My LT (79k miles/126k kms) appears to be burning oil judging by the smell of it and it's good and black in the window. It smokes like a newly lit coal fire after being on the side stand for more than a minute and the most noticeable thing is the smell of burnt oil. The smoke quickly clears within a kilometer or two and there is no smoke screen behind me once the bike is warmed and riding as normal, it doesn't use a whole lot of oil between changes and I was very careful not to overfill on the last change.

Now before you wags chip in about me being too tight to change the oil and filters, it is on its second change in 6 thousand miles. I'm using Valvoline 15w-40.

Any ideas as to cause of the burnt smell and appearance?

Could it be related to the restrictor I have fitted?

88

sounds strange will

yeah mine goes dark pretty quickly as well and i do suffer from the lean over on side stand smoking issue although later models like yours had "pinned rings " i think

i had put it down to blowby ,,as old gerty wouldnt have all the best compression after all these years ,,but still good enough for me .

i have no experience with what the restrictors would do to the mix mate ...could your girl be running lean ? creating more heat in there ? ,,,i seem to recall that more fuel (a richer mixture ) tends to cool the combustion chamber ,,i wonder if this is a concideration ... anyway the combination is complex

perhaps you have a valve stem seal issue as well ? the inlet cams seem to me to be the most likely angle to catch oil and let it pass into the combustion chamber ...just the angle of them when the bike is level (although the exhaust is the more prone to heat issues ).

just a question ...you dont have a slight leak near the exhaust ...or just in front (like the bleed hole out of the oil - water pump area or sump) spitting a little on the exhaust ?

have you tried a different brand of oil ?

my old man used to sell castrol ...but in all the years that i have used different oils ..i really dont like the stuff ..since his day with all the new formulas ...it always seems to me to be thin and dosent last the distance that i expect + the engine always runs noisier than normal ...not having a go ...just what i have noticed .

i know that i prefer 20-50 out here in the warmer climates ...and i guess that 10-40 would suit your enviroment better

but try a different brand of oil mate ...they are not all the same... just dont think on an old girl that synthetic would be the best is what im saying



at the moment i have some poxy shell 20-50 helix in (in the red container ) and it is crap ... i guess it carries a high sf rating ...which might be great for all these high output 4 cylinder thingys with really tight tollerances ...but i recon the old bm isnt designed quite like that ..from what i have seen in the tech manuals regarding all the bits and pieces

going back to my el cheepo stuff made by caltex but branded differently ,,,for gerty it is good stuff ...

you will find your stuff ...just be willing to give it a try ...talk to others and see what their experience is around your land of greenery

a couple of thoughts from an old fart ...hope it helps mate

Hi Will, on Saturday how about an experiment - all K's on side stands for a bit, start them up and see who's smokes and who's doesn't or who's smokes the worst. Might put your mind at rest and worry someone else instead! I have a wee drip of gear oil coming out of the shifter seal, falls onto the exhaust and stinks, makes it seem worse than it is.

GMcQ

I purchased my 1987 K100RS 8v in the UK and rode it for about 200 miles to get the Dublin boat. No smoke - I do understand that the K bikes smoke when left on the sidestand but on arriving in Dublin and starting the bike I proceeded to fill the boat with smoke !. (What have I purchased I thought). I then decided I better get home by the quickest route which involved paying in the Dublin Port Tunnel - I also managed to fill it with smoke - a bit concerning when you look back and can see nothing - but as I got closer to home the smoke cleared. I did change the oil soon afterward and I have had no problems since (have done about 10K miles), apart from the normal side stand smoke.

We could have a good competion on Saturday to see who produces the most smoke :smoke:

Doing a little oil change tonight in anticipation - should the winners or loosers get the cigars??

My '89 LT never smoked but the '84 will smoke like a train if I don't follow a simple routine.
When I pull up, I let the engine tick over for 10-15 seconds before switching off. You can appear dead cool about it by removing your gloves while you are waiting.
Then I can park it on the side or centre stand without the embarrassing smokescreen when I start up.
Don't know why. Must be something to do with the oil settling down after the engine running at higher revs.

