Re: KTM Duke 390 - Ownership Reviews and Experiences

Me thinks the compression readings are low.. even i was only able to spot that youtube video that showed 200psi. For a 12.6:1 compression ratio i think you should be hitting at least around 180psi.
maybe you can remove the fuse for the fuel pump/ignition coil (fuse 4 iirc) and then do the compression test. With the fuel pump working, the injector is going to keep spraying in fuel, which u don't want on dry test.
So,
First warm up the engine so that the temp bar is around half way up on the lower segment, shut it down and wait for around 10 minutes. Pull out the fuse for the fuel pump/ignition. I think this fuse also controls the starter relay so you might not be able to crank the engine so here is what you do:

Keep the key position to ignition on, but flip the kill switch to the kill position !! This will kill the fuel pump but still let you crank the engine.

Now connect your compression gauge and ask someone to keep the throttle wide open, then try cranking the engine for 3-5 seconds take a reading. Repeat cranking and take 3-5 readings.

Then squirt in few drops of oil.. crank again with throttle wide open and take 3-5 readings.

Re: KTM Duke 390 - Ownership Reviews and Experiences

I was thinking the same. 12.6 * 14.7(atmospheric pressure) = 185. So it should be somewhere around 185 Psi. But there are other forums mentioning around 130 to 140 is the correct one. Keeping key position to on, killing the switch and then testing might yield a better outcome.

Re: KTM Duke 390 - Ownership Reviews and Experiences

that is the correct way along with keeping the throttle wide open. i wont be surprised if it yields higher values. and make sure the compression gauge is screwed in all way tight.
if you look at that video from youtube, you will notice that the engine is off the bike, not connected to the fuel system and the intake side open (throttle body missing).

from what i've researched, it looks like ktm relies on leakdown tests rather than compression test and so probably doesn't publish the figures for compression in psi.

Re: KTM Duke 390 - Ownership Reviews and Experiences

Since last 6 months i am daily traveling 30kms in mild traffic where average speed is 30 km/hour.
Today i started traveling and bike heated like normal then fan started as normal after 10 minutes fan stopped which is normal as fan keeps on and off.
But after sometime fan didn't started even though temp reached last bar and bike stopped with high coolant temp alarm.
So had to wait outside the road for 10 minutes to cool down the bike.
After that started journey again without any problem and fan kept running for rest of the time doing it's job in hot summer.
Now the question is why fan didn't started when it was required? And why the issue occurred only once?

Bike has 21kkms, 2 years. and apart from little engine oil leak from gasket no other problem. Even coolant level is steady and was replaced a 10 months back.

Re: KTM Duke 390 - Ownership Reviews and Experiences

Do the bolts that are used on the engine case differ in size ?

Re: KTM Duke 390 - Ownership Reviews and Experiences

Yes. Front sprocket/magneto cover bolts differ in size.

As long as the fan was operational post the HCT warning, there's nothing to be alarmed per se. What I'd recommend though is keep a tab on the coolant level and how efficiently the fan operates. If the fan shrieks and shrills or the rpm of the fan is slower than usual, it's time to replace the fan. For now, keep a tab on the coolant reservoir and the liveliness of the fan.

From what I can perceive here, the readings are absolutely fine. Post the wet test, the compression ratio did go up, although by a few psi's which is perfectly normal. The other thing you can do is a leakdown test. This is a sure shot way to find any compression leak. First compressed air leaks either through the rings itself, second through the head-gasket (which also causes bubbles in radiator meaning, we have coolant leak) and third through intake and exhaust valves. A leak down test requires a little dexterity and the right tools, though it's extremely accurate.

In the end, as long as the engine runs fine, suggest leave it as it is, unless there is perceivable dip in performance. If you do do a leakdown test, keep the numbers jotted down.

Cheers!
VJ

Re: KTM Duke 390 - Ownership Reviews and Experiences

I do not have the equipment to perform leak down test and not planning to get one for now. As I had the compression tester, was just curious to find out the readings. The bike runs well and it's still a bomb in acceleration department. Though, I am yet to find out the reason for minor coolant draining, except that, there is absolutely no issues. But from the tests I performed, I feel head gasket is not the issue. Please do correct me if I am wrong.

Re: KTM Duke 390 - Ownership Reviews and Experiences

Again, as long as the acceleration and early morning engine cranking behavior is perfectly normal, the engine is perfectly fine. Secondly, if you want to know if you have a compression leak, you can do this little test. Though for this you'd have to sacrifice all the coolant inside the coolant tank. Remove the radiator cap (removing it will drain all the coolant from the expansion tank as it sits directly above the radiator)

Crank the engine, let it mildly warm up. Now, slowly yet steadily increase and decrease the RPM, you shouldn't observe any bubbles or any gargling of the coolant inside the radiator. You should see mild increase in the level of coolant as the engine RPM goes up and down. If you see constant bubbles with increase in RPM, you have a compression leak which means your head gasket is bust, which means mild coolant ingestion. If the coolant level just goes up and down with RPM, you head gasket is perfectly fine.

Cheers!
VJ

Re: KTM Duke 390 - Ownership Reviews and Experiences

Hi VJ,

Finally fan given up and not at all kicked in as normal.
I think it's temperature sensor or wiring..Will be going to service center this weekend.. let's see ..

Re: KTM Duke 390 - Ownership Reviews and Experiences

Changed battery to Amaron 8ah (1900 rs) as it was 3.5 year old, to remove one of the possibility.
Checked earthings and fan started working.
But while returning from service center again fan give up.
Went back to service center and found that fan is failed.
Will be replacing fan next week as it was not in stock. SC quoting ~ 2.8k (1800 for fan rest for labor and coolant)

Re: KTM Duke 390 - Ownership Reviews and Experiences

Thanks to all for their valuable inputs. So comming into the problem part, well there wasn't any. Yesterday coolant flush was done in my m/c and as per the mechanic, it was just rust(particles) which got accumulated at the top of the reservoir and everything is fine.
Now I can live peacefully[emoji4]

Re: KTM Duke 390 - Ownership Reviews and Experiences

just relax and ride, or maybe after a few 100km drain the oil and coolant and check. that's a sure shot way of knowing if coolant is mixing with oil.
otherwise it might be a minor external leak maybe along the hope pipes or evaporation loss (check the expansion tank if it has a crack)

Re: KTM Duke 390 - Ownership Reviews and Experiences

Neither coolant nor engine oil was dissapearing. The problem was there was some black strain in the top of coolant reservoir and after cleaning the same with the help of cotton buds no such accumulation was found after 2 weeks. So I guess it was some sort of rust or something similar to that. Any ways coolant flush was done yesterday and after riding around 100 kms, it seems fine.

Re: KTM Duke 390 - Ownership Reviews and Experiences

If you'll rewind back to my post, it was exactly what I mentioned. Radiators rust over time on the inside and the rust residue is browny and sometimes form benign lumps which are almost like mud residue. These alter the color of the coolant in the system over time. Always keep a habit of replacing your coolant every 6 to 12 months if your usage is mostly city commuting where the engine usually always reaches peak temperature pretty fast. Always make sure you get premixed coolant or if you dilute the coolant yourself, make sure distilled water is used. Using tap/salt/brine water WILL induce rusing and pitting inside the radiator.

Cheers!
VJ

Re: KTM Duke 390 - Ownership Reviews and Experiences

Yes Sir you did mentioned the exact thing which I was facing. As most of my riding part comes under city commuting so I guess expecting such thing was obvious. Thanks [emoji5]