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Discussion Starter #1 (Edited)
I recently purchased a nice '91 K75s and really like it. Unfortunately, I laid it down two days ago and it now starts and runs rough. Some front fairing damage resulted from the accident but my speed was only about 5mph so there is no apparent damage other than a broken signal housing and scratches. It did lay on its side for about 10 minute before I picked it up. Upon trying to start it it seemed that the battery had died as it wouldn't turn over. After a few minutes it slowly turned over and started. Running rough and would barely idle, with some white smoke from the exhaust as it warmed back up.

Any thoughts on where I should start looking for the idle issue? Should I run it and see what happens? I'm afraid that there is some issue that I'm not familiar with that is going to bite me. Engine should be fine. Trying to narrow the search down to mechanical or electrical.
 

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You can expect some smoking after it lays on it's side. You should have waited at least 15 minutes before trying to start it. This lets the oil migrate back to the pan. First check the battery. If it's not an AGM you might have acid that escaped but it should be AGM unless the previous owner put a regular wet cell battery in. Check for good clean and tight connections at the battery and that it's secured properly. Next, make sure the throttle isn't in a partially bound state giving a false high idle. Move the handlebars from full stop to stop and make sure the throttle cable isn't getting pulled tight and there is plenty of slack. Then I'd ride it for at least 20 miles keeping an eye on everything. If it's still idling too high then adjust it down just a little at a time. I'm suspecting the throttle cable is giving you the higher than normal idle and that you might free it up by messing around with it and it goes back to normal, but it may not and require the adjustment. Not really much can happen in a minor fall like that so do some careful inspection of those cables before doing anything else with the idle.
 

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Remove the spark plugs---which is easy to do and turn the engine over and any excess oil that may have leaked into the combustion chamber should just 'spurt' out.

Run 1/2 can of Techron, available at auto parts stores, in a tank of gas and I bet the problem will clear up. Seafoam and Lucas work well too.

I've had 5 Beemer's but not a K75. They are a nice bike.

R series BMW's and 1500 Goldwings, if parked on the sidestand, especially when hot, would 'PUFF' out a little white smoke on startup, from oil leaking from the valve cover, seeping past the valve stem seals, past guides and into the cylinders/ combustion chambers. Perfectly normal per BMW and Goldwing service depts. I've had two 1500 GW's and one 1800. I don't remember the 2012 GW smoking after being left on the sidestand.

Sam:)
 

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Discussion Starter #5
Thanks Folks, Quick update. Bike starts and runs rough, smokes after heating up. White smoke, no oil smell.
It appears that the front cylinder isn't firing. Both other plugs look normal, front plug is black and much cooler. I'm currently looking into ignition problems. Any thoughts will be appreciated.
 

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Just changing the plug might solve the problem. I'd try that before tearing into it deeper.
 

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Discussion Starter #7
Wellllll...... I changed the plugs, and charged the battery a bit. It started right up and after a few minutes of smoking it's back to running well. I'll sleep better tonight! Hogcowboy, I don't know what was up with that plug but your advice was perfect. Thank you all for the suggestions.
 

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Glad to hear you are back in the saddle
 

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