[mithunvvijayan]

Originally Posted by ebonho

Lots of engineers here. I'm just a doctor. Who rides.

Call me paranoid, but if a bike heats up to just shy of its max threshold limit, and then stays there under load (running hard), but then refuses to budge even a bar even after more than 10-15 minutes of idling (no load), with the radiator fan on full blast, and then as has been claimed by one of the members here, still shows essentially the same high temperature 3 hours later to the motor being shut off, I would at the very least SUSPECT that something is not right.

Of course I could choose to be an optimist and believe that the company designed it this way. For fast thermodynamically efficient getaways ... after periods of inactivity or rest.

However, for a variety of reasons, I do not have that luxury.

Fact of the matter - on the Duke 200, as with all radiator cooled vehicles, after a hard ride/drive the fan comes on, stays on for some time (either with the engine on or not), and then shuts off. Max a couple of minutes.

Not so on the 390? Why? Whats different? Whats special?

I am not sure if KTM has designed the radiator fan, in such a way that it keeps the engine near maximum temp, for fast get aways. I just thought that may be we need not be that concerned. From what manofsteel pointed out, about a superbike experience, I think, after a hard run, we may have to wait for while, before switchinf off.

[mithunvvijayan]

Originally Posted by man_of_steel

Please do explain why putting a bigger fan will not aid in better cooling.

And by 'bigger exhaust', did you mean bigger radiator fan?

Yeah, I meant radiator fan. And bigger fan definitely aids in better cooling. But do we need better cooling is the question.

Anyways some Bajaj R&D guy must be laughing at our post. They might not even have considered the problem at all, in the first place!!!

Originally Posted by man_of_steel

In real world scenario Both point A and B means the same thing. Let me put forward my understanding.

The basic task of a cooling system is to transfer the heat from the engine block to the atmosphere. In case of liquid cooled engines, engine heat is first transferred to a fluid(coolant) and then dispersed into ambient air through a radiator.

And no cooling system is capable enough to transfer the complete heat produced by the engine to the ambient temperature while the engine is operational. Thats why you will always see even an idling engine hovering at 60-80deg C even while the ambient temperature will be 25-35deg C. And due to that practical limitation all engines works best (or atleast designed to work) at an optimum operating temperature and the cooling system (radiator is an inccorect term) will be able to bring down the temperature to only that optimum operating temperature with sufficient flow of air around the radiator.

I agree to one point that the 390 could have used a heavier cooling system (bigger capacity radiator and fans). But there is always electrical load, engine load, weight and even climate of even other countries to be considered.

We need to have a debate on this. I think it will qualify as a technical topic. But since the source is from the duke 390 radiator conundrum, I think, this post merits a place here.

For any heat engines, there must be a heat source and a sink. Here the heat source is the fuel combustion, the sink is the atmosphere and not the radiator. The heat is NOT transferred from the engine to the atmosphere through the radiator. It is done through the EXHAUST. I think a confusion exists between the refrigeration cycle and the Otto cycle(in our case), where the heat transfer is done through the condensor( radiator).

The heat is analogous to current, and the temperature difference between the heat source and the sink is analoguous to voltage (potential difference).

The heat engine strives to convert some of the heat produced in the engine into work(output).
The more the temperature difference, between the heat source and the heat sink, the more efficient the heat transfer. I do not want to go to the efficiency equation and stuff.

So the engine temperature is critical for heat transfer. The radiator simply functions as a cooling system, that prevents overheating of the engine and engine oil.

Mod Note: Please use the EDIT or MULTI-QUOTE buttons instead of typing one post after another on the SAME THREAD!

To know how to multi-quote, click here.

[shan_ned]

Originally Posted by sandeepmohan

I find the trigger for the radiator fan a little too aggressive. You stop at a long traffic light. I keep the engine idling. Fan starts up and keeps running. Traffic light turns green, I start moving at a speed of no more than 20-30kmph considering I am in the thick of traffic inching slowly to cross the signal. In this short time I have started to move, the radiator fan turns off, possibly instruction from the ecu that the bike has started moving and natural air flow can take care of cooling. Not good. Its taking place too soon. Temperature starts rising, fan restarts.

