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[Trev]

My 2008 EFI was bit tempremental just after starting when I first got it (only 2000 miles) but now with nearly 7k on it's fine even with K&N and shorter, de-cat silencer. I like to kick-start it just 'cos it has one but the lever on these is weird contraption to my way of thinking, once you fold it out it's halfway to the ground already! Not really conducive to a good old kick more of a long, consistent swing. I too prefer to kick it with stand up and then leave on the side stand (I've removed the switch, not left one down yet in 35 years of riding) ticking over while I kit up and it's normally warm enough to toddle off with no issues.

BTW have any others removed the centre stand, I found it touched down a little too easily for my liking and I'm used to bikes without them?

[jefrs]

Nigelphoto - yes the torque on the little exhaust stud nuts doesn't want a lot of force. I have strong wrists but a somewhat faulty huge torque wrench called Hughie for reasons I won't go into.. I deliberately use a nut driver (the thing that looks like a screwdriver in the socket set) so I do not over-tighten small nuts 'n bolts, no leverage. The reason for tightening exhaust studs hot is if you do it cold then the studs expand, they do get very hot, and the nut loosens off, so of course they provide a cold torque in the book of worms. Sod's Law applies.

The reason for using a brass nut (I've not found a pair yet) is they are soft so you get an interference-fit grip by distorting on the steel stud when you tighten them, and they do not weld themselves onto exhaust studs. It's old school, many old engines were so fitted.



I have the after market free-flow exhaust and the pukka ceramic cement biscuit (the flat one) does not fit and so use the copper ring which does. I did not know there was another for the 535, it may be that which I've used (H just sent it).



Popping and banging on the EFi may be customary but not acceptable to me and I'm gradually dialling it out. The PCv does help sort the fuelling out. Raising the idle a trifle on the bypass seems to help but the big thing with banging is ensuring no air leaks on the exhaust, which I think I've got mostly sorted now.



Most ECU do shut off the injector at zero throttle and high revs but they do have to provide fuel at low revs (idle on zero throttle) or the engine will die. Some of the still occasional errant banging is probably where cold air (injector shut, no fuel) is passed through the combustion chamber, hits the hot exhaust and expands very rapidly with a loud retort.

[jefrs]

Aha - the probable reason the workshop manual gives cold torque for the exhaust studs is they describe it whilst stripping down and rebuilding the motor. They're doing it cold and they're not running it. They do not give hot re-torque numbers.

However the w/s joke book for my model says 60Nm (and big layout typo) which is far too high because it exceeds the standards for M8 bolts (12/13mm spanner) of 9.5 to 45Nm maximum; torque is based on the bolt cross section area, the steel strength, contact area of threads and the job it has to do. Some bolts have a strength marking, 8.8/9.8 is the middle range and max 25Nm so 14-ft.lb 20Nm seems far better.

[jefrs]

Trev - you can take the kick start lever off and move it up a notch or two to give you a longer swing. It doesn't need a longer swing, it's not a DBD34, just a quick prod. I have however moved mine up to clear my heel better.



Does the centre stand scrape? Is there some difference between models? I've put a little nick in the silencer but I thought the brake lever should contact first. On the left it looks more like the pannier (or my foot) will touch down before the stand does.



I assume the bistarter has so much slack like that to ensure it shuts completely. I do wish it would stay open like a proper cold start but I assume again that they do not want you to ride off with it on, like the side stand.

[Thack]

Rattlebattle, forgive me for being a nitpicking bastard!



But, opening the additional airway in the throttle body does not result in the ECU enrichening the fuel supply. There is no need for any manual intervention to tell the ECU to enrich the supply, because it already knows the engine temperature. That is what it uses to decide how much enrichment to give.



The bi-starter is simply a manual fast-idle device. Even with enrichment, cold engines need a bit more throttle to idle reliably because of the additional viscous friction from the cold oil. One most modern bikes the ECU controls an actuator which will open the throttle plate slightly to achieve that end.



