BMW K bikes (Bricks)


You are not connected. Please login or register

K100-forum.com » Technical, repair and troubleshooting » Engine and transmission » Valve Clearance K100

View previous topic View next topic Go down  Message [Page 1 of 1]

1Back to top Go down   Valve Clearance K100 Empty Valve Clearance K100 Mon Sep 21, 2015 2:30 am

Kafflut

Kafflut
Silver member
Silver member
It's a 1984 K100. The odometer is bust. I bought it like that, stuck at 86 000 km. I did not run the engine after changing a shim. The new one is 0.10mm thinner than the one I took out, but the valve clearance is exactly the same. I rotated the engine a few times and measured again - no change.

I'm puzzled Shocked 

I did not remove the cam shaft - I used the hook and spacer recommended in the manual.

http://bmwk100k75.weebly.com/
    

2Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Mon Sep 21, 2015 5:56 am

92KK 84WW Olaf

avatar
Life time member
Life time member
If you read off the thickness off the one you took out, is it possible it was worn concave? The top surface can wear ever so slightly and if so the thickness at the cam lobe contact point may be no different. If its an original shim there could be slight wear. Can you check the thickness at the cam lobe contact point of the shim you took out as opposed to reading it off, see does it match the stated thickness?

Second thought is that the new shim is not seated properly.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 51,800 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 63,390 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

3Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Mon Sep 21, 2015 8:11 pm

Rick G

Rick G
admin
admin
Measure the shims at the centre using a micrometer. If the reading is less at the centre than the rim then discard the shim. There are many very old shims around so you need to be watchful of them.
Slightly tight inlets and loose exhausts are OK to within 1 shim size.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

4Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Tue Sep 22, 2015 4:14 am

Kafflut

Kafflut
Silver member
Silver member
Thanks Rick & thanks Olaf


I checked and it is indeed as you suggested. Sort of; the one side is not concave, it is convex, thicker at the centre.

So, for now, put back the old one. Get another one, the right thickness, later.


Surface grind back to flat so the whole shim is the thickness it now is at the edges seems an option. My friend, Peter has an engineering workshop & suggested it, but he's too busy & staff short at the moment - can't do it right now. Besides what would one rather do when pressed for time, do a friend's surface grind little job or your regular high volume customers' jobs? What a Face


I could turn the shim around, convex side toward the valve and the flat surface running against the cam, but then the convex surface sits on the bottom of the bucket and would that be a problem?

http://bmwk100k75.weebly.com/
    

5Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Tue Sep 22, 2015 4:41 am

92KK 84WW Olaf

avatar
Life time member
Life time member
Don't even think of that last option. The convex [?] side means the shim runs the risk of breaking up with catastrophic consequences.....Question mark is because I would expect the centre to be concave as in thinner through being very slowly hollowed out where the cam lobe contacts the shim surface. Uneven contact places stresses its not designed for.

Either way I reckon its a new shim. Your checking and fitting methodology seems to be spot on, including checking all was right after fitting the new shims.

I think you have highlighted a need to actually measure the shim being removed in case the thickness does not match the stated thickness due to wear, something I hadn't thought about. Even Clymer simply goes on the stated thickness of the old shims for its calculations rather than a micrometer check of the old shims so this would seem to be good advice going forward.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 51,800 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 63,390 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

6Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Tue Sep 22, 2015 5:58 am

Holister

Holister
Life time member
Life time member
Convex seems weird!! How could that happen? Turning it around would mean it possibly wouldn't sit evenly in the bucket. Just bin it. They're cheap enough.
Leave the new one in there in the interim and use that to calculate your new shim size.
Might be worth physically checking all the other shims to make sure they're not the same.


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808		 Valve Clearance K100 Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

7Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Wed Sep 23, 2015 1:09 am

Kafflut

Kafflut
Silver member
Silver member
Kaptain Holister wrote:Convex seems weird!! How could that happen? Turning it around would mean it possibly wouldn't sit evenly in the bucket. Just bin it. They're cheap enough.
Leave the new one in there in the interim and use that to calculate your new shim size.
Might be worth physically checking all the other shims to make sure they're not the same.

