Stalling problem on '94 XJ400

Hi guys, I bought my XJ400 a few weeks ago, rode it back home (15 miles) and 4 times since. I really enjoyed riding it but now have a problem and I am hoping somebody can help me.

It is my first bike and although I don't have any experience in repairing bikes, I am quite technically minded and don't mind getting my hands dirty.

The last ride, I was on my way back home, after about 20 miles, going up a slight incline I noticed the engine cut out. The throttle did nothing but the weight of the bike kept the engine running in gear until I came to a stop light at the top of the hill. Ihinking I had run out of petrol, I switched the fuel tap to prime and got the bike started again after a couple of attempts. I switched it to reserve and kicked it into gear but as soon as I tried to rev the engine, it cut out. I started again and the same thing happened so I switched it back to prime and tried again - same thing.

I was lucky that I was round the corner from a petrol station so pushed the bike a few mins and filled up. I started the engine without any problem and managed to get the revs high enough to move off - then it cut out again! I sat there with the engine running a couple of mins and tried to pull away, keeping the revs quite high but as soon as I got to the slight incline to leave the petrol station it cut out.

I called the AA (breakdown recovery) and the guy checked a few things out and told me it seemed like the fuel pump had failed. He showed me the fuel filter and how it was half full of air and how on the centre stand I could tilt it back a bit and the air would go through and cut out the engine.
I got the bike towed back home and found a suitable replacement on ebay and switched them over myself.

There was nothing wrong with the fuel pump - I still had the same problem. Since then, I have checked the voltage going to the pump which was around 12 volts and replaced the fuel filter, including emptying the fuel tank and cleaning out all the fuel lines. The fuel I emptied from the tank was kind of jelly like - not very thick but I decided to use fresh and also put in some fuel system cleaner. I still have the same problem although with the choke out, the engine seems to run ok and revs ok too.

It's been a couple of weeks since the breakdown and I really feel like giving up and selling it on now as a non runner. If anybody has an idea what the cause might be, I would really appreciate suggestions for what to try next.

Thanks

Andy

 

We have a fuel pump? I thought ours was gravity/vacuum operated. Are you referring to the petcock, or is this just a hole in my knowledge? (second thought: realized, this is a '94? Maybe they did put a fuel pump in...)

However, running that fuel through your system has probably messed everything up, unfortunately. You should have emptied it before riding it even once. Aside from a possible petcock issue, the entire fuel system is going to have that crap 'jelly' (seriously?) gas gumming up everything. The wizards are probably going to come in here and tell you your carbs will need to be taken apart and completely cleaned. It might run ok on the choke because you got lucky and your enrichment circuit isn't completely gunked up and is giving you some fuel to make up for the loss from everything else gumming up.

I'm still an amateur myself, but that would be my guess from what you're describing. Let's hear what the experts have to say.

 

Jelly sounds bad.

It should certainly be worth flushing out the petrol tank and making sure that whatever else goes in is clean petrol. The Americans talk about off things happening to their petrol, but over here we're usually okay. Whereabouts are you ?

You might be lucky and be able to drain the carbs and flush them out with clean petrol, but other than that jelly in the carbs is going to mean it needs to be cleaned out.

I wondered about the fuel pump too...

You're sure that your fuel was going solid ? If you have lumpy fuel it could even be just blocking the fuel line, but that really WOULD be lucky.

 

I think the "jelly" description is misleading.
When I emptied the fuel tank, it went into 2 buckets.
1 looked cloudy, the other, only half full I started to empty back into the tank until I noticed the clean fuel was sitting on top of some slightly sludgy looking fuel.
When I cleaned out the fuel tank, attached to the fuel tap were 2 tubes which went up to different levels inside the tank and there is fine gauze at the end of these tubes - anything too thick wouldn't have gone through.
Anyway, the recovery guy and I had the bike running for a good 10 mins - without the choke and it ran ok.
The fuel pump is connected to the fuel filter and the one I took off, connected to my trickly charger for a second did pump fuel out of itself.
If I start the bike up, it will run for a few seconds before the revs start to die off.
Hope the above comments help you to help me further...

 

you mean *with* the choke it ran ok, right?

fuel filter--the inline fuel filter? Still waiting for someone that knows about an XJ with a fuel pump, that's news to me.

sludgy is very bad. You should probably pull the carbs off and look at them. The tininess of the passages in there will surprise you--it doesn't take much by way of 'sludge' to clog them at all.

