VFR's broken down again

**Coyote** · 5th December 2007, 19:10

The mudguard broke off, then it started to stutter as if it wasn't getting fuel but the tank was half empty. Then each cylinder stopped going, one by one. I tried starting it, it spluttered a bit but then nothing. Luckily it broke down in town so I was able to go to my mum's work and borrow the phone and get picked up (no mobile, had to buy a tyre instead of replacing my stolen phone).

A quick glance around the electrics around the dash/headlight shows no broken wires. What could be the problem? I imagine the mudguard knocked something, but then that could be total coincidence. No fuel appears to be leaking.

**riffer** · 5th December 2007, 19:15

Jesus mate you work in a bike shop... tell Mac you need some shop time.

Otherwise, three words:

Air

Fuel

Spark.

Let me know if you need help.

**Coyote** · 5th December 2007, 19:22

Originally Posted by riffer

Jesus mate you work in a bike shop... tell Mac you need some shop time.

Otherwise, three words:

Air

Fuel

Spark.

Let me know if you need help.

I'm a small timer there, it'd take a fair bit of arse kissing to take up space and demanding the mechanics advice

should be fine to do it at home, I'm still doing afterschool hours there despite having finished school (I have asked for extra hours but I'm not needed).

Spark plugs are due I imagine, haven't touched them myself since owning it. Should be no reason why the fuel and air are obstructed, but I'll take a look anyway.

Would be good if I can get your help with the brakes sometime. As hard as I try I somehow manage to leave some air bubbles behind.

**wildpudding** · 5th December 2007, 19:37

Check obvious things first, obviously.

Check things like the fuel hose isn't kinked, the vent line isn't either. See if you're getting spark on each plug, check the voltage of the battery, check the tyre pressures and so on.

Faulty rectifier/regulator?

Stefan

**Coyote** · 5th December 2007, 19:43

Originally Posted by wildpudding

Check obvious things first, obviously.

Check things like the fuel hose isn't kinked, the vent line isn't either. See if you're getting spark on each plug, check the voltage of the battery, check the tyre pressures and so on.

Faulty rectifier/regulator?

Stefan

I haven't got a multimeter to check electrical stuff. The recitfier was meant to have been faulty and then was replaced by previous owner with an aftermarket one that shouldn't give any problems.

I'll go and check out the bike now. Did have plans to go to turners tomorrow and check out the bikes wrecks, still keen for that.

**Warr** · 5th December 2007, 19:57

Air

Fuel

Spark.

Like the man said check basics first.
Sounds like a fuel problem. The 750's have a fuel pump. down the back on the left hand side. If you have one would be a good place to start

**koba** · 5th December 2007, 20:08

Originally Posted by Warr

Air

Fuel

Spark.

Like the man said check basics first.
Sounds like a fuel problem. The 750's have a fuel pump. down the back on the left hand side. If you have one would be a good place to start

NC21 Four hundies don't. Not sure if the NC30 would be the same.

Pull a plug and make sure its sparking, if it aint find out why. If it is find out what else may be stopping it from being wrong.
If its electrical you can't be "sure" somthing is ok you must KNOW its ok before you exclude it from possible faults.

**Coyote** · 5th December 2007, 20:12

This has been another case of I should've checked it out myself before asking questions.

Took off the tail, and as I was about to disconnect the tank I noticed the small pipe going to the fuel tap was off. It had a tear so it wouldn't sit on the tap properly, so I cut it short and put it back on. The bike now runs. So it was a fuel problem.

Now what is this pipe? Is it to create a vacuum?

The mudguard was a coincidence, yet another thing to sort out for it's warrant...

**Warr** · 5th December 2007, 20:18

Pull the tank off and see if there is any fuel flowing. If yes run some into a jar and make sure it looks good fuel, no water or rubbish in it.
Could be rubbish in the carb float bowls .. be my next place to look.
Each bowl may have a bleed screw to facilitate draining them.

**Ivan** · 5th December 2007, 20:22

Lol man serious I know both Mechanics therefucken well,

If you asked them for there opinions they are bound to know.

