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1Back to top Go down   Misfire on over-run Empty Misfire on over-run on Mon Aug 06, 2012 4:35 pm

Paul Friday

Paul Friday
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I've got a 1985 8 valve K100RT.
It's just started misfiring on the over-run. The effect is that I'll close the throttle, coast or brake. When I open the throttle again the engine runs on three for a bit and then kicks in. I've just done the obvious and pulled all the plug caps. Number 1 had a white powdery deposit inside. I've not had a chance to run it since - could I have fixed it or is there something else I should be checking while I've got the toolbox open?

http://www.theostry.com
    

2Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Mon Aug 06, 2012 4:38 pm

Two Wheels Better

Two Wheels Better
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If you have an ohms readable multimetre, check the resistance of each HT lead and compare their readings. 5K ohms is the usual (if OEM) resistance but see if any are well off that mark. It's a place to start.


__________________________________________________

"It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts."

Arthur Conan Doyle
1970 R60/5, '77 R75/7-R100, '85 K100'87 K75C, '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R'04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - all of the Beemers in my life I can recall, owned still or sold on.
    

3Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Mon Aug 06, 2012 6:42 pm

Inge K.

Inge K.
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Just want to add to the info allready given by GITH about the 5K ohm resistor at the plug cap, that it also is a 1K ohm resistor at the coil end.


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

4Back to top Go down   Misfire on over-run Empty Misfire on over-run on Mon Aug 06, 2012 8:04 pm

RT

RT
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As an aside, check that you have the little screw on caps on top of your spark plugs, I had a white powder in my lead caps because there were no screw on caps on the plugs. Running was awful.
RT


__________________________________________________
2011 R1200RT
    

5Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Mon Aug 06, 2012 8:54 pm

krambo

krambo
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Might also be worth checking the TPS (Throttle Position Sensor) it may have been disconnected by PO - do a forum search for Throttle Position Sensor Wink


__________________________________________________
1984 BMW K100RT, 1993 BMW K1100LTIC,1982 Kawasaki KZ1100 Spectre
"Aut viam inveniam aut faciam." Misfire on over-run Uk-bmw12
http://www.its-personal.net
    

6Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Tue Aug 07, 2012 4:44 am

charlie99

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@RT wrote:As an aside, check that you have the little screw on caps on top of your spark plugs, I had a white powder in my lead caps because there were no screw on caps on the plugs. Running was awful.
RT

hard to tell from the information given ...but "rt" is spot on ...the ngk and some other brands dont come with furules installed these days ....champion and a few others do ....but you shouldnt see the white powder in the connection to the plugs or the actuall connection points (coils and plug tops) they should be clean and shiney ....if not ...make it so .

hope you find the issue and enjoy the ride ...cheers !


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

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

7Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Tue Aug 07, 2012 5:02 am

Inge K.

Inge K.
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@charlie99 wrote: they should be clean and shiney ....if not ...make it so .

This is how they should look like:

Misfire on over-run Pluggh10


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

8Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Tue Aug 07, 2012 5:20 am

charlie99

charlie99
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aye inge ...good pic !


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

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

9Back to top Go down   Misfire on over-run Empty Misfire on over-run on Tue Aug 07, 2012 7:25 pm

RT

RT
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You can't fool me Inge, that has to be a brand new one.
Otherwise mine still are shameful.
RT


__________________________________________________
2011 R1200RT
    

10Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Tue Aug 07, 2012 7:47 pm

Inge K.

Inge K.
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Misfire on over-run Autoso10

Misfire on over-run Laughi10


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

11Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Wed Aug 08, 2012 4:14 pm

sidecar paul

sidecar paul
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I bet your toothbrush tasted horrible after that,Inge. Misfire on over-run 261959

Paul.


__________________________________________________
'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015) 
....No CARS never ever!
    

12Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Thu Aug 09, 2012 2:12 am

Inge K.

Inge K.
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Misfire on over-run Gebiss10

+

Misfire on over-run Haytry10


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

13Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Thu Aug 09, 2012 5:41 am

charlie99

charlie99
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Misfire on over-run 44271


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

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

14Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Thu Aug 09, 2012 4:34 pm

sidecar paul

sidecar paul
Life time member
Life time member
+1 Misfire on over-run 44271


__________________________________________________
'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015) 
....No CARS never ever!
    