Because of the cheap 'n' cheerful nature of the system on our bike, there is no throttle actuator. This means the rider must provide the fast idle manually, which is all the bi-starter does. Once even a small amount of heat has built up (half a minute, maybe), the viscous drag falls and the engine will idle on the normal throttle opening.



In summary: the ECU does not need "telling" to enrich the mixture because it already knows how cold the engine is and looks after the mixture itself. However, the ECU cannot crack the throttle to maintain a reliable cold idle, so that is left to the rider with the bi-starter control.



My bet is that this naff system will disappear in the next generation of models.

[Presto]

I wouldn’t want to disagree with Thack, but this question – the point of the Bi-stater and its function – has puzzled me and continues to puzzle me. If as, Thack says, the Bi-starter merely increases tickover speed until the engine oil thins sufficiently not to offer any significant resistance to moving components, why does the Bi-starter return to its ‘off’ position instantly? One cannot see how this, extremely brief, period of increased tickover makes any difference whatsoever to initial running. Nor can one see how an increased tickover can in fact aid starting, for if the Bi-starter only increases tickover, it cannot help starting, when, by definition, the engine at that time is not rotating, but static. Also, is it not a feature of multi-grade oils to maintain a (fairly) consistent viscosity?

[Thack]

Presto: I'll have a go at your questions.



Firstly, you are totally right: the fact that the bi-starter snaps back straight away makes it a bloody nuisance because you may well have to hold it operated until the engine will run unassisted.



About your other point, which is well made. The reality is that a cold engine will benefit from a slightly larger throttle opening than usual in order to fire and pick up. On most of the old Brit bikes with Amal Mk1s and Amal Monoblocs, you achieved this by pressing the tickler (for enrichment) and holding the throttle open a crack when kick-starting it.



The Japanese bikes came with better carbs, which included a fast idle (or throttle-cracking) function along with the choke mechanism (such as most Mikunis). On those you didn't need to crack the throttle yourself.



So cracking the throttle on a cold engine helps it fire and pick up, and also it helps maintain a reliable tickover until it will run reliably without assistance.



About multi-grade oils: it's a common misconception that their viscosity changes very little between cold and hot. A straight grade oil thins out a LOT with temperature. A multigrade also thins out a lot, but notice it's only a lower case "lot". In simple terms, the viscosity changes less steeply with a multigrade than a monograde, but still changes.



So yes, a multigrade will indeed thin out plenty enough to make a noticeable difference to tickover speed.



One of the best improvements we could make to a standard Bullet would be to make the bi-starter "latching" somehow, so the engine will idle reliably while you're putting your gloves on. Personally I've given up on the whole rubbishy thing and implemented my own, temperature-controlled fast idle systeml

[Rattlebattle]

Thack, yes I know, but by allowing more air in more fuel is added too isn't it? I accept that you are correct in saying that mixture is not enrichened directly by the opening of the port. The system is not really much different to that on the oilhead BMWs which also had a lever called a "choke" that consequently misled countless owners on forums. All that lever did was hold the throttle open a pre-determined amount, as you say, to minimise the risk of the engine stalling until it was warm. At least that "choke" had a detente that held it open. For really cold weather you could hold the lever open manually, rather like the RE one, opening the throttle a little wider. Like I said in an earlier post, I just open the throttle myself like I did on the Beemers as it achieves exactly the result. What I can say is that if I did forget to turn off the "choke" on the Beemer it would become apparent through higher than normal revs when the engine warmed up. I would expect the same on the RE, so I don't know why they don't put a detent on it. Like you say, all my other more modern EFI engines have stepper motors to speed up the engine from cold automatically. It can't be long before RE does the same.

[Thack]

"Thack, yes I know, but by allowing more air in more fuel is added too isn't it?"



Yes, absolutely. But that in itself doesn't make the mixture richer. It just adds the necessary extra fuel that you would expect when you let a bit more air in. In other words, it adds the right amount of fuel to keep the mixture the same, exactly as you'd expect if you cracked open the throttle.

[Thack]

As we all agree now, it doesn't need any input from the rider to say "make it richer because it's a cold start". It already knows it's a cold start from its temperature sensor.