Im flumoxed

[grizzler]

Ok everyone any assistance with this problem wont get my hair back but it will help me stop making the head sized hole in my garage wall any bigger. My 03 fzs600 foxeye is playing silly beggars. If I ride for several miles at a speed over 70mph she dies as in fuel starvation.  A few on/offs of the ignition and the cards are primed and were moving again. 60 mph is fine she will run all day. So logic says the fuel pump is caput yet it seems to be in fine working order, points and all. So could the tps cause the pump to pump slow?  Even if the tps checks out ok when tested?    Help!!!!!

[joebloggs]

Airlock?
You tried riding at same speed with your fuel cap open, not with a full tank please

[red98]

Have you checked the fuel filter ?

[Shappaeye]

Checked the air filter? Sucking too much air perhaps?

[grizzler]

Shappaeye, she has had a new air filter. no difference. red 98, she has had a new fuel filter. no difference. joebloggs, that's a new idea i will try it out when the fuel level allows.. Thanks everyone. all suggestions are gratefully accepted...

[darrsi]

TPS won't affect it like that.
Next time it does it undo the fuel cap and see if the tank gasps for air.
Or just make sure the breather hole is clear anyway.
Also make sure your fuel tap is turned fully on.

[joebloggs]

Checked the air filter? Sucking too much air perhaps?

Sorry but how the foc would u check the airflow through a filter and if by chance it was flowing more air than usual, would it cause the above symptom.
Check the other two.

[darrsi]

[quote author=Shappaeye link=topic=20224.msg233193#msg233193 date=1464638314]
Checked the air filter? Sucking too much air perhaps?

Sorry but how the foc would u check the airflow through a filter and if by chance it was flowing more air than usual, would it cause the above symptom.
Check the other two.
[/quote]

As long as it's not a leak it would probably appreciate the air at higher speeds, bit like if you added a K&N filter.
If it was an air leak, like at the carb rubbers for instance, the bike would just bog down every time you try and overtake or give it a bit of welly.

[grizzler]

Trust me when i say she can zoom, just not for long..lol.. She accelerates very well and just keeps on pulling.
I replaced all filters when i replaced the engine. I had the same symptoms with the old engine (and no i didn't change the engine because of this problem). The gearbox was on it's last cogs..lol..
I luckily got my mits on a sweet 23000 miler for £50 off flee bay.

[grizzler]

Just had a quick check on the breather and it seems fine. i shall continue  :wall  for now..lol...

[unfazed]

What you need to do is rule things out.

Lift the tank check to ensure the fuel pipe is not kinked and routed properly, it should be routed under the frame cross brace and not over it.
If it is over it reroute it under the cross brace

Check the flow from the Fuel tap, lift the tank turn off the fuel tap pull off the hose and attach a long piece of hose to it. direct it into a can, turn on the tap, there should be a full even flow.

Next is do what Joebloggs suggested, rule out a blocked tank vent and ride it with the fuel cap open. If it is ok with the cap open, clear out the tank vent. Press in the two clasps to release the key and put the cap down but not closed.

If the problem still exists, bypass the pump by connecting the pump outlet to the fuel filter outlet, now fill the tank to the absolute brim, a full tank will not require the fuel pump. If it is ok now replace the pump.

Let us know how you get on

[grizzler]

Cheers for those ideas, fuel pipe is not kinked and routed correctly, the other checks shall be attempted this week as time permits..


Thanks for the advice everyone. More ideas are still welcome..

[Bretty]

Just out of interest.. what tells the fuel pump when to come on and off? And how does it decide when to be on and off?

Mine ticks away when the ignition is first switched on. I assume filling the carbs, but what tells it to stop? Is it constant speed or variable? It's one of those things I've never taken the time to understand.

Sorry to detract from the original post.. although on topic. 

[Shappaeye]

[quote author=Shappaeye link=topic=20224.msg233193#msg233193 date=1464638314]
Checked the air filter? Sucking too much air perhaps?

Sorry but how the foc would u check the airflow through a filter and if by chance it was flowing more air than usual, would it cause the above symptom.
Check the other two.
[/quote]

Just trying to help, heard a call for assistance, so I contributed. I won't do that again in a hurry!


Sent from my iPhone using Tapatalk

[Jules-C]

Just out of interest.. what tells the fuel pump when to come on and off? And how does it decide when to be on and off?

Mine ticks away when the ignition is first switched on. I assume filling the carbs, but what tells it to stop? Is it constant speed or variable? It's one of those things I've never taken the time to understand.

Sorry to detract from the original post.. although on topic. 

There is a pressure switch built into the pump that switched it off

[joebloggs]

[quote author=joebloggs link=topic=20224.msg233199#msg233199 date=1464640810]
[quote author=Shappaeye link=topic=20224.msg233193#msg233193 date=1464638314]
Checked the air filter? Sucking too much air perhaps?

Sorry but how the foc would u check the airflow through a filter and if by chance it was flowing more air than usual, would it cause the above symptom.
Check the other two.
[/quote]

Just trying to help, heard a call for assistance, so I contributed. I won't do that again in a hurry!


Sent from my iPhone using Tapatalk
[/quote]

Don't take my comment to heart, having myths dismissed is good for the forum.

[Fazerider]

You say you've changed the fuel filter, but there are three in all...
It'd be worth checking the one in the tank attached to the fuel tap and the little one in the T-piece at the back of the carbs.

[Shappaeye]

[quote author=Shappaeye link=topic=20224.msg233220#msg233220 date=1464649684]
[quote author=joebloggs link=topic=20224.msg233199#msg233199 date=1464640810]
[quote author=Shappaeye link=topic=20224.msg233193#msg233193 date=1464638314]
Checked the air filter? Sucking too much air perhaps?

Sorry but how the foc would u check the airflow through a filter and if by chance it was flowing more air than usual, would it cause the above symptom.
Check the other two.
[/quote]

Just trying to help, heard a call for assistance, so I contributed. I won't do that again in a hurry!


Sent from my iPhone using Tapatalk
[/quote]

Don't take my comment to heart, having myths dismissed is good for the forum.
[/quote]

That's a good point actually, now I've stopped crying into my helmet, I understand, thank you.


Sent from my iPhone using Tapatalk

[grizzler]

Some very good ideas have been put forward here and i thank each and every one of you for them. Re tank open--- It made no difference so i'm going to remove that possibility. I checked the T piece filters when i had the carbs off during the engine replacement and they are fine. I've not checked the tank one yet but will as soon as i can though the fuel flow seems fast and constant when poured directly from the tap. getting a bit stressed now as i'm due to take on Germany in 3 weeks and still cant find the cause.. German autobahns at 60mph is not appealing..lol...

[joebloggs]

I'd take a quick look at the carb diaphragms just incase they are perished or split. Could be that its not starved of fuel but that the slides wont lift high enough