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96 R850R Bogging Down

apalm_r850r

New member
A few weeks ago, my bike had started behaving strangely, especially while warming up. It would randomly seem to almost lose power for just a moment, but otherwise ran and idled perfectly. Just recently, I had a little mishap in the rain and dropped it (nothing major, just a scuff on the valve cover), but now whenever I try to give the bike anything more than about 1/2 throttle, it bogs down completely and sometimes stalls. Since then, I've replaced the fuel filter, fuel lines, spark plugs (Autolites), and fuel pressure regulator; on top of cleaning the BBS passages, re-torquing head bolts, doing a valve adjustment, and a throttle body sync, with no change whatsoever. Its a 1996 with only 27,500 miles. Any ideas or suggestions greatly appreciated!
 
Did you check the throttle cables, especially the right side, to make sure that the cable ends are seated fully in the adjusters?
 
Be dead sure that there is no chance of shorting - you risk damaging your motronic.

Properly rewired they look like this and are good for life of the bike.
 

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My advice, send it to GS. I got a rebuilt unit from him and couldn't be happier. It also helped with the trade value of the bike.
 
No change

Finally got to put my sensor in, bike still has the exact same problem. Operating under the assumption that the sensor is functioning properly, what else could it be?
 
Bad gas? Drain the tank completely & refill with known good stuff.
Plugged gas tank vent hose or nipple? Mis-connected venting lines?
Still have the charcoal canister? Maybe it got wet in the tip-over and is now NFG (AKA non-functional gear); nuke it with extreme prejudice.
 
Bad gas? Drain the tank completely & refill with known good stuff.
Plugged gas tank vent hose or nipple? Mis-connected venting lines?
Still have the charcoal canister? Maybe it got wet in the tip-over and is now NFG (AKA non-functional gear); nuke it with extreme prejudice.

I went ahead and replaced the breather lines in the gas tank (the old ones were yellow and dry) and connected them according to the BMW diagram. The charcoal canister was deleted by the previous owner, is there anything I should check related to the delete (vacuum leak maybe)? At this point I'm just about convinced that the issue is probably electrical/ignition based.
 
I went ahead and replaced the breather lines in the gas tank (the old ones were yellow and dry) and connected them according to the BMW diagram. The charcoal canister was deleted by the previous owner, is there anything I should check related to the delete (vacuum leak maybe)? At this point I'm just about convinced that the issue is probably electrical/ignition based.

Just make sure the stubs take-off ports on the bottoms of both throttle bodies are sealed with good vacuum caps.
 
Just make sure the stubs take-off ports on the bottoms of both throttle bodies are sealed with good vacuum caps.

Both throttle bodies are capped off. I just performed a spark test, both sides have a nice blue spark. My last assumption is low compression and that I may have damaged the engine, don't have a tester on had to check though.
 
I had also noticed that both plugs were almost completely black already, and the exhaust has a strange, almost sweet smell to it
 
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