[ebonho]

Originally Posted by navin_v8

Point taken what about engine refusing to start after a hot ride in bumper to bumper traffic and shutting off the engine at the traffic lights. I have experienced this while waiting at the signals and seeing Duke 390 owners struggling to start their motorcycles.

Do you also give a mild throttle while doing this or just press the thumb starter?

Mild throttle only in above mentioned hot trafficky sudden shutoffs (more because of MHB - i.e. morons honking behind) and usually when you've pulled in the clutch in-gear.

Besides I have rode my cousin's Duke 390 and have found ad tleast two instances where the motorcycle refused to start after it was manually stopped by me. I had to wait for two to three minutes before I could crank it and get it started.

Nope. That has never happened to me.

Btw, which post have you given a link to? I cannot find any post about difficulty starting.

[navin_v8]

Originally Posted by ebonho

Mild throttle only in above mentioned hot trafficky sudden shutoffs (more because of MHB - i.e. morons honking behind) and usually when you've pulled in the clutch in-gear.

Oh ok

Nope. That has never happened to me.

Lucky you, I wasn't that lucky.

Btw, which post have you given a link to? I cannot find any post about difficulty starting.

Post no.3029

[ebonho]

Originally Posted by navin_v8

Post no.3029

Its about engine temperatures, how much to idle before shutting off the bike, temperatures at shut on etc. The discussion was centering around the radiator fan cut in and cut off and best practises (as 390 guys will tell you, the fan just does not go off at idle after a hard ride - you need to finally put off the bike - so most have started putting it off immediately if for a long halt; and keep the engine on at traffic lights .....).

Nothing to do with starting difficulties.

[navin_v8]

Originally Posted by ebonho

Its about engine temperatures, how much to idle before shutting off the bike, temperatures at shut on etc. The discussion was centering around the radiator fan cut in and cut off and best practises (as 390 guys will tell you, the fan just does not go off at idle after a hard ride - you need to finally put off the bike - so most have started putting it off immediately if for a long halt; and keep the engine on at traffic lights .....).

I am unaware of this practice as I am used to riding air cooled engines. So maybe I was caught unaware like many such riders. But I still dont understand on keeping the engine running on at traffic lights, I instinctively switch off the engine while waiting at the traffic signal.

Nothing to do with starting difficulties.

I can keep giving references as to hot starting problems with the Duke 390 for example: http://www.ktmduke390forum.com/forum...ont-start.html

http://www.visordown.com/road-tests/...iew/23724.html (read the comment by keith baker)

There are some riders who have experienced this including me.

[hillram]

Originally Posted by navin_v8

Coming back to my query this is to you Hillram, I am still not convinced as to how a underbelly exhaust helps in keeping a balanced centre of gravity.

Dear Navin...This is what i meant. It is sourced from KTM website : http://www.ktm.com/in/naked-bike/390...l#.VQLfruGHdN0

[hillram]

After my last ride on NH 44, i noticed that the coolant started leaking rather badly after every run. I took my bike to SVC and investigation began.
First i was told that the thermostat and the Coolant water temperature sensor need to be replaced and i agreed.Still the coolant leakage issue was not fixed.
Second round of investigation began and this time the coolant tank was emptied and washed. Here came out the culprit. Some had deliberately dumped a fistful of fine sand and mud in the coolant tank and it jammed the radiator completely.
I was advised to change the radiator and i couldn't possibly disagree. Since then there has been no coolant leakage, But it now scares me to park my 390 anywhere, just in open as anyone can do the same mischief as the coolant tank is very accessible to any miscreant who wants to dump anything in it.
Damages to my pocket :
- Coolant Water Temp Sensor : 200.50
- Thermostat Assembly : 380.00
- Radiator : 2731.00
- Labor : 300.00

[navin_v8]

Originally Posted by hillram

Dear Navin...This is what i meant. It is sourced from KTM website : http://www.ktm.com/in/naked-bike/390...l#.VQLfruGHdN0

I was thinking the weight of the silencer exhaust does not affect the centre of gravity but reading this makes me wonder if this helps. I rode the Duke 390 and felt is is sure footed due to its overall light weight and trellis frame coupled with that marvellous chassis. We should check with people who have opted for aftermarket exhausts for their dukes like Akrapovic, Yoshimura, etc. If having changed their stock exhausts to the ones mentioned above have made any changes to the centre of gravity or not.

