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[Thack]

Oops, sorry - I think the recommended idle speed for the UCEs is 1050rpm, not 1100. Either way, it's far too fast for the character of the bike.

[jefrs]

It's an old post - I was just showing a solution to what seems a common problem, getting at that bypass screw.



I have fitted the O2 eliminator with the PCv from H free-flow + K&N package, it does smooth the response but the bottom end still flat-spots requiring idle about 1100rpm to semi-eliminate that. Difficult to explain - with a lower idle the engine braking is very strong, if I go into a tight and I mean tight corner with mud all over the road the last thing I want is a sudden strong dose of power and the front going light or popping a wheelie in first as I open the throttle again, I want a gradual gentle feed in. The work around is to apply the back brake with the throttle held just off zero, it's a bit of a juggle and use the clutch; it could be better. It will idle much lower but makes normal riding tricky.



I've also had problems with the iridium plug fouling. Once fouled it misses sparks and then residual unburnt fuel makes the mix rich and soots everything up, which only makes it get worse. I've replaced with the normal NGK and added Redex, and take it for an italian tune up to burn it out.



There are two idle adjustments, the bypass which does enrich the mix and a throttle stop which has a blob of paint on it. The latter is usually set by measuring the gap on the butterfly and left well alone. On a carb we adjust both of these, the slide and the air screw, on the injector we don't but I'm wondering if a judicious tweak of the throttle stop may be in order. It's a work in progress.

[Rattlebattle]

When I had a problem with my C5 a few weeks ago (tps had become disconnected) I had a general chat with the mechanic at the dealers. He was quite emphatic that you must not fiddle with the throttle stop screw. He said if you do so you risk rendering the throttle scrap. Maybe a bit melodramtic, but the advice has been the same on the basic throttle stop settings on the K series R series throttle bodies. On the latter there was a problem with the butterfly spindle wearing, admitting unwanted air and making it difficult to synchronise the two throttles. When sending them away to have the spindles renewed and thew tb rebushed, the advice, which I heeded, was to ensure that thge repairer did not alter the setting. If you did you had to carry what became known as the "zero=zero" procedure - essentially ensuring that on both tbs closed throttles actually equalled zero values (I forget on what precisely) but there were many many posts requesting assistance from people who had screwed up (technical expression) their throttle settings. Don't go there, or if you do, let us all know what happens.

[Rattlebattle]

Jefrs, an afterthought. I think the O2 eliminator you have and what I am talking about are two different things. I guess you mean the plug that replaces the hole into which the O2 sensor is screwed. I have one of those too, but I am also referring to a little plug that plugs into the main loom where the O2 sensor wire used to go. What I will be doing (when I've fitted it) is running open loop permanently. The little plug is there to extinguish the MIL light that would otherwise be permanently on. The PCV takes care of all this, albeit at much greater cost.

[jefrs]

Yes - the throttle body has a throttle position sensor (TPS), so if you don't know what you're doing do NOT touch the throttle stop. The ECU and the PCv for that matter both need to be reset for min and max volts from the sensor, they have different procedures, full reset and 'calibration'. Not totally dissimilar to doing a car with a fly-by-wire throttle.



However it must be said that the butterfly gap is usually set by sticking a small drill bit under the flap and setting down on that as a gauge, done at Chennai, and as we know, these bikes vary a lot ...

The bypass bleeds a little air around the closed throttle, function like opening it. Not significant once the throttle opens but can lead to a big jump from running on one to the other near zero throttle if they're not matched up; there should be a sweet position (maybe it's my bike that's out of step). Unlike a carb, the needle and jet, the injector looks after itself.



