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Old 18 Jan 2012
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F800GS .. bad fuel warning .. don't let one tank of bad fuel end your trip

don't let one tank of bad fuel end your trip

a bit of warning on F800GS ... since it's not equipped with knock sensors. there is nothing except operator to stop engine from destroying itself from detonation.

In the unlikely event you get a bad load of fuel. say a home reseller, accidentally mixes kerosene with gas? this warning apply even after a remap allowing use of 91 octane (ron)

detonation can destroy your engine in short order. especially if one has ear plugs and full helmet on. And most importantly not knowing to listen for engine knocks. Don't keep on riding after getting a load of bad fuel.

if after a refuel, engine starts to run abnormal ... significant loss of power ... STOP! don't keep on riding. take your helmet/ear plugs off and listen to engine carefully. LIGHTLY apply throttle and listen for engine detonation (knocks) a tiny bit of detonation like applying throttle in too high a gear will not hurt your motor.

should be simple to fix ...drain bad fuel ... put in good gas and be on your way. vs keep on riding and destroy your engine. IHMO BMW should have never designed a 12:1 compression GS bike without knock sensors.

have tried my best to write this warning without going into technical mumbo jumbo.
here's a few links for those that need more details.





R90S, R80G/S PD

Last edited by _CY_; 19 Jan 2012 at 15:19.
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Old 19 Jan 2012
Mike.C's Avatar
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The F650twin does not have a knock sensor.
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Old 4 Feb 2012
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Maybe fitting a det counter as used on two strokes would be a solution? They're cheap enough and doesn't involve much more than access to the spark plugs...
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Old 4 Feb 2012
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Not meaning to sound thick (although potentially succeeding!), what would this involve / how would it work? I own an F800 and this sounds interesting.
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Old 4 Feb 2012
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Originally Posted by Endurodude View Post
Not meaning to sound thick (although potentially succeeding!), what would this involve / how would it work? I own an F800 and this sounds interesting.
really not that complicated... sure it'd be nice to add a gizmo to count number of detonations.
main objective is to first know about possible problem and how to handle it. do a search, Lots of folks has destroyed their F800 engines in remote locations. what's missing is ... why?

BMW is not exactly sending out notices to warn folks how to keep from destroying their engine from the unlikely event you should get a load of bad fuel. (diesel mixed with gas?).

all you have to know is .... if your engine start running funny and losing power immediately after a refuel .... STOP!!! don't ride on!!

take your helmet/ear plugs out... lightly apply throttle... if you hear engine knocking.... drain bad fuel out, put new fuel in... let engine idle contaminated fuel until gone. hopefully cost little to nothing to fix.

when you can apply full throttle without engine knocking again... you are good to go.

ride on with engine knocking = destroyed engine = $2,500+ to fix
R90S, R80G/S PD
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