Bajaj Dominar 400 Ownership Experience Thread

[arya809]

My personal suggestion to you would be, be present at the garage when they assemble your motorcycle. Trust me, you will spot many things they don't. z

VJ

SVC towed the motorcycle a week back, I didn't wish to go there everyday. Finally went there yesterday and found out that they had already changed the head assembly and block piston set. Now it runs smoothly BUT there's a new issue. While driving in any gear, if I accelerate HARD at 4k-5k rpm, there's a loud clicking/ticking noise from the engine.

I request all the members to listen to this short audio clip. NOTE that the extra clicking noise is way louder and distinct in person, I kept my cellphone near the left-side engine to record this audio, so it equalized all audio frequencies. In person, that sound is tinny and high frequency.


Google drive link:

https://drive.google.com/file/d/1WA8bGF-gZ_hqkeRJdKcwntCDoI9Y5p3k/view?usp=sharing

UPDATE:
I researched a lot on this issue. From what I could gather, the sound is because of KNOCKING/PINGING/PRE-IGNITION. It is all a GUESSWORK, I don't know how to test/prove this theory.


It especially happens in a high compression engine (12.1:1 for Dominar). Also, the mechanics swears to God, it happens in KTM bikes also when they replace engine. I think he may be right.

When a KTM/Dominar is new, the ECU knows the TRUE Odo reading so it controls the ignition timing precisely for a new engine, in other words it doesn't send advance ignition signals for a new engine.
Then after completing 2000 kms, the ECU sends regular ignition timing signals i.e. way before the TDC piston position.

After putting a new engine, the ECU still thinks it is controlling an OLD engine (2200 kms odo reading in my case), so it still sends regular ignition signals i.e. way before the TDC position BUT that results in knocking or pinging or pre-ignition. It gets resolved after completing around 1500 kms because of carbon deposition.

I sincerely hope, all that is true and there's nothing wrong with my motorcycle.


@B7ACKTHORN
Is it possible to RESET the ECU to zero kms reading, to inform it that the engine has been replaced?

[arya809]

UPDATE:

Finally my motorcycle is ready with new parts under warranty - New head assembly and new cylinder piston set.

When it broke down on 10th Jan, I wasn't in a hurry (as I don't use it for commuting) and told the SVC about it, BIG MISTAKE! Since that day, They kept making the same excuse that Bajaj sent wrong spare parts and they have re-ordered the parts. Finally I had enough and registered a complaint with Bajaj on 24th Feb.

The SVC manager requested me to close the complaint and promised to get the spare parts soon, I didn't budge and told them that I won't close it until my motorcycle is fully repaired.

I also contacted the showroom owner and told him the issue, he gave me the contact of Area sales manager (ASM). When I called him on 26th Feb, he also made tall promises but I told him bluntly that I am losing my patience and if I don't have a working motorcycle within a week, I will file a consumer court case! That triggered something and he started singing like a canary!

The very next day, they towed it to the SVC on their own, dismantled the engine (while spare parts were under transport) and tested the engine parts thoroughly. They also found that there was heavy compression loss and piston rings were sucking up oil into combustion chamber. So they informed me that they will change the cylinder piston set also under warranty.

And within 5 days of that call, the motorcycle is fully repaired with a new engine. Now I have to redo the whole running-in process, at least for 1500 kms.

[Indivar]

hello guys,
It happens to some of you that you accelerate with the handlebar and when releasing it the motorcycle continues to rev for a couple of seconds, it happens to my motorcycle being hot either with the carburetor fan on or without it, it is a Dominar 400 Version 1 with only 1600kms of travel (There were 2 units that were left in a local dealer and I bought it 100% new 25 days ago, black color with gold wheels).
I took it under warranty and they don't know what the problem is, they think it's the ECU, they've already checked the throttle guide and the throttle body and nothing.
Thanks and greetings from Colombia!

Here is a video showing that: (the video is hide, only persons with the link can watch it ) (https://youtu.be/OczvEBhNuvo)

Did they change the ECU ?

