The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: erod1 on May 29, 2012, 03:41:48 PM
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My 86 R65 has a racing idle. If the bike is sitting for a few days it idles normal. When it warms up the idle starts to climb. It can go to 2500 rpm's. Is this a carb problem or could it need a valve adjustment ? The bike was sitting for about 10 years.
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It probably would be a good idea to check the valve clearance before doing any adjustments on the carbs .
Check the clamps on the rubber hoses between the carb and heads for tightness, or if they may be stripped .
If you do perform a carb adjustment, it needs to be done on an engine that is up to operating temperature, doing it on a 'cold' engine can cause the problem you are having now .
A sticking centrifugal advance mechanism in the ignition 'bean can' is also a possible problem .
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+1 with all of Bob's suggestions - and, definitely DO ensure that the valves are properly adjusted before trying to diagnose a possible carb issue - one can end up chasing "ghosts" otherwise.
One quick trick that *sometimes* works for diagnosing an air leak between the carbs and heads is to spray some carb cleaner or WD40 on the rubber hoses - if the idle suddenly changes and/or you see white smoke from the exhaust then there is definitely an air leak there. This doesn't always give good results, though, and doesn't rule out the possibility of issues elsewhere in the carb (or that the carb may have been adjusted with a not-warmed up engine last time).