VFR's broken down again

[Coyote]

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]

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]

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 :p 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]

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]

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]

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]

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]

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]

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]

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]

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]

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 :p

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.

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]

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]

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.

[Storm]

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

So I guess you dont get too many offers to ride other peoples bikes anymore then?

[vifferman]

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?
I don't think modern bikes have this, but I'm just guessing.
On my VF500, it was a bit of a prick of a thing. If the diaphragm perishes, then it means the engine sucks extra fuel into whichever intake manifold's connected to the vacuum tap. Which it did.
If the vacuum tube perishes, hen it means the engine sucks extra air into whichever intake manifold's connected to the vacuum tap. Which it did.

So, #1 cylinder at times ran either extra rich or extra lean. :buggerd:
And of course, although the tap was able to be disassembled (or taken right off, if you want to completely drain your tank because it's got rusty pinholes in it, which it did), the diaphragm wasn't available as a separate item, at a reasonable price. But (however!) you could buy the whole tap as one unit at a totally unreasonable price.

For all these reasons, the vacuum-operated fuel petcock is a triumph of SafetyNazism over pragmatism and practicality.

[Coyote]

For all these reasons, the vacuum-operated fuel petcock is a triumph of SafetyNazism over pragmatism and practicality.
Yikes. Something to look out for since everything on my bike is inevitably going to go wrong.

So I guess you dont get too many offers to ride other peoples bikes anymore then?
You've got to be pretty dumb to let me ride a bike in the first place. Dealers seem pretty keen though, guess it's cause they get their money if I crash it :rolleyes:

[vifferman]

Yikes. Something to look out for since everything on my bike is inevitably going to go wrong.
You should sell it and buy a Honda, preferably a VFR. They almost never break down....:blink:

Actually, I've owned 7? 8? Hondas, and the only times I've been let down by them (apart from when they were strewn all over the road after an altercation with another vehicle) was twice when I had a dodgy R/R. Both times I knew what the problem was, and was on my way home, but ran out of ergs to drive the sparky things.

[Coyote]

You should sell it and buy a Honda, preferably a VFR. They almost never break down....:blink:

Actually, I've owned 7? 8? Hondas, and the only times I've been let down by them (apart from when they were strewn all over the road after an altercation with another vehicle) was twice when I had a dodgy R/R. Both times I knew what the problem was, and was on my way home, but ran out of ergs to drive the sparky things.
I've found the one that makes you say 'almost'.

I made what I knew were obvious mistakes but my lack of money and my current mode of transport was failing (edit: and my desire to get something cool...) so I was forced to get 1: bike with high k's and 2: buying off trademe unseen. The second point wasn't so important cause chances are I would've got the bike if I had seen it. It looked great, shame I had to drop it the next day. But the age is what's getting me. All the consumables are at the end of their use by dates (brake disks at both ends, suspension bearings, fork seals, etc.) and it's all getting old (frame creaks, shock leaks and the spring is fucked, etc.) and there is other general damage, bodywork scratches are my own undoing but the subframe is bent and the front wheel I think is buckled.

Whenever I look at the bike I feel stupid.

The great irony of all this is I sold the old bike to Koba. He's had few troubles and the bike is running fine. In fact he commutes on it.

[vifferman]

But the age is what's getting me. All the consumables are at the end of their use by dates
Yeah, that's a pisser, that is. We've got a car a bit like that. It was a great car to drive, goes like a rocket, etc. Cost $5600, and since then we've spent maybe $9000 more on it. It would've been sensible to have just quit while we were behind, but it seems a real shame to junk a 'perfectly good' car.
We bought another car for $5k, and have spent only hundreds on it in the 3 or more years we've owned it. The difference is, the first one is 18 years old, high-performance, and has been thrashed to within an inch of its life since we bought it, while the second is 10 years old, 'soft', relatively gutless, boring, and is driven occasionally, gently and sensibly.

[Coyote]

Yeah, that's a pisser, that is. We've got a car a bit like that. It was a great car to drive, goes like a rocket, etc. Cost $5600, and since then we've spent maybe $9000 more on it. It would've been sensible to have just quit while we were behind, but it seems a real shame to junk a 'perfectly good' car.
We bought another car for $5k, and have spent only hundreds on it in the 3 or more years we've owned it. The difference is, the first one is 18 years old, high-performance, and has been thrashed to within an inch of its life since we bought it, while the second is 10 years old, 'soft', relatively gutless, boring, and is driven occasionally, gently and sensibly.
The VFR is exactly like that. It'd make sense to get rid of it now and get what money I can get back. But Motomart only offered $2000 in a trade in, so I'd only be able to get about $2000-2500 private sale, maybe more once I've tidied up the fairings. I've only owned it for about 8 months and it's depreciated by $2000, and I've spent about $1500 on it so far and it needs several more hundreds of bucks to be sorted (windscreen, rear brake disk, front cylinder valve clearance check - could only afford to get half the engine done...). Since I've spent so much it doesn't feel like much sense to get rid of it now because all I'll be left with is debt, I perfer being in debt but having a bike to show for it at least.