[colosocool]

hello guys,
It happens to some of you that you accelerate with the handlebar and when releasing it the motorcycle continues to rev for a couple of seconds, it happens to my motorcycle being hot either with the carburetor fan on or without it, it is a Dominar 400 Version 1 with only 1600kms of travel (There were 2 units that were left in a local dealer and I bought it 100% new 25 days ago, black color with gold wheels).
I took it under warranty and they don't know what the problem is, they think it's the ECU, they've already checked the throttle guide and the throttle body and nothing.
Thanks and greetings from Colombia!

Here is a video showing that: (the video is hide, only persons with the link can watch it ) (https://youtu.be/OczvEBhNuvo)

[Vishal Wagh]

I think this is best you can do now to make sure you will get brand new factory assembled engine. Which will gain yours confidence to not only for riding her longer distance touring without worries but also to keep this baby for long term.

[arya809]

Thank you for the kind words Arya, please I am no expert. Sharing what I have seen and observed. In their order.

Cheers!
VJ

Since that day, I didn't drive it, didn't even start the engine.

On that day, I could see minimum amount of oil in the glass window, it was frothy/bubbly. After that, I drove it home, around 5 kms.

Today I took it out and tried to start, didn't start. After 5-6 tries, engine started and I kept it idle for 1 minute but engine stalled and died. At that point, I noticed THAT THERE WAS NO OIL WHATSOEVER!

I immediately opened the oil filler cap, there were thick white fumes inside, smelled like evaporated oil! Fumes looked like liquid nitrogen, I mean it wasn't like steam which rushes out with pressure, the fumes were floating inside like clouds or liquid nitrogen.

That was 4 hours ago, I just checked the oil level (without side stand) and it's still zero, nothing's visible in that window.

I am afraid the engine is seized or damaged.

I went to SVC and told them that there is no oil in it and whether I should refill oil or not. They agreed to tow it back to SVC for free, after all they were the ones who forced me to drive back home that day despite my reluctance to do so.

Now I am seriously thinking about sending a complain to the top officials in Bajaj Head office. I will tell them to change the whole engine since it might be damaged beyond repair.


EDIT: I just googled "cam OR valves cause oil consumption". As I imagined, huge clearance or timing variation in camshaft can result in oil consumption via valves. Since it's proven that my bike's engine head is all messed up, is it SAFE TO ASSUME that engine oil will not disappear after changing the whole head assembly?

[kiran2508]

I can't IMAGINE the reasons for such loud tapping noises in my motorcycle. My GUESS is that since it's DOHC so there's no rockers, hence it shouldn't make such noises which is common with SOHC rockers?
I am imagining the worst that somehow the camshaft etc are misaligned, timing is way off or some parts moved from its place. I mean how else can there be a loud ticking noise in a DOHC engine?

Again, all that is wild speculation, I watched a few Youtube videos of DOHC engines and imagined the rest, please explain the actual facts.

DOHC engine of Dominar doesn't have a convectional rocker arm but they have a finger follower type rocker arm which make a tick tick tick sound at high temperature.
There are chances of faulty manufacturing defects timing chains where it's expanded beyond the actual tolerances, hence the cam is running out of sync, hence the wired sounds.

Fun Fact: Mahindra is recalling brand new Thar's around 1500+ cars due to faulty camshafts in their diesel engines.
https://www.timesnownews.com/auto/ca...n-india/715881

So no manufacturer is immune to manufacturing defects, as companies source parts from 3rd party vendors. Even a minor imperfection or improper Heat treatment will lead to faulty component.
Since your bike Service center has already to replace things under warranty, nothing to worry.

[arya809]

For all the spec numbers, ask for Domniar service manual from you SVC, you'll find all torque specs, valve clearances, piston ring clearances etc etc.

By the way, I was searching for the terms "dominar + engine + head", found few videos on Youtube in which owners of D400 2019 had similar engine head problems. Few of them got the Head assembly replaced, for others the mechanics simply replaced and adjusted new cam and valve set. It seems to me that quite a lot of Dominar 2019 are plagued by this issue. My SVC had already ordered 1 head assembly for another D400 2019, then ordered another for me.

