BMW K bikes (Bricks)

You are not connected. Please login or register

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


1Back to top Go down   Misfire under load,  Empty Misfire under load, Mon Oct 17, 2011 2:36 pm

bandaid

avatar
active member
active member
I have cleaned or repalced virtually every connection on the bike now, and apart from this missfire, its all fine. The bike starts and runs a treat if its in neutral, free revs up to the redline without complaint, however, when its under load, like in gear, it goes to 3500-3700 and misfires badly.

When in neutral I get good spark at all 4 cylinders , I confess I havent had the courage to pull the plug lead off at 3,00+ revs..I think the plug leads maybe original, and perhaps 1991 is ages for a high tension lead to last, and its time for replacement. It maybe that this cures the problem, but I thought I might ask if anyone has any other ideas I can try before or after the lead change..thanks guys.



Oh, its had new plugs in the past couple of months , so although its possible that one of them is duff, I cant remember having a bad plug from new for years on other vehicles.

    

2Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Mon Oct 17, 2011 2:51 pm

charlie99

charlie99
VIP
VIP
certainly worth a try bandaid ....

if you have a multimeter you could check the lead resitances first ....about 5k per 1/2 meter of lead length ....

but i would be checking the coils as well 10-12k on the secondarys ...and about 2.4 ohms on the primaries ,,,,,

but im an electrics man so please forgive me if have stated the obvious ...

outside of that i would be looking at fuel delivery ...under load ...the delivery and presure that can be maintained is verry important ...things that might be worth concidering might be ...fuel filter ...as we have seen partially blocked filters before ...causing all sorts of issues

without load i would suspect that you wouldnt notice this effect as you rev ....it should still deliver enough fuel to do the job ...its just that under max load and torque these things are certainly put to the test ..


another thing that may contribute could be ignition timing ,

along this line of thinking would be to clean up the ecu under tank and the injection conrol under the seat .......

of corse rubber fractures in the fuel feed bits around the plenum , throttle bodies and vacume lines and crankcase breather could certainly affect mixtures with the flow being demanded worth a look, but it seems that you have a steady idle and every thing up untill that rev range
so i would be thinking the tb rubbers might have a crack ...topside of the throttle boddies ,,,,,just make sure the aircleaner to plenum is sealed well around that clip that is hard to get at to tighten on the plenum side

hope this helps

    

3Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Mon Oct 17, 2011 3:45 pm

bandaid

avatar
active member
active member
Thanks for that, I am one of those people who think that all electrics are the work of magic, so its pretty much guesswork for me.

I am, going to try everything you suggested in the morning, ....I shall report the huge success....I hope.

Very Happy

    

4Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Mon Oct 17, 2011 9:08 pm

RicK G

RicK G
admin
admin
What you describe certainly sounds electrical and plug leads especially. That is where I would be starting.


__________________________________________________
"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 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

5Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Mon Oct 17, 2011 9:13 pm

blaKey

avatar
Life time member
Life time member
Mine did exactly the same thing. Lucky for me it was just an unseated plug lead.

Hopefully yours is just as simple.


__________________________________________________
Neil
K100RS 1986 RED!

Dress for the ride and the potential slide.
    

6Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Tue Oct 18, 2011 10:36 am

bandaid

avatar
active member
active member
I tried the plugs, leads and the lt leads too, as suggested by the genius named Charlie99, and there was nothing I could find wrong with any of them, cos they all gave the readings I was told to expect.

Cant try the plugs, obviously, but I shall buy one more and swap them round til I do all four.

The worse news is that without touching any other part of the wiring, I got no speedo now.

Having said that, the ICU connection appeared loose as a loose thing, so I cleaned it up, push fitted it tight and cable tied the thing, when I get the tank and stuff done, I shall try again.

I found out that if I spill petrol on the cellulose painted tank, it takes the paint off.....which made me really angry, cos I just finished a 5 week repaint and it was looking lovely. ( well, lovely to me, cos its red and was Paramedic yellow.)

