Bike very hard to start and won't crank with choke on? urgent help needed!!

hi guys. i have a KTM 450 EXC 2004 model.

lately when i go to start the bike, its VERY hard to start. so much so that sometimes it even drains my battery trying to crank it(using the e-start). today(with a full battery), i had the choke engaged and i noticed while the choke was engaged, the bike had heaps more trouble starting/cranking...but with choke off, the bike cranked/started as it should and at least tried to start. when it did start, it stalled when i twisted the throttle(after about a minute of the bike running). during start up, there is a pretty strong fuel smell, kind of like its flooded but there isn't any fuel leaking out the overflow hose.

im wondering what the possible issue could be?
i am thinking its possibly fuel related. unless the new starter motor has already gone or on its way out. im just confused because i don't see how a carby/fuel problem would stop the bike from cranking....?
I have ruled out a lot of possible causes:



-checked all valves, all are in spec(if anything, they are 1mm loser with a 0.13mm gap as opposed to 0.12mm)
-checked for spark, has strong spark
-brand new spark plug
-has a brand new starting system on it(starter motor, starter solenoid and battery).
-fuses have been checked
-also replaced the stator and upgraded my regulator/rectifier not long ago, to match my stator.
-bike is timed correctly(as per manual). checked all the timing marks.
-took the carby apart, jets appeared to be fine(not clogged).
 
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Standard procedure for any bike these days is as follows:
Clean the carb twice really really well. then when done clean it again.

Todays junk fuel really stitches up the carb.
 
probably a weak battery.... you can only crank them a couple times and if the ciylder is loading with fuel it makes it harder... pull the sparkplug and let it air out while you pull the carb and clean it.throw a charger on that battery while you're at it....:thumb:
 
On those 450's isn't there an accelerator pump on the carburetor? If it has an accelerator pump I would check and see if that is working. I believe they are needed for starting and take off. :noidea: Maybe, it has nothing to do with your issue but, it sounds to me that you have a carburetor problem somewhere. Let us know what you find to be the problem. I do believe that a four stroke carburetor does a pump action on them.
 
On those 450's isn't there an accelerator pump on the carburetor? If it has an accelerator pump I would check and see if that is working. I believe they are needed for starting and take off. :noidea: Maybe, it has nothing to do with your issue but, it sounds to me that you have a carburetor problem somewhere. Let us know what you find to be the problem. I do believe that a four stroke carburetor does a pump action on them.
The fcr accelerator pump is a common spot to build up gunk
 
With the choke on its probably trying to actually start, but the starting system is to weak to start it. Starter/battery/timing....(Timing just not being the timing off, could be valves too tight or too loose)

If the bike has a kick starter, will it kick start?

Will the bike start easy with the battery charger on it?
 
So......how does it kick when the e start fades, is it harder or not with choke on?

With the choke on its probably trying to actually start, but the starting system is to weak to start it. Starter/battery/timing....(Timing just not being the timing off, could be valves too tight or too loose)

If the bike has a kick starter, will it kick start?

Will the bike start easy with the battery charger on it?

nah the bike has the same issue trying to kick start it with the choke on.
nope even with battery charger on, doesn't start
 
nah the bike has the same issue trying to kick start it with the choke on.
nope even with battery charger on, doesn't start
I would guess its over fueling whether that's the cause of the hard start or not, the fact it starts cold without the choke, and also the smell of raw fuel when it's warm, tells me that, you need to start there and then see if getting the carb straightened out fixes the hard start problem. Check float level and needle and seat to start with, also is accelerator pump leaking? Could be a lot of things causing it.
 
I would guess its over fueling whether that's the cause of the hard start or not, the fact it starts cold without the choke, and also the smell of raw fuel when it's warm, tells me that, you need to start there and then see if getting the carb straightened out fixes the hard start problem. Check float level and needle and seat to start with, also is accelerator pump leaking? Could be a lot of things causing it.

yeah the accelerator pump and diaphragm have been checked. the push rod pushes down in the diaphragm section all correctly. the diaphragm doesn't appear to have any cracks or bends in it.
the smell of raw fuel is not when the bike get's warm, its during start up when i am unable to start it. like its flooded or something.

i am thinking its possibly either the main air jet(bikes getting starved for air), the choke circuit or the starter jet.

also, if its my valves, wouldn't too tight cause the hard cold starts, not too loose? because my valves are only 0.1mm loser then what the manual says. i thought too loose caused hard hot starts only.
 
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