Basically, as far as I can tell, it sounds like your bike isn't getting fuel. No reason to assume it isn't getting air; no reason to assume it would suddenly start flooding itself periodically; you sound like you are getting spark; you evidently still have compression. All of that means that you are probably not getting enough fuel.

Fuel goes from tank, to petcock, to inline fuel filter if you have one, (next is apparently your mystery 'fuel pump'), to the carbs, through the boots, and into the cylinder, explosion, out the exhaust. Carbs are the smallest bottleneck in that system, and are thus prone to getting clogged if the system isn't maintained.

Next is a possible petcock issue, those go bad sometimes. There's guides here for rebuilding the petcock, if you search. Replacing it is also an option.

I don't think you're just blocking the fuel line (that WOULD be awesome luck), but you could always pull them off and check pretty easily.

 

UKAndy - - can you give us your VIN # please !!
There's only 1 XJ with a fuel pump that we know of - - it's the TURBO,
Except the oddball water-cooled XJ400 JAP market bike might have a fuel pump. A picture would be good, too.

Best advise for you right here on XJBikes !!

What you described sounds like tainted water in your gas bogged you down.
The bike idles on gas, but the MAIN JET dips into the water.

You would want to drain your carbs at the bowl screws, with the screws out, blast some carb cleaner in there, tape a bolt to a small hose and siphon your tank again, working the end of the hose into the corners. Put a bottle of HEET or fuel de-icer in the tank as an added measure, then run it set on "RES" for a bit.

 

The XJ400 is an import version of an XJ600 Diversion - Seca II to most of the members here. Yes, it does have a fuel pump!

Sounds like the carbs to me - but Andy desperately needs a service manual. A bit of Googling might come up with a free one - or a secondhand one from ebay.

 

Thanks to all for the replies so far.
It is a jap import XJ400
It was the inline filter I replaced.
I'm no expert but surely if the carbs were blocked then running and revving the engine with choke on would flush it out?

 

No. My old 600 ran like a dog until the revs reached 4000. The pilot jets were blocked,
Did the bike come off ebay? It is likely to have stood/been a problem to the previous owner if it wasn't ridden over the winter.

I have sent you a PM with a suggestion as to where you can download a manual. Read the section on carbs and you will see all the intricate passages and jets from the pictures.

Post your location - there are a few UK members!

 

Thanks Markie.
I had previously found that user manual online, couldn't find one in english either.
I've been thorough it twice now looking for what you've described without success.
Can you tell me which page you're referring to?
I did search though the forums before posting and came across a thread entitled confirm my carb suspicions so I have a rough idea where to start anyway.
There was something about setting the float height, is that something I will need to do after cleaning them out?
I got the bike from gumtree and the previous owner said he had ridden out recently.
p.s. I'm in Newcastle

 

Thanks for the instructions TIMEtoRIDE
I'm not clear on the bit where you say "tape a bolt to a small hose and siphon your tank again"
When I drained the tank, I disconnected the hose from the fuel filter and let it pour through into a bucket - took about 15 mins but completely emptied it.

 

If you stand your tank on end, and tape or zip-tie a bolt or fishing weight to a small hose, you can get to the bottom corners of your tank and suck out every last drop of water, if that is your problem- -

Speaking of water, is your bike water-cooled??

Can you post your VIN ?? I'm sure there's a few curious people waiting . . .

 

Sent another PM with another suggestion, hopefully in English!!

 

TIMEtoRIDE - thanks for the suggestion and explanation
I emptied the tank completely, even removing the petcock but I did pour some of the liquid I removed back in and now that I think about it, it was very clear looking. Is fuel normally so clear?
It was the last to come out - would the water sit on top of the fuel in the tank?
The frame number is 4BP-027031

Marky - Thank you very much - a full haynes manual, in english!
I had a look and it gives clear instructions on everything I need so I will definitely be giving this a go at the weekend.

One question though - a suggestion above mentioned cleaning the carbs by removing the bowl screws and blasting carb cleaner inside - would I be risking flushing the dirt / crap further into the engine by not removing the carbs completely. It seems like a much quicker and easier option than full removal and overhaul but I don't want to risk a much bigger job by trying a quick fix.

 

I had a look through the carb faults page of the manual - and Haynes says it can be virtually anything!

I guess it is going to be a process of elimination to track down the fault but try and eliminate the simple things first, based on how many miles it has done and if it has stood for any length of time.

Has somebody thrown the air filter away (Or is it exceptionally dirty)?
Worse still, has somebody fitted pod (Individual) filters?
Was there water in the tank?
Are the spark plugs gapped correctly?
Is the bike firing on all 4 cylinders?

