VFR owners' thread, for VFRPS members and prospective members

[vifferman]

That vacuum-operated fuel tap was a real bugger at times. Had one on my VF500 - ran from the tap to the left rear intake manifold. It either sucked air in, making that cylinder run lean, or sucked fuel through the petcock diaphragm, making it run too rich.
One other thing - you said the bike was rotting and you had to weld and bog the tank. Are you absolutely sure there's no rust flakes getting into the carbs?

[Theflash]

Thanks all, there is already a vacuum line going to the fuel tap, but I'm still thinking it is a vacuum/ petrol problem.

I pulled the fuel tap apart already had to drill out the rivets (fitted screws) and clean gunk out of tap seal.

Going to run the beastie with the tank and air filter off to see if i can nail it.

Anyone know if the CDI boxes pack up, there is one on TM for $50, maybe buy it and see if that's the prob, if not good for spare (LOL).

Will keep you informed.
G.

[Theflash]

Re rust in carb, I apoxy resined inside the tank (apoxy meths mix), should have bonded down any rust. I bled the carbs before running to check rust, all OK.

The problem seems universal. EG: all cylinders are doing it, so i figure it is a vacuum issue or something.

[motorbyclist]

are you sure the vacuum lines to operate the CV carb diaphragms are intact and connected?

what do the plugs look like?

Is it the vacuum line?

On my NC30's, there is a vacuum line running from there to the fuel tap. Runs quite rough without it on there.

Not just run rough, my NC35 used to cough and splutter to a complete halt at lights then fail to start if the vacuum line came off..

+1 technically the bike shouldn't run at all without a vacuum opening the diaphragm to supply fuel to the carbies....

i'd be concerned if the bike still ran long after it should've died...

[Morcs]

+1 technically the bike shouldn't run at all without a vacuum opening the diaphragm to supply fuel to the carbies....

i'd be concerned if the bike still ran long after it should've died...

Do you remember the first time it happened to you?
I was stuck on the pavement for ages trying to figure out what was wrong

[koba]

Re rust in carb, I apoxy resined inside the tank (apoxy meths mix), should have bonded down any rust. I bled the carbs before running to check rust, all OK.

The problem seems universal. EG: all cylinders are doing it, so i figure it is a vacuum issue or something.

Are you using a good battery?

[Theflash]

are you sure the vacuum lines to operate the CV carb diaphragms are intact and connected?

what do the plugs look like?





+1 technically the bike shouldn't run at all without a vacuum opening the diaphragm to supply fuel to the carbies....

i'd be concerned if the bike still ran long after it should've died...

Yes, the Vacuum cutoff is working fine, the "bowls" of the carbs are full of petrol. Im gonna run it with the tank off today to see if I can find the problem.
Cheers.

[Theflash]

Are you using a good battery?

Battery was stuffed, but I'm using a new sealed lead acid, starts the bike fine and is about 14.2V when bike running.

[Theflash]

Still after a look at a NC21 or NC24 to see fairing mounts, if anyone has one and I could come over with a digital camera.
E-mail theflash@vodafone.co.nz

[koba]

Still after a look at a NC21 or NC24 to see fairing mounts, if anyone has one and I could come over with a digital camera.
E-mail theflash@vodafone.co.nz

http://www.kiwibiker.co.nz/forums/sh...00#post1731113

[Theflash]

Damn it, it was the vacuum cutoff, must have been restricting the flow a bit.
Took it apart and moved spring to other side of diaphragm. I guess the "bowls" don't hold much petrol and it was using it up reasonably quick and bogging out.

Cheers all for help.

G.

[motorbyclist]

are you sure the vacuum lines to operate the CV carb diaphragms are intact and connected?

what do the plugs look like?

Yes, the Vacuum cutoff is working fine, the "bowls" of the carbs are full of petrol. Im gonna run it with the tank off today to see if I can find the problem.
Cheers.

so not checked the plugs and those aren't the the vacuum lines i was referring to....


good to hear it's sorted though

[gatch]

Does anyone have a shim kit that they wouldnt mind loaning out ?

NC30 sin machine is nearly at 20k, thought I should give it a birthday..

[motorbyclist]

NC30 sin machine is nearly at 20k, thought I should give it a birthday..

pffft is that all!?

[gatch]

Yeah man

Was imported from Japan in January this year. Had 15k on the clock then, has just passed 19k now. Only things I am not happy about are the IRC tires, and I suspect the carb jets weren't adjusted when the owner in japan put on the yamamoto can..