If D390 is behaving same as what you have described, then is that not the right way for a cooling system to behave ? If on the move from a traffic stop helps in getting more natural air flow, it looks logical for the fan to get switched-off. So when the engine temp rises again, it looks much more logical for the fan to take over again. I am seeing this to be the right behavior, but I may be missing something which you are aware of. Or may be you are not okay with the fan kicking in and off very aggressively, but what if that is the right intended and optimistic behavior by design to keep the system stable ? It may also turn out to be what mithunvvijayan is suggesting about our concern and speculation on an non-existent issue.

Originally Posted by mithunvvijayan

I am not sure if KTM has designed the radiator fan, in such a way that it keeps the engine near maximum temp, for fast get aways. I just thought that may be we need not be that concerned. From what manofsteel pointed out, about a superbike experience, I think, after a hard run, we may have to wait for while, before switchinf off.

This helps !!!

As both man_of_steel and mithunvvijayan points out that the engine heating is a known phenomena exhibited by most of the superbikes, then do we see the same behavior of the fan running for extended periods (while idling) even on other superbikes ?

May be I am beating a dead horse on this engine heating issue .. Of course I do not wish to hijack this thread by discussing this same issue of engine overheating again and again ...

[mithunvvijayan]

Reading my earlier post, even I got confused. So I will try to simplify.

The piston moves and rotates the crank shaft. The piston is inturn pushed by the expansion of the gas mixture after it is ignited by the spark plug.

In the above process, the heat energy generated by the ignition is partially converted into mechanical energy. Rest of the heat is wasted through the exhaust.

Now, if the engine is cold, the process of expansion is hampered. The heat generated by the fuel has to be converted to work, not to be transferred into a heat exchanger( radiator).

If the radiator fan works in excess, the radiator will remove some heat from the cylinder, which is meant to be converted into work.

Phew!! Guys forgive me for being too technical.

[basuroy]

Guys please help me with my situation , my tire is losing pressure rapidly and let me back that up with data -
1st check - 28F , 30R
2nd check after 50km - 25F , 23 R , re-inflated to 25F and 35R
3rd check after 50km - 18F , 28R .

Odo reading , 150km brand new bike and hence tire . Sedate riding so far barely involving any bad sections . No puncture as per tire chap , what is the probable cause in your opinion ? SVC is closed tomorrow and I am not sure if I am doing the tires harm by every kilometer I ride right now , a friend reckons there is a wall leak . How complex is the solution to a wall leak ?

Another thing that happened today during an acceleration run ( almost WOT ) in 2nd gear was the rev limiter kicking in right at 7.5k rpm (I clearly observed the rpm as the situation allowed for such distraction) . This run was i influenced by a run previously(3rd gear and similar throttle application , speed around 80/90) where I had observed strong jerks at a very high rpm(but distinctly recall feeling this is too soon for 10.5k , my assumption was this was not normal for the rpm I figured i was at and hence I believe it was around the same mark as my 2nd observed run) but could not figure out what happened as I have never previously experienced rev limiter kick so did this run .
After this I tried accelerating twice more(both 2nd gear) , first at a moderate manner and the bike went up to 8k rpm and 2nd time somewhat faster and it went up to the 10/10.5k mark . What is the probable explanation to this ? As I understand , they merely set the shift lights at an lower rpm or can they somehow manipulate the limiter to kick in during run in period (150km ODO reading) ?

[Motard_Blr]

Originally Posted by basuroy

Guys please help me with my situation , my tire is losing pressure rapidly and let me back that up with data -
1st check - 28F , 30R
2nd check after 50km - 25F , 23 R , re-inflated to 25F and 35R
3rd check after 50km - 18F , 28R .

