Won't idle for more than 5min then it dies

[kawagirl]

Hi again... just finished introducing myself under NEWBIES... anyway... I bought a GPZ400R recently. It ran perfectly then suddenly started spluttering and overheating badly.

I took it to a mechanic for a service, as he thought the carbs just needed to be cleaned and it just needed an overall good service. I gave the bike to him in October and have just got it back yesterday. He did the service and long story short, just about put in a new engine and rewired the entire bike.

So a couple of grand later I now have a bike that purrs like a kitten, doesn't overheat, BUT, only runs or idles for 5 min then it cuts out. Almost like its run out of petrol. Then I have to let it stand for 5min before it will start again.

The mechanic is at a loss and doesn't know what to do and I am just frustrated with the whole situation.... no I'm just plain pissed off really. Does anyone have any suggestions to what might be wrong with it. He says it could be the head gasket... but after him saying "I think its this and I think its that for 3 months" I don't know anymore.

[Gosling1]

sounds like you may have a problem with fuel flow ??

If this bike has a vaccum fuel tap - pretty sure it does - you need to make sure that the fuel cap breather is clear. If it is not, then your tap will eventually not be able to draw fuel out of the tank - and the bike will stop running. The breather could be a hose that runs out from the rear of the tank, which may be kinked, or it could be a small pin-hole in the cap area, which is blocked.

Leaving it for 5 minutes and it re-starting is the classic symptom of this - while the bike is not running - the pressure in the fuel system equalises, and fuel can once again be drawn out of the tank by the fuel tap......but only for a short period....

The fact that you can re-start your bike after 5 minutes, rules out any issues with battery or electrics, or head gaskets, or any of that other shit.

[HYPE]

good words Gos... was thinking similar

perhaps test the theory by leaving the full cap open and running the bike

[kawagirl]

Thanks will try that this afternoon when i get home... hope it works

[seiko1]

Well maybe 6maniac is wrong!
Had a Honda and some pud had reversed the vacuum hoses......
Running it would suck the fuel valve shut and stopping it would allow it to open...
letting just enough fuel through to run a couple of mins

[kawagirl]

ok im no bike mechanic... and half the time most things make no sense to me. I understand what Gos is saying and what I need to do or check. But Seiko what do you mean by reversed vacuum hoses... I ask you this as I was advised not to get advice form you... LOL

[6maniac]

This is why ..........

[-b-r-e-n-t-]

HAHA

[IsleofNinja]

Ooooh dear ............


Out of curiosity 'kawagirl' , does it run smooth at idle before it dies or is it sounding a little off song then finally gives up trying to idle?

[adge82]

This is why ..........

Hehe, i love it...

[seiko1]

This is why ..........

Hehe, i love it...

Silence....................I kill you

[kawagirl]

ok.. so i took your advice "Gosling".... did what you said and nope... she still dies.

And to answer your question "IsleofNinja" she starts first time and PURRS like a kitten.. considering the fact that I've literally repaired and replaced everything in the engine...

[waynemorgan]

Still sounds like a vacuum issue - check that the hoses from the tank to the carbs are not kinked or pinched. Did that on my 500 once and it did what you've described.

[seiko1]

I repeat............................
The mechanic can fix it in two seconds flat

[kawagirl]

it just spent 3 months at a mechanic and SAR6000.00 later... don't you think he would have checked that... anyway... i posted some pics