Me....numpty!!

[wildwill]

Hi all, firstly,apologies for my lack of basic knowledge of how my bike works. I'm trying to do some basic maintenance and it looks like I've fell at the first hurdle.
I've took the tank off the bird, along with all the plastics and the air filter and filter housing. I've changed the plugs and oil and the petcock diaphragm. When I went to start the bike just now, it fired up but was running dead rough before it cut out. I've got the fuel tank on the bench with hoses about 3 feet long running to the bike. There's no fuel getting to the carbs.
When I disconnect the fuel lines and let them hang down, a small amount of fuel runs out. When I turn the fuel tap on, should the fuel run freely out of the two outlets or is it drawn to the carbs by a vacuum?
I've double checked the petcock assembly but if that could be the problem, I have no reservations about starting again.
Any advice warmly welcomed, I'd hate to have to take the bike to a mechanic, cap in hand.

 

[wildwill]

Quick update:
I raised the tank and the bike started...woo hoo!1 However, it only seems to run normally on full choke. When I knock the choke off, it sounds like a tractor. Maybe I should forget the idea of balancing the carbs and just put the air filter and tank back on and take it from there.

 

[ianrobbo1]

Glad you've discovered gravity, might it be an idea to drag someone that knows how to do the job and watch as he does it, rather than plunge straight in, I found it to be by far the cheaper easier option !! :dunno:

no offence intended.

 

[Jaws]

Welll.. as you discovered the tank has got to be above the carbs.
There is no pump and the fuel is just gravity fed..

Canna answer as to why it is running so rough without choke.. but a couple of ideas..
Are the carbs seated properly on the inlet manifolds.
Over the years I have seen more than a few where the jubilee clip has been over tightened and effectively squeezed the carbs up and off the rubbers..
A nice big air leak and you have the symptoms you are suffering

Have you refitted the vacuum pipe to the inlet manifold and tank ?
Have you confirmed the petcock is working ok by turning the tap on and sucking the vacuum pipe ( put a bowl under the petcock to catch the amber liquid though )

 

[wildwill]

Thanks for the advice, Ian absolutely no offence taken mate, if I could rope someone in who could show me how to do it, I'd have him like a shot. Unfortunately, nobody's available
John, I haven't done anything with the carbs and they were fine before I started tinkering, so I'm assuming they're ok. I haven't connected the breather pipe to the tank, but I will do. I'll test the petcock as you say. I take it that when I give it a suck,it should flow freely. Hopefully, when its all back together, it'll run smooth............gulp!!!
Again, thanks so much for the help.

 

[DEG5Y]

Do you still have the air filter box attached to the carb's? That's the the joint JAWS is referring to. The bird doesn't like to run without the air filter on and tickety boo.

 

[wildwill]

Somehow, I thought I'd seen a vid where the carbs are being balanced with the air box and filter missing......doh!! I'm busy tomorrow but first chance I get, all gubbins that I've taken off shall be replaced, and the bird will run perfectly and all will be well with the world.

 

[Jaws]

Do you still have the air filter box attached to the carb's? That's the the joint JAWS is referring to. The bird doesn't like to run without the air filter on and tickety boo.

Actually it aint :-0)
I have seen the carbs 'pinched off' the inlet tract rubbers too !!!

John, I haven't done anything with the carbs and they were fine before I started tinkering, so I'm assuming they're ok. I haven't connected the breather pipe to the tank, but I will do. I'll test the petcock as you say. I take it that when I give it a suck,it should flow freely. Hopefully, when its all back together, it'll run smooth............gulp!!!
Again, thanks so much for the help.

It aint the breather pipe but the vacuum pipe.. The one that attaches to the front of the petcock assembly ( front as in the other side of the unit to the actual tap )
Without it the pet cock will only allow a dribble through at best ( should not let any through really but sometimes will )

 

[wildwill]

Actually it aint :-0)
I have seen the carbs 'pinched off' the inlet tract rubbers too !!!




It aint the breather pipe but the vacuum pipe.. The one that attaches to the front of the petcock assembly ( front as in the other side of the unit to the actual tap )
Without it the pet cock will only allow a dribble through at best ( should not let any through really but sometimes will )

Thanks Jaws, I haven't connected the vacuum pipe, but I'll get it done. I'll post on here and let you know the outcome.

 

[wildwill]

Thanks Jaws, I haven't connected the vacuum pipe, but I'll get it done. I'll post on here and let you know the outcome.

Success! Reconnected the tank etc today and the bike started straight away. It's probably nothing to the more experienced people on here, but I got a great deal of satisfaction knowing that I'd done a bit of maintenance on a bike I've owned for 18 years.
Thanks again for all your help, I've no doubt it'll be needed again.