Odo reading , 150km brand new bike and hence tire . Sedate riding so far barely involving any bad sections . No puncture as per tire chap , what is the probable cause in your opinion ? SVC is closed tomorrow and I am not sure if I am doing the tires harm by every kilometer I ride right now , a friend reckons there is a wall leak . How complex is the solution to a wall leak ?

Another thing that happened today during an acceleration run ( almost WOT ) in 2nd gear was the rev limiter kicking in right at 7.5k rpm (I clearly observed the rpm as the situation allowed for such distraction) . This run was i influenced by a run previously(3rd gear and similar throttle application) where I had observed strong jerks at a very high rpm(but distinctly recall feeling this is too soon for 10.5k , my assumption was this was not normal for the rpm I figured i was at and hence I believe it was around the same mark as my 2nd observed run) but could not figure out what happened as I have never previously experienced rev limiter kick so did this run .
After this I tried accelerating twice more(both 2nd gear) , first at a moderate manner and the bike went up to 8k rpm and 2nd time somewhat faster and it went up to the 10/10.5k mark . What is the probable explanation to this ? As I understand , they merely set the shift lights at an lower rpm or can they somehow manipulate the limiter to kick in during run in period (150km ODO reading) ?

Puncture repair guys usually check only the tread and the valve. Ask them to remove the wheel and submerge it water and then check for leaks. The problem could be the tyre, the rim or both.

[basuroy]

Originally Posted by Motard_Blr

Puncture repair guys usually check only the tread and the valve. Ask them to remove the wheel and submerge it water and then check for leaks. The problem could be the tyre, the rim or both.

The check was a very cursory one(i did one myself at home , didnt observe any nails etc) , just a visual check so his observation is not iron clad but he did mention in case of a puncture , tire would have lost a lot more pressure than just 5/7psi in 50km of riding(is he correct ? ) . My friend who owns a NS200 feels the same , he is of the opinion an wall leak can however result in slower deflation rate , I am a tubeless tire newbie so don't have a clue .

I really don't want to let some roadside or for that matter a proper shop take off my wheel and brakes this early , don't the SVC attend to these issues ?

[Motard_Blr]

Originally Posted by basuroy

The check was a very cursory one(i did one myself at home , didnt observe any nails etc) , just a visual check so his observation is not iron clad but he did mention in case of a puncture , tire would have lost a lot more pressure than just 5/7psi in 50km of riding(is he correct ? ) . My friend who owns a NS200 feels the same , he is of the opinion an wall leak can however result in slower deflation rate , I am a tubeless tire newbie so don't have a clue .

I really don't want to let some roadside or for that matter a proper shop take off my wheel and brakes this early , don't the SVC attend to these issues ?

A puncture too could cause a slow leak. It depends on what caused the puncture and if it is still embedded in the tyre. If it's a small nail, you may not even notice it if it's pushed in below the tread surface.

In my experience, ASC also take punctured tyres to nearest the puncture repair guy and charge you for the privilege! If you don't want to go to a roadside guy, you could go to a decent tyre shop. Same job, same methods, more money.

[basuroy]

Originally Posted by Motard_Blr

A puncture too could cause a slow leak. It depends on what caused the puncture and if it is still embedded in the tyre. If it's a small nail, you may not even notice it if it's pushed in below the tread surface.

In my experience, ASC also take punctured tyres to nearest the puncture repair guy and charge you for the privilege! If you don't want to go to a roadside guy, you could go to a decent tyre shop. Same job, same methods, more money.

Thank you and that is news to me but both tires , damn my luck (Assuming it is a puncture , Hell to KTM if it is a rim defect/wall leak ) . Is there any other explanation along the line of this being possible with new tires ? I know I am clutching at straws but both tires is just too much coincidence :( A 3rd check is in the process , another 30km and I check again and then to shop/svc.

Can I trust a reputable shop from appearance to remove and then mount the brakes properly (does ABS line pose any complication for example ? ), I have never experienced this kind of problem before and hence I am not aware of any potential mistake they might make .

