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- - By aware Date 02.10.18 11:01
Any way to increase idle rpms by 100-200?

Thanks for any help in advance.
Parent - - By HelmetHair Date 02.10.18 14:13
slacken the battery connections, or tip out half the acid from the battery.
This will fool the ECU into thinking there's a charging issue and up the revs to compensate.


fix the problem that is making the engine rev too low


accept that the engine is revving at the correct level.
Parent - - By aware Date 02.10.18 15:14
Third point makes sense 100%. I seem to wrongly explain the fact that the bike is doing a knocking noise while idling with the somewhat lower idle.
Either there is a big fault at the big end of the engine or an 83000 km bike is expected to have worn out parts that sound like banging metal.
Btw already swapped vdo idle controller, injector, fuel filter, air filter, spark plug and spark plug cap with no difference.
Parent - By HelmetHair Date 02.10.18 22:03 Edited 03.10.18 07:20
Sounds like the engine is about to die. At 83,000 km I'm not surprised.
Parent - - By HelmetHair Date 03.10.18 07:21
Is this the bike that keeps showing low oil pressure light?
Maybe the oil pump is knackered, hence light, hence big end broken.
Parent - By aware Date 03.10.18 12:24
Today I went to BMW and a mechanic listened to the engine. He suspects cam chain tensioner problem. I will swap soon and check.

And yes this is the bike with low oil pressure light that used to be flickering at idle.
Parent - - By alunt Date 03.10.18 12:23
I can’t really hear anything wrong from your video, but the sound is only coming out of my iPad speakers...
There’s no reason why these engines can’t go beyond 83000 km if they’ve been serviced regularly and the oil level maintained. I’ve seen some way beyond this, I think there’s a 75000 mile one on eBay at the moment, with no declared engine faults.
I’ve got a 200 with similar mileage on it, 50000, and runs runs well and sounds good. I had to sort out a leaky exhaust and injector sealing to make it run properly. I don’t think previous owners were meticulous with servicing, but they had done enough for it to survive. I checked it’s compression when I got it and it was just as good as the compression on my 25000 mile 200, which was encouraging!

People have complained in the past that their C1s are very loud and they need ear plugs when riding them. I’ve never found this with a full face helmet, but maybe some are louder than others - possibly due to the dreaded sound deadening kit, but I doubt it. I’ve removed some of the kit from my 50000 miler where it causes damage, and it doesn’t seem any louder.

I would put yours back together and ride it until it won’t go any further. There’s nothing you can do about a worn big end anyway, just put some thicker oil in it and see what happens IMHO.
Parent - - By aware Date 03.10.18 16:45
BTW the sound is much more pronounced when engine is hot.
Parent - - By aware Date 04.10.18 18:53 Edited 04.10.18 19:01
Today I swapped cam chain tensioners.
The one that was already in place (changed 5000 km's ago) was very stiff, I pressed hard on a table and it couldn't move but only 1 mm. I don't think is good conition.
The one I put instead was from the one left after the 78000 km's change of chain and tensioner. This could be pressed with lots of force on a table. Seems to me natural.
Anyway, I fired the engine and it was sounding very nice. The idle speed was higher and I was really imprerssed the low idle problem vanished so easily.
Then I applied some throttle and it died... Hmmm maybe something to look for. So I look and realise that I had left disconnected the plug of the throttle cable position sensor.
I put it back and drove the bike. Seems a bit better (placebo?) but the idle is again not as high as it was after firing the engine. Even if I disconnect the plug or then connecting it again. It seems like an offer you miss on Lidl... You will most probably never see it again...

