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Bike very hard to start and won't crank with choke on?

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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

-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).

Edited by pdee4t

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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
-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).

 

What happens when you have the choke on...and when cranking over if you were to open the throttle, would it start cranking faster?

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What happens when you have the choke on...and when cranking over if you were to open the throttle, would it start cranking faster?

when i have the choke on it has trouble cranking. once the bike is started, when i turn the choke on, all is fine.

when i open the throttle while cranking with the choke on, it tries to start but still doesn't. the cranks are a little faster but not much.

Edited by pdee4t

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when i have the choke on it has trouble cranking. once the bike is started, when i turn the choke on, all is fine.

when i open the throttle while cranking with the choke on, it tries to start but still doesn't. the cranks are a little faster but not much.

How about when you kick start it,will it fire up fine?

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nah. same issue.

Edited by pdee4t

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yeah air filter is clean. cleaned it just before i had this issue. was going to be riding it but this issue came up.

 

there was barely any fuel in the float bowl. also i should mention that when i took the fuel hose off when i was disconnecting my carby, barely any fuel came out of the hose(after it had been running for a couple mins). usually there is a lot that comes out.

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nah. same issue.

Take the disconnected fuel hose from the carb- and turn on the fuel petcock to On and then Reserve and you shoud have good flow both positions,could have a plugged tank filter,but dont see that causing a slow crank condition...

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What style carb?

Model and make?

keihin. fcr-mx 39mm

Edited by pdee4t

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Take the disconnected fuel hose from the carb- and turn on the fuel petcock to On and then Reserve and you shoud have good flow both positions,could have a plugged tank filter,but dont see that causing a slow crank condition...

don't think my bike has a tank filter.

fuel flow from the tank is fine anyway. i think its when it reaches the carby that there is an issue.

there was barely any fuel in the float bowl when i took it all apart...maybe just a few little drops and when i took the fuel hose off when i was disconnecting my carby, barely any fuel came out of the hose(after it had been running for a couple mins and fuel switch in the closed position). usually there is a lot that comes out but tested the fuel switch in the on position with the hose and heaps pours out.

 

what would it be caused from? and would fuel starvation cause low cranking?

Edited by pdee4t

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Have you checked the oil for the presence of fuel ?

When did you last change the oil ? .

oil was changed just before this whole issue. i had done a full service just before this whole issue, changed filters, changed oil then went to start it up and it wouldn't.

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yeah air filter is clean. cleaned it just before i had this issue. was going to be riding it but this issue came up.

there was barely any fuel in the float bowl. also i should mention that when i took the fuel hose off when i was disconnecting my carby, barely any fuel came out of the hose(after it had been running for a couple mins). usually there is a lot that comes out.

Could you have possibly over oiled the air filter? I did this once and had a heck of a time starting my bike cuz it wasnt getting enough air...

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don't think my bike has a tank filter.

fuel flow from the tank is fine anyway. i think its when it reaches the carby that there is an issue.

there was barely any fuel in the float bowl when i took it all apart...maybe just a few little drops and when i took the fuel hose off when i was disconnecting my carby, barely any fuel came out of the hose(after it had been running for a couple mins and fuel switch in the closed position). usually there is a lot that comes out but tested the fuel switch in the on position with the hose and heaps pours out.

what would it be caused from? and would fuel starvation cause low cranking?

My bad.

This carb looks to have a pump, diaphragm in it.

At least my search shows one. I'd be checking it.

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Could you have possibly over oiled the air filter? I did this once and had a heck of a time starting my bike cuz it wasnt getting enough air...

highly doubt it. i squeezed the excess off the air filter as i always do.

im cautious about over oiling air filters.

My bad.

This carb looks to have a pump, diaphragm in it.

At least my search shows one. I'd be checking it.

the float?

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