Is no puncture is observed , what do I do then ? In case of a wall leak or worse rim defect surely SVC must assume responsibility (including financial ) in a bike that is basically brand new and babied so far.

[Motard_Blr]

Originally Posted by basuroy

Thank you and that is news to me but both tires , damn my luck (Assuming it is a puncture , Hell to KTM if it is a rim defect/wall leak ) . Is there any other explanation along the line of this being possible with new tires ? I know I am clutching at straws but both tires is just too much coincidence :( A 3rd check is in the process , another 30km and I check again and then to shop/svc.

Can I trust a reputable shop from appearance to remove and then mount the brakes properly (does ABS line pose any complication for example ? ), I have never experienced this kind of problem before and hence I am not aware of any potential mistake they might make .

Is no puncture is observed , what do I do then ? In case of a wall leak or worse rim defect surely SVC must assume responsibility (including financial ) in a bike that is basically brand new and babied so far.

I suggest you ask your friends who have bikes with disc brakes which tyre shop they would recommend.

If it's a puncture, repair at your cost. If it's a defective rim, repair at Bajaj's cost (hopefully!).

Don't worry so much - it's probably just a minor issue. You can get it repaired and start to really enjoy your bike.

[unk9ja]

Originally Posted by basuroy

Guys please help me with my situation , my tire is losing pressure rapidly and let me back that up with data -
1st check - 28F , 30R
2nd check after 50km - 25F , 23 R , re-inflated to 25F and 35R
3rd check after 50km - 18F , 28R .

Odo reading , 150km brand new bike and hence tire . Sedate riding so far barely involving any bad sections . No puncture as per tire chap , what is the probable cause in your opinion ? SVC is closed tomorrow and I am not sure if I am doing the tires harm by every kilometer I ride right now , a friend reckons there is a wall leak . How complex is the solution to a wall leak ?

Check out the valve and its stem on the rim. If not properly fixed, then it can leak from that point.

[VW2010]

If the radiator fan works in excess, the radiator will remove some heat from the cylinder, which is meant to be converted into work.

The radiator function is simply to cool the engine. The heat generated by combustion is so high that without cooling you are basically destroying the engine block.

And the radiator fan is simply a way of transferring heat from the alum coils into atmosphere and its the same heat exchange which naturally happens when the bike is in motion.

There is no way a radiator fan can remove the amount of heat you are talking about to make the engine inefficient.

And my minimal technical knowledge and my assumption is as below. If its not right...Ignore

The coolant carries the heat from the engine blocks and the fan merely transfer the heat from the coolant to the outer surrounding. This is such a closed loop that the fan speed, the size of the fan and the overall effectiveness is barely minimal in most of the bikes. Even super bikes find it tough to maintain that level of heat removal using radiator that riding them actually is more effective.


A better efficient radiator will operate way before the engine starts over heating. Like if we have an option to adjust when the radiator kicks in, i would try playing with the setting. Worst case, i may bypass that circuit and have a manual switch to switch on the radiator whenever i want. Why wait till the engine is completely stand still while you can achieve that gradual heat removal as the vehicle slows down.

My guess is
- Coolant not getting pressurized enough to 1- Avoid boiling but also letting it cool down enough to actually remove heat.
- Coolant circulation speed is too fast for the actual cooling cycle to remove heat from the coolant via radiator fans.
- Overall design of the radiator and the way the thermostat and sensor work. May be the component is not operating the way it should to regulate the fan speed.

The design has so many variables that its tough to pin point but overall i would say bad design for such a small system.

[basuroy]

Originally Posted by Motard_Blr

I suggest you ask your friends who have bikes with disc brakes which tyre shop they would recommend.

If it's a puncture, repair at your cost. If it's a defective rim, repair at Bajaj's cost (hopefully!).

Don't worry so much - it's probably just a minor issue. You can get it repaired and start to really enjoy your bike.

