[Jaggu]

Originally Posted by lark63

Guys I have a serious problem.
Yesterday I was riding my bike as usual and the engine became suddenly louder and hollow sounding
====
The service guy called me just now and says the tensioner became loose and the engine seized.
Anything anybody can tell me on this ?

Ouch seems to be a part failure, can happen to anyone but if your bike is anywhere close to warranty try to see if KTM can help with that. Unless you open and check, one can't really find out the extent of the damage. How much are they quoting for the repair?

[VijayAnand1]

Originally Posted by lark63

Guys I have a serious problem.
Yesterday I was riding my bike as usual and the engine became suddenly louder and hollow sounding. In under a minute engine died. Attempts to restart failed. There was no cranking sound even.
Fortunately very nearer to the spot service center was there. I pushed the bike there and left it with them. The service guy called me just now and says the tensioner became loose and the engine seized.
Anything anybody can tell me on this ?

Hard luck indeed. If the sound progressively worsened along with a loud metal clanking and tinny sound, it's bad news. In most cases it is seized cylinder or crank bearings or both due to low oil.

I'm surprised to know that a loose tensioner caused this, and probably first time I'm hearing a failure of this sort in a D390. Most were either related to low engine oil and coolant leak. Nevertheless, if you're not under warranty, expect expenses north of 20k plus easily if the cylinder kit is to be replaced.

Unless, we see it in person, it's hard to conclude what exactly caused this. Low engine oil or oil starvation is what I "suspect" but do keep us posted.

Cheers!
VJ

[lark63]

Here is an update. I am not much knowledgeable on the technicalities but here is the version doled out to me by service guy. The images of the part accused to have affected the timing and as a result two valves are damaged are attached. Another pic shows where it is mounted on the cylinder.

Knowledgeable may please comment. Ofcourse I am going ahead with repair as advised by service tech but in case it turns out to be fraud I can atleast look for an alternate center.

[scorpian]

Where you at high speed when this happened? Usually tensioner failure leads to sound and probably if you were at speed it could have slipped the timing chain but again that's rare.I re-collect in the karizma there was a batch which had bad tensioners and it would make noise but like me many others rode their bike for couple of hundred kilometers without any issues.

[lark63]

Originally Posted by scorpian

Where you at high speed when this happened? Usually tensioner failure leads to sound and probably if you were at speed it could have slipped the timing chain but again that's rare.I re-collect in the karizma there was a batch which had bad tensioners and it would make noise but like me many others rode their bike for couple of hundred kilometers without any issues.

Nah. I was doing around 30 at that moment with lot of traffic around. The service guy also said it can still run but in this case it didn't. My bad I guess.

[ashwinprakas]

Originally Posted by lark63

Knowledgeable may please comment. Ofcourse I am going ahead with repair as advised by service tech but in case it turns out to be fraud I can atleast look for an alternate center.

That is the timing chain tensioner, as the name suggests it tensions the timing chain.

The timing chain is the link between the crank and the cam, as per the position of the crank it ensures that the cam opens and closes valves as well.

Timing is critical because the piston is connected to the crank using a connecting rod, and if the timing of the crank and cam aren't correct then there'd be a scenario where the piston hits the valves, in which case the motorcycle would stop running.

Modern timing chain tensioners are automatic I.e spring loaded but at times they seize up, this causes improper tensioning of the timing chain which causes timing chain noise as well as the possibility of there being too much slack that the chain skips a tooth on the cam causing the timing to be off which would as already explained result in the impending doom.

The fix is simple, you change the cylinder kit, and overhaul the head with new valves and cams in place, you may be able to reuse certain parts depending on wear and tear, but consumables should definitely not be on that list, and that includes timing chain pads and tensioner.

Do share details of ownership, I.e km's clocked in total, maintenance intervals or the lack there of etc, would help current and potential owners learn from your experience.

Regards,
A.P.

[Sutripta]

Is the D390 engine an interference design? What about the Dominar?

Regards
Sutripta

[ashwinprakas]

Originally Posted by Sutripta

Is the D390 engine an interference design? What about the Dominar?

Both the 375cc motors run very high compression ratios at around 12:1, it would be highly unlikely to make a non-interference big bore design that'd run such high compression.

My math may be poor but I simply cannot imagine how.

Do feel free to correct me.

Regards,
A.P.

[Sutripta]

^^^
Actually needs to be checked. One cannot say just on the basis of CR.

Regards
Sutripta

[ashwinprakas]

Originally Posted by Sutripta

^^^
Actually needs to be checked. One cannot say just on the basis of CR.

Regards
Sutripta

Okay, then what about the presence of valve pockets on the piston crown.

[Sutripta]

^^^
Maybe. The pockets could be so that it doesn't interfere.
Needs to checked.

Regards
Sutripta

[rahul4321]

Just completed a Gujarat-Maharashtra-Telengana Ride on the D390

Its a fantastic motorcycle. Power, Feedback of road surface, Braking stability and a sublime balance. What it lacks is comfortable seats, torque at low rpms in lower gears {wheel slippage encountered getting off standstill in sand, dirt and gravel) and a cramped riding posture.

But even so- the postives far outweigh the negatives (atleast for.someone like me who knew the negatives even before i bought it)

[itisravi]

A comprehensive Duke/RC 390 engine rebuild youtube video (2 parts) in Hindi that came up in my recommendation. Thought folks might be interested in viewing and hence sharing the links:

http://www.youtube.com/watch?v=dwtrtFn6VQI

http://www.youtube.com/watch?v=cRYHg_saqUo

[tabrez]

The updated Duke 390 has been spotted again in the wild

https://www.motorbeam.com/2021-ktm-d...otted-testing/

Although it looks far from being production-ready, the re-routed exhaust is evident & in my opinion, much needed for our climate. Other changes include (as claimed by the publication) a revised frame, re-worked swing-arm, front fork & rear suspension.

[rahul4321]

Got back from Hyderabad to Ahmedabad today. 2800 kilometres, 4 days. 4 states. Have attached a few pictures below. I think i will pen down an ownership review of the D390 this weekend. The Duke will be 3 years old in February.


Oh and by the way, ,incase anybody is wondering. I travel solo and don't have anybody to take pictures of me - that's why you will only see the bike in all my pictures

I tried to take one picture of myself but faced two issues as you can see in the last photo

(1) The MI 6 Pro Camera has a maximum timer of 5 seconds
(2) I am fat and I waddle like a duck