Strange goings on in the fuel department...

[grizzler]

Hi guys,
I am experiencing a strange problem, well 2 problems but i think they may well be related.
My baby is a 2003 FZS600 foxeye (carbs not injection).
So here it is. I switch her on, let the fuel pump stop clicking and press the button for an instant start with no choke needed, unless deep winter is upon us. so far so good. She pulls well though the revs and has no signs of any problems. Problem 1 is after riding for several miles, say about 10 miles, at low speed stop start at 30 -40mph,  she will bog down on acceleration. If i get to ride at a constant speed of over about 40mph she clears up and runs fine but the problem returns after a few miles of congestion.
Problem 2 is when i get to the faster part of my trip to work i can accelerate and have my arms pulled out of there sockets but,[/size][size=78%] [/size][/size]i cannot constantly run at over 65mph or she dies, dropping to 3 pots then 2 then dies.[size=78%][/size][size=78%] T[/size][/size]hat problem would seem to me to be the fuel pump as when i switch the ignition on and off say 10 times she starts and runs fine. [size=78%]
[/size]Has anyone had either of these problems and found a solution?[size=78%]

[/size]Any help would be gratefully received.Cheers.Chris-a- aka Grizzler[size=78%]

[slappy]

First things I would check is aiir filter to see if it is dirty or the intake is partially blocked.
Check the fuel filter, do you know when air filter and fuel filter were last changed?
Is the air vent in the tank clear?
Is the fuel line kinked?
Check these first as all are easy to check.

[flakey]

you could try releasing the fuel cap, if the caps not breathing then air cant replace the used fuel so youl have a fuel starvation problem, my best guess

[unfazed]

First things I would check is aiir filter to see if it is dirty or the intake is partially blocked.
Check the fuel filter, do you know when air filter and fuel filter were last changed?
Is the air vent in the tank clear?
Is the fuel line kinked?
Check these first as all are easy to check.

:agree :lol Check the easy things first, before you go assuming things.

A common problem is fellows routing the fuel pipe over the frame brace instead of under it and the tank flattens the pipe limiting the fuel flow.
And as flakey says it could be a blocked vent and opening the fuel cap will solve it
Put some white paper sheet under the carbs and open the drain screws to see what crap comes out. The remnants of water petrol mix can be a gelatinous substance (if the bike has been out in the rain and idle for a while) which can clog the main jets.

[grizzler]

Thanks guys... The investigation so far... The fuel and air filter are both Aok, all fuel pipes are not restricted and when i open the fuel cap i hear no hissing noise to suggest a blocked air pipe (should there be one?)
I did however find that the TPS was slightly miss-aligned was reading 10,000 instead of 5,000, now re-adjusted.


The confusing part of this is that Gertie (my babies name) will ride all day at 60 mph but she will drop to 3 pots or less when going faster than 70 for a short time or stop start riding below 30 mph.


I commute a round trip of 38 miles per day (Mon - Fri) and play out at weekend so she is very rarely idle. Weekends just aint the same at 60... (and no that's not my age)

[darrsi]

I've had 2 TPS units fail on me, but they misbehaved rather than just died, with either erratic readings (the first one) or the position stuck on 10,000rpm (2nd one).
Both made the bike run very ropey, although it did still run.

I'm not saying it is this, but certainly worth keeping in mind.

The bike was fine again after replacing them.

[grizzler]

Well Darrsi, i have reset the TPS but need to hit the hay :z  as i am up for work in 6 hrs so i wont know of any difference till tonight on my way in. I'll let you know...

[unfazed]

Out of curiosity how do you know it is running on 3?

[Sannox]

Have you checked the resistance on your plug caps? I had a similar thing on my 02 foyeye, would run no problem except under load but if you got past the 3 cylinder firing and popping, it would kick in and all ok, was worse in winter, I had 2 caps higher resistance, one twice the book value, higher resistance, less spark, poorer running, esp under load, the fuel mix would be too much for the spark. Worth a check.