I suspect next I should check timing of chain.
And also the oil pressure while cold and warm should be checked next too, it makes very much sense that the initial good behaviour was with the leftover oil pressure inside the chain tensioner that quickly adapted to the oil pressure of the engine.
Parent - - By aware Date 05.10.18 08:03
I checked oil pressure. Cold start around 3.5 bar. Then after 5 minutes of idling settled down at 1.1 bar.
Seems to me something is wrong and I have low idle and this has been put up as an issue on the German forum but no solution has been confirmed to be explaining it.
Parent - - By aware Date 09.10.18 15:26
I would like to test if possible before opening the engine if there is some rod bushings problem. Any idea how to do?
By the way, when the engine is cold then I can't hear the banging sound but after some minutes the banging is very loud (makes the same sound like when a car has higher than normal gear in transmission and tries to drive uphill - this "trembling of the engine" weird sound).
Parent - - By aware Date 10.10.18 11:11 Edited 10.10.18 15:23
Today I measured oil pressure on bike with problem AND on my second C1 which is much younger (20.000 km's).
Surprisingly, both measured almost the same. I could expect some lower values from the one with 83.000 km's.
In brief:
Cold idle: Problematic bike starts with 0,8 and quickly climbs to 3,4 bar / Other bike starts at 0,5 and climbs quickly to 1,65. Strangely enough the older bike has higher oil pressure at cold idle.
Warm Idle 77 degrees Celcius: Problematic bike settles around 1,65 bar / Other bike settles around 1,5 bar. Almost identical and above minimum limit.
Warm @ 7000 rpm: Problematic bike around 3,65 bar / Other bike around 3,3 bar. Almost identical and above minimum limit.

So in essense I can't notice any difference. Maybe you can explain it differently.
By the way, the test with screwdriver shows no problem. I press hard and the piston doesn't move even a little.

Random thought 1: Last thing I changed was a water pump. Maybe something wrong there (however it is a knocking sound - not pinging or rattling).
Random thought 2: Higher rpm's don't worsen the knocking sound but make it smoother - when I drive eg at 70 kmh I swear the sound of the engine is the most melodic one, like perfect. This may mean that something frequency tuning may take place.
Random thought 3: The temperature should be at least 60 degrees celcius before this banging sound starts. It's so strange that it sounds also melodic when I cold start it but when it reaches the 60 degrees then at traffic lights is annoying in a way like it speaks to me that it something is really bad.

I now upload the video clips on youtube and will post later when they finish.
Parent - - By aware Date 10.10.18 18:00
Given the fact that this takes places @ temperatures higher than 50-60 degrees, I start suspecting debris formation leading to knocking.
This engine should have compression of around 14 bar and recently has risen from 15 to 15.5 bars.
What do you think?
By the way revving up lowers substantially the knocking sound.
Parent - - By aware Date 11.10.18 09:02
So until now basic conclusions: 1) it is not oil pressure related but temperature related (above around 50-60 degrees Celcius) 2) it diminishes gradually as rpm's increase. Go figure...