I'm keen on upgrading to a motard, since when they fall it's not so fatal to your wallet (or you since you're not travelling so quick to get your kicks). Normally I'd be more keen on the higher performing but higher maintenence KTM 525 and suchlike, but now the model of interest is the XR650. Desiring a reliable vehicle above all... I've turned into my Dad!

[more_fasterer]

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?

It is indeed a vacuum feed to the fuel tap. Should you feel the desire to bypass it, the instructions are at: http://www.akhara.com/nc30/fueltapmod/index.html
But then you should get into the habit of turning the tap off all the time - I have done the above mod and leave the tap on, and haven't had any fuel leaking out of the carbs; the oil smells free of petrol too.

With that said, I do use the bike daily - if it was to be left for more than a few days I'd turn the tap off.

[Coyote]

It is indeed a vacuum feed to the fuel tap. Should you feel the desire to bypass it, the instructions are at: http://www.akhara.com/nc30/fueltapmod/index.html
But then you should get into the habit of turning the tap off all the time - I have done the above mod and leave the tap on, and haven't had any fuel leaking out of the carbs; the oil smells free of petrol too.

With that said, I do use the bike daily - if it was to be left for more than a few days I'd turn the tap off.
Interesting, but I'll leave the bike alone. I now know to check for this problem when the bikes next breaks down on me. Just cutting the split end of the pipe has improved it and it shouldn't come off now.

[Morcs]

I had the vaccuum feed problem on the rvf

The hose decided to snap at a set of lights.

Luckily westie found the problem damn fast and I rode home.


Daniel, get a new hose. trust me. If the hose broke it was due to it being perished (its had a long life, with a bit of uv, lots of heat etc...
Once you cut the end off its shorter, and depending how much you took off it might be pretty damn tight and prone to coming off or snapping again.
As soon as I try and lift my tank off the hose comes off..

[Coyote]

I had the vaccuum feed problem on the rvf

The hose decided to snap at a set of lights.

Luckily westie found the problem damn fast and I rode home.


Daniel, get a new hose. trust me. If the hose broke it was due to it being perished (its had a long life, with a bit of uv, lots of heat etc...
Once you cut the end off its shorter, and depending how much you took off it might be pretty damn tight and prone to coming off or snapping again.
As soon as I try and lift my tank off the hose comes off..
I'll try get hold of a pipe. Untill then I think it'll be fine for now and hopefully if it happens again I'll know what to do rather than get a ride home on a trailer

[HenryDorsetCase]

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...

there is a vacuum operated fuel shut off diaphram in the fuel tap. Vacuum in the intake tract of #1 cylinder sucks the diaphram open, allowing fuel to flow.

It is easy to disconnect if you want to, but it is a safety feature. (i.e. you can pull the tank off with the fuel lever set to "on or "Res" and fuel wont come out. It was often disabled on racing VFRs because running for long periods at high speeds wouldnt generate enough vacuum to allow fuel to flow, causing a high speed leanout and fuel starvation.

(according to a website I read....) I disconnected the vacuum hose from my trackday NC30 its pretty easy to do.

[Warr]

My experience with the vacuum petrol setup was on my XJ900. The one on the bike was a bit sus as you would expect after 20 years. In the XJ Discussion forum / CD they suggested that a Kawasaki part number xxxxxxxx was a direct replacement for the diaphram only. So I visited local Kawasaki shop and ordered this obscure part. Cost about $20 and when it turned up it was in-fact identical to the Yamaha part. Sweet !!

I think the concept is great. I have owned some years ago British bikes that if you didnt tuen off the tap you would end up with puddles of petrol on the ground. ..... Tho it made cleaning up the deposited oil easier :laugh:

[F5 Dave]

The mudguard broke off, then it started to stutter as if it wasn't getting fuel but the tank was half empty. .

See the problem is your tank was 1/2 FULL rather than 1/2 EMPTY.

Good to have fixed it, but buy yerself a multimeter so you can check up on things, like if the reg is still working etc. Cost ~ $10 for an elcheapo from DickSmith or Supercheap & you can learn how to use it from the instruction sheet or internet. Even if you just use it to measure the voltage across the battery you can monitor how the charging system is coping.

[Coyote]

See the problem is your tank was 1/2 FULL rather than 1/2 EMPTY.

Good to have fixed it, but buy yerself a multimeter so you can check up on things, like if the reg is still working etc. Cost ~ $10 for an elcheapo from DickSmith or Supercheap & you can learn how to use it from the instruction sheet or internet. Even if you just use it to measure the voltage across the battery you can monitor how the charging system is coping.
Pessimism is the best form of optimism, you always get a better result than you expected :p

Will do. I've had a CDI blow up on me, I thought since I could kick the RG into life I didn't need the battery to be working... lesson learnt. And I ought to learn more electrical stuff anyway.