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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Duc750 on September 06, 2011, 01:26:56 PM
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Right guys I need some help
Having recently bought an ex police K11LT with a relatively low mileage I'm stuck.
The previous owner had tried to silence some of the K bike rattle and fitted a new Cam chain at about 45K - the Bike is now at 48.6K.
The bike has always been a bit vibey at idle so I've though the TB's to be out.
No worries I though I'll do a full annual on it and sort it all out......
However when coming to check the timing I get stuck - I can hardly turn the engine over from the back wheel (in 5th) Ok fI think I've still got the coolant in so I'll drop that but it shouldn't be adding that much resistance (unless the watrepump is a prop off an ocean liner)
Coolant dropped slightly less resistance but a load of gravel and swarf in the coolant (crap - that'll be job number 2 then)
Try to crank the bike to TDC on cyclinder 1 - finally achieve as close as I can get - Inlet 1 is at 0.15 inlet 2 is at 0.1mm
Exhaust - not a hope from this position
Hmmm think again then and have another go - crank over again to TDC cylinder 1 - no change sit down at the back of the bike and think - look down the cam shafts - crap! the slots on the end of the cam aren't parallel.
The damned cam shaft (one of them) is out!
Any suggestions on how to re time the thing ? - where are the timing marks ? the Clymer assumes that no one is stupid enough to get the things out of time when they do a cam chain change or change the buckets so there's nothing there that I can see.
One other question - exhaust clearance should be 0.35 at Cylinder 1 TDC or at the point where the cam lobe is 180 degrees away from the bucket ? The Clymer says TDC but my logic looking at the cam timing is that I need to roytate the crank shaft to get to a point I can measure it (fully closed)
So I guess the help I need is - firstly at TDC what orientation should my cams look like (to make sure that its not miles out)
Secondly where the hell are the timing marks on the crank/flywheel ? and how best to get to them
Thirdly - Gravel and swarf (some of it magnetic) in the coolant means to me - new water/rebuilt pump at the minimum but what else is going to need replacing (and what the hell could be disintegrating in there to cause it.
For what its worth the bike hasn't run badly for the last 2K miles since I got it but it has vibrated a bit at low revs (hence the TB thought) and been a little gut less flat out (top out at 120) although I put that down to what I believe is a lower ration final drive than standard.
Sorry for the long post - all help gratefully received
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The timing marks are on the Hall Effect sensor. In my experience they're not really needed though. Usually you can get the timing spot on by aligning the notch in the HES with the notch where it mounts. Every time I've done it that way and then checked it with a timing light there has been no need to adjust it.
Turning the engine via the rear wheel is easiest if you put it in 5th gear and remove the spark plugs. If the spark plugs are in then you're working against engine compression.
DIY Can Chain Tensioner Depresser (for 4V K bikes) (http://www.motobrick.com/index.php?topic=971.0)
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About the posibillity of one of the camshafts out of position:
When #1 at TDC it`s a triangle on each camshaft sprocket which should be pointing straight down.
Inge K.
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From the "BMW Motorrad GmbH+Co.", Service Department, Repair Manual, K-Models, Page 11 - 80.0
Bring cylinder # 1 to top dead centre.
Camshaft gears - Installing
Loosely install the camshaft gears to the camshafts with the retaining screws.
Rotate the camshafts until the marks on the camshaft gears are aligned with the joint between the bearing cover and the cylinder head.
Place the timing chain over the sprockets (keep the tension side tight)
Secure the camshaft gears to the camshaft.
Camshaft gear retaining screws 54+- 6 Nm
I can scan parts of this book and email them, it is an excellent source of information for the "K"s . While the printed areas scan well the pictures do not. The book is like a pocket manual. ( 5 x 9 inches) What ever we can do to help you put this back on the road.
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http://www.motobrick.com/index.php?topic=276.0 (http://www.motobrick.com/index.php?topic=276.0)
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Guys, thanks for your help so far
I was looking at the cam wheels looking for a stamped mark on them - not realising they were actually triangle shaped holes !
The inlet cam as close to TDC as I think I can get is at this position
(http://img.photobucket.com/albums/v280/Duc750/utf-8BSU1HLTIwMTEwOTA2LTAwMDA3LmpwZw.jpg)
At the same crank position the exhaust cam looks like this
(http://img.photobucket.com/albums/v280/Duc750/utf-8BSU1HLTIwMTEwOTA2LTAwMDA4LmpwZw.jpg)
So I think one of them is out between one and two teeth !
Looking at the plugs its definetly been running rich so I think the exhaust has been advanced and so has not been scavenging properly
As far as the coolant residue goes I'm still not exactly comfortable with it - it looks as if someone has tipped a small bag of snad in there at some point !
Coolant residue in the bowl
(http://img.photobucket.com/albums/v280/Duc750/utf-8BSU1HLTIwMTEwOTA0LTAwMDA1LmpwZw.jpg)
Build up on water pump impellor
(http://img.photobucket.com/albums/v280/Duc750/utf-8BSU1HLTIwMTEwOTA2LTAwMDEwLmpwZw.jpg)
Now I can see what the issue is with the cams and have a route to solve it I'm going to wip off the water pump and sort that out then bolt all the covers back on and start doing the clutch etc.
Thanks again for your help guys
Cheers
Andy
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You can also double check the camshafts position relative to each other by the grooves in the rear ends, where the genuine locking tool should be mounted.
Inge K.