep things from getting into the engine and then are forgotten upon reassembly.

Just a guess, but good luck figuring it out!

 

[RJ2112]

You must have fuel, air, and spark for the engine to run. Isolate which is missing, and you will solve your problem.

Are the spark plugs dry, or wet after the engine stops?

 

[S0nic]

You must have fuel, air, and spark for the engine to run. Isolate which is missing, and you will solve your problem.

Are the spark plugs dry, or wet after the engine stops?

Nothing's missing - you see, the engine does run for some seconds.

 

[S0nic]

Is something blocking airflow going into the airbox, or the TB's themselves? I've seen a couple instances where tape or a rag is stuffed in to keep things from getting into the engine and then are forgotten upon reassembly.

Just a guess, but good luck figuring it out!

No, nothing's blocking the airflow.
And by the way, what do you mean under TB?

 

[Kenward]

Also, post pics of the bike when you get the chance! haha

 

[Kenward]

No, nothing's blocking the airflow.
And by the way, what do you mean under TB?

Did you pull the airbox off? Some people will tape off the openings of the throttle bodies or stick clean rags in them to keep debris out.

 

[S0nic]

Did you pull the airbox off? Some people will tape off the openings of the throttle bodies or stick clean rags in them to keep debris out.

Sure, I did that, but I've removed them before installing the airbox.

 

[RJ2112]

Nothing's missing - you see, the engine does run for some seconds.

But it stops.... what goes away? I'm guessing you have a fuel line kinked, and the engine starves for fuel. The fuel pump can pull enough into the fuel rail to supply idle for a few seconds, but it cannot maintain pressure when the demand is greater.

Try setting the fuel tank off to the side, with the lines routed to the motor as they would be and see what happens. That is more easily done than pulling the spark plugs to check for wetness, indicating lack of spark.

 

[Kaisersoze]

Nothing's missing - you see, the engine does run for some seconds.

Forgive me for the correction, but the engine doesn't sound like it is running. Its losing one of those three ingredients after turning over and thus stops running. Pull the plugs after it stops to see if wet. Check airbox. Did you disassemble the fuel pump from the tank? Is the filter clogged? Are all the wires reconnected on the bottom of the tank? Is the fuel line pinched due to the position it is in?

 

[S0nic]

But it stops.... what goes away? I'm guessing you have a fuel line kinked, and the engine starves for fuel. The fuel pump can pull enough into the fuel rail to supply idle for a few seconds, but it cannot maintain pressure when the demand is greater.

Try setting the fuel tank off to the side, with the lines routed to the motor as they would be and see what happens. That is more easily done than pulling the spark plugs to check for wetness, indicating lack of spark.

I did that tonight. I had similar thoughts. But everything remains same.
And by the way, when I disconnect the fuel hose, the fuel starts leaking out from the tank (this wasn't so before disassembling). What could be the problem?
Thanks!

 

[S0nic]

Forgive me for the correction, but the engine doesn't sound like it is running. Its losing one of those three ingredients after turning over and thus stops running. Pull the plugs after it stops to see if wet. Check airbox. Did you disassemble the fuel pump from the tank? Is the filter clogged? Are all the wires reconnected on the bottom of the tank? Is the fuel line pinched due to the position it is in?

Tomorrow I'll disassemble what's inside the fuel tank to check for any problems and will report in this thread.

Well, I guess, the engine doesn't get enough fuel.

 

[RJ2112]

I did that tonight. I had similar thoughts. But everything remains same.
And by the way, when I disconnect the fuel hose, the fuel starts leaking out from the tank (this wasn't so before disassembling). What could be the problem?
Thanks!

Also, try doing the experiment with the gas cap open. If the vent line is blocked, the pump will not be able to continue to supply fuel against the vacuum in the tank. Start the bike, wait for it to die, then open the cap. If you hear a whooshing sound, the vent is blocked.

 

[ChevyFazer]

Are you sure theres fuel in it...lol hey I know it sounds like a stupid question but many people sometimes forget...nevermind I read a post backwards I thought u mention fuel would run out before but not now....dyslexia

Sent from my R800x using Tapatalk

 

[S0nic]

Are you sure theres fuel in it...lol hey I know it sounds like a stupid question but many people sometimes forget...nevermind I read a post backwards I thought u mention fuel would run out before but not now....dyslexia

Sent from my R800x using Tapatalk

Poured about 4 liters in there.

 

[S0nic]

Also, try doing the experiment with the gas cap open. If the vent line is blocked, the pump will not be able to continue to supply fuel against the vacuum in the tank. Start the bike, wait for it to die, then open the cap. If you hear a whooshing sound, the vent is blocked.

I'll try that. That's possible, because I've replaced the cap with the custom one, and it has not yet been tested.

 

[Motogiro]

I noticed you had a problem with the neutral safety switch connection. Make sure this connection does not have any loose strands hitting where they're not supposed to. This could be a long shot but, usually that circuit is a variable voltage circuit on most bikes that the ECU reads so that it can retard timing in the lower gears. This was designed into many bikes to meet state and federal emission standards. I believe this would be the same circuit used for those aftermarket gear indicators which work off the variable voltage. This is how the gear indicator learns and remembers what gear the bike is in. Not knowing all the possibilities could there be a problem the ECU sees from this area and it's trying to deal with it??

 

[abraxas]

Just my own thought:

Something i did was swapped the 1-4 on the plug caps. :ban:

However, similar symptoms to what you describe.

From seat side: 1 on left, 4 on the right.

Otherwise i'm with fuel hose, supply.

 

[S0nic]

Just my own thought:

Something i did was swapped the 1-4 on the plug caps. :ban:

However, similar symptoms to what you describe.

From seat side: 1 on left, 4 on the right.

Otherwise i'm with fuel hose, supply.

I've marked them with special flags before disassembling like "upper coil upper wire" etc.

Guess, it's fuel pump. Because the fuel leaks out when I disconnect the fuel hose. That's NOT right.

 

[RJ2112]

I've marked them with special flags before disassembling like "upper coil upper wire" etc.

Guess, it's fuel pump. Because the fuel leaks out when I disconnect the fuel hose. That's NOT right.

I would re-check the fuel line connections, to ensure they had been applied to the correct ports on the fuel tank. Did you take the pump out of the tank?