Possible Causes:
Vent tube damaged engine, rich or poor mixing, air box and manifold leak.

Will, Comberjohn,

Two things.... it is always better to let an engine settle to an idle before turning off, particularly if one has been having a hot run. The K engine runs hot and that is particularly important. Of course that does allow oil back down to the sump.

No matter how good the piston rings are there is always oil at the underside of the pistons and inside the bores. Oil control rings make sure this goes back down to the sump with each stroke. Most turbo [diesel] engines have an oil spray on the underside of pistons to cool them but I havent checked if the K has this.

When the engine cools the piston rings will of course contract so that the end clearance in the manual opens up. A clever mechanic will make sure the end clearance in the oil control ring is on the upper side so when it cools the resultant gap is up high and does not let any oil through. K bikes being unburstable means it must be done at factory. Of course the K bike on a sidestand means the little bit of oil in the bores can run up through any gap and into the combustion chamber. Entirely harmless, burns off quickly after firing up.

Second place is the valve guides but a good friend has told me look at the other option and dont worry too much.

Changing oil make or grade can cause a problem, go back to the old oil type before doing anything. I have encountered this many times. As a matter of interest mine has been having Total 10W40 as far as I know.

Will, when we were at Stradbally in August and at Antrim in September your K did let off a good puff of blue smoke after being on sidestand but it disappeared very quickly. If anything I might have thought yours was running a little richer but restrictor may do that. Not sure if anything much is to be done, better slightly rich than excessively lean. There did not seem to be anything wrong and I did many miles behind you.

Try mainstand only for a while and see if it makes any difference. I also generally kill the engine and then remove gloves etc before dropping the bike onto the sidestand. I also dont fire up until its up in the vertical. Not sure it makes a difference but it has got 102k miles up. I do occasionally get some smoke on start up but that only happens if its been sitting for a few weeks. Not sure I would be going at the engine.....

joao.c130 wrote:Possible Causes:
Vent tube damaged engine, rich or poor mixing, air box and manifold leak.

Joao/Olaf - I suspect poor mixing - this is a result of fitting a restrictor to keep me EU compliant for another 10 months. (My licence had lapsed and I didn't resit the test before the legislation changed.) The restrictor kit is basically 4 big washers in the intake tubes reducing the airflow.

Have changed oil - last used Valvoline 15w-40 didn't like how thin it looked coming out. have replaced with same weight Comma and will see how that behaves.

88

PS Olaf I always put the bike on the centre stand except for mounting/dismounting...the smoke has me too embarrassed not to

Will,

That sounds distinclty like Christy Moore...Ride On......

Enjoy Saturday!!

[quote="Comberjohn"]My '89 LT never smoked but the '84 will smoke like a train if I don't follow a simple routine.
When I pull up, I let the engine tick over for 10-15 seconds before switching off. You can appear dead cool about it by removing your gloves while you are waiting.
Then I can park it on the side or centre stand without the embarrassing smokescreen when I start up.
Don't know why. Must be something to do with the oil settling down after the engine running at higher revs.[/quote]

You are closer to the truth than you know. The output shaft gear throws oil up into the cylinder bore. Running it at low rpm the gear doesn't spray as much oil and it gives the piston rings a chance to clear the cylinder out.

The Mason your last sentence suggest's that the smoke comes from 1 cylinder only ? Is that true???? just the gear spray on one cylinder???

will try that....last thursday my son asked if i had been riding...I said yes why....he said he could see a trail of smoke for hundreds of metres hanging in the air...mmmmm side stand and trialling some 0W40 fully synthetic....will try your advice...

do'nt forget, all unpinned piston rings rotate at a rate of one revolution per thousand revs of engine speed, so it's pure chance that the oil seeps into any, all, or none of the 4 combustion chambers.BMW must have noticed this during the original development and testing, but decided not to rectify it. Perhaps they had already placed the order for pistons with Mahle !.