Any way to increase idle rpms by 100-200?
Thanks for any help in advance.
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.
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.https://youtu.be/CWBSJ8QFtLw
Sounds like the engine is about to die. At 83,000 km I'm not surprised.
Is this the bike that keeps showing low oil pressure light?
Maybe the oil pump is knackered, hence light, hence big end broken.
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.
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.
BTW the sound is much more pronounced when engine is hot.
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.
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.
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).
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.
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.
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.
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....
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.
Another mystery is that the right sprocket if the chain jumped one tooth then the mark should be lower by one. Mine is higher.....
it maybe worth checking to see if the sprocket has moved on the camshaft It has been known for this to happen.
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.
THere is nothing wrong with that timing. Leave it alone!
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.
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.
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.
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.
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
So you intend to swap things you know are working for ones that only might?
Not a good idea!
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.
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.
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! :-)
>engines aren’t designed to have staples in them!
I endorse this statement....
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.
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.
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.
I wouldn't do that.
I'd reassemble and drive it.
Without changing or fixing something it will behave the same.
Removing some staples can't fix the knocking sound IMHO.
Leonm explained why the staples on the sensor could cause the problem, and I agree with him.
give it a go !
Today I swapped ECU (very hard to dismantle from seat side), TDC sensor, flywheel and exhaust but no result!
Surgery is due
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
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.
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
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
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
The camshaft is a cast iron material and does not have any coating on the cam lobes
Clearances were 0.07 mm for both inlet tappets.
then the shims cannot be worn out
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