[ArizonaJim]

I probably shouldn't have said spark plugs can't melt.

Yes, there are conditions where the metal electrode can become hot enough to melt but these conditions are rather unusual.

If the ignition timing is advanced too far, the fuel/air will ignite long before the piston reaches top dead center. While a little advance before TDC is needed, too much advance will greatly overheat the piston and spark plug.

Very lean air/fuel ratios burn fast and hot. This creates a condition similar to the timing being advanced too far causing the pressures and temperatures in the cylinder to damage parts like the piston and spark plug.
If this is coupled with a over advanced timing it will cause knocking (pinging, pinking) which can rapidly destroy not only the spark plug but the piston and valves as well.

If the spark plug is not tightened securely the steel body of the plug cannot transfer the heat to the cylinder head where it can be dissipated.
This of course will overheat the spark plug although I've never seen a case where this actually caused an electrode to melt.

A spark plug with an incorrect heat range (too "hot") will overheat which can result in the center electrode melting. That is why there are several different heat ranges available to meet the demands of how the engine is used. (Mild, easy, low speed riding needs hotter spark plug heat ranges. High speed, wide open throttle riding needs colder heat ranges).

Please notice that all of these conditions are things that will not happen if the engine is properly tuned and it has the correct spark plug installed.

Any overheating that might happen to the spark plug is NOT due to the engine being a air cooled design.

[21Archer84]

Came across a couple of videos showing the bike under testing. But i feel the first video is better in terms of capturing the bikes note, though only for a few of seconds. I personally liked the grunt

https://youtu.be/VX7BUztrgcI

The other being this, not sure if it was already shared. Has more of wind noise

https://youtu.be/tfb_Fee2q1s

[aravind.anand]

The first video has caught a GT650 and also an Interceptor. It was nice to see the Interceptor snake through traffic like that, there seemed to be a nice flow in the way he managed the bike there. He video seems to have been shot from a Himalayan and hence it might not be the right yardstick, but still the twins seem pretty quick.

And the bonus is that they have a lovely rumble to boot !

[tsk1979]

Originally Posted by ArizonaJim

I had to bite my tongue when I read nikhn's comment about melting spark plugs.

Simply put, spark plugs don't melt regardless of how hot the engine gets and whoever suggested to him that they do, made one of the dumbest comments in my opinion that I've heard in a long time.

Originally Posted by TRR

I don't know how you're claiming it as a matter of fact that spark plugs can never melt. A simple google search for spark plugs melting is all you needed to do to be making informed comments. I don't have the best of technical knowledge in this area, but from what I gather from googling for this issue is that this can happen when a car engine overheats.

I know we're talking about bikes here, but I fail to see any reason why this cannot happen here as well. Could you please let me know why you think a bike's spark plugs never melt even if the engine gets extremely hot? What makes a bike's engine so vastly different from a car engine that this issue cannot happen in bike's?

Originally Posted by nikhn

I'm not sure if this is going off topic but anyways let me just put it up here. I am unable to put up my source since it's somewhat confidential. I would rather trust them since they are more closely related to the engine development of the RE 650/750cc series.

On a side note, spark plugs can melt. It's not funny. There are cases all over the internet. Even possible reasons are mentioned with one of them being insufficient cooling. Your wonderful explanation of air cooling vs liquid cooling, with its partially complete advantages and disadvantages is surely well known to RE or anyone else in this forum for that matter. No debate about it. Ultimately it's for RE to decide. I am not demeaning RE or their bikes here. Infact one of the source owns a RE and loves it.

Also , sharing a link for people who would like to expand their "knowledge".
Spark plug Melting and it's possible causes

https://www.amazon.com/dp/0470057572

Bosch has a very nice book on Gas engines.
Spark plugs do not melt. However the electrodes can melt.
Now this has nothing to do with Air or water cooling. This is due to knocking causing thermal overload

However if only ground is melted that means its due to deposites/additives etc., interfering with regular flow patter of the chamber.

I have not gone through this thread, so I do not know whats the debate, however if there is excessive spark plug electrode melting being reported for RE it could mean issues for combustion chamber (design defect), or aggressive compression ratio not suitable for our fuel.

[aravind.anand]

Look what I found during a casual visit to the Royal Enfield website! The rpm at which the peak torque is achieved has already jumped up from the earlier listed 4000 rpm to a rather high 5250 rpm, and the RE Twins are already starting to look a little too jaded. The biggest DNA trait that people love about RE is the torque wave that is available from low down in the rev range, but looks like that will not be the case with the twins

[ArizonaJim]

Although the maximum torque doesn't happen until the 650cc engine reached 5350 rpm that does not mean there isn't plenty of torque at lower revs.

With 650cc of displacement I have no doubt it produces much higher torque than the RE 500cc engine's at all rpm's, including at low rpm.

Torque is a function of displacement and the ability to breath in the air/fuel mixture to keep on producing torque as the engine speed increases.

Where a graph of the 500cc UCE single's torque curve flattened out at about 4000 rpm at 41.3 Nm, the 650's torque curve keeps on climbing up to 5250 rpm when it reaches its 52 Nm max. (That's a 26% increase over the 500's torque).

This higher torque of the 650 at its higher rpm continues to maintain itself until the maximum 47 horsepower is reached at 7100 rpm while the 500cc singles torque fell off at a much lower rpm limiting it to 27.2 horsepower at 5250 rpm.

