[rvrmvaishnavi]

Hi folks,

First some background. After having dreamt of owning a big bike pretty much all my life, things finally came together for me in March 2020. I picked up a brand spanking new KTM duke 790.

On paper, pretty much the perfect bike for my needs. Doesn't look or feel big. Super light, blends in, huge ground clearance and easy to live with even for daily rides. Huge on power, torque and all imaginable rider aids to cover my inexperienced rear end. Made my grin like a baby every single time I twisted the throttle!

The ownership experience over the past 2 years was ok, a few niggles here and there. over the last 2-3 months, things turned terrible.

The whole saga started about 2 months ago.

First symptom was an overheating caution. Rode to safety and stopped, asked dealer for help. They asked me to bring it in. Observed that fan was not working. Got the fan replaced under warranty. (I have replaced like 3 fans on my first batch first gen 2013 duke 390 so far in its 9 year lifetime, so no biggie)

Everything was fine for about 1k kms and then again, got an overheating caution. This time fan was working fine. On inspection, coolant expansion tank was empty and radiator was short by about 400ml. Manual says upto 500ml loss is ok, but I still reported to dealer, who, surprise, asked me to come in again. Needless to say no obvious signs of external coolant leak, no pooling in parking lot, no stink of burning coolant dripping onto header etc etc.

At the dealer, dropped oil, checked filter. Oil qty was about 2.4-2.5L (manual says 2.8L capacity) and no obvious signs of coolant in oil, very minimal stress lines seen on oil filter. But this was after 4k+ kms after the last oil and filter change and was inconclusive. So, we put in new oil and filter and decided to observe for 1k kms.

Then after a 1 days 700 kms ride, came back and saw that again compensating tank was empty and radiator was short by 600ml!! Decided to drain coolant and switch to good old regular green coolant just to ensure that we aren't missing some external leak as engine ice is a little harder to spot. Filled , bumped system. Updated dealer, instruction was to come in after 1k kms as mentioned before

Again, another day, another 2-300 km ride and another 200+ml lost in a day!! Took it back to the dealer

Once again, dropped oil. qty was fine (2.6+L), no obvious sign of coolant mixing especially given the qty of coolant lost (~1Litre). Then examined oil filter and there was a lot more twisting of lines. Clear sign of trouble.

Started opening engine, alternator cover...nothing obvious. Clutch cover and found a LOT of mixed oil + coolant residue...

Kind of gave up on it, left bike with dealer and headed home.

More details in the following post.....

[anjan_c2007]

It's a clear case of blown gasket/s and /or oil seal/s that have aided mixing of such compartmentalised fluids.

Needs a good diagnosis, identification of the blown out seal/s and/ or gasket/s, identification and replacement of affected spares, thorough clean up job of the affected spares that are reusable and change of oil filter, total change of coolant and oil.

Perhaps, the engine has been saved from a major damage as the fault was identified at a proper time.

[rvrmvaishnavi]

Sometime later, they tried to change the coolant pump gasket, checked the impeller shaft seal and replaced the heat exchanger gasket. And then tried a run on the test bench with fresh oil + filter. Once again, found strained lines in the filter... so that was not it!

Today, brought the engine down at dealer. opened the valve cover, found mixed oil + coolant on the valve cover. Then found scuff marks on the exhaust camshaft, although the claim was that it wasn't bad enough to be replaced. Removed the head and found that all FOUR intake valves were leaking!!

Inspecting the head gasket showed some sort of deformation, but wasn't super clear to me personally.

[subincb]

Chances are more for blown gasket. But you may check with replacing o-rings or gaskets behind the water pump before opening head.

[rahul4321]

Originally Posted by rvrmvaishnavi

Sometime later, they tried to change the coolant pump gasket, checked the impeller shaft seal

I was in the market for a 790 due to the mouth watering discounts just before Covid hit and sadly couldnt get my hands on one. However, during my research as i was upgrading from a 390 i found a lot of complaints online about the 790 engine; with the prime complaint centered around oil leaks and gaskets being blown. Seems that KTM was honouring claims under warranty for the affected customers as it was a known issue. Also the online reviews said, this was why KTM switched to a completely new 890 rather than upgrading the 790's next iteration.

https://www.reddit.com/r/KTM/comment...m_source=share

[rvrmvaishnavi]

Cylinder block didn't show anything obvious to me.