I have a basic knowledge. I can't IMAGINE the reasons for such loud tapping noises in my motorcycle. My GUESS is that since it's DOHC so there's no rockers, hence it shouldn't make such noises which is common with SOHC rockers?
I am imagining the worst that somehow the camshaft etc are misaligned, timing is way off or some parts moved from its place. I mean how else can there be a loud ticking noise in a DOHC engine?

Again, all that is wild speculation, I watched a few Youtube videos of DOHC engines and imagined the rest, please explain the actual facts.

[kiran2508]

4) I am paranoid about losing compression when these local mechanics replace the head, how can I make sure that they replace head assembly with precision, please tell me the exact points like using torque wrench, diagonally tightening nut/bolts, decarbonizing piston, order of putting parts/gaskets etc etc.

As VJ mentioned in previous post, there is no one size fits all.
To give you an analogy, Maggi is sold all over the country coming out of same factory, yet no two hotels/houses cook the Maggi same way. All have their minor variations in their cooking process. Even though clear instructions is printed on the back of the packet.

Same way the parts come straight form assembly line of Bajaj, parts which would have gone on to one of the production bikes to be assembled and sold in showroom.
If done right and parts are assembled properly (like my engine which was shattered to pieces inside the head), it should be as good as new bike if not on par better than brand new.
Expertise of the mechanic and number of engines rebuilt by him till now, makes a difference. Someone who either follows the book or who follows his skill.

Try to ask for someone who has a "Certification to work on Dominar and trained by Bajaj training camp", not some Discover, Platina mechanics.

Principles of putting together a ICE engine is same for all 2 wheelers, cars, be it single cylinder or twin or inline 4 or V6 or V8.

Piston goes in the cylinder connected to crank, head goes which is faced(if needed), add the head gasket, valves lapped to clearances with new oil stem seal, valve clearances checked to specs with correct shims/screw setting, cams and timing chain adjusted to TDC and BDC marks, cover with came guide cover, put some gasket maker and cover up the valve cover. Tighten everything up. Voila. You've a fully rebuilt top-end.

For all the spec numbers, ask for Domniar service manual from you SVC, you'll find all torque specs, valve clearances, piston ring clearances etc etc.

[B7ACKTHORN]

Glad to hear from an expert.

1) I already asked the head mechanic about chain tensioner but he said it's not a problem, no need to change. Should I visit again to force them to change it? They will need to order the parts in advance if not in stock.

2) I don't know all the detailed parts in cam & valve assembly, kindly elaborate "completely new parts for the valve train". When they change the complete head assembly, doesn't it include all new parts of a valve train?

3) I had previous suspicions about the valve clearance, I was noticing clear and loud tappet noise since 3 months now, that too while accelerating quickly FROM 6000 rpm (I mean I don't accelerate hard from lower rpm's which causes knocking). But mechanics kept telling me it's insignificant and doesn't need tappet adjustment so early.

4) I am paranoid about losing compression when these local mechanics replace the head, how can I make sure that they replace head assembly with precision, please tell me the exact points like using torque wrench, diagonally tightening nut/bolts, decarbonizing piston, order of putting parts/gaskets etc etc.

Thank you for the kind words Arya, please I am no expert. Sharing what I have seen and observed. In their order.

1. Parts sometimes fail sooner, whether the mechanic justifies it or not, when they fail, they fail and it's absolutely no point for a guess work when half the engine is being stripped. Insist on replacing the chain, tensioner and if possible the cam shaft too.

2. They do and they do not; partly because a mechanic can salvage parts deemed necessary for him, refer to the first point (when parts fail, they fail, they don't ask for a mechanic's consent ) though a mechanic may still say a part is great. Making sure everything is replaced in the head, removes guess work out of the equation and definitely doesn't warrant future unnecessary follow-ups.

3. Please refer part 2.

4. This is a totally different chapter altogether. There are those who do things with and without a torque wrench. I have known people who can put a torque wrench to shame primarily because of the finesse and the dexterity at which they do their job, and knowing when and what tool to use for a given project on hand. Then there those who have them but still do a fidgety job which eventually leads to shoddy work. Don't worry about the torque specs, what matters here are new parts, correctly installed and the rest will follow naturally.

