New Yamaha Petrol Tap and still no fuel in filter XJ650

Hi gang,
Finally arrived. Genuine Yamaha Petcock.
Though I had the problem licked.. No issues for two days until I thought I was going onto reserve yesterday. No joy...My bike limped to a halt and yet again no fuel to be seen in the glass filter. Even happens on prime.. I had to blow into the tank to get her home.So I cant think of anything else other than the petrol cap. I took her apart and blasted her through with some high pressure carb cleaner. Some crap seemed to come out where the key fits in.
This morning when I started her I noticed when I put my thumb on the keyhole I felt a small bit of suction through the cap. So now I am hoping the problem is solved.
Any ideas.?
Thanks as always,
Morg..

 

You also might want to check the vacuum line from the #3 intake to you fuel petcock. I think I read somewhere that you need to make sure that it is a vacuum line and not rubber tubing as it might get to soft from heat and collapse flat having the same effect as turning off the bike by shutting off the fuel. just a thought..

 

Thanks BruceB
I checked the vacuum line..Anyways..my understanding is that the vacuum has nothing to do with the prime position on the petcock.
It only kicks in when the petcock is in the "on" and "res"
Prime should flow freely without the need for vacuum.
Thanks for the advice.
I am hoping its sorted now..
Morg.

 

How much fuel do you actually still have in the tank? Sounds like you are really out of gas.

 

Hey hogfiddles,
Doesnt cause much issue if the tank is near full.
It usually happens when I am lowish. I am trying to see if reserve is working and this is why she is low at the moment. Without reserve kicking in its easy to run out altogether.
Thanks again,
Morg.

 

Then pull the petcock back out and check to see if the 'tower' fell off. I've had that happen. Problem there, I'd never hit reserve........just run out. It would stumble just like time for Res, I'd switch over, but it was already way too late. LOL

 

Petcock is new out of the box and the tower is well tight. I checked it before I fitted the tap.
Am I right in saying that when the fuel is sucked out by the vacuum air is also sucked in through the vent in the gas cap.? Reason why I ask is since I blasted the cap yesterday I can feel a bit of suction when I place my thumb on the keyhole on the cap when the engine is running.
Or am I simply losing the plot here lol.

 

Yes air must be able to get in through the fuel cap vent so the fuel can get out. I'd say the fuel falls/flows out rather than sucked out, it's that damn gravity we all live in. Have you tried with the fuel cap unlocked while riding-not too full of fuel tho that will slop out- if the fuel flows properly with it open then you need to dismantle and clean the cap.

Compliments of Schmuckatelli Heavy Industries a How To, pizza optional
http://www.xj4ever.com/gas%20cap.pdf

 

Thanks Bushy,
This is the thing.. I dismantled the cap yesterday and blasted it through with high pressure carb cleaner. Looks like some crap came out of the keyhole.. Now I can hear a hiss of sorts and am hoping its sorted now.
Morg.

 

Just a thought. How clean is the inside of the tank? I worked on a Radian that the fuel line was packed full of rust from the inline filter (which was in backward) to the fuel valve.

 

Tank has been flushed out a number of times. Filter is new as is the fuel line.
I'm convinced now that air wasnt getting thru the fuel cap. Hope I havent jinxed it now hehe.
Thanks bmarzka..

 

The pizza is NOT optional

 

i kinda like the smell of petrol in the morning but pizza's give me indigestion

 

Not my cup of tea first thing either first thing.
Gonna see how she goes now.. Letting her run low so I can see if reserve works. I would assume that XJ's run better with a full tank though... Fingers crossed eh....

 

Next time it happens open the gas cap and run it that way and see if it fixes it. You will be low on fuel at that point is sounds like so spillage should not be a problem unless your on rough roads or something.

 

I wouldn't mind coming to your beautiful island and helping you. Maybe tip a couple of pints of Killian's while we ponder the possible remedies of the situation. Might even get it fixed. Anybody up for a road trip?
You MUST post pics of your bike and the scenery.