And then on inspecting the lower section of the engine, found some of the balancer journal bearings worn. Apparently everything else is ok!

Current direction is to replace the following: new valves, seals, gaskets, con rod bolts all affected inserts

I am not sure at what point of time its ok to cry foul and ask for a new engine. This is just after 10k kms and its basically a full rebuild.

Originally Posted by rahul4321

I was in the market

As for other issues @rahul4321 Lots of people have had valve cover gaskets replaced. There was even an updated part number. Lots of folks with some external coolant leaks from near hose clamps etc etc. But those I would still call niggles. In most cases, they were not urgent and were quickly forgotten once one is on the bike for even 5 minutes. On request, KTM even made extended warranty available for the bike for an insance price of just 4k to extend to 4 years !!! Sweet deal.

But of course, this issue has blown past all previous known issues in terms of severity (afaik).

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Thanks.

[neil.jericho]

rvrmvaishnavi, congratulations on your Duke 790. Unfortunately, this fun middleweight motorcycle was infamous for its engine issues, so Im not at all surprised to read about all these problems on your bike. As rahul4321 rightly pointed out, there were just so many problems that KTM didnt bother fixing the 790 engine but tried to rectify things with the 890 instead. God knows what testing they did before the launch. No wonder enthusiasts say that KTM Bajaj is a match made in heaven!

Since you have extended warranty, enjoy the bike to the fullest for 4 years and then take a call on whether you want to live with its reliability issues or if you want to move to something that gives you complete peace of mind. I look forward to more positive updates on your bike and hopefully an ownership thread as well.

[no_fear]

First off, my sympathies on seeing the issues you are facing. From my past experience in rebuilding an engine, this looks likely to be a blown gasket. Have the service tech check all the hoses and coolant / oil contact points.

If you are covered under warranty it should be taken care of. A lot of bikes have coolant / oil mix issues and through trial error the issues can be resolved.

[Pretorian]

Originally Posted by neil.jericho

As rahul4321 rightly pointed out, there were just so many problems that KTM didnt bother fixing the 790 engine but tried to rectify things with the 890 instead. God knows what testing they did before the launch. No wonder enthusiasts say that KTM Bajaj is a match made in heaven!

790 is their first parrallel twin, it wasn't going to be easy, they said But they had to go this path, since the 690 single cylinder with its vibs couldn't go any bigger, so without loosing that character, the 790 was born. It is a great machine.

890 gets its traction for other reasons, updated emission norms, matching up competitive pricing of power to weight ratio with other middle-weight naked manufacturers. If KTM had indeed identified those engine issues with 790 and are rectifying the same on 890, they could simple share those common compenents with 790 and 790 Adv as well, but it isn't the same story, 890 forums too have more or less those niggles, but this is a different chapter.

This engine is warped! Any high performance machines, with this much warpage should simply be replaced with a newer engine by the manufacturerer, we are not talking about commuter bikes here, these are high torque monsters, a rebuild so soon is not warranted, especially when the user has promptly got his bike checked by his respective consulting SVC. The standard practice of topping up coolant only accelerated the issue further, this issue should have been quickly caught by the technicians, could have saved the engine much earlier. They shouldn't have relied on simple visual inspection of engine oil, it yielded a wrong analysis. KTM should simply own the problem, and get the engine replaced under warranty, replacing a few components (which they have been doing), by hit and trial is just prolonging the problem, at the user's expense (relative to time, stress & user experience). If KTM India had the technical know-how to debug this problem, they would have recalled all the 100 bikes sold here in India to fix it, but they are clueless. They should be more serious with their current top of the line halo bike in India, if they are serious about getting the 890 and 890Adv or even the upcoming 490 Adv.