More embarrassing was the fluffy soot from where the iridium fouled up, other than dismantling that will require burning out by getting the engine hot. The engine is a lot quieter and smoother since I've finally managed to seal pipe to head; easier to hear the motor and the soot does not sound like a mechanical (the engine sounds sweet), probably my fault for letting it idle too long and maybe the iridium really is unsuitable. The standard NGK (I can't rememember the hieroglyphic numbers) seems to let the motor rev more easily as if the iridium spark was breaking down under pressure; but the weather was so cold yesterday I could only give it a quick test blast, I must remember the longjohns.

I've always liked NGK but may switch to the Bosch with twin electrodes although the Bosch-India was a corroded pos.

[jefrs]

Rattlebattle - the 'eliminator' plug thingy that goes into the loom is provided with the Hitchcocks Power Commander (PCv) kit, as well as the blanking plug on the exhaust 'bung' hole. The only problem I can foresee in eliminating it is taking the bike to 18,000-feet up the Himalayas, because RE built the bike to do that.

[jefrs]

Rattlebattle - I'm not sure what you mean by 'two throttles', please explain.

[Rattlebattle]

Jefrs, sorry I should have made it clear that I was talking about BMW oilhead twins when I mentioned two throttle bodies. Obviously that isn't relevant here; I was just trying to elaborate on why, if one doesn't know what one is doing, one really shouldn't mess with the baseline throttle stop adjustment. I didn't know that you get an O2 eliminator plug with the PCV; thanks for that. My understanding of the real advantage of iridium spark plugs is that they last a long time without deterioration. They are, therefore, often recommended for use in modern multis where you need a coal ming degree to extract them. My experience of the iridium plug in my C5 was not good; the engine has started first kick since I put in the "cooking" NGKs. Re the Bosch ones, even the genuine ones were rubbish in my BMWs; most owners agreed. The best were considered to be Autolite, but they are not so easy to get in the UK. Again, I found the ordinary NGKs to be fine. I guess you are aware that the twin electrodes doesn't mean two sparks, or if it happens it won't be for long. The spark will of course jump whichever gap is the smaller, the idea being that as the electrode erodes the point will be reached where the other gap takes over, so they last longer without wearing out. In practice I and many others have found that they do not perform as well as a good conventional plug. But I guess spark plug choice is like oil; everyone will have an opinion.

[nigelphoto]

If you look back at the beginning of this Thread there is a link to a very good Youtube vid on spark plugs, especially the colour of the insulator and the residual SOOT around the exposed threads - thats what EFI's run like https://www.youtube.com/watch?v=9-SUrx_L66E
I have tried NGK BPR6ES and BPR6EIX Iridium and there is no difference in the running, perhaps very slightly better mpg with the latter but both have same insulator colour and soot on the threads. I tend to ride my C5 fairly fast (on second thoughts, the words 'fast' and 'Bullet' should never be used in the same sentence!) so perhaps I am clearing the Iridium plug and its not showing poor starting/idling and pick up that some have reported. I haven't tried the (rusty!) Bosch WR7DDC4 which came with the EFI engine service kit.

[jefrs]

The plug colour is a bit meaningless on the EFi compared to traditional carbureted engines, it is supposed to be lean burn. Hard black on the ceramic meant the plug was too cold to be self-cleaning but scalded grey-white meant it was too hot, correct colour is pale tobacco brown or something. The EFi has a temperature sensor etc and juggles the mix around accordingly. The iridium plug has a tiny needle point for an electrode, once that gets fouled it can't find a clean spot to spark through. The iridium was good as new especially compared to the dodgy Bosch-India WR7DDC, and it was good again after I cleaned it but I have now swapped it for the non-iridium BPR6ES which I hope that with its broader electrode area will not foul i.e. will not miss and so won't build up soot and so will self-clean. The common or garden WR7DC is the wrong plug with single electrode, the second 'D' in WR7DDC means twin or double electrode. This Bosch has a resistor-supressor and may need a different HT cap to the NGK which doesn't have one. The OEM HT cap was a pos too and this may well be a cause of missing sparks and fouling the plug. Soot may be normal on the EFi but I don't find it acceptable and pretty sure it's fixable.