[grizzler]

Hi unfazed, i admit this is an assumption by the fact that i lose power (3 pots), then more power (2 pots) then dies... if i sit for 5 mins and switch the ignition on and off several times and i can hear the pump priming till it stops clicking then off she goes again no problem until i cruise at 70 or more. It takes about 3-4 miles for this effect to happen but when it does there is no going back till the pump is primed again...


The TPS adjustment had no effect on the over 70 mph problem.


Hi Sannox, she pulls like a team of horses all the way through the revs in all gears but when cruising at 70mph or over she drops power, then drops some more, then dies as above.


I have replaced the fuel pump once and the electronics same effect. It has to be fuel starvation but how???? :wall

[Jules-C]

It sounds like a fuel pump problem to me.  The pump isn't delivering enough fuel to keep up with the engine's needs at 70mph and carbs are slowly getting drained.

[sinto607276]

For my twopence worth....
I had a bike years ago doing something similar... Found out it was rubbish in the tank going through to the carbs, flushed out the system and put in an inline fuel filter and problem solved.
I don't actually know if there's one already on the Fazer but worth a look and even clean that if it has one?

[darrsi]

For my twopence worth....
I had a bike years ago doing something similar... Found out it was rubbish in the tank going through to the carbs, flushed out the system and put in an inline fuel filter and problem solved.
I don't actually know if there's one already on the Fazer but worth a look and even clean that if it has one?

They have a fuel filter, only a few quid and easy to change.

[unfazed]

It does sound like fuel starvation.
Easy to check the pump, lift the tank follow the fuel pipe down to the pump, pull the outlet pipe off and put on a longer one, Direct the free end into a container. Turn on the ignition, turn the kill switch to on. It should pump at an even flow, any variation change the pump or the contacts.
The contacts can pit on the pump causing uneven pumping, not an overly common problem, but it does happen.

However I would remove the fuel tap first to see if everything is clean in there. If that is clean bypass the pump putting the outlet pipe on the pump onto the outlet side of the filter. You will need the tank to be over half full for it to have sufficient pressure to keep the float bowls full at high revs. Make sure you disconnet the fuel pump plug when doing the bypass.

In answer to Sinto there are 3 filters in the fazer a mesh filter on the tap in the tank one large inline filter next to the pump and one small mesh filter in the t-piece in the carbs. Only very fine sediment will get through and lodge in the float bowl. Which is why draining the carbs onto white tissue paper will show.

[sinto607276]

They have a fuel filter, only a few quid and easy to change.

Good to know, noted in my wee book, cheers darrsi.

[grizzler]

Hi guys n gal,


Jules i agree, logically it mhas to be that. i just need to find out why. :'( [size=78%] [/size]



I have had the cap off this evening to check the air balance pipe. There are 2 metal pipes inside the tank, one under the left false bolt for water to drain (i assume) and a 2nd under a nipple which sits in the rubber seal towards the hinge of the cap. This one would seem to be the air balance.
I tried to blow it through but i am not sure i can i would think there would be some sort of return stop so as no fuel could squirt out. Does anyone know how to clear this very thin and seemingly long pipe?


Mr unfazed sir, thank you for that info. I will do the pump check this weekend as i have a gig straight after work tomorrow. If i remember correctly doesn't the back of the pump come off to allow access the points or will i need to repair it after i remove it?

I am awaiting the new fuel filter. The old one looks fine but i may as well swap it.


At least i am getting to play with my tools again...lol...  :eek (mucky minds!!!)

[unfazed]

At least i am getting to play with my tools again...lol...  :eek (mucky minds!!!)

To much information here  :lol


Yes the rear of the pump can be removed to check the contacts.

Push the wire in as you remove the cap and do the reverse when refitting.

Lift the tank and put a hose on the outlets on the base of the tank and you should be able to blow through

[grizzler]

Right. I admit i settled for just getting to work and back and as it was working i left it alone but this time i am going to solve this problem...
Yesterday i changed the fuel filter and today i got about 4 miles from my house and it died. I wasn't going over 30mph and it would not re-prime.
I have been searching for a set of pump points for my 2003 model but i can only seem to find points for models up to 2001.


Are the points different after 2001 (like non existent)?

[darrsi]

Still sounds air related to me, maybe a leak somewhere, carb rubbers okay?