What causes carbed bike to have trouble starting after standing a while?

So I havent been out on the bike for a while (5 weeks? ish) and last weekend I did an oil/filter change as it was due one.

Starting her up took so long I was scared the battery was going to conk out before it caught.

After warming the oil up and getting the new oil in, it fired without any hesitation. Temp was mild, say 19C or something. Not hot, but def not cold.

Got me wondering...what causes this, assuming everything else is in good working order?

FI's seem to have less issues, so I'm assuming its something to do with fuel delivery or something.

What can I do to help the situation, or is there not a lot I can do?

Not sure but my curvy starts on the first spark most of the time, never had any issues. A bit of choke and it kicks up fine every time.

I'd try a fuel additive carb cleaner first but, if that doesn't really help, give them a clean by hand and maybe balance them. Maybe check your choke's adjusted right?

Originally Posted by radicalry00

Not sure but my curvy starts on the first spark most of the time, never had any issues. A bit of choke and it kicks up fine every time.

Even if left standing (outside/inside? dont kno if it makes any difference) for weeks on end?

Edit: I have never touched the carbs on my bike since owning it, it's on my to do list this winter) but runs ok mostly. No issues to speak of as such.

My XT does the same after standing for a good while.

[Sid Squid]

After 5 weeks it's probably low battery voltage, allied to a dab of fuel evaporation/degradation.

[andrewsmith]

Originally Posted by Sid Squid

After 5 weeks it's probably low battery voltage, allied to a dab of fuel evaporation/degradation.

A carb jet wouldn't block that quick would it?

Fuel evaporation is what I've always put it down to. Start it every day and it fires first time.

[andrewsmith]

Originally Posted by -Ralph-

Fuel evaporation is what I've always put it down to. Start it every day and it fires first time.

Fair enough Ralph.
What time scales you talking before it becomes a sod to start?

[Sid Squid]

Originally Posted by andrewsmith

A carb jet wouldn't block that quick would it?

Not what I meant - some of the more volatile elements in the fuel will disappear causing it to be harder to fire. Put that together with a partly discharged battery and a consequently poorer quality spark will have a harder time lighting it all up.

This is an area where FI is better than carbs - the fuel at the sharp end isn't open to atmosphere like the fuel in the float bowl of a carb, and as such takes much longer to degrade. But, as Ralph quite rightly points out, if you use it constantly it won't be a problem.

[andrewsmith]

Sid I knew what you were on about.
As a side are the fuel stabilizers worth the cash or a waste of time?

I was referring to a different issue that takes a bit longer to happen