[littleowl]

Just wondering from those of you lucky to have bikes, what is your idling speed (both cold and warmed up)? Mine is around 1600-1800 rpm, I thought it a little high, and whether it is associated with my snatchy throttle. I did see a Full Throttle started up yesterday from new, and it seemed much lower than mine.

 

[El Toro]

No idea. I've just jumped on mine and ridden the arse off it

 

[littleowl]

No idea. I've just jumped on mine and ridden the arse off it

Have a look for me though, will ya?

 

[BiKenG]

Is it adjustable on the Scrambler? Common practice these days is for it to be 'hard-coded' and impossible for the user to adjust. This drives me nuts as the manufacturers always set the idle speed way faster than I want. As far as I'm concerned, an engine should tick-over at the lowest possible speed it can, without stalling. This invariably is well below 1,000 rpm, yet manufacturers insist on it being about 1,500 these days.

First of all I'd really like to know why they think they need to do this and secondly I want to give them a good hard slap for not allowing the customer to be able to adjust it to how THEY like it, i.e. the ones who have paid good money and will be the ones actually riding the bike. Idling too fast just uses more fuel while waiting in traffic etc and even if that's not terribly significant, the additional heat being generated certainly is.

There is some debate about how high some riders think a bike should idle and undoubtedly there will be those that disagree with how I like it set. That's OK, it's up to you, but the problem is we have no control over it and everyone HAS to abide by what the manufacturer has decided and this I think is unacceptable. I wish there was some way to force the manufacturers into again providing some adjustment of this.

 

[tonyjuliano]

Idle is controlled by the ECU and is not user adjustable. A dealer can alter it though.

The Ducati spec is 1800, however.

 

[tonyjuliano]

Is it adjustable on the Scrambler? Common practice these days is for it to be 'hard-coded' and impossible for the user to adjust. This drives me nuts as the manufacturers always set the idle speed way faster than I want. As far as I'm concerned, an engine should tick-over at the lowest possible speed it can, without stalling. This invariably is well below 1,000 rpm, yet manufacturers insist on it being about 1,500 these days.

First of all I'd really like to know why they think they need to do this and secondly I want to give them a good hard slap for not allowing the customer to be able to adjust it to how THEY like it, i.e. the ones who have paid good money and will be the ones actually riding the bike. Idling too fast just uses more fuel while waiting in traffic etc and even if that's not terribly significant, the additional heat being generated certainly is.

There is some debate about how high some riders think a bike should idle and undoubtedly there will be those that disagree with how I like it set. That's OK, it's up to you, but the problem is we have no control over it and everyone HAS to abide by what the manufacturer has decided and this I think is unacceptable. I wish there was some way to force the manufacturers into again providing some adjustment of this.

Preaching to the choir...

There are so many things "locked down" on this bike, it's not even funny. So many, that if I had known before-hand, I would have never bought one.

My problems were solved by purchasing a Rexxer unit, which gives me control over all ECU driven parameters - but it shouldn't be this way.

 

[BiKenG]

Preaching to the choir...

There are so many things "locked down" on this bike, it's not even funny. So many, that if I had known before-hand, I would have never bought one.

My problems were solved by purchasing a Rexxer unit, which gives me control over all ECU driven parameters - but it shouldn't be this way.

Hm, Rexxer, not come across that. I need to look into that.

 

[BiKenG]

Idle is controlled by the ECU and is not user adjustable. A dealer can alter it though.

The Ducati spec is 1800, however.

Can the dealer change it? I've heard this before with Aprilia, but in fact they cannot. I'll ask the local Ducati dealer if this is possible.

1800 rpm idle? How utterly stupid is that. I must admit, I didn't find it to intrusive when I tested, but it wasn't for that long. I just KNOW I'm going to want to reduce that somehow.

 

[littleowl]

Funnily enough after having the bike for nearly 5 months it doesn't bother me now - must just have got used to it!

 

[Graeme]

Looking at the rev counter the idle speed seems to be about 1800 rpm. I thought it was a little higher that what I would expect but doesn't bother me. It is in for its first service next Friday at Ducati Leeds so will ask about it.

 

[Chet Jr]

A high idle speed helps air cooled engines live a longer life.

