Gs500f, tough to cold start / running rich.

[Bigred]

I have a 05 gs500, started getting tougher to cold start in last few weeks and noticed a rich smell from the exhaust. Went out to start other day and can't even start with choke on, have to start with choke off and throw it on as soon as it turned over.
My 1st thought was on the valves, been awhile since adjusted/checked.. but just checked them and all except the left intake are @ a .08mm/ the left intake is at a .04mm.still within spec. so shouldn't be giving me a problem.. I don't think..
Leaning on maybe a vacuum leak but doesn't seem right because the thing was running sweet and slowly progressed into this issue recently.
Any guidance on where to start?..

Carbs were just cleaned, synced , and tuned within 2500mi. ,.
Plugs replaced then as well.
She idles great, good throttle response, and starts right up still once warmed up. Have noticed a very slight loss in power at the top end.

[Watcher]

Any gas smell in the oil?

I wonder if you have a slow leak in the needle/seat or your floats just barely aren't closing enough and fuel is slowly getting into the cylinders at rest.
That would mean that the longer it sits the more fuel invades the cylinder.  By the time you get to a cold engine you could be on the verge of flooded.

Just speculation.  Don't know if that's actually a viable diagnosis.  Someone else is sure to chime in.

[gsJack]

Couldn't start mine one cold morning with choke on but it did start with choke off.  It died immediately after starting unless I gave it choke quickly after start.  Turned out to be dirty air filter element caused it to suck more gas with air flow restricted while cranking.  Problem eleminated with new air filter.

[Watcher]

What gsJack said sounds much more likely and much easier to fix.  I'd trust him, he's been at this much longer than most of us.

[Bigred]

Yeah it does sound like a good start, I completely over looked that because I just threw a new filter in not too long ago. Hopefully I can get one in this weekend and see, thanks!