5. My personal suggestion to you would be, be present at the garage when they assemble your motorcycle. Trust me, you will spot many things they don't. z

Good luck.

Keep us posted.

Cheers!
VJ

[arya809]

The Dominar is a great one at that, but definitely not the best out there in terms of reliability and pestering issues. Good luck on your saga, and keep your observations posted.

Cheers!
VJ

Glad to hear from an expert.

1) I already asked the head mechanic about chain tensioner but he said it's not a problem, no need to change. Should I visit again to force them to change it? They will need to order the parts in advance if not in stock.

2) I don't know all the detailed parts in cam & valve assembly, kindly elaborate "completely new parts for the valve train". When they change the complete head assembly, doesn't it include all new parts of a valve train?

3) I had previous suspicions about the valve clearance, I was noticing clear and loud tappet noise since 3 months now, that too while accelerating quickly FROM 6000 rpm (I mean I don't accelerate hard from lower rpm's which causes knocking). But mechanics kept telling me it's insignificant and doesn't need tappet adjustment so early.

4) I am paranoid about losing compression when these local mechanics replace the head, how can I make sure that they replace head assembly with precision, please tell me the exact points like using torque wrench, diagonally tightening nut/bolts, decarbonizing piston, order of putting parts/gaskets etc etc.

[B7ACKTHORN]

Chances are you have issues sinister than what a bad fuel can be summed upon. First off, the Dominar doesn't come with any knock sensor, all it does have are a couple of sensors generic to an FI unit and an oil pressure sensor switch on the head. Many chances of Dominar failing have been to three reasons, primarily, engine coolant vanishing without a trace, secondly faulty valve train and thirdly some batches plagued with faulty ECMs and failed stator coils. As you've summed up right, limp mode basically restricts the free revving RPM to a preset RPM level enough to move the vehicle on its own for a proper diagnoses.

As a goodwill that they agreed upon to change the entire head assembly, I would also insist you replace your timing chain, chain tensioner and completely new parts for the valve train. Make sure your valve clearances are triple checked and the right size shims are used; if required make sure the SVC manager assistance is obliged upon to make sure you are completely satisfied with the work carried. I'd also strongly recommend you to inspect your fuel pump pressure to make sure it's maintaining and supplying the right pressure to the injection system.

The Dominar is a great one at that, but definitely not the best out there in terms of reliability and pestering issues. Good luck on your saga, and keep your observations posted.

Cheers!
VJ

[arya809]

@kiran2508

Good explanation, but that depends upon the assumption that I filled adulterated fuel. I was on the highway for only 80 kms round trip, got the tank full in the city from my regular BP petrol pump, plain petrol.

I am not sure, but isn't "limp mode" exactly opposite of my case? As far as I know, in cars and bikes, "limp mode" means the engine runs smoothly and perfectly, starts easily and holds idle rpm but the max rpm is limited to a lower level like 3000, 4000 rpm's etc. In my case, the engine was rough, refuses to start, doesn't hold idle and can only be run at higher rpm's.

I took it to SVC today morning. I bluntly told them that I will sell this junk as I can't trust it anymore, the SVC manager voluntarily agreed to get the head assembly changed under warranty. They have placed the order and it will be done once the parts arrive.

They made this decision based on the horrible ticking noises from the engine head. Today morning when I started the bike, there was a loud ticking/clicking noise for 10 seconds. After 10 seconds, the noise was slightly lower but constant and easily audible, there is considerable loss of power and no refinement whatsoever.

I am more irritated by the fact that I will have to follow engine running-in procedure for 2000 kms after the head replacement. And still bewildered as to what could be the reason for the valve or cam assembly going kaput like this.

[kiran2508]

Great, Bajaj has started showing its inferior quality!

Today while on a highway ride, engine stalled without any reason. It's a D400 bought in Dec 2019, 2nd free service was done 2 weeks back, total odo reading is 22xx kms. Since the engine running-in was over, I was riding at full throttle on the highway, keeping it between 7k to 9k rpm's. The auxiliary LED light (30 watts) was on since it was late evening.

