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Old 05-17-2010, 11:47 AM   #1
squirrelscoundrel OP
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Joined: Apr 2009
Location: Fabulous Rhode Island
Oddometer: 45
Airhead sounds like a jiffy pop

My r75/6 sounds like a jiffy pop when it is warmed up and revved higher than 5,000 RPM or it is sitting in traffic and hot at lower RPM. There is a pop pop pop pop coming from the Left Cylinder or the Left Carb (I think that it is the carb) There was originally a leak between the L tube and the carb which I fixed. Before I fixed it, Every time it would pop, there would be air coming out of the leak in the coupling. The bike rode fine for about 50 miles after the fix and then began to pop again on the highway. The seal (duct tape) is still good, but it is still popping and is barely capable of highway speeds because when she starts popping, the power declines considerably. Does anyone know what coulc be causing this? Too much gas? not enough gas? Too much air? not enough air? How can I fix this? Thanks a lot for your Help. As always, it is appreciated.

Doug
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Old 05-17-2010, 02:27 PM   #2
caponerd
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Maybe a badly leaking intake valve?