Nathan would be one of the best Mechanics I have ever come across he is a legend,

And Dion he is pretty onto it considering we worked together for the past 2 years at tech

When you have bike problems ask them lol

**Ixion** · 5th December 2007, 20:35

Originally Posted by Coyote

This has been another case of I should've checked it out myself before asking questions.

Took off the tail, and as I was about to disconnect the tank I noticed the small pipe going to the fuel tap was off. It had a tear so it wouldn't sit on the tap properly, so I cut it short and put it back on. The bike now runs. So it was a fuel problem.

Now what is this pipe? Is it to create a vacuum?

The mudguard was a coincidence, yet another thing to sort out for it's warrant...

Sounds like the vac feed to a vac controlled tap. Tap has a diaphragm instead of an on off lever. When the motors running the vacuum holds the diaphragm open allowing fuel through. Motor off no vacuum (OR, pipe disconnected!), diaphragm closes, no fuel flows. Invention of the devil, 'orrible things, should be banned .

**Coyote** · 5th December 2007, 21:28

Originally Posted by Ivan

Lol man serious I know both Mechanics therefucken well,

If you asked them for there opinions they are bound to know.

Nathan would be one of the best Mechanics I have ever come across he is a legend,

And Dion he is pretty onto it considering we worked together for the past 2 years at tech

When you have bike problems ask them lol

They're great guys and I've gotten some good advice from them in the past. Just don't want to force myself upon them, bringing in the bike and working on it with their tools and getting in their way. I've got my Dad's stuff for that

Nathan is apparently starting up his own shop in Featherston. Heard about that? I don't really know anything more than he's leaving Maidstone to do so.

Originally Posted by Ixion

Sounds like the vac feed to a vac controlled tap. Tap has a diaphragm instead of an on off lever. When the motors running the vacuum holds the diaphragm open allowing fuel through. Motor off no vacuum (OR, pipe disconnected!), diaphragm closes, no fuel flows. Invention of the devil, 'orrible things, should be banned .

Interesting. Is there any reason why they'd choose this system? Would it stop the tank from spilling fuel if you took the fuel line off but kept the tap on? Would make things awkward if you're trying to empty the tank (which I might have to if I want to paint it).

**Ixion** · 5th December 2007, 21:38

Originally Posted by Coyote

Interesting. Is there any reason why they'd choose this system? Would it stop the tank from spilling fuel if you took the fuel line off but kept the tap on? Would make things awkward if you're trying to empty the tank (which I might have to if I want to paint it).

Well, it would, but I doubt that was a significant reason.

Partly it was the safety mantra again, since it means the fuel will automatically shut off in the event the engine stops (eg a crash). Mainly though it was because float needles sometimes leak. If the fuel tap is a manual on off, many people are forgetfull or lazy (I am) and leave it turned on. On bikes (eg V engines, two strokes ) where the inlet tract is downward (carb higher than head) the fuel can then run into the cylinder. That can cause hydrolocking, or, more commonly it runs past the rings, into the sump and dilutes the oil. Which then causes big end failure. A common problem on the VTR250. So the vac tap ensures the fuel is turned off every time the motor is stopped.

**Coyote** · 6th December 2007, 07:02

Originally Posted by Ixion

Well, it would, but I doubt that was a significant reason.

Partly it was the safety mantra again, since it means the fuel will automatically shut off in the event the engine stops (eg a crash). Mainly though it was because float needles sometimes leak. If the fuel tap is a manual on off, many people are forgetfull or lazy (I am) and leave it turned on. On bikes (eg V engines, two strokes ) where the inlet tract is downward (carb higher than head) the fuel can then run into the cylinder. That can cause hydrolocking, or, more commonly it runs past the rings, into the sump and dilutes the oil. Which then causes big end failure. A common problem on the VTR250. So the vac tap ensures the fuel is turned off every time the motor is stopped.

Doesn't sound like such a horrible thing that needs banning to me. I've always left the tap out of nievity and not wanting to forget to turn it back on.

Do most modern bikes have this? Or should I look out for it if I was to get a new bike?

This explains how my mates VTZ250's bottom end siezed on me whilst I was riding it.