I think it is straightforward to remove the carb rack and then access the float bows and jets.

DO NOT separate the carbs from the rack keep them together!

You will need some carb cleaner (athough I used isopropanol alcohol as we have it at work) decent screwdrivers and a compressed air supply to clean out the jets and passages.

Have a look at the carb cleaning "Stickys" on the site - yours are slightly different but they do the same job.

Dirt from the carbs will not hurt the engine.

 

If you've got gas jelly, that means the bike had been sitting for an extended period of time.

This means you have alot to investigate if you want to get it running correctly.

I would not recommend spraying carb cleaner directly into the carb bowls because it can eat away rubber seals which will cause you more problems. The carbs need to be removed and cleaned properly.

 

Been thinking about it again this morning.
Is it not strange that the top half of the inline fuel filter is full of air?
I thought that indicated a blockage but after changing the filter & checking the lines I didn't find anything. The sludgy fuel was not thick enough to block anything anyway.
The fuel pump whirs into life for a few seconds when switching the power on, I thought this was normal?
My thoughts were that maybe there was a circuit which fires the fuel pump controlled by the engine speed. I will check the haynes but as it was for a 600, I'm pretty sure I won't find that info there...
It almost seems like the higher idle using choke is pulling the fuel through but switching it off and revving doesn't get it past the point of sucking the air through first.

 

YOU NEED TO CLEAN AND THEN PROPERLY ADJUST THE CARBS.

That's the solution. Period. If you found "jellied" fuel, then there is some in the carbs that's now harder than jelly.

There IS NO QUICK solution.

This is a true statement; and it reinforces all of the answers you've been given so far.

Have at it.

 

THANKS FOR THE CLARIFICATION FITZ

I suppose it was only a matter of time until a jerk chimed in - this a chat forum afterall.

Anyway, I guess nobody else thought the extra information meant anything so I will go on as planned with the carb cleaning at the weekend...

I'll update you guys on the progress. Thanks to all who have helped so far.

 

Both of this jerk's XJs run just fine, thank you.

Oh, and you might want to take a quick stroll through "XJ FAQ Suggestions" and see how many photo "how-to" articles this jerk has written.

Just to help out fine upstanding gentlemen like yourself, who seem to spend more time trying to figure out quick and easy solutions to problems that don't have one than they do diving in and doing the work.

Oh, and once you get the carbs clean, you'll need the valves in spec to be able to adjust them properly.

 

I appreciate your suggestions.
I appreciate your helpfulness to beginners like myself with the guides etc.
I do not appreciate the tone of your first reply.

 

Andy - is this your bike??

http://www.ebay.co.uk/itm/1994-YAMAHA-X ... 2082633099

What a BIG oil cooler for a 400 !
When water gets into gas, it attracts all the dirt and dust into the water, due to polarity and surface tension, leaving the gasoline clean and floating on top.

 

Similar to mine but:
I have an exhaust each side, the handle bars are different. The rear suspension is a single unit under the seat and the seat is plain and no strap - same shape though.
The front brake is only 1 disc but everything else looks almost the same...
I'll post pics at the weekend for all interested.

 

Dude, Calling Fitz a jerk is the wrong thing to do. Fitz is probably the most helpful person on this forum. You really don't want to burn that bridge.
Fritz is cool. There was no tone. He simply likes to stress the most important things.

 

Simple facts of the XJ world....

If Fitz or Rick tell you you NEED to do something...
DO IT , it's that simple

 

I have to agree oldbikerdude. I always find fitz's posts helpful while thread searching. The "tone" of his replies are probably due to having to tell people with performance issues the same things over and over again, most of which is regular maintenance that should've been done prior to posting the "problem" on here anyway. Go do a search on valve clearances and see how many times he has told people to check them and you should understand his "tone". Just my opinion

 

I already mentioned that this is my first bike and I'm looking for advice.
I posted information about the problem and got some helpful suggestions.
I thought I may have missed some important information so posted it.
No matter where you're from in the world, on the internet CAPS MEANS SHOUTING.
I don't care if this is his website, if he sponsors it or just posts helpful stuff for others - that post by Fitz was rude and uncalled for.
If the information didn't seem relevant then that was all that had to be said not STFU NOOB

Anyway, on to the reason I started this thread...

I cleaned the carbs and the bike fired up first time, it was running a little rough for a minute or so. I just left it idling, then carefully increased the throttle building up the revs and hey presto! The bike now seems back to normal.

Thanks for the help guys.

As promised, here are some photos of the bike and 1 of the spare fuel pump.