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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: 1986 k75s on August 17, 2012, 01:57:21 PM
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So recently i brought an old 86 bmw k75 decided to change the air filter fuel hoses and oil in the engine gearbox and dif and change the plugs . Having done all this the bike has now developed jerky low throttle control and a misfire with actual flames coming from the exhaust in a loud explosion . When i changed the fuel pipes i noticed that one of the pipes the one which travels around the rear intakes and between the airfilter housing has a slight bend as it meets the tank . The fuel pipe i replaced it with had no such bend and i noticed that when pushing the tank back on there seemed some resistance from side of the fuel pipes . I was wondering if the fuel is perhaps getting squashed flat by the tank or bent to the point of starving the engine of fuel ? Is this is what causing the poor throttle response ?
I also as said changed the air filter i noticed on the filter there is an arrow with the wording TOP OBEN i presumed this meant that the arrow should be facing upwards is this correct ? I managed to just undo the clips slide the old filter out in cassette fashion and slide the new back in then reclip the housing is this ok ?
I changed the plugs they were black and sooty and for a brief moment the bike actually ran with some extra vigour however it has now returned to being sluggish and sometimes dies out on heavy throttling would i be right to presume the plugs have just sooted up like the originals ? Obviously this is a too rich fuel mix how do i correct this ?
On top of this i noticed while riding at night that the fairing and housing for the front light moves with such distance other motorists think im flashing them it really seems very loose how is this tightened ?
The engine has done 32,000 miles have all old Mot s so im guessing its genuine ?
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Arrow shows air flow direction.
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The K75S has a plastic main fairing bracket. Its possible that is cracked/broken. (Drop me a line if you need a good one.)
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Arrow shows air flow direction.
Which is, "up". :bmwsmile
Tom
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Well black sooty plugs indicate your running rich so the fuel is plenty enough.
The temp sensor could cause rich running as the ECU never thinks the engine
is warm so always dumps in too much gas (petrol). That's the best guess.
Not enough air would do it too but you put in a new filter (and they just never
get that bad anyway). Everything else would cause lean I guess. So check/change
that temp sensor!
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Arrow shows air flow direction.
Which is, "up". :bmwsmile
Tom
This time. :giggles