Overheating - Bike Stalling

Gidday,

I have an '99 CBR600F4. That I have owned since Jan '03. In this time
I have never replaced the battery. The bike starts first time fine
every day ( I commute to work ) with no issues, fires first time every
time.

In Sydney's traffic ( back to school grid lock ) and the heat the last
few weeks the bike has been running hot, the fan kicks in ( as it
should ) but then the bike has trouble maintaining idleing revs and
when you apply throttle it stalls.

When the bike stalls I can't start it again, the bike turns over but
doesn't fire. The fan is still blowing. I am able to jump start it
easily enough though.

The idle revs is usually around 1200-1500 rpm, When it's hot it drops
to under 1000 and possibly closer to 800 or so rpm. You hear the bike
almost stall, but it corrects itself as it should. When you then go to
take off, it's almost like it's choking of fuel or not enough power to
fire the spark plugs.

Basically I have been sitting at lights or in traffic holding the bike
at 2000 rpm to stop it from stalling at low revs.

Is this possibly an old battery with not enough juice to handle the
load of the fan and a hot bike. Or is it something else? The bike is
serviced every 6000km as scheduled, it's currently still got 2000km to
the next recommended slot.

Cheers

 

Sounds like your fuel is vapourising in the lines to me.

Theo
Assuming carburettors are fitted.

 

Yes it is a carburettored bike.
Is this just because there so hot, would a service remove this issue?

I have noticed this bike has always run hotter than my previous '98
CBR600 F3.

Cheers

 

Possibly, if it is tuned incorrectly, it will run hotter tha it should. Is
it possible to re-route the fuel lines so that they run in a cooler area. A
lot of bikes have fuel-lines that cross over behind the engine. This can
cause the problem you describe. If possible run the line from each side to
the nearest carb or carbs. The fan is possibly making the problem worse when
it comes on by blowing hot air over the engine area.

Theo

 

I'd be suspecting the alternator / battery myself - sounds like
insufficient charging current. It'd be worth checking what current is
being generated.

JL
(but it's only a guess)

 

I'd be suspecting the alternator / battery myself - sounds like
insufficient charging current. It'd be worth checking what current is
being generated.


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I agree. Stick a multimeter on it. Easy enough for it to be the first thing
you check.

Fraser

 

In my experience - take the simple things first.
Check the electrics here with this .....
www.electrosport.com/Images/fault_finding.pdf

Important for you is the charge voltage of the chart in the first instance.

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What have you done to the attributes Fraser?
If it turns over but doesn't fire it may be low on battery but surely would
have enough to run the ignition without the starter motor. ??

Theo

 

True. But a multimeter takes 2 seconds to check.

Fraser

 

Only if you know what you're looking at.

Theo

 

I'm on the fuel bandwagon instead of the alternator/battery one.

Easy enough to check though; just find the temp sensor and pull the wire
off.
Now; with the bike running ground the wire. Does the fan start?
OK; now get the bike warm and idling smoothly and then ground the wire.
If it upsets the idle you've got an electrical problem, if it still idles
smoothly look to fuel/carbs.

You may also wish to pull the four sparkplugs (don't mix them up) and see if
one looks different to the others (burnt, sooty or oily).
Check the vacuum line to the fuel-tap for cracks or perishing and drain the
carby float-bowls (then turn the tap to 'prime' and flush them through with
clean petrol).
If that doesn't fix it it gets trickier from here on......

 

A multimeter isn't it ? That's what it looks like ..

 

Hehe, I was envisioning the OP looking at a multimeter, after asking the
Dick Smith person to show him where they were.

Theo

 

If it's a Honda and you suspect the battery, I'd be giving the reg/rec a
good examination as well, given their reputation for failure and the
implications that has on battery life/performance.