 

Gang, Tearing me hair out now..
Still no luck..She can go a day or two no problem and then dies at the side of the road. I have no idea whats going on.
Yesterday I took the fuel hose off the tap and on prime fuel lashed out. Soon as I connect the hose all is well but 20 miles down the road and empty fuel filter again.
This time I had to blow into the tank to get the fuel going.
The tank has been flushed twice, the tap is new. Just cant understand why sometimes the filter dries up.
Even tried with the gas cap open. Anything else I am missing.?
Thanks all.
Morg.

 

Fuel line kinked or air lock in fuel line or vac' line from tap to manifold not actually vac' line and it closes /compresses with vacuum or vac' line kinked.. ??

 

Thanks Bushy
Are you saying that the vac line will prevent fuel flow even on prime.?

 

I know the petcock is NEW, but it might be worth it to take it apart and check it out. Seriously, there could be some assembly error that is causing this. I don't think it's too far fetched that someone could have assembled it wrong (I do that all of the time after a few beers).

The fuel should flow just fine on "PRIME" regardless of vacuum.

Maybe try bringing an extra length of vacuum line with you on your next outing. When it dies, immediately pull over and throw it on. If fuel line starts filling up with gas when you suck on the thing, I guess there's a vacuum issue.

How quickly does the fuel line fill back up? Like drip-drip-drip, like when you start messing with it, or quickly?

 

No not on prime, engine doesn't need to be running for prime to work.

 

Thanks lacucaracha
That's the problem..This also happens when on prime.
I dont think its the fuel tap... Its a new genuine Yamaha out of the box.
Had the same problem with the old tap..This is why I replaced it.. So I doubt its the tap to be honest.
Drip drip drip..Unless I apply pressure to the tank by blowing in.

 

At home, engine off, take off the fuel line put the end in a container to catch the fuel turn to res', cap closed. You should be able to drain the tank, if the fuel stops or goes to a trickle open the cap, see if it flows properly. I'm out of ideas.

 

I don't get it. The fuel will still slow-drip with the cap open or closed? To me, that points straight to the tap. There is no other explanation. Like Bushy said, you have to see what it does without the fuel line connected.

There's only one more thing this could be, and the fact that it seems to happen after riding a bit....

Some shit in your tank.

But honestly I feel like the diaphragm is not working properly. I think your vacuum line is collapsing. Try a NEW NEW line. It will cost a few cents(pence?) and seems like all of the symptoms point to it.

 

Has the inside of the tank been coated? It's possible the coating has peeled off and is flopping over the fuel tap.

 

Thanks lads,
It does it on prime as well. So I don't think its the vacuum..
Earlier today I removed the fuel pipe from the tap and on prime the fuel flowed out. Just checked a few minutes ago and the filter is three quarters full..An hour ago she was empty. Left her on prime.
I can go a day or two and then she stops. There is over half a tank of fuel now. I have flushed out the tank twice in the past week. Its not bad inside from what I can see.
Just wondering if I'm getting an air lock somehow. This problem was there before I replaced the petcock. Still there with the new petcock so I aint suspecting the tap. It must be something else. Maybe the fuel line is too rigid.. Perhaps a softer hose maybe.

 

What filter did you use? How is it positioned? Air trapped in the filter will prevent fuel from flowing. Too fine of a filter media will prevent fuel from flowing in a gravity feed system. A paper-eliment filter can prevent fuel from flowing in a gravity feed system.

 

Thanks k-moe,
You could be onto something now. I changed the filter a few months back. This is around the same time the problems started. Its pointing downwards and not level. Looks like paper inside. But if its the type of filter would it not prevent fuel flow all the time as opposed to every day or so.?
thanks a mill.
Morg.

 

Thanks all.
Gonna change the filter and position it closer to the tap.Where she is now is below the number 1 carb. It is possible that if I place the new one inches away from the tap it may solve the problem. Also gonna change the vacuum and fuel hoses too. Before I have no hair left hehe.
Cos this problem seems to coincide with the fitting of the filter. Fingers crossed and HAPPY Friday.
Morg.

 

Uh huh " filter below #1 carb " = air lock to me, get it and the fuel line above the carb's. Gotta keep in mind that damn gravity and where air bubbles like to sit. Blowing in the tank forced the air bubble to go down rather than up where it wants to be.Well..that's another 2 bobs worth from me.

 

Thanks Bushy.. there's a pint of the black stuff with you name on it if yer ever over.
That goes for all of ye that chipped in.
Morg.