Looking for ideas and running out of options.
2009 klx 250 runs great untill it reaches warm up around 10 mins. Then at low rpm it dies like..it will start back up sometimes and die again.
It is currently at the Kawasaki dealership and there running out of options for repair.

This is a list that has been checked or replaced with no effect on problem.
New gas and tank cleaned ..no kinks in hoses or vacuum lines.
Bowl still has gas in it when bike dies
Carb rebuilt 2x and also a new jet kit kit was installed after that.
Engine tore down valves checked
New sparkplug
Checked voltage hot and cold on electrical system
Finned voltage regulator replaced and grounds checked
Voltage was checked on coil ..dealer said when a coil goes it will just fail.
Fuel filter cleaned
Dealer contacted kawasaki engineers And have tried there ideas .
compression also checked
When choke pulled out bike will run but at a high rpm.
With all these items checked or changed Ike still has same problem.

Any ideas please ..labor bill on diagnostics is adding up with no fix.

Thank youll all ideas greatly appreciated!

 

You mention around 10 minutes of running. Is that eventually with the choke off, or does the choke have to be engaged all out or to some degree to get the bike to run? So, is it capable of idle without the choke up to that 10 minute mark?

 

You're "doing good" coming here with your problem - if it's a KLX250, someone here knows the solution.. WE ROCK !

Much more detail is needed regarding the below.

"it will start back up sometimes and die again"
Versus and/or in addition to:
"When choke pulled out bike will run but at a high rpm."

Does is ALWAYS restart and run when you pull the choke out (and leave it out) ?
Does it SOMETIMES restart, without choke, and run perfectly fine (at least for a while, and if so, how long) ?

 

And as per @TNC 's post, if you are running a whole 10 minutes with the choke pulled out, then you've got to start all over - giving the details when the bike is being ridden & operated correctly..

 

Thank You'll

Okay more details:
Motorcycle will run normal with choke in until it reaches normal operating temp. At that time anything under i would say 2000 rpm it will start what i call a misfire and die or when the rpm lowers it will just shut off. It will start back up most of the time with the same problems. The only way it will perform normal operations is if you let the bike cool down.
The choke reference was me saying when its warmed up and showing the problem i can pull the choke out and it will stay running above 3k rpm.
It just feels like its a electric/ignition problem because the bike runs really great until warm up.

It's at the dealership 3 weeks now and there even working with the Kawasaki engineers to try and resolve it. No idea so far after the changes listed. it still has the same problem there with them. It is getting very costly racking up dollars for diagnostics which if there was an outcome i could see would make it easier.

I really appreciate the help!

 

Lets look more at this:

1), "The choke reference was me saying when its warmed up and showing the problem i can pull the choke out and it will stay running above 3k rpm."

Versus this:

2). "Motorcycle will run normal with choke in until it reaches normal operating temp. At that time anything under i would say 2000 rpm it will start what i call a misfire and die or when the rpm lowers it will just shut off."

These two do not make sense.. #2 implies the bike will stay running as long as it's kept above 2000 rpm, but #1 implies that it won't unless the choke is pulled..

 

sorry for the confusion.
Okay lets take the choke off the table.

When bike is cold choke closed ( 80 degree avg outdoor temp). it will run great until its at normal operating temp. At that point it tries to misfire and die at anything below 2k rpm. If i burp the throttle and keep the rpm above 2k i can usually keep it running. It does feel like a misfire and not like flooding or starving for fuel? Almost feels like if you bumped the kill switch quickly on and off every few seconds. I'm trying to be descriptive here and i apologize for not knowing the correct explanations. the bike will do this until you let it cool back down and it runs fine till its at normal operating temp. Could it be the coil? Kawasaki engineers keep steering away form that idea.

Thank You

 

Find a better mechanic. Coils and other electrical components fail under heat or moisture. I'd probably run the bike and spray it with some water while running, and if that doesn't point to an issue I'd guess that the coil is a possible and easy item to replace. It could be the cdi, or just weak ground wires as well. Most dealers are horrible with electrical. If the valves are set correctly, I'd do the coil. A bike this simple needs air, fuel, and spark. You can eliminate fueling issues with a tube and funnel directly to the carburetor which they should have done IMO to eliminate anything up stream of the carb.

[Edit to add that I believe the '09s are in the age where grounding was more of an issue than the newer ones. I'd still look at the coil, but adding some temporary grounts to bulk up the cdi grounding would also be a possibility. Given that all grounds should be 0V checking for any nonzero voltage between grounds can show issues, but it's usually easier just to bulk up the grounds temporarily to see if the problem goes away.]

 

Ok then, taking the choke out of the equation, and considering all other "findings", your carb is just fine - no more effort towards the carb should be made.

The problem is obviously heat related and therefore only components and faults that manifest with operational heat, and are benign otherwise, should be considered.

Coil and/or spark plug wire is the obvious candidate at this point in the troubleshooting - when coils and plug wires are failing, they "act up" when they get warm/hot - they do not "just fail" - this means your "Dealer" is an idiot and will require skilled and gentle coaxing/persuasion to focus on possible coil /plug wire faulting. There are examples of coil faulting in here BUT bad/dirty wiring connectors (which cause lower voltages) and bad groundings are much more common. I assume the reason the bike will still run when kept above a certain RPM is due to the characteristics of the charging system - above a certain RPM, output takes a rise - which may keep the faulting coil and/or plug wire from coughing up furballs when its' input voltage is kept high.

That's about all I got on "heat related faulting" - the other possibilities, that I can think of, are strictly speculation without actual forum cases (to back up the speculation)..

Anyone else have any ideas ?

 

The fact that you can get the bike to start at a decently mild ambient temp of 80 degrees without the choke, doesn't seem like a fuel/carb related problem. It's starting to sound like one of the electrical components heating up more than anything fuel related.

Sometimes the ability to start the bike cold without choking it indicates a fairly rich jetting setup, but 80 degrees isn't that cool. If rich enough to cause the bike to stumble badly and die upon full warm up, you'd see black fuel smoke and an extremely strong fuel smell from the exhaust. This does not sound like your problem.

Checking electrical components that fail when reaching operating temperature but work during warmup are often a PITA to diagnose.