FZR600 Fuel pump question

[Pr1ngle]

Hi there, I'm looking for an answer to a theory I have.

My partner recently bought a 95 Foxeye, it looked like it was a clean bike, until it arrived at home (dealer through ebay job, whoops!!).
Whilst the engine appears to be sound, and it's covered 22,000 miles, unfortunately somebody previous to us tried to "Track Prep" her and did a terrible job.

We quickly discovered that the fuel light didnt work, upon scouring these very forums and several others i decided to investigate further and found a splice wire running off one of the wires coming out of the fuel pump on the tank. I've reconnected the wire as it was hanging loose, still no fuel light, now though, the tacho is hopping round to 8k rpm, back to 1k rpm, then back to zero. Again, i did my research and found that one of the members on here has posted a video to youtube, watched that, and found that it meant something was wrong with the fuel system.
...my conclusion, whoever track prepped her disconnected the splice wire to avoid the 8k fault code.

I then stumbled across someone that mentioned the fuel light could flag up the 8k code, so i pulled the bulb to check it. Though there was NO BULB there to light up. I've fitted a bulb i knew was good, turned the ignition on and bing, it lit up!

So, I now have a working fuel light, and a tacho that DOESNT show the 8k code, although the fuel light is now permanently ON.

It's at this point I should drop in that i know the fuel pump is knackered, as it doesnt prime when the ignition comes on.

Which leads me to my theory...
We also have an '89 Exup 1000, it's fuel pump is external to the tank.
My theory is that if i buy an external fuel pump (£20 as opposed to the £471 CMSNL want for an internal one) and fit it, that the fuel pump should work as normal.
Though, the FZR 1000 doesnt have a fuel sender unit, i'm curious as to how it switches onto reserve, which perhaps is a question for the guys over at exup1000, but i was wondering if anybody knew on here as I cant be the only one that has had this idea.

Has anybody fitted an external fuel pump? Did it work as it should normally? Is there any way I can fix the fuel pump myself? (I'm quite competent with a spanner, but i dont want to budge that fuel pump seal under the tank without knowing i can sort it first). If I do buy an external pump, what PSI should it operate at? The one i'm looking at is 1-2PSI.

Thanks for the help, sorry if this is considered a repost, I've spent the day searching this particular subject and come up with nothing. Cheers!

[DonTZ125]

Before you declare the pump toast because it doesn't come on with the key, there are several other things to check. First and foremost, does the pump chatter when you hook it directly to a battery?

The FZR1k does have a sender unit, but it only goes to the TCI. There is no gauge or indicator light; the ignition cuts out either the pump (so the bowls empty and you run out of fuel) or it cuts the 2-3 spark channel, and the bike runs like a bag of hammers. I'm not sure which is correct; I don't have one myself, and I've read both versions. When the RESERVE switch is thrown, the TCI decides you know that you're low on gas, and turns back on whatever it turned off.

The fuel pump on these bikes is is a simple lift pump, getting the fuel from the bottom of the tank to the carb bowls. (Above ~ the 2/3 line, you don't actually need the pump, although "running out of gas" at 2/3 full is pretty annoying.) 1-2psi sounds about right.

[willandrip]

The fuel level sensor of the 1000 unit is inside the tank and is a complex system.

It is basically a thermal unit kept cool by fuel, when the reserve fuel level is reached the sensor heats up being no longer cooled by fuel, forms a different resistance that is monitored by the TCI unit which in turn drops spark to one coil emulating carbs running out of fuel.
When the reserve switch is operated the system is bypassed and the TCI reverts to normal operation.

My recommendation is source a guaranteed replacement stock unit from a breaker if you are 100% sure the original is defective.

An old 4JH before refurb;

[Pr1ngle]

Hi guys, thank you for the replies, they are exactly what I was hoping for.

I hadn't bench-tested the fuel pump yet, I didn't even think to do it which in itself is a rookie mistake but I shall make it a priority tomorrow.
I just had a look on ebay and saw a Fuel Pump Relay for a '93 bike, is it safe to say that there is also a relay on the '95 as well? It isn't clear on the microfiche i'm using if there is one, it just mentions "relay" but doesnt say what it's for. Whilst i'm testing systems I might as well hunt for that too. There is a relay on the bike but it looks like it had a fire at some point, I was assuming up until now it was the headlight relay (definitely not the ignition relay either).

Ultimately we can live without the Reserve function. My Speed Triple used to manage 80 miles before it needed refilling, so it's just a case of being vigilant and perhaps keeping a Litre of Fuel under the seat in case of emergency.

I wish the missus would have bought a 4JH as clean as that, as it is, her's is wearing Fibreglass race fairings, and is missing it's passenger subframe, i'll try and get some photo's up of the pair of bikes so you can both have a laugh. One of them is a Turd pretending to be a Tulip, the other is a Tulip pretending to be a Turd haha!

Thanks guys!

[DonTZ125]

The fuel pump relay is part of 3EN-81950-00-00 RELAY ASY, along with the starter cut-off relay and a selection of diodes and a resistor. As seen in the pic, it has a rectangular 11-pin connector; check the manual for testing procedures.

[Pr1ngle]

Don, you're a Scholar and a Gent!

Unfortunately I got called in to work today to cover one of my Staff's sickness so I haven't had chance to look at the bike. My next day off is Thursday so I shall sort It then!

The bike didn't come with a manual, I know it's a lot to ask but do you know of one on the net? I've had a quick Google and found Carl Salter offering them for free, though the dont have either the FZR 4JH or the YZF 4JH listed. They do however have the later models available.

Thanks in advance!

[DonTZ125]

The 4JH manual is an elusive beast; fortunately, the FZR600 3HE used the same relay assembly, as did the FZR1000 (all years) and the YZF750. The later 4TV YZF600 did NOT use that part.

[willandrip]

Which manual ?

Service manual.....hosted on 400Greybike;
http://www.400greybike.com/files/FZR600 ... %20(1).pdf

95 Supplement ;
http://www.400greybike.com/files/FZR600 ... ce-sup.pdf

An original owners manual is easily obtainable used at auction for about £10.
Unusually for Yamaha they are quite thin to fit under the seat and only in English ...not the usual 15 different languages and thick as the phone book.

[DonTZ125]

That's not the service manual; just the specs etc. 40pp? A monkey bike comes with a thicker manual!

[willandrip]

Right.....You find a better one for the lad...

f*ck me no wonder this forum is dead as a dodo.

[Pr1ngle]

okay gents, so far i've managed to swap the relay over from my thou onto her 600, the relay on hers is making my fuel pump prime, and my relay is doing nothing on hers so that's telling me that it's definitely the pump that's the issue, not the relay.
I taped up the "scorch hole" on her relay for the time being, looks like it just got a little too hot whilst touching something as it's "loose", not pinned to the bike where it should be.

This wire that needs soldering on the actual pump? Either of you gents got a picture of it? Or can you point me exactly at it via a walkthrough? Also, is it common to need a new gasket if i take the fuel pump out of the tank? my thoughts being if it's a rubber gasket, it should be reusable atleast once?