    

7Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Tue Oct 18, 2011 4:22 pm

charlie99

charlie99
VIP
VIP
there are three external likely places that the speedo plays up

junk (fine metal) can bridge the actuall speedo sensor ....in the bevel box , take the sensor out (4mm screw) and clean it up ....carefully goes there the seal around the sensor needs to be good

loom connector ....on the right hand side cover location , follow the cables along the swing arm area up to there ...many have found this connection ( 2pin )corroded ,,clean up required ...whilst there do the tank connection (fuel pump and level sender).

instrument connection ...multipole connector at the back of the instruments ....a little tricky but can be cleaned up with a cleaner on the pins projecting out of the instruments ...but dont forget to do the socket parts as well ..my advice, when doing this part is to remove battery power before starting ...as when the connector goes back on it is easy to get "one pin out" on the first attempt to seat it home

other wise its inside the guages ....there have been lots of threads on that repair throughout the forum ...with pics as well

good work on the icu connection

your probably aware that a lot of us aussies love the deoxIT product for cleaning electricals, it does an amazing job.



good luck !!


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

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

8Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Tue Oct 18, 2011 6:23 pm

bandaid

avatar
active member
active member
Thanks Charlie, I been there done that with the sensors and connections, and nothing is apparently amiss there, I decided to simply bypass the whole speedo situation and stick on a new digital aftermarket thing, which turned up today, and is now on, and working fine. I have to say that you need a pair of binoculars to see the rest of the stuff on the new unit, but thats OK, cos the only thing I needed was the speedo. Works with seriously strong magnets, and, of course magiic.



Still farting about with connections all over the place, I hate the Technicians who simply cut the Emergency Service equipment off without thought for the rest of humanity trying to sort stuff out. Thus far the ICU cleanup has been relatively simple, cleaned up the connections on the wiring with a specialist circuit board cleaner, and they are all shiny and lovely looking, the ICU connections I have been very carefully rubbing with teeny tiny slivers of wet and dry paper, should ave them clean by 2013. ( and thats not nearly 8:15.)

MAybe I shall get it going soon, if not I shall burn the bloody thing.

    

9Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Tue Oct 18, 2011 7:22 pm

beanoldboy

beanoldboy
Life time member
Life time member
bandaid,
hello mate, thought i would share a similar tale to try and alleviate some of your frustration with camaraderie .
I bought an 88 rt, ran like a watch, with the intermittent speedo being its only problem. so i dedicated a weekend to cleaning all the electrical contacts and now the bike runs rough as , couldn't ride it , it stalls at idle and smells fuelly . i have spent hours on it and hours staring at it with workshop manual and laptop(this forum).
On the plus , i have learned a lot about this bike (peculiar animal that it is) in a short time and now it is clean clean clean, under the air box and all behind the throttle bodies was grime but now its shine.
I have changed hoses and sensors and found an electrical fault in the headlight switch connector.
the bike is still in the shed in part disassembly, but i don't mind because i am not alone , there is so much knowledge and information available here and all are polite and helpful that i look forward to coming home and staring at a non running bike that i broke through trying to make it better.
in re reading this it probably isn't a motivational tale after all.
It seems trial by fire is the k100 way, we wouldnt be part of the fold if we didn't undress the thing and delve into its recesses on the odd occasion
have fun amigo
N.

http://www.airware.com.au
    

10Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Wed Oct 19, 2011 2:27 am

walfish

walfish
Life time member
Life time member
when checking these connectors many of us have simply ensured that the connectors are joined together ie. clipped in, but what is needed is connectivity, so the connection needs to be opened cleaned and then put back together, do it systematically, and check each as you go along, under the tank there are multi. wires onto an earth connector, remove and clean each connector, also clean the frame connection point.
Got the T shirt

    

11Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Wed Oct 19, 2011 3:35 am

charlie99

charlie99
VIP
VIP
yay good one ungaas and yes i agree ,,,to the novice things look fine till someone who has done it before looks as well ....



nice fix bandaid ...well kinda sorta..... gigles ....it dont matter mate as long as you happy not giving them boys in blue.. your hard earned cash


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

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

12Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Wed Oct 19, 2011 6:35 pm

bandaid

avatar
active member
active member
Worst thing is, I spent 28 years as a Paramedic and was a Parmedic Bike repsonse bloke for 6 of them, having said that, we used, ......dont shoot me, ......pans Europeans. They have the same ham fisted technicians taking the stuff off.

I did think I wouldnt ever buy another ex service BMW, but probably they are all the same.

Still trying guys, thanks for the hand holding, sort of.

