KTM Duke 390 Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Hi all,
I have 2017 390 Duke with 37500km on the odo.
I recently started facing an issue where when I cold start, the engine cranks normally but after riding quite a while (say 15-20km) when I turn off the engine, and try to start again, it sometimes cranks only half way like something is stuck and then starts. Sometimes it does not even do that, it doesn't start and it's like it's stuck again (but it starts after 2-3 cranks). The battery is new but the voltage at the time drops to 9.5-10.5 like the battery is pushing power and struggling to get the motor working. I took it to the service center as well and they say it's normal but i feel it's not.
Please help if anyone is you has had something like this and if you were able to find a solution.
Thank you!
 

·
Registered
Joined
·
313 Posts
Did they test the current draw on the starter when the problem is occurring?

Did you check for voltage drops, such as between the positive post and the starter terminal, and between the starter body and the negative battery terminal, while cranking?

These are the least invasive checks you can do to help isolate if the problem is electrical... or actually elsewhere.

Oh yeah, you just joined, welcome to the club! (y)
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #3 ·
Did they test the current draw on the starter when the problem is occurring?

Did you check for voltage drops, such as between the positive post and the starter terminal, and between the starter body and the negative battery terminal, while cranking?

These are the least invasive checks you can do to help isolate if the problem is electrical... or actually elsewhere.

Oh yeah, you just joined, welcome to the club! (y)
Thank you!

Yes, they checked all the terminals and the draw and everything seems fine.
Could it be something related to valves or piston? Because they were replaced under warranty back in 2018 and over the time these things could have developed?
 

·
Registered
Joined
·
313 Posts
you can have good connections but still have excessive voltage drop in a cable.
did they actually test the voltage drop between the engine case and the battery, versus the assumed voltage of the battery during cranking?

IOW, the battery voltage might be 10.5V during cranking, but if the negative cable drop is 2.2V, the actual voltage applied to the starter is logically only 8.3. See what I mean?

But enuffa that(?).

Also...
there's a decompression device on the right side of the exhaust cam, under the valve cover.
if it malfunctions, it will make the bike harder to crank.
Harder to crank because it doesn't prop that valve open, and lower engine compression, until the engine starts running.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
you can have good connections but still have excessive voltage drop in a cable.
did they actually test the voltage drop between the engine case and the battery, versus the assumed voltage of the battery during cranking?

IOW, the battery voltage might be 10.5V during cranking, but if the negative cable drop is 2.2V, the actual voltage applied to the starter is logically only 8.3. See what I mean?

But enuffa that(?).

Also...
there's a decompression device on the right side of the exhaust cam, under the valve cover.
if it malfunctions, it will make the bike harder to crank.
Harder to crank because it doesn't prop that valve open, and lower engine compression, until the engine starts running.
I understand. They tested it and one of the bolts of the relay under the pillion seat was loose and they fixed it and checked it again and the issue still remains.. I'll take it again and get that decompression device checked.

Thank you so much :')
 

·
Registered
Joined
·
313 Posts
Hey... real quick like --
I mean nobody any offense, I just sometimes hafta recheck on the language basis of what we're talking about.

I don't know your mechanic, so I can't speak for him, understand?
But even some that I work with, and even mentor at times, end up surprising me occasionally with their off days.
We laugh at each other about it, we're friends.

And yes, good point also. If the voltage drop is across that 'high load' item, the starter relay, a voltage drop test there will confirm it!

Ok, GTG.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #7 ·
Hey... real quick like --
I mean nobody any offense, I just sometimes hafta recheck on the language basis of what we're talking about.

I don't know your mechanic, so I can't speak for him, understand?
But even some that I work with, and even mentor at times, end up surprising me occasionally with their off days.
We laugh at each other about it, we're friends.

And yes, good point also. If the voltage drop is across that 'high load' item, the starter relay, a voltage drop test there will confirm it!

Ok, GTG.
Haha, I get it :)

Sure, will take it again and get that checked..
Take care!
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #9 ·
Did this problem start before or after you replaced the battery?
I had replaced the battery in 2018 (the stock went bad) and just because the frequency had increased of this after 2020 Feb or so, I took it to the battery guys and got it replaced again in 2020 June (because of the lockdown) and I still am facing it even after replacing. So I'm not sure if it's the battery.
 
1 - 10 of 10 Posts
Top