PS: it's funny that only a handful of members are here still to provide technical advice, one by one evaporate....
Parent - - By aware Date 11.10.18 12:56 Edited 11.10.18 14:42
Parent - - By aware Date 12.10.18 08:27
Aha moment:
One tooth off for both cam sprockets.
Exhaust clearances very tight (0,11 vs minimum 0,20)
Wrong timing probably brought quick wear of the valve seats.
Parent - - By aware Date 13.10.18 05:52
Another mystery is that the right sprocket if the chain jumped one tooth then the mark should be lower by one. Mine is higher.....
Parent - - By jeb Date 13.10.18 11:02
it maybe worth checking to see if the sprocket has moved on the camshaft     It has been known for this to happen.
Parent - - By aware Date 13.10.18 14:31
Very hard to check... I need to unscrew the screws and all posts on forum say that screwing back is always a problem.
Still your point is more than valid and must find a way to check.
Parent - - By HelmetHair Date 13.10.18 15:23
THere is nothing wrong with that timing. Leave it alone!
Parent - - By aware Date 13.10.18 16:35
Especially given the fact that I have only rotated CLOCKWISE always the 13mm screws of the sprockets.
BTW today I timed correctly the sprockets and no improvement, maybe even worse.
Parent - - By leonm Date 15.10.18 09:29
I have encountered low idle problems before. In one case on my 125  it was intermittent and on the half a dozen occasions when it happened, it cleared up after a couple of stop/starts.
From memory, the second bike, a 200, exhibited the same behaviour and it did not unduly worry me until it started cutting out both at idle and while running, but she would re-start provided you waited a couple of minutes. The cutting out and slow idle  was solved by replacing the tdc sensor.
Before replacing the sensor, check sensor to magnet wheel clearance and check for steel whiskers on the magnet and on tdc pole. Remove whiskers with prestik.
The tdc unit is a generic item and I bought mine for £8.50 from a bike shop. No need to  pay bmw prices.
The ecu adjusts idle speed by opening and closing the air bypass channel in the throttle body, so check that air channel is free from gunk.
Any chance of doing an ecu swop?
Did you check timing marks with tdc locking bolt in position? This is a MUST. I agree with HH that your timing looks ok as per the photo.
Parent - - By aware Date 15.10.18 10:55
Thanks for the insightful replies, today I discovered some bad to horrible things:
1) Staples were attached to the flywheel and TDC sensor. How on earth these entered the system is very mysterious (same with ones I have in garage; my little boy threw them in oil container?)
2) Oil filter is full of aluminum paste. No idea what this is. Look at pic with filter on my gloves, the paste is on my fingers
3) Magnetic screw had a lot of black particles (very thin ones like dirt) which is peculiar given the fact that I washed it some 100 km's ago.
4) Timing is OK with TDC screw in place.
5) I jog the flywheel and realise that rod and crank move together and present no slack (this is the only maybe positive news)

Seems one-way street that I must at least remove oil pump to check.
Parent - - By aware Date 15.10.18 11:59
Parent - By p.gill Date 15.10.18 15:04
The angle looks ok to engage with the vee in the crank web, usually by winding it in by hand & jiggling the crank back and fore the screw tightens in the vee and the crank cannot be moved.
Parent - - By leonm Date 15.10.18 15:35
long staple wires on the magnetic wheel could play havoc with your timing (making it too advanced) which may explain the knocking (pre-ignition) and the slow idle.
your timing setscrew looks ok.   is it long enough?
what looks like aluminium paste could be sludge loosened by the use of detergent oil after prolonged prior use of a less aggressive oil. check for magnetic particle inclusions.
Parent - - By aware Date 15.10.18 17:29
I think now I will just swap TDC sensor and flywheel given that is alternator cover is already open and thus will save some time.
If this doesn't work, I will swap ECU (if I remember correctly I have to disconnect battery first - valid?)

PS: timing screw is longer than the one in the video but similar pointy
Parent - - By HelmetHair Date 15.10.18 18:30
So you intend to swap things you know are working for ones that only might?
Not a good idea!
Parent - - By aware Date 15.10.18 18:57
I have two problems concurrently:
1) One has to do with low idle and also bad idle after revving down.
2) Other has to with knocking sound that accompanies this idle issue.

There are 2 basic scenarios here as I see it:
Scenario 1: I have F* something electronic and ECU can't handle well the mix. I had an electronic issue almost one year ago (kill switch cable broken around steering wheel. I bridged the cable behind the dash and removed the diodes box in the fuses box. So very likely this nice solution proved harmful in some way. Given the fact that the screwdriver test didn't show any bit of slack, this scenario can be tested by just swapping TDC and ECU (actually by trying them on a working bike). Easier to test than scenario two.
Scenario 2: The flickering oil light that I had some months ago has slightly and gradually worn the rod bearings and since this is an early stage, the screwdriver test is not helping to identify it. Also driving eg @ 70 kmh and engine sounding healthier than ever may mean that this rod knock is just not yet pronounced enough to make the appropriate sound. This scenario can be tested by removing engine and dissasembling everything to the heart (I have done with Honda 50cc bike and it was not an easy feat especially remembering how to assemble everything back with no misses).

