The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: he235 on May 10, 2012, 04:20:42 PM
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Hello all
Having just bought an R65ls I introduced myself in the general section and was directed to post my questions here.
I am having a few issues with the engine
It will not idle until fully warmed up one of the chokes is not connected but I have been assured this is normal even when in fine fettle.
It does not seem to like revving past 4000 rpm, it seems to reach 4000 then stop accelerating. the only way to get past this is to back off the revs and increase them very slowly with gentle throttle input.
There also appears to be a leak in a gasket or valve on the left cylinder. I am not sure which as air escapes out of the top between the cylinder and head/rocker cover making a slight hissing sound. there is also a very fine deposit of oil around this area.
I'll try and get some videos up tomorrow to show the issues.
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With one of the 'chokes' disconnected, chances are good it's not going to runcorrectly until the engine is up to operating temperature .
You need to check to see that the choke is fully closed .
Your high rpm issue could be a tear or hole in one of the carb diaphragms .
There are three fasteners holding the rocker arm cover on, two 10 mm nuts that are in the cooling fin area of the head .
The other is a 13 mm nut in the center of the rocker cover .
It is a problem area, it gets tightened up too much and the threads pull out of the cylinder head and the threaded stud gets loose .
My guess is that the stud is not doing it's job, that's why you have an air leak in the area of the gasket between the rocker cover and head .
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If the carbs and engine are properly adjusted and operating normally - with both chokes operational - the engine should warm up with the choke on the 1/2 position (there is a detent/stop position there) for about the first mile of riding, and then you should be fine to ease the choke off. Full choke for starting on cold engine conditions is normal for cooler (below 20C) temps for the first 20-30 seconds. IF it is very warm out (80F and above), even with a cold engine, I can sometimes start her up with only 1/2 choke but generally still try to do it with full choke and quickly switch down to 1/2 to avoid carboning things up..
+1 with Bob's comments - either one or both carb diaphragms have holes in them, or they aren't fitted properly in place and air is leaking past them. This will cause an extreme unwillingness to rev past 4K.