[vijai]

Not sure what really happened and I do not own a D390. Thought this would be the most relevant thread to post the news in.

A Duke390's engine case broke and fell down on a ride which happens to be due to cracks caused by excessive heat. No official statement from KTM yet.

https://www.drivespark.com/two-wheel...eo-032089.html

[ashwinprakas]

Originally Posted by vijai

Not sure what really happened and I do not own a D390. Thought this would be the most relevant thread to post the news in.

A Duke390's engine case broke and fell down on a ride which happens to be due to cracks caused by excessive heat. No official statement from KTM yet.

https://www.drivespark.com/two-wheel...eo-032089.html

Nothing new here, this is an inherent issue with the 390 Motor.

Modern motorcycles have an interference counter-balancer meaning the balancer weight rotates in between the weights of the crank shaft, here's a picture from Ari Henning's rebuild video to give you an idea;



The engine above is of a Honda CBR250R's which has a similar interference design, in its case the counter balancer shaft snapped and the weight got free and hit the big end of the crankshaft resulting in the catastrophic failure and the case cracking.

Repairing a Honda CBR250R With a Wrecked Engine

In the case of the KTM 390's, what happens is that the counter balancer weight is held in place by a key worth about Rs.5/-, though cheap this key shown below is responsible for locking the balancer weight to the balancer wheel.



Meaning when the key fails the weight is free to rotate without respect to the crakshaft and thus hits the big end of the crankshaft, and this happens when both the balancer weight and crankshaft are both rotating at thousands of RPM.

In short, it is poetry in motion, the balancer weight and crankshaft meet at opposing speeds and the result being the aluminum crankcase shatters like glass.



The above pic from the same incident you've shared, I had a better picture shared by a fellow enthusiast who used to work for KTM but I can't find it.

This is a common issue with the 390 motors as it isn't common with the rest of the Duke line-up, even the 250 which shares most of the premium internals of the 390. The earlier generation SOHC Dominar's weren't prone as I do not recall of any shared experiences but the new DOHC Dominar's do have a few reported cases, like the below;

Bajaj Dominar 2019 || Engine Blast �� �� worth Rs.75000 || Almost Died || See what happened

All things considered, the key failing is not such a big deal as we've seen this happen on the Himalayan as well, though it was the Magneto's key that failed which rendered the motorcycle unrideable but easily fixable as seen in the video below;

The Himalayan Jugaad

Tough luck for the 390 enthusiasts since the key is in effect responsible for preventing the motor from going ballistic.

Ride Safe.
A.P.

[ast.ggn]

Originally Posted by vijai

A Duke390's engine case broke and fell down on a ride which happens to be due to cracks caused by excessive heat. No official statement from KTM yet.

People will now understand why 5 year warranty from KTM is a blessing even if it costs 10k (double of it's current cost). I hope his bike is under warranty and if it is not, KTM should cover it under goodwill. His repair bill is going to run in thousands. If I am not wrong, similar case was reported in forum long back (or may be Xbhp).

[Red Liner]

I can't wait for the weekend to begin!

[nitinkbhaskar]

Originally Posted by Red Liner

I can't wait for the weekend to begin!

Wow. Everytime you post pics on this thread I turn green with envy. Was this a solo ride?

[vijai]

Originally Posted by ashwinprakas

Tough luck for the 390 enthusiasts since the key is in effect responsible for preventing the motor from going ballistic.

Ride Safe.
A.P.

Couldn't believe just a pin worth ₹5 is holding the engine is a way to catastrophe. I wonder why manufacturers don't provide a better foolproof design or at least a fail-safe? Its rare to happen but when it does it's terrible.

Originally Posted by ast.ggn

People will now understand why 5 year warranty from KTM is a blessing even if it costs 10k (double of it's current cost). I hope his bike is under warranty and if it is not, KTM should cover it under goodwill. His repair bill is going to run in thousands.

I guess, it is. Vaahan says the bike is 1year and 2 months old. Pretty short for such a massive engine failure in my opinion.

[ashwinprakas]

Originally Posted by vijai

Couldn't believe just a pin worth ₹5 is holding the engine is a way to catastrophe. I wonder why manufacturers don't provide a better foolproof design or at least a fail-safe? Its rare to happen but when it does it's terrible.

Life is a Bell Curve.

High strung performance does come at the cost of more efficient(PITA) design, and the design is such because without the balancer wheel being separate from the balancer weight it'd not be possible install the cases, as seen below;









Above are snaps taken from Jeet Bhaskar's rebuild series of the Duke 390, one of the better Indian YT'ers if I may say.

The reason you've not heard of this happen on Pulsar's and the likes is because the counter balancer is of a non interference design and even if it fails the motorcycle at best vibrates a lot and nothing more.

But then again you cannot compare the two, the 390/250 engines offer state of the art performance and technology compared to the older agricultural engines. It offers the modern 2 Piece connecting rod instead of the prehistoric single piece connecting rod, it offers journal bearings for the crank instead of the old roller type bearings etc which even the Duke 125/200 still comes with, heck it even has 2 Oil Pumps.

So all things considered the engine going for a toss is just happenstance as its mostly limited to the 390 motors, and as gory as it may seem it really isn't cause if you were to replace the crank bearings on the 250/390 then also you'd have to replace the cases as the inserts aren't sold separately by KTM, so either way you still end up replacing the cases.

If at all a consolation, I'd say its still a win considering the performance on tap i.e provided the owners are aware of what they're getting into, cause IMHO all said and done one cannot simply buy a European motorcycle and then complain that its not as reliable as a Japanese motorcycle since both offer completely different experiences.

P.S. Not a KTM Fanboi.

Cheers,
A.P.

[Red Liner]

Originally Posted by nitinkbhaskar

Wow. Everytime you post pics on this thread I turn green with envy. Was this a solo ride?

No it wasn't!

[Red Liner]

I am loving this bike on B roads and interior arterial roads that connect little villages dotted around the country side. The bike doesn't feel big amd clamour for attention like my versys did, but has sublime grunt to do a peaceful trot which allows me to admire my surroundings and the proceeding village life.

[nutcracker]

KTM is supposedly working on the KTM 490 Adventure, which is going to be a twin cylinder. I'm already drooling.

[Red Liner]

When your motorcycle takes you to places like these, its all good.

This bike seems to pull pretty well even two up on the trails!

https://youtu.be/P8__zt4O_Bg

[Axe77]

Originally Posted by Red Liner

When your motorcycle takes you to places like these, its all good.

Wow!! Your pictures are simply stunning. And fully agree, a nice light Adv with enough grunt is truly a joy in terms of the kind of last mile places you can access with it.

Keep the posts and the pics rolling here please. This is going to be my definitive 390A reference thread.

Safe riding.

[Motard_Blr]

The latest project by the well known Hemant Darbar of HDT customs:

https://m.youtube.com/watch?feature=...&v=qLtlN_aa1RE

It looks quite well executed and makes the bike look purposeful. Serious off-road and enduro enthusiasts should definitely consider these mods.

[Red Liner]

Originally Posted by Red Liner

Just something from this morning to keep this thread going!

Just a tiny little montage from this ride over on instagram

Hope you like it and makes your Monday morning a little more tolerable

[shyamg28]

YouTube is free and so was I.

https://youtu.be/HMQYsj_YkLw