I got it from a fellow club member who owns a K75 & never chucks anything Very Happy I can't tell how the shim got to that shape. My guess is not through wear and normal use - it is the shape I would expect it to have if aggressively lapped at some stage of its life

http://bmwk100k75.weebly.com/
    

8Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Wed Sep 23, 2015 1:25 am

Kafflut

Kafflut
Silver member
Silver member
92KK 84WW Olaf wrote:I think you have highlighted a need to actually measure the shim being removed in case the thickness does not match the stated thickness due to wear, something I hadn't thought about. Even Clymer simply goes on the stated thickness of the old shims for its calculations rather than a micrometer check of the old shims so this would seem to be good advice going forward.

I discovered the odd shape by holding it up to the light with a straight edge against what was supposed to be flat surface. I don't think it was wear, probably vigorous lapping at some point in its history.
Thanks for the comments.
BTW following Clymer and some internet video on how to do the job made me feel like a very ham-fisted idiot; that "small screw driver" "easy" removal of shims is a fairy tale. I have a special tool I'll recommend to BMW one day - they can give it a fancy number and equally fancy price. It's a small magnet, about 1.5mm thick attached to a slightly curved piece of scrap. It goes "easily" between the cam and the shim - click - pull it out with shim stuck to it.

http://bmwk100k75.weebly.com/
    

9Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Thu Oct 08, 2015 1:30 am

Kafflut

Kafflut
Silver member
Silver member
92KK 84WW Olaf wrote:Don't even think of that last option. The convex [?] side means the shim runs the risk of breaking up with catastrophic consequences.....Question mark is because I would expect the centre to be concave as in thinner through being very slowly hollowed out where the cam lobe contacts the shim surface. Uneven contact places stresses its not designed for.

Either way I reckon its a new shim. Your checking and fitting methodology seems to be spot on, including checking all was right after fitting the new shims.

I think you have highlighted a need to actually measure the shim being removed in case the thickness does not match the stated thickness due to wear, something I hadn't thought about. Even Clymer simply goes on the stated thickness of the old shims for its calculations rather than a micrometer check of the old shims so this would seem to be good advice going forward.

Here's my solution for shim thickness measuring:

Valve Clearance K100 6045368

Dial gauge secured to a table top. Zero the dial gauge on the sheet of glass and insert the shim.

It is very sensitive - don't touch the glass, not even light finger pressure. Move the shim around with the tip of a pencil and it gives one a pretty good impression i.e. ± 0.01mm  of the shape/unevenness of the surface.

http://bmwk100k75.weebly.com/
    

10Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Thu Oct 08, 2015 11:31 am

Holister

Holister
Life time member
Life time member
Those shims look like they have a chamfer?? Also, there seems to be a divet in the middle of the r/h one with unusual wear.
Any chance of a close-up pic in a decent size? Very Happy


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808		 Valve Clearance K100 Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

11Back to top Go down   Valve Clearance K100 Empty Re: Valve Clearance K100 Thu Oct 08, 2015 1:53 pm

Kafflut

Kafflut
Silver member
Silver member
Kaptain Holister wrote:Those shims look like they have a chamfer?? Also, there seems to be a divet in the middle of the r/h one with unusual wear.
Any chance of a close-up pic in a decent size? Very Happy
I can't do more photos; I've put stuff back together again and the cover is on.

That "chamfer" on the L/H is in the photo - reflection or bad focus or something. The actual edges are beautiful and very sharply defined. That "divet" concerned me at first. The shim is as it came out of the engine and the face that you see is the face that runs on the bucket, the not-cam face. I could see what was left of the size in the very centre, only one digit; the rest of the size number was polished off.

I gave it a 20 second lap with 600 grit paper and it came up shiny like a mirror. In fact take a close look at the one on the L/H side - you will see the dial gauge is mirrored in the surface. The divet one looked the same after I cleaned it. I checked the surface with the dial gauge and can absolutely confirm, there is no indentation.

http://bmwk100k75.weebly.com/
    

Sponsored content


    

View previous topic View next topic Back to top  Message [Page 1 of 1]

K100-forum.com » Technical, repair and troubleshooting » Engine and transmission » Valve Clearance K100

Permissions in this forum:
You cannot reply to topics in this forum