Can someone rule out 100% the TDC and ECU possibility? Because imagine if I break the engine into 100 pieces and see no sign of wear then all this hassle will be for no reason.
Parent - - By leonm Date 15.10.18 20:29
since the staples on the magnet wheel is a very likely culprit, coupled with the ease of fitting/removing of the cover, i would give this a try before proceeding.
in my opinion, it is highly unlikely that a low oil pressure at idle could have resulted in any engine wear/damage.
Parent - - By alunt Date 16.10.18 10:00
Have a good look for any more staples before you start it again. Do you think they got in there via the oil fill hole? In which case do your best to check the sump for more staples - some kind of magnet firmly fixed to a piece of wire perhaps? Go through both drain holes with it. Don’t lose the magnet in there though! Check in amongst the alternator windings as well.

Those staples must have something to do with your problems, engines aren’t designed to have staples in them! :-)
Parent - - By HelmetHair Date 16.10.18 12:29

>engines aren’t designed to have staples in them!

I endorse this statement....
Parent - - By aware Date 16.10.18 16:59
The next step is to remove oil pump and water pump (last thing changed and close to the time the whole thing started messing with idle).
Seems that at the time I changed oil during water pump change, the wire staples entered the oil and this may be related to the abnormal oil pressure behaviour (oil light flashing at idle) as well as the bad idle (crank sensor possibly affected by those staple wires attracted by the flywheel).
Even all this alu paste can be a result of those wire staples grinding into the oil pump.
I wonder if the chain jumped a tooth too because of this.
Parent - - By HelmetHair Date 16.10.18 18:03
I find it interesting that the staples became attached to the sensors and didn't sit in the sump and get attached to the magnetic drain plug.

It makes me think that when you last had the cover off the staples ended up in the cover. You then replaced the cover and the staples went straight on to the sensors.
Parent - - By aware Date 16.10.18 18:28
Makes sense, but I store the staples very far from the place I work with the bike. My son also wasn't last time at garage while cover was open.
Also a weird finding is that most of them are stretched and bent which means that they passed through some "milling" and this imho can not happen in between the TDC sensor and the flywheel.
Parent - - By aware Date 17.10.18 19:11
Today I opened oil pump and found it in very good condition.
However, these wire staples scratched badly the flywheel and slightly the crank sensor.
Water pump in mint condition too.
This means that all signs lead to something wrong with the rod and will open little by little to check.
Will keep you posted.
BTW my son had no idea about these wire staples, so most probably I have been a vandalised. This damn dipstick can't lock and this can bring lots of troubles.
Parent - - By HelmetHair Date 17.10.18 20:02
I wouldn't do that.
I'd reassemble and drive it.
Parent - - By aware Date 18.10.18 04:29
Without changing or fixing something it will behave the same.
Removing some staples can't fix the knocking sound IMHO.
Parent - - By HelmetHair Date 18.10.18 08:33
Leonm explained why the staples on the sensor could cause the problem, and I agree with him.