[gururajrv]

What?! This is still prevalent in bigger KTM’s? This issue plagued a lot of NS200, Duke 390 engines since it’s entry into the market. KTM / Bajaj are still giving mediocre designs in newer engines in 2022? This is absolutely disappointing!

I really hope you get that peace of mind back with all issues resolved soon enough!

[Pretorian]

https://www.instagram.com/p/CbF0C50qKGT/

Amidst all this, ktm has announced the new 2022 Duke 790.

[dj_666]

Originally Posted by rvrmvaishnavi

Sometime later, they tried to change the coolant pump gasket, checked the impeller shaft seal and replaced the heat exchanger gasket.

Had the same problem with an RC8R.

Changing the impeller shaft seals along with an oil + coolant flush sorted out the issue.

[neil.jericho]

Originally Posted by Pretorian

790 is their first parrallel twin, it wasn't going to be easy, they said But they had to go this path, since the 690 single cylinder with its vibs couldn't go any bigger, so without loosing that character, the 790 was born. It is a great machine.

890 gets its traction for other reasons, updated emission norms, matching up competitive pricing of power to weight ratio with other middle-weight naked manufacturers. If KTM had indeed identified those engine issues with 790 and are rectifying the same on 890, they could simple share those common compenents with 790 and 790 Adv as well, but it isn't the same story, 890 forums too have more or less those niggles, but this is a different chapter.

Pretorian, as much as I enjoy watching Youtube videos of enthusiasts enjoying the hooligan nature of the Duke 790, I find it awfully difficult to call this a great machine. If we look at ownership reviews, we can find so many problems like immobilizer issues, cruise control failures, engine issues and so much more. KTM knew that fixing these issues while also trying to keep up with the market and meet Euro 5 norm was going to be impossible, so they jumped to the 890. Which as you said is also riddled with problems. A lot of it comes down to KTM's core engineering philosophy and DNA. We dont find any of their competitors having as many problems as these KTMs. I like what KTM offers the market but I would never buy one for myself.

Anways, I didnt mean to derail rvrmvaishnavi's thread. Its just that these engine issues from KTM were not at all a surprise to me. Its part and parcel of owning a big KTM, that too in India where the technical training to the dealers, is not as great as what it is for its competition. At least, that is what I have heard from my little birdies. Anways, I hope KTM India is able to provide a satisfactory resolution to rvrmvaishnavi and he enjoys tens of thousands of trouble free miles on his hooligan Duke 790.

[amol4184]

Like mentioned above, 790 is back in the market with what seems like exact same engine and other components as the OG. It even costs significantly less than the when it launched. The power/torque figures are all same, except for Europe where it now makes less power to make it comply with A2 license tier. There were talks of 500cc twin by KTM but it appears that isn't going to happen soon with comeback of 790. Strange really.

Though this relaunch should help the existing owners like OP. If the 2022 model has fixes for blown headgasket, may be it can retrofitted to older models. All the best.

[rvrmvaishnavi]

In all fairness, i must say , that despite all the niggles i have had around minor coolant leaks and valve gasket issues and side stand issues and so on, all of that is forgotten the instant you ride the bike . just 5 mins is enough to just bring back that wide sheepish grin under the helmet

And, ofcourse there is a failure rate for any machine. Unlike the 2nd gen 390s which have had a lot more of such failures, at least on the international 790 forums there are hardly 1-2 other instances of major failures. So i dont think its fair to say they are all terrible/unreliable etc. Again, its hard to argue with the value prop of the machine.

The worst part is, i am so spoilt by the lightweight torque rocket, its hard to be impressed by anything else reasonably priced inthe middleweight naked space. I am not a pro by any means, but i have ridden the other options barring the new monster , while they each have some amazing aspects, none are as much of a hooligan as this one.

All that ofcourse is true unless you are that one lucky blessed sould in a 100,000 to be the guy with a major failure. which i am :-|

Anywany, lets see what happens. going to do a status check tomo..wlil keep this updated.

PS: There was a question about external leaks, those were checked thoroughly and eilminated. the only remaining causes are the head gasket or the coolan impeller shaft seal..