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1Back to top Go down   Help, engine running on 2 cylinders Empty Help, engine running on 2 cylinders Fri Aug 01, 2014 8:02 pm

Crazy Frog

Crazy Frog
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For the last 2 years, I have a funny problem with the 1985 RT-sidecarL.

The bike is running well and suddenly, it starts to run on 2 cylinders. On idle it's running almost perfectly but if I open the throttle it sputters.
If I stop the bike and restart the engine, same problem. If I stop the engine for at least 2 minutes, it will run perfectly again for sometimes up to 2,000kms.

What could be the problem? Not the Hall sensors, because they don't have time to cool down within 2 minutes.
Ignition or FI....
Anybody experienced the same problem?

CF


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Help, engine running on 2 cylinders Frog15Help, engine running on 2 cylinders Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

92KK 84WW Olaf

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If you let it cool down to cold and then restart the bike. Feel which exhausts are cold. Each coil runs two cylinders 1/4 and 2/3. Sounds very possible its a coil issue. Once you find which two are cutting out you can swap the coils. If the non running cylinders change then a new coils likely. If it stays same check the electrical connections into the coil and also the plug leads. If you have a spare bike or a friendly K owner you could swap them.


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

RicK G

RicK G
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I can't say that I have had similar problems but as soon as I read the post I thought fuel and a partial blockage.
Reason is that many years ago my father and I and a friend of dads used to go fishing in a boat that the friend had built himself. For ages the engine would just splutter and then come good or occasionally stop. Dad got him to pull the top off the carby and sure enough no fuel but as soon as he tried to start it ,it would pump fuel up and away we'd go.
It ended up after months of frustration to be a large Gum nut (seed nut from a eucalyptus tree) rolling around in a flat bottom tank and every so often would get sucked over the inlet tube and stop the fuel but  of course when the engine stopped so did the suction and the nut would drop off the tube and the pump would fill the carby and away we'd go, sometimes for the rest of the weekend and sometimes for only 10 minutes.
I have heard of a flap of rubber from the inside of a fuel line doing similar things but at a far more regular rate.
Idling OK means to me that a very small quantity of fuel is always getting through and that stopping the engine removes the blockage until the right set of circumstances arise and it happens again like maybe when there is a high demand on fuel.
I think you have a second tank in the sidecar do you draw fuel directly from that or pump up to the regular tank and always use fuel from there. Just looking at places a problem could be as you have more than usual.


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

Crazy Frog

Crazy Frog
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92KK K100LT 193214 wrote:If you let it cool down to cold and then restart the bike. Feel which exhausts are cold. Each coil runs two cylinders 1/4 and 2/3. Sounds very possible its a coil issue. Once you find which two are cutting out you can swap the coils. If the non running cylinders change then a new coils likely. If it stays same check the electrical connections into the coil and also the plug leads. If you have a spare bike or a friendly K owner you could swap them.
The bike restarts perfectly within 2 to 5 minutes. It's almost impossible to check anything as without moving the bike or turning the handle bar it starts to work again. The time lapse between the failure and the bike running is so short that you don't have any time to do any testing.
Within 2 minutes, the exhaust don't cool down and this is why I don't know where to start.
If it was a bad connection, it wouldn't fix itself.


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Help, engine running on 2 cylinders Frog15Help, engine running on 2 cylinders Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

92KK 84WW Olaf

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If you could swap one coil with another one and see does the problem show itself again.you can try one coil and then another. It sounds like a coil problem.


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

Crazy Frog

Crazy Frog
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@RicK G wrote:I have heard of a flap of rubber from the inside of a fuel line doing similar things but at a far more regular rate.
Idling OK means to me that a very small quantity of fuel is always getting through and that stopping the engine removes the blockage until the right set of circumstances arise and it happens again like maybe when there is a high demand on fuel.
I think you have a second tank in the sidecar do you draw fuel directly from that or pump up to the regular tank and always use fuel from there. Just looking at places a problem could be as you have more than usual.
Thanks Rick.