I'd strongly suggest caution in lowering the idle speed on any air cooled engine. My modified Honda GB500s always include instructions to the new owner NOT to lower the idle speed.

 

[DaveK]

I agree with you Chet.

 

[Graeme]

A high idle speed helps air cooled engines live a longer life.

Am intrigued, so would be grateful if anyone could explain why having a "high" idling speed could increase life of the engine. Again, idle seems fine to me and have no wish to change it but just interested; also might help others thinking of reducing idle speed , by whatever means, have a better understanding of any consequences.

 

[tonyjuliano]

Am intrigued, so would be grateful if anyone could explain why having a "high" idling speed could increase life of the engine. Again, idle seems fine to me and have no wish to change it but just interested; also might help others thinking of reducing idle speed , by whatever means, have a better understanding of any consequences.

I'll try...

At idle, if your engine is turning relatively slowly, let’s say 1000 rpms, it gets little airflow through the intake. The throttle is closed, so very little fuel and air are being drawn in to the cylinders. This small amount of combustible mixture burns very quickly, so for maximum efficiency, the spark needs to start when the piston is very near top dead center.

The elevated head temperatures of an air cooled motor can sometimes cause pre-ignition, If this happens, the pressure from the ignited mixture will hit the piston while it is still coming up the cylinder and be wasted trying to shove the piston down before it reaches the end of it’s travel - this causes excessive stress on the piston, connecting rod and crankshaft.

Setting a higher idle speed increases the flow of cooling fuel and air through the intake, preventing this type of condition.

 

[Graeme]

Tony
Much appreciated, I'm a little wiser

 

[BiKenG]

I'll try...

At idle, if your engine is turning relatively slowly, let’s say 1000 rpms, it gets little airflow through the intake. The throttle is closed, so very little fuel and air are being drawn in to the cylinders. This small amount of combustible mixture burns very quickly, so for maximum efficiency, the spark needs to start when the piston is very near top dead center.

The elevated head temperatures of an air cooled motor can sometimes cause pre-ignition, If this happens, the pressure from the ignited mixture will hit the piston while it is still coming up the cylinder and be wasted trying to shove the piston down before it reaches the end of it’s travel - this causes excessive stress on the piston, connecting rod and crankshaft.

Setting a higher idle speed increases the flow of cooling fuel and air through the intake, preventing this type of condition.

Nonsense.

 

[tonyjuliano]

Nonsense.

Hey... That's the theory, don't "kill the messenger".


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[BiKenG]

Ok, promise not to kill you. :biggrin: But you do know that 'theory' is nonsense, right?

 

[tonyjuliano]

Ok, promise not to kill you. :biggrin: But you do know that 'theory' is nonsense, right?

I don't believe it 100 percent, but there are elements that make sense. A lot of this comes out of the old air-cooled VW camp. It's within that crowd that I've heard the most about setting higher idle speeds due to air cooling.

This totally contradicts that last bastion of air cooled motorcycles, the big twins from Harley Davidson, and their very slow loping idles. But the components in those motors are seriously overbuilt, and this nay be one reason why.

In the end, I'm not sure - but it's something that has been talked about for years.


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[BiKenG]

Old single cylinder engines could idle at 500 rpm, but they were long stroke and with big flywheels. Reduce either of those and you raise the minimum idle speed. But as with so many things these days, the manufacturers have gone too far. 1800 rpm is absurd.

I don't know for sure why they choose to do this. My guess is partly emissions and partly product liability. Mostly the former probably as it's likely the emissions can be better controlled at the elevated idle speeds. But also a slow idle can make the throttle respond seem more snatchy than if it's already turning over at a faster speed. It also affects engine braking which is greater these days due to the higher compression ratios used. Personally I like engine braking, but it is a problem in racing (4 strokes) and raising the idle speed is one way to counteract it. Maybe the manufacturers see possible law suits because the rider over-braked and crashed, claiming it was due to engine braking. It also avoids complaints about the engine sometimes stalling on its own. Raising the idle speed reduces this possibility.

As I said, I don't know for sure, but I do know water cooled engines of today have EXACTLY the same problem and there's no inherent technical reason for either.