Tyres fully inflated, cleaned and lubed chain myself 2 days back, Battery was fully charged, spark was generating, half tank fuel, all fuses okay, starter motor kept cranking then stopped on its own after few seconds BUT engine never started. Called a friend to tow it with his car. I planned to try to start it in gear at higher speeds while towing. Engine reluctantly started working in 2nd gear and 40 kmph speed.

Engine kept stalling at lower rpm's (like when a carburetor bike runs out of petrol), I had to rev it constantly to keep it above 5000 rpm else engine stalled within a blink. Rode it at high rpm's constantly and took it to the SVC, apparently they were closed for the past 3 days so they decided to work full time today. The mechanic attached the ECU diagnostic tool and it was showing an ECU malfunction (as told by them). They reset the ECU or cleared the malfunction, I am not sure. But immediately after that, the engine started behaving normally (somewhat normal). They told me to bring it again tomorrow morning for full workup.

My queries:
1. What happened to the ECU all of a sudden? I am seriously starting to mistrust it, do they use the same brand/model ECU in KTM's as well? What needs to be done to make my motorcycle trustworthy enough for long highway rides?

2. The engine is still far from normal. After keeping it off for a few minutes, it stalls at idle then I have to start it again and rev it a few times, then it holds idle and runs normally.

3. Since this issue, I am noticing a tik-tik noise coming from the left engine side. It is a constant ticking noise which can be heard across entire rev range. If it's the valve clearance (tappet gap) then how did it occur all of a sudden?

Only one answer from my side: Bad/Adulterated fuel which you topped up on the highway, either contaminated with water/kerosene or bottom of the barrel fuel collected with sludge, dirt, mud

1. Engine has a knock sensor built-in, sensors detected a knock due to bad fuel, hence ECU started adjusting on-the-fly the Fuel ratio to prevent the knock. Hence bike went to "limp mode". Reset of ECU cleared the knock warning, and everything is happy and normal again

2. Again, drain all the old fuel, clean fuel filter, clean spark plug head, and check for any mud/sludge/water contamination.

3. That's normal tappet noise, after break-in period and when engine is fully open, valve clearances do expand and contract need re-adjustment with correct shim sizes in some cases. Nothing worrying, you can run on it till next service and ask for "Stethoscope sound inspection"

[arya809]

Great, Bajaj has started showing its inferior quality!

Today while on a highway ride, engine stalled without any reason. It's a D400 bought in Dec 2019, 2nd free service was done 2 weeks back, total odo reading is 22xx kms. Since the engine running-in was over, I was riding at full throttle on the highway, keeping it between 7k to 9k rpm's. The auxiliary LED light (30 watts) was on since it was late evening.

Tyres fully inflated, cleaned and lubed chain myself 2 days back, Battery was fully charged, spark was generating, half tank fuel, all fuses okay, starter motor kept cranking then stopped on its own after few seconds BUT engine never started. Called a friend to tow it with his car. I planned to try to start it in gear at higher speeds while towing. Engine reluctantly started working in 2nd gear and 40 kmph speed.

Engine kept stalling at lower rpm's (like when a carburetor bike runs out of petrol), I had to rev it constantly to keep it above 5000 rpm else engine stalled within a blink. Rode it at high rpm's constantly and took it to the SVC, apparently they were closed for the past 3 days so they decided to work full time today. The mechanic attached the ECU diagnostic tool and it was showing an ECU malfunction (as told by them). They reset the ECU or cleared the malfunction, I am not sure. But immediately after that, the engine started behaving normally (somewhat normal). They told me to bring it again tomorrow morning for full workup.

My queries:
1. What happened to the ECU all of a sudden? I am seriously starting to mistrust it, do they use the same brand/model ECU in KTM's as well? What needs to be done to make my motorcycle trustworthy enough for long highway rides?

2. The engine is still far from normal. After keeping it off for a few minutes, it stalls at idle then I have to start it again and rev it a few times, then it holds idle and runs normally.

3. Since this issue, I am noticing a tik-tik noise coming from the left engine side. It is a constant ticking noise which can be heard across entire rev range. If it's the valve clearance (tappet gap) then how did it occur all of a sudden?