BMW K bikes (Bricks)

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FreyZI

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I'll post gaps in a bit, but is there anything to explain mostly tight clearances in '85 K100 2V?

    

Laitch

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Wear.
How many miles on the bike? Do you know if the clearances have ever been checked previously?


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1995 K75T 68,000 miles
    

FreyZI

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Alda has ~104K mi. †I have no idea when it was last serviced.

Clearances:

I1 .152
I2 .127 (tight)
I3 .127 (tight)
I4 .152
E1 .229 (tight)
E2 .178 (tight)
E3 .279
E4 .229 (tight)

Incidentally, I took the muffler/silencer off to look at header pipes for oil. †Headers from cylinders 2 and 4 appeared oily; 1 and 3 were dry).

    

RicK G

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What that means is that most of your valve clearances are tight. Not by much and that they have been neglected and need to be rectified. Check them each major service and adjust as necessary.


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"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats."† from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

Holister

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Inlets 1 & 4 @ 0.152 I would call tight also. While still in spec (just), I doubt it would be long before they were out as well. Best to re-shim them all to the loose end of the spec.


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1988 K100RT†††† VIN No.† 0094680
1989 K100RT † † VIN No.† 0097367 (naked)††
1996 K1100RS ††VIN No. †0451808
† † Fuel:† 95 Octane
Engine Oil:†Nulon Full Synthetic 15W50
Gear Box Oil:† Nulon Synthetic 75W90
    

charlie99

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its probably an early series motor

there was some speculation about unleaded fuels requiring better metallurgy of the valve train . engineering changes occurred back in the late 85 -86 models that changed the valves and seats for the better

long story short the early models may have softer seats ...allowing for what we call valve regression to happen more quickly when using unleaded fuels (LEADED FUELS PROTECT valve seats and exhaust valves better†) .. ie valve clearances gets tight

regression happens normally as seats and valves wear but in the earlier models this may happen quicker that later models

just get the shims required to make the clearances correct

your Kawasaki dealer usually carries shims for klr 650 bikes , which are a match for our valve shims† so possible readily available† for swapping .

my local Kawasaki service shop does them exchange for $5.00 each ...so could be better cost effective than buying new ?

good luck


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

MartinW

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You will need special tools to change the shims, you can get them from†mailto:polepenhollow@yahoo.com.
It is also possible to make them, the drawing for the tool specs used to be online but I can't find it, somebody may post it. Basic hand tools needed files, hacksaw can be used although an angle grinder makes it easier. You will also need a welder to attach the handle.
Regards Martin.

    

Chocolate

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Only a few activities make me experience my senses in a way motorcycle riding does, it is like swimming in the nude in a river.
K75 BA/1992 ABS, K75 BA/1991 noABS, Ducati, Mobylette M1/1973
    

duck

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Even though I have the special tools I find it easier just to use a screwdriver. †I put the blade tip parallel to the circumference though.


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Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

FreyZI

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Thanks, all. †More fish to fry, as I've just removed head and this looks to be a more significant project. †I'll start a new thread.

    

FreyZI

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Uff da.† So, I've just gotten the head back from the shop where they did a valve and seat job.† I also had them replace the valve seals while they were in there.† Nothing untoward noted.† Put cylinder head on cylinder block and reassembled the buckets, shims, cams, and caps on the head.† Now instead of the slightly tight gaps I had before, I have essentially zero gap at any shim.† Doesn't seem like anybody who knew what they were doing could put the valve assembly back together wrong (other than maybe lower spring plates upside down?).† Is this normal after disassembly of the valves?† Any suggestions?

Just to allay any potential concerns: copiously oiled parts during assembly, all the buckets and shims are on the valves they were on before, all the caps are in the same, correct places, slow and careful rotation of each camshaft is possible without particular difficulty or noises.

    

indian036

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A service to the head and valves will usually mean that the valve faces and valve seats will be ground or machined, so the valve will sit slightly higher in the head. This will mean that they will be closer to the cam and so smaller clearances will be expected, with the amount of difference related to how much had to be removed to get a good seal.
If the clearances were unchanged, I'd be suspicious whether they'd done any work at all.† Smile

You will probably need to obtain some new shims, but you may be able to re-use some on different valves to get the right clearances.

Bill


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1985 K100RT †VIN 0028991† My original Very Happy † (Historic rego)
1985 K100RT †VIN 0029036† BOB the Blue Old Bike† (Historic rego)
1990 K100LT †VIN 0190452† Work in progress
1984 K100RT† VIN 0023022† Work needing lots of progress

1986 K100RT† VIN 0090542† Work needing lots and lots of progress
1993 K1100LT† VIN 0183046† Work in progress
1993 K75S †VIN 0213045† Newest toy, slightly non-original
    

FreyZI

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Thanks, Bill.† Perfect explanation.

    

charlie99

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@FreyZI wrote:Uff da.† So, I've just gotten the head back from the shop where they did a valve and seat job.† I also had them replace the valve seals while they were in there.† Nothing untoward noted.† Put cylinder head on cylinder block and reassembled the buckets, shims, cams, and caps on the head.† Now instead of the slightly tight gaps I had before, I have essentially zero gap at any shim.† Doesn't seem like anybody who knew what they were doing could put the valve assembly back together wrong (other than maybe lower spring plates upside down?).† Is this normal after disassembly of the valves?† Any suggestions?

Just to allay any potential concerns: copiously oiled parts during assembly, all the buckets and shims are on the valves they were on before, all the caps are in the same, correct places, slow and careful rotation of each camshaft is possible without particular difficulty or noises.

pretty common issue

when I did my head porting project , I asked them how much total they had removed from the valve faces and valve seats ...was about 10 thou in total ...
so I got them to trim the valve stems†(length of valves ) by about the same amount ...so result was 7 of the 8 valves were extremely close to spec ...but 1 valve was another 6 thou loose ...I guess they hit that one twice ....lol †

but still in range for a standard shim ..so most were around 2.4 - 2.6 thickness but the rancid one 2.85 ...bugga ...the local kawaski dealer does an exchange service with klr 650 shims for $5.00 each ...so all sorted

good luck


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

jbt

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I've heard many scary stories about valve recession on BMW engines.
I've also opened and overhauled many BMW engines. Hundreds. From 1970 to 1995.
I've seen ONE recessed (?) seat, measured out of the limits. Only one - exhaust- on only one cylinder.
If unleaded fuel was to blame for this, it would have caused recession on all the cylinders, don't you think?

I would blame the valve guide for destroying the seat instead. The valve has not only a movement in translation but is also turning (it's normal, to spread the wear all around the seat). But when the guide is worn, this rotation is not coaxial anymore, and the valve is grinding and digging in the seat.

Valve guides are wearing much quicker than seats. When they are replaced, valve seats need to be machined to maintain the valve, the seat and the new guide coaxial. So according to me, we should pay attention to the guides much more than to the seats.

    

charlie99

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well interesting you should say that jbt
that is why I reconditioned the head
pitting of the†valves was consistent across all valves but much more evident on the exhaust valves

heres an example





cleaned up a little



and an inlet







after service† what I put back in




seats




and after


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

88

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Good idea on shaving the Valve stems/shafts. I'll do that with K1100rs head.

@ Charlie.....did you see how they did the job? Just wondering how they would chuck the flared end of a valve!


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88....May contain nuts!

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

Dai

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Will - you clamp it on the parallel part of the stem and give it a virgin's kiss with the tool.

(Damn - somone's gonna get me with that one).


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'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

charlie99

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most of the engine re-conditioners have special grinding wheels set at appropriate angles will

for the special performance types they can do a 3 angle cut of the valves ,but many performance mods have geared up for 5 cut angles at exorbitant prices

the refurb of my valves was only a 1 cut angle ...and still within spec for the distance from the valve face (by a certain amount )† I was happy with the angles of the grind to allow the angles of the natural valve profile to flow†a 3 angle process , you may have noticed that the exhaust valve had a protruding edge above the valve face , after which was cut back to nearly no protrusion in the edge† and more a straight cut - edge

the tool doing this was like a fine stone on a bench grinder with preset angles on the valve stem guides to the grinder '' there was a heavy reliance of estimation to how much was ground off , by the operator of the equipment

in truth I hadn't done my homework properly and should have measured the lengths from top of seat† to valve stem top† to estimate how much they had either removed† or what ever , I would imagine to do this might have been out of my skillset , with the tools I had to hand .
but may have been replaced into to the cylinder head and reassembled before estimating the top cut required† to fall close to the original shim thickness†..then work with the calculator

hope that answers some questions ?


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

Dai

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https://www.youtube.com/watch?v=y5nTXDIgWaM

Serco cutters are more common in the UK.


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'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

nobbylon

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I just did my clearances yesterday. Bike has 84k kms and is a very early model so was built to run on leaded. Only 2 inlets were tight. Previous owner didnít but I will be using shell millenium fuel additive. I think these K engines are fine valve wise on any fuel.

    

RicK G

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There have been many here who have found the early heads to be quite tolerant to the unleaded fuel but a few have cropped up that have been failing and needed fixing.† Thing is that after 30 years and more the heads probably have been swapped or fixed so fewer and fewer are surfacing and more than likely on engines that have been found in the back of a barn or cave after being there for many years.


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"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats."† from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

Dai

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The other thing that helps is the material that the valve seat is made of. I have no idea what BMW used but there was a huge panic in the Guzzi world when leaded fuel went out. Turned out that the valve seats were old enough to have work-hardened and be immune to unleaded fuel. Mind you, I have two burnt-out exhaust valves on the shelf...


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

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