give it a go !
Parent - - By aware Date 18.10.18 17:40
Today I swapped ECU (very hard to dismantle from seat side), TDC sensor, flywheel and exhaust but no result!
Surgery is due
Parent - By HelmetHair Date 18.10.18 18:13
I give up.
Parent - - By leonm Date 18.10.18 20:43
Short of reading the whole saga again, I assume that your problems are limited to 1) low idle, and b) knocking sound, in which case I would suggest the following:
1.  Bring engine up to normal working temperature and take note of idle speed. Remove drive belt and start engine. If idle speed is now higher (normal?) it could point to excessive drag in the clutch assembly. If it remains low, I would look at the idle control motor wiring. Remove unit, insert 3 pin plug and switch ignition on for a split second while holding the plug in position. Motor should react by moving plug in or out. If no reaction, check wiring in engine compartment and if necessary back to  ecu.
2.  Have you also swopped out the throttle position sensor?
3.  Is your hand throttle cable set up properly ie. with adequate play?
4.  Have you swopped out the ignition coil?  And the suppressor?
5.  Bad idle can also be caused by injector with bad spray pattern (or leaking). This in turn can be caused by low fuel pressure or dirty pintle. Have you measured pressure adjacent to injector? From memory should be 2.25bar irrespective of engine speed.
6.  On the question of the staples, even the finest of metal whiskers bridging the air gap between the magnet and the sensor pole, will affect the tdc coil back emf pulse, hence my comment of using prestik to clean all vestiges of filings/whiskers.
7.  When swopping out things like ecu, coil etc. no need to unbolt. Just remove plugs and insert in test item while loose. Everything is separately earthed and quite safe.
Hope these ideas bear some fruit
Parent - - By aware Date 19.10.18 05:03
Yesterday was a long day with much problematic stuff going on.
I first dismantled ECU from old bike (problematic) and loosely (as leonm said) plugged onto my new (working ok) bike.
No difference, young bike was smooth.
Same test with TDC sensor, flywheel and exhaust of old bike to new one (together swapped). New bike had some weird rattle noise around the exhaust area but no problem with idle or knocking. Mysterious.
Then I decided to put TDC sensor, flywheel and exhaust of new bike to old. The findings were even more mysterious; Same problem with idle and knocking when hot engine AND some good ticking noise (like valves or similar). Give me a break; this surpasses all of my last healthy brain cells now.
By the way, there is no wire staple in oil (extacted all and nothing there). Of course new filter.
So today I have to see if timing is intact. Then I have to extract cam sprockets because these may have slipped in relation to camshaft.
Then I have to drink many Red Bull cans to relief my nerves of this confusing thing.
By the way, the throttle cable position sensor is impossible to unscrew, the heads of the screws are worn enough and no screwdriver helps. Another difficult one.
Reminds me of the story almost one year ago with broken cable in steering wheel where all tests were leading to nowhere and things were worsening quickly.
Really grateful to all help.
Parent - - By leonm Date 19.10.18 10:05
As I see it, you have now shown that the following items are NOT faulty:
TDC sensor,flywheel,ECU and exhaust

In my opinion. this leaves the following most likely candidates (do all tests with hot engine):
Cam sprocket locating pin broken. Brazing is probably the best fix
Fuel pressure
Swop out the entire throttle body with injector, position sensor and idle controller intact. Not such a big job from what I recall.  this will prove the above items all in one go, as well as the throttle body.
Coil, ht lead and suppressor. Just unplug coil primary and insert in loose test coil.    As a matter of interest, my V8 S500 mercedes  uses the near identical coil.
Faulty underseat wiring. Forcefully jiggle around.
Run  motor at idle with drive belt removed
Parent - - By aware Date 19.10.18 11:01
The knocking sound and abnormal idle is still there without variator on.
Today I dismantled camshafts.
Sprokets locating pins OK.
Only interesting finding the unevenly worn out inlet tappets.
These are the ones I had grinded myself by hand 5000 km's ago.
Maybe this damaged the cam lobes and thus affected opening and closing of inlet valves.
My mind connecetd this with the increased alu paste in the oil filter, the cam lobes either are enamaled with some non magnetic material or it's something not related.
Following pictures show the camshaft and on the LEFT is inlet tappet (hand grinded) and RIGHT is outlet tappet (never grinded) for comparison reasons.
Parent - - By jeb Date 19.10.18 12:21
If the shims were case hardened, then you may have removed some of the hardness when you ground them.      not a good practice I think.   If this is the case then you would have less valve opening  you do not give the valve clearance so worth checking
Parent - - By jeb Date 19.10.18 12:24
The camshaft is a cast iron material and does not have any coating on the cam lobes
Parent - - By aware Date 19.10.18 12:44
Clearances were 0.07 mm for both inlet tappets.
Parent - - By jeb Date 19.10.18 16:23
then the shims cannot be worn out
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