    

13Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Wed Oct 19, 2011 7:11 pm

Toto_jp

avatar
Platinum member
Platinum member
Check vacuum may have split hose ( engine breather hose ) could be getting gut full off air then runs rich as computer tries to correct


__________________________________________________
K100 RS 1986
    

14Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Wed Oct 19, 2011 9:05 pm

RicK G

RicK G
admin
admin
@bandaid wrote:They have the same ham fisted technicians taking the stuff off.

They send the same technicians zoob out to Oz to take the gear of police bikes as well. Both the K100 and K1100 were ex police and both had been butchered taking the extras off.


__________________________________________________
"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 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

15Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Thu Oct 20, 2011 1:02 pm

bandaid

avatar
active member
active member
I spose its reasonably understandable, the techs DO take as much care of the bikes as possible, theres budget restraints to take into consideration, like Fleet Managers who dont ride bikes, so they dont understand that brake pads need chainging when they are still over the wear indicators, and tyres can be improved but they wont cos they cost more.

WHen the bikes go for sale, the techs just get told, " take the gear off" and you got like.....half a day to do 12 bikes or whatever, so the time is limited. However, it would be nice if they could cover the ends or put labels on the cables or something.

However, back to mine, I am now at the point of no return, for 6 hours today, I checked, cleaned, checked and where needed replaced with solder joints. I have checked vaccumm hoses, fuel pipes, fuel pump, filters and virtually everything else. I even checked the tyre pressures cos I have run out of everything else to check. So, over the next few days I shall be putting the bitch back together again then seeing how she runs. If she good, then I shall be trumpeting it from the highest point of this forum. If not, then I shall break it into teeny tiny pieces and then pee over it.

    

16Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Thu Oct 20, 2011 2:23 pm

bandaid

avatar
active member
active member
Oh and by the way, I found a company which will do a spring clean of the injectors for the bike at 15 quid each, inc vat. Simtek, never used them before, so I shall send off the items, and then, I'll give a shout some where on here if they are good, bad or indifferent.

    

17Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Thu Oct 20, 2011 7:01 pm

ReneZ

ReneZ
Life time member
Life time member
Mate, these are not difficult bikes to keep running good, just a bit different. Keep at it and we'll get her right!!


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

Rene


BMW K100 - 1985 (0030029) Misfire under load,  Rain
BMW K1200GT - 2003 (ZK01223)
    

18Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Fri Oct 21, 2011 9:06 am

bandaid

avatar
active member
active member
Well they must be OK , cos theres bloody dozens of them, but I think that its best to keep them right and not changed , cos thems a pain otherwise.

    

19Back to top Go down   Misfire under load,  Empty mystery missing Sun Oct 23, 2011 11:07 am

mikeeeee

avatar
active member
active member
back about 15 years ago i decided to pamper my bike with a set of NGK platinum spark plugs.

big mistake, internal impedence is way different than stock bosch plugs.

in a k-100 plugs fire twice and one pair of plugs fires up and the other set fires down.

ngk plugs would work fine in a k-75.

replaced plugs with stock oem bosch and miss went away.

BTW; BANDAID, soldering the wires to the connectors makes the joint brittle, keep a weather eye on the ones you soldered, been there done that.



Last edited by mikeeeee on Sun Oct 23, 2011 11:11 am; edited 1 time in total (Reason for editing : addendum)

    

20Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Mon Oct 24, 2011 6:47 pm

bandaid

avatar
active member
active member
Thanks Mikeeeeee, its difficult to know what to do for the best, I dont like multi connectors, or chop blocks or whatever they're called, and scotchlocks arent highly thought of, yet, soldered joints, with shrink wrap seem to be the preferred choice of the knowledgable..i.e. anyone but me,

I shall keep an eye on the joints, I have to say, the chances of me keeping this bike are remote, and if it dont go properly, then its going to be in bits for sale, ( I already threatened it with being burned, but it took no notice...)....I shall sneak up on it and take the bugger by surprise, see if that works.

    

21Back to top Go down   Misfire under load,  Empty Re: Misfire under load, Mon Oct 24, 2011 8:07 pm

mikeeeee

avatar
active member
active member
bandaid, have you unscrewed the brass idle screws and wiped the carbon crud off of them?

count the turns, unscrew, clean and replace to the same number of turns.

    

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

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