In case of wall leak , how complicated is the repair job ? Any precaution I must ask them to take while carrying out the job , bareilly workmanship can be very shoddy and I may not have time to check online if wall leak is the issue .

Not trying to let the minor issues bother me but at the same time , they end up bothering me . For example I found an excuse to both ride and test a few things just after dinner , I cant help but feel the bike's control is not as accurate as it should be . I have no benchmark to judge against but for example earlier today , I found it drifting rightwards(the pull was noticeable , around 30kmph speed ) with a pillion who was not moving and again now it didn't really handle the way I have read and expect it should . These small issues which are very hard to quantify are always at the back of my head being a new purchase and all :/ . Tomorrow I know I am going to clock another 20-40km and check the pressure again even though good sense says I should prioritize diwali and the associated obligations , hard to ignore the bike though ....

Originally Posted by unk9ja

Check out the valve and its stem on the rim. If not properly fixed, then it can leak from that point.

While I hope the tire guys took due care to do that , I will still check them out myself . It is often small things like this that end up being the cause and I honestly hope so is the case this time


What mileage do you guys get for day to day riding in mostly 2nd/3rd gear hovering between 4-6k rpm (average speed around 35kmph)? Is the on board mileage calculator accurate (within an error of +/- 1 Ltr , if not what error you normally figure ) ?

Is the on board fuel level indicator accurate(within reasonable error of say 500ml or at worst 1 ltr) when bike is held upright , does the engine being hot/cold affect the reading ?

[mithunvvijayan]

Originally Posted by VW2010

The radiator function is simply to cool the engine. The heat generated by combustion is so high that without cooling you are basically destroying the engine block.

And the radiator fan is simply a way of transferring heat from the alum coils into atmosphere and its the same heat exchange which naturally happens when the bike is in motion.

There is no way a radiator fan can remove the amount of heat you are talking about to make the engine inefficient.

And my minimal technical knowledge and my assumption is as below. If its not right...Ignore

☺By radiator fan I meant the radiator fan/ coils combo. Anyways as you said the effect will be minimal. I thought I would clarify what I mentioned earlier, that we don't need to worry too much about radiator fan for 390.

Infact I have started to ignore all the small niggles. What bike with a power to weight ratio of more than 270 Bhp/ton, mileage of more than 25 kmpl, state of art high strung engine, standard ABS bybre, WS suspensions, Metzlers, an international model which requires more than an A2 licence in Europe for the standard version, brand image of KTM, will you get for around $3000, anywhere in the world? I am waiting for the first service to get done, and slowly my Dr Jekyll will turn to Mr Hyde��

Guys, please advise.

What is the socket type for headlight bulb for 390? Is it H4? I have seen a few people change the standard bulb to phillips extreme vision. I also changed my stock head lamps to phillips extreme vision in my car, but found it not so effective, so using P8 Xenons.

Can anybody suggest an alternate solution, which will not cut any wires/warranty? What about Led bulbs? Do they have it in H4 types?

I come late from office. Very difficult to see the pot holes when people from the opposite side, refuse to dim their lights.

[abhinav.s]

Originally Posted by basuroy

In case of wall leak , how complicated is the repair job ? Any precaution I must ask them to take while carrying out the job , bareilly workmanship can be very shoddy and I may not have time to check online if wall leak is the issue .

Basu, am late but nevertheless, congrats on the D390!!

With regards to the loss of air from the tyres, I would suggest you monitor the air pressure at home until the festival is over and the service center opens up. Get it checked at the service center itself! Reason - If it is a tyre issue, the dealer will no doubt get it done from a tyre shop nearby and it might cost you a few rupees extra, but if its a rim issue, it can be dealt with in that single visit rather than you going first to a tyre shop and then to the ASC again. And since you say that the workman ship in your place is not up to the mark, why risk it with a new bike?

Just my personal opinion but up to you to decide. Hope the issues are sorted out quickly and you get to enjoy your bike to the fullest!