15Back to top Go down   Misfire on over-run Empty Hmmm, maybe not the HT leads... on Sun Aug 12, 2012 6:05 am

Paul Friday

Paul Friday
active member
active member
Thanks for the ideas guys. I cleaned the plug caps and plug tops and it made no difference. Since the problem occurs when I close the throttle, I'm now looking at the fuel injection and the throttle position sensor.
As an aside, aren't HT leads a ridiculous price? I looked at a well-know parts supplier and they are quoting £18 each for second-hand leads. Has anyone tried making their own - using parts from say, Vehicle Wiring Products? (See http://www.vehicle-wiring-products.eu/VWP-onlinestore/htterminals/htterminals.php)
Misfire on over-run 3041425650

http://www.theostry.com
    

16Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sun Aug 12, 2012 4:33 pm

charlie99

charlie99
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tps ...yes ...but also check for vacuume leaks paul ...rubber hats over take offs ...throttle body rubbers , plenum to crankcase ...etc ...dont forget the oil filler is screwed up and sealed


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

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

17Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sun Aug 12, 2012 4:41 pm

twincarb

twincarb
Life time member
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funny Paul I had the same view on them being over priced... £30 each from the main suppliers...

this place have got them for far less... RAM HT Leads


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Misfire on over-run 169042 Misfire on over-run 169034
    

18Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sun Aug 12, 2012 9:13 pm

88

88
Life time member
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€41.75 each affraid ......or is that for a set?

88


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Misfire on over-run Ir-log11 88....May contain nuts!Misfire on over-run Ir-log11

"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.
    

19Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sat Aug 18, 2012 4:08 pm

brickrider

brickrider
Life time member
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Poor running and backfire on trailing throttle is something my 1985 K100RS just began to do. I've traced the problem (I think) to intake leaks, but I'm mystified at what to do about them. I'd just recently replaced the rubber bits between the TB and plenum chamber. To do that, I coated the parts to be joined with silicon grease and after much cursing and tool throwing, everything went together. 1,500 miles later, there's leaking again. So, what's the solution?
I've never heard that it's necessary to glue the rubber connectors to the TB and plenum. Should I? When I fitted the new rubber connectors, I examined them to see if there was a top and a bottom -- could find no indication of that. At present the hose clamps are as tight as I can make them, visually, all the pieces seem to mate as closely as is physically possible, yet the idle speed jumps up when I spray electronics cleaner around the connectors! What else can I do to make the intake trace leak-free?
Anyone have a clue? Rolling Eyes

    

20Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sat Aug 18, 2012 7:20 pm

yankeeone

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Hi, I think the rubber parts that connect the plenum to the bodies have two diameters I believe there are two sizes of clamps as well.

    

21Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sat Aug 18, 2012 7:46 pm

Inge K.

Inge K.
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Top clamp: 50mm, bottom clamp: 48,5mm.


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

22Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sat Aug 18, 2012 10:18 pm

yankeeone

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I dont know if you could put the rubber parts on up side down or not , but when I did mine, I did not even consider there was a difference till I orderd the parts.

    

23Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sun Aug 19, 2012 8:32 am

twincarb

twincarb
Life time member
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88KE wrote:€41.75 each affraid ......or is that for a set?

88

I think/hope it's a set.... not been brave enough to phone them up yet!!!


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Misfire on over-run 169042 Misfire on over-run 169034
    

24Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sun Aug 19, 2012 10:16 am

blaKey

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"€41.75 each ......or is that for a set?"

It's a set. I purchased a set of those leads and they are excellent. Not a problem at all.


__________________________________________________
Neil
K100RS 1986 RED!

Dress for the ride and the potential slide.
    

25Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Sun Aug 19, 2012 10:52 am

twincarb

twincarb
Life time member
Life time member
owwww would that mean if I buy a set I won't be expected to clean up my old ones?!


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Misfire on over-run 169042 Misfire on over-run 169034
    

26Back to top Go down   Misfire on over-run Empty Solution found on Tue Aug 28, 2012 9:17 am

Paul Friday

Paul Friday
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Swapped out the plug leads for a better but second-hand set and it runs like a charm.

Of the original set, the leads for cylinders 1 and 3 showed no continuity at all on my meter. That would be why it was mis-firing, then.

Thanks for all the suggestions.

Very Happy

http://www.theostry.com
    

27Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Tue Aug 28, 2012 10:06 am

RicK G

RicK G
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I just love happy endings Misfire on over-run 212902


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

28Back to top Go down   Misfire on over-run Empty Re: Misfire on over-run on Tue Aug 28, 2012 10:11 am

RicK G

RicK G
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On my K100 I used the non restive Blue silicone leads and resistive plugs which still did the same job but heaps cheaper NGK DR7EA instead of D7EA


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

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