Because horsepower is a function of torque times rpm (T X N), increasing both torque and rpm to higher values allows the 650cc engine to produce 73% more horsepower than the 500 UCE could.

[Surya-TJet]

Originally Posted by aravind.anand

Look what I found during a casual visit to the Royal Enfield website! The rpm at which the peak torque is achieved has already jumped up from the earlier listed 4000 rpm to a rather high 5250 rpm, and the RE Twins are already starting to look a little too jaded. The biggest DNA trait that people love about RE is the torque wave that is available from low down in the rev range, but looks like that will not be the case with the twins

While I do thank you for noticing this change in the specs on the webpage, let me reassure you that unless one sees a dyno run power & torque graph, we cannot comment on how the torque is built up in the engine.

With today's modern technology, many engines are tuned to produce 80-90% of max torque from very low revs and then achieve a small bump up to make the "Max Torque" at a specific rpm.

For example, the Dominar 400 (again a single cylinder) makes 35 Nm torque at 6000 rpm, it develops 28 Nm torque right from around 3000 rpm.

So, while the original specs of the RE650 stated max torque at 4000 rpm; but we did not know how much torque it made at 2000 rpm.

Now, with this newer tuning, maybe they could have improved the availability of torque 2000 rpm; meaning it could have more pull right from 2000 rpm all the way to 5250 rpm and beyond, when the power would kick in very well. This helps in avoiding any flat spots between the point where the torque tapers off to the point where the peak power delivery starts kicking in.

Also, twin cylinder engines have better tractability compared to single cylinder engines - An example of this:

I used to own a Thunderbird 500 and while that was a real torque rocket, the "SURGE" it had from 80 kmph was surreal. If a first time RE user / NOOB user were to whack open the throttle at 80 kmph in 5th gear, he'd be in for a real big surprise by that pull from this single.

But, having ridden my friend's Ninja 650, I can tell you straight away that if you did the same in this bike, it would pull really well without the feeling of that SURGE of torque, as the twins have a more even & smoother spread of torque (remember - two power strokes for every two rotation of the crankshaft compared to one big bang for every two rotations of the crankshaft).

So, while in that aspect of "SURGE", the newer configuration "COULD" be different - The indisputable fact remains that unless we ride the motorcycle in real world, there is no way of telling what it could feel like. This is the reality and no amount of "Specs" on paper can replace the riding experience.

So, my view is, please do not jump to conclusions just yet. Maybe, they have a surprise in store for the motorcycling community.

O.T - I just hope they will clear all the oil leak / reliability issues and make this a niggle / trouble free high quality product, worthy of the premium that Siddharth Lal expects to rob from his customers.

[aravind.anand]

Yes yes, I am certainly not jumping the gun and making a judgement without even riding one. I own a 100 bhp Fiesta in my garage, which we all know drives far better than the 110 bhp global Fiesta that replaced it. So spec sheets seldom convey the full story - agreed, but I was a little disappointed to find that the peak torque had moved a little higher up the rev range, as the 4000 rpm peak torque figure was one of the figures that caught my attention.

Anyway, let's just hope that this change would translate into a fruitful benefit for us riders, and yes keep hoping that the bikes would be launched real soon!

[Shumi_21]

Originally Posted by Surya-TJet

With today's modern technology

Modern technology and Royal Enfield

Originally Posted by Surya-TJet

O.T - I just hope they will clear all the oil leak / reliability issues and make this a niggle / trouble free high quality product, worthy of the premium that Siddharth Lal expects to rob from his customers.

Shouldn't this be applicable to ALL motorcycles that have the RE badge? I understand RE is big on tradition, but this is one tradition I would love to see them break with the 650 twins. Maybe the reintroduction of Jawa will finally nudge them to improve their QC. Let's hope for the best.

Edit: Hope to see dedicated service bays/technicians for the 650 twins at RE service centres, whenever they are launched.

[aravind.anand]

Originally Posted by Shumi_21

Edit: Hope to see dedicated service bays/technicians for the 650 twins at RE service centres, whenever they are launched.

Very good point! With the huge jump in the Classic 350 sales, and the continuing growth means soon the service bays would be overflowing with Classic 350 bikes and the scene would start looking like Honda showrooms stuffed with Activa scooters everywhere. To provide a premium feel to their flagship motorbikes, this is something they should address.

[neil.jericho]

I think its unlikely that Royal Enfield will be able to carve out separate service bays for the 650s in existing service centres. They already service a ton of bikes every day and if you have observed how they work, its like a well oiled machine with bikes rolling on and off the ramps with minimal delays. New dealerships however may be able to cater to separate bays for the 650s if the volumes are there, but I doubt it will happen.

[sukiwa]

First ride of twins scheduled in Sept '18.

Source

[TorqueyTechie]

According to this article on Motorbeam, RE Twins India expected launch in November.

[aravind.anand]

So that is a full circle from the time they first displayed the motorcycles at EICMA 2017. They seemed to have a target of April 2018 for the launch in European countries as they wanted to tap the 'riding season' in Europe, but not with a October / November launch will the European countries still be the first markets to get the twins, or will India take precedence now has to be seen.

[aravind.anand]

New set of pictures of the twins from social media, as the internal video shoot of the motorcycles seem to have been started already. Also Royal Enfield has brought in 'storiesofbike' team, who are quite popular with motorcycle videos on social media to shoot these videos.

Videos of the Continental GT 650 is being shot near RE's design centre in UK





While the Interceptor 650 is exploring the geography near RE's manufacturing plant here in Chennai



I personally love the picture below