[ebonho]

Originally Posted by navin_v8

I was thinking the weight of the silencer exhaust does not affect the centre of gravity but reading this makes me wonder if this helps. I rode the Duke 390 and felt is is sure footed due to its overall light weight and trellis frame coupled with that marvellous chassis. We should check with people who have opted for aftermarket exhausts for their dukes like Akrapovic, Yoshimura, etc. If having changed their stock exhausts to the ones mentioned above have made any changes to the centre of gravity or not.

The aftermarket exhausts you refer to for the Duke weigh a fraction of what the OE exhaust system with the big catcon does.

[navin_v8]

Originally Posted by ebonho

The aftermarket exhausts you refer to for the Duke weigh a fraction of what the OE exhaust system with the big catcon does.

Ok may not the be exact make which I have mentioned, but is it just the weight of the stock exhaust vis a vis the protruding aftermarket silencer that makes the difference? If KTM is claiming better centre of gravity with the stock exhaust there must be something to it other than marketing. Physics and Geometry experts need your help in decoding this.

[ebonho]

Originally Posted by navin_v8

Ok may not the be exact make which I have mentioned, but is it just the weight of the stock exhaust vis a vis the protruding aftermarket silencer that makes the difference? If KTM is claiming better centre of gravity with the stock exhaust there must be something to it other than marketing. Physics and Geometry experts need your help in decoding this.

Let me put it this way. The same weight as the OE exhaust, if slung to the side of the bike and not centered as it is now, would cause serious balance issues.

OE is OE. Aftermarket is aftermarket.

A bike, any bike, is designed to be perfectly balanced and centered.

[man_of_steel]

Originally Posted by navin_v8

I was thinking the weight of the silencer exhaust does not affect the centre of gravity but reading this makes me wonder if this helps. I rode the Duke 390 and felt is is sure footed due to its overall light weight and trellis frame coupled with that marvellous chassis. We should check with people who have opted for aftermarket exhausts for their dukes like Akrapovic, Yoshimura, etc. If having changed their stock exhausts to the ones mentioned above have made any changes to the centre of gravity or not.

The real question here is how many of us are really capable of noticing such a small difference in the bike's overall CoG. Strap on a heavy tail bag to the pillion seat and you will immediately notice the change in the bike's nature. But as for a difference between a similarly weighing underbelly vs/ traditional exhaust popping off one side of the bike, I don't know how noticeable it might be. Atleast for moderately talented riders like me. I would say that the whole weight of exhaust becomes apparent on the bike's CoG only in case of an under seat or similarly mounted exhaust! You might be well aware of many iconic under seat exhausts that were ditched in the recent past in the name of function over form!

Theoretically yes, KTM has placed the underbelly exhaust closer to the overall CoG of the bike which should attribute to the sure footed nature of the bike. Again, theoretically this might balance the CoG between left to right of the motorcycle and also from front to back. This balance might be critical to the KTM R&D guys but will be invisible to normal riders!

And don't bother asking the guys with genuine Akra or 'Mura exhausts as those will be lighter than the stock exhausts anyway!

[ebonho]

Originally Posted by man_of_steel

And don't bother asking the guys with genuine Akra or 'Mura exhausts as those will be lighter than the stock exhausts anyway!

That was my point too. And its not jst the Akras and Yoshis and Brothers. Most aftermarket exhaust systems are much lighter than the stock ones they replace. Easily 4-5 kilos difference in some cases.

[navin_v8]

[quote=man_of_steel;3664385]
Theoretically yes, KTM has placed the underbelly exhaust closer to the overall CoG of the bike which should attribute to the sure footed nature of the bike. Again, theoretically this might balance the CoG between left to right of the motorcycle and also from front to back. This balance might be critical to the KTM R&D guys but will be invisible to normal riders!
[quote]

This might be a valid point here, yes it might be possible theoretically but I haven't ridden a Duke 390 with a protruding exhaust hence cant comment about the centre of gravity. Even Kawasaki Ninja 650, Bennelli TNT 600 GT and many more sport similar exhausts, so there must be something about the centre of gravity with these exhausts.

[Roomy]

Originally Posted by hillram

A
Second round of investigation began and this time the coolant tank was emptied and washed. Here came out the culprit. Some had deliberately dumped a fistful of fine sand and mud in the coolant tank and it jammed the radiator completely.

Yours is the second reported case in this forum IIRC. I am wondering whether this actually is the handiwork of vandals or does the sand mysteriously find its way into the coolant tank.
Experts advise please.

[Sojogator]

Originally Posted by Roomy

Yours is the second reported case in this forum IIRC. I am wondering whether this actually is the handiwork of vandals or does the sand mysteriously find its way into the coolant tank.
Experts advise please.

Service centers themselves ? Won't put that out in our country either. They already might be hating that KTM has increased the service intervals.