Today, the first thing that I did was to open the tank's gas cap to be sure that the tank was not in depression or sucking mode (This can happen when the air vent is plugged).
I am now thinking that the Pressure Relieve Valve may have a problem. With the sidecar attached to the right of the bike, this is a big job to access it.
The auxiliary tank on the sidecar is just to refill the bike's tank.


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Help, engine running on 2 cylinders Frog15Help, engine running on 2 cylinders Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

Crazy Frog

Crazy Frog
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92KK K100LT 193214 wrote:If you could swap one coil with another one and see does the problem show itself again.you can try one coil and then another. It sounds like a coil problem.
This is easy as I have spare coils  Very Happy . This is not a bad idea as I have to start troubleshooting somewhere.


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Help, engine running on 2 cylinders Frog15Help, engine running on 2 cylinders Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

Be made

Be made
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Check the HT leads, they go when cold, not when hot if faulty

    

charlie99

charlie99
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could be leads ....was my first thought ....with the added load of acceleration - revs ...snuffing out the spark ?
I had a similar experience a while ago ....bike felt off tune or at times would load back to 2 cylinders ... till I bumped one of the high tension leads back into the tower on a ride with twb out to drake for lunch (to meet rick ) ....was a while ago now ...I guess the really bumpy roads out there just wiggled the lead out a bit more so it became a more permanently noticeable fault .


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'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OHelp, engine running on 2 cylinders 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 ..
    

ReneZ

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All good tips. I don't hink it'll be the FPR, as that would affect all units equally.

With a lead problem I wouldn't expect two units to fail, but what do I know :-)

I would try to identify which cylinders fail (water spray on exhaust or even better a laser thermometer?? but meantime have a good look at the wiring/connectors under the coils (the 'input' side of them) It might be that one is wonkey and therefore not always have that coil working correctly, which would affect two units at the same time.


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

Rene


BMW K100 - 1985 (0030029) Help, engine running on 2 cylinders Rain
BMW K1200GT - 2003 (ZK01223)
    

11Back to top Go down   Help, engine running on 2 cylinders Empty Re: Help, engine running on 2 cylinders Sat Aug 02, 2014 11:59 am

japuentes

japuentes
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Hi, I think that the most probable culprit would be a coil, go for the swap.
Best regards
JAP


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Help, engine running on 2 cylinders 2854237993 1988 K100RS SE/ABS
    

Inge K.

Inge K.
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If the coil, HT lead swap don't give succes......it could be a idea to check the
hall sensor connector under the tank, the rubber cap that should protect it is
usually rotted away after just a few years.


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

Be made

Be made
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@charlie99 wrote:... till I bumped one of the high tension leads back into the tower on a ride ....was a while ago now ...I guess the really bumpy roads out there just wiggled the lead out a bit more so it became a more permanently noticeable fault .
I had this too, one of the leads just "fell" out, bike began running on 3 , thought it had thrown a plug, limped to the nearest cycle shop, replaced the plugs, no, change . checked where they plug in to the coil and there it was, just hanging there. Another time I replaced the leads due to intermittent misfiring on 2 of the four cylinders. Basic trouble shoot says fuel, plugs, leads, then off in to deeper territory

    

sidecar paul

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Bert,
A quick way to check if the pump is supplying pressure to the fuel rail is to squeeze the fuel line at the input of the fuel rail while pressing the starter button. You can feel the pressure build up in the line.
Just a thought.
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!
    

Crazy Frog

Crazy Frog
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@sidecar paul wrote:Bert,
A quick way to check if the pump is supplying pressure to the fuel rail is to squeeze the fuel line at the input of the fuel rail while pressing the starter button. You can feel the pressure build up in the line.
Just a thought.
Paul.
Thanks Paul, that's a good tip. I was also checking if the fuel was returning to the tank to be sure that the pump was working.


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Help, engine running on 2 cylinders Frog15Help, engine running on 2 cylinders Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

sidecar paul

sidecar paul
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I've just had another idea, could the problem be caused by cavitation at the fuel pump?

Later pumps had an 'anti-cavitation' vent tube fitted to the pump filter, so that implies that earlier pumps could be affected. I suppose that after a couple of minutes standing, the air bubble would disperse and things would revert to normal running.

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!
    

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