BMW K bikes (Bricks)

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jonnyqq

jonnyqq
Silver member
Silver member
Following Mr K2's shock at having the loose washer inside the starter he has done about 1K miles without problems.

There is approx 1-2 second loss of power,intermittent but I can now reproduce it as follows.

Firstly, only occurs after bike been on road for 10 mins or so,presume to operating temp.

Secondly, only occurs after sudden deceleration, eg after snapping throttle shut when changing gear. Revs sharply decelerate ,as expected , but when opening up throttle nothing happens, then suddenly power cuts back in (hang on Jonny I cried!) after approx 1-2 seconds.

Accelerates up nicely until next gear change or slowing down in traffic , same thing occurs .Otherwise , bike is running sweet and powerful.

I am aware of another similar post "engine cutout" which is really interesting so i apologise for troubling you again.

My attempts to fix thus far...

1. Replace fuel filter. Tank spotless inside.
2. Cleaned plugs,deoxit all HT connectors and all coil connections. (plugs 1-3 slightly oily, plug 4 sl grey).
Used just over 1L oil over 2300 miles.
3. Swapped ECU from salvaged Mr K to Mr K2.
4. Tank off, check for obvious loose connections.

Still got problem. Reading around above post i'm thinking about the relay box ,but as usual gentlemen the honest answer is simply once again that i havent got a #¥+<$*€ clue! cheers

Therefore any advice would be most appreciated please. I am in The envious position of having Mr K to salvage bits from.

Time now to swap over to the humour section where i feel able to make a small contribution to ease my conscience for bothering the forum again.

Cheers

Jonnyqq

    

Inge K.

Inge K.
VIP
VIP
It seems like you have checked the HT side of the ignition good, but have you measured the cables, and is the nipples at the spark plug connecto present?

The reason I mention this is because I did have similar behaviour on my K11, when it was a bad connector inside one of the plug caps.
Then it was cutting on that cylinder after a deceleration, but only now and then.


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

jonnyqq

jonnyqq
Silver member
Silver member
Thanks Inge , yes caps are on all plugs , will check leads next after replacing broken lead on my meter !

    

ReneZ

ReneZ
Life time member
Life time member
And the bike is a ... ? Please put it in your signature?

Could be the TPS, where it stays as if closed, whilst the rack is opened again. Humidity in the connection of the TPS?


__________________________________________________
Greetings from Florida! Having a 'new' K  :cyclops:    Surprised-o: 

Rene


BMW K100 - 1985 (0030029) Short-lived "loss of power" , intermittent yet v specific. Rain
BMW K1200GT - 2003 (ZK01223)
    

jonnyqq

jonnyqq
Silver member
Silver member
Thanks Renez
Sorted signature ,oops.
Will def check that out TPS.

Cheers

    

jonnyqq

jonnyqq
Silver member
Silver member
Thanks ReneZ

I thought problem solved but after 25mins riding same thing happened.

This is what i found inside the TPS connector...


Short-lived "loss of power" , intermittent yet v specific. 01412

the middle spade connector was heavily corroded , I could also see blue deposit up inside the corresponding female connector . I cleaned both up as best i could with Deoxit. Took bike for a run, fast , slow, multiple gear changes and as i was convinced it was cured off it went again with v frequent decelerations. I kangerood home. !

So, I reckon we are close to a fix as the problem usually started after 10 mins. Maybe the connector inside the plastic end cap is corroded out of my line of sight. Or, is the TPS itself at fault.

I do have both components from old bike to change so will try TPS change first., then fuel inj loom change next unless of course anyone can suggest anything else

once again all much appreciated

cheers

jonnyqq





__________________________________________________
K100LT 1991
Ex police bike
    

Crazy Frog

Crazy Frog
admin
admin
2 months ago, I temporarily disconnected the TPS as many people think that the bike is smother.
This is true, and I have no plan to re-connect it.
Gas mileage has not changed, and the bike doesn't back fire anymore when decelerating.
(I was suspecting a bad TPS). Try it first before re-connecting a new TPS.

CF


__________________________________________________
Short-lived "loss of power" , intermittent yet v specific. Frog15Short-lived "loss of power" , intermittent yet v specific. Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

jonnyqq

jonnyqq
Silver member
Silver member
How v interesting indeed!
Will do and report back.

Thanks CF


__________________________________________________
K100LT 1991
Ex police bike
    

jonnyqq

jonnyqq
Silver member
Silver member
Disconnecting the TPS has SOLVED the problem. Went out for 40 minutes and acheived 30 troublefree miles ie. no sudden unexpected decelerations.

Furthermore, as suggested by Bert, whilst this bike did not backfire it certainly "popped on the overun under 2500rpm" and that annoyance is also now CURED.

In addition,yes the ride does feel smoother and yes a small decrease in engine braking efficiency of little practical significance.

Its good learning about our beloved bikes and fixing them either at home or on the roadside.

Thanks to all

Cheers

Jonnyqq


__________________________________________________
K100LT 1991
Ex police bike
    

ReneZ

ReneZ
Life time member
Life time member
Good stuff, happy you got it sorted; now ride the thing!!

In all fairness we always recommend to give all connectors a good once-over when you get it. Bit of a job, but then you can keep the maintenance up easy and it solves a lot of silly little issues that don't necessarily make sense :-)


__________________________________________________
Greetings from Florida! Having a 'new' K  :cyclops:    Surprised-o: 

Rene


BMW K100 - 1985 (0030029) Short-lived "loss of power" , intermittent yet v specific. Rain
BMW K1200GT - 2003 (ZK01223)
    

charlie99

charlie99
VIP
VIP
good find jonny !


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OShort-lived "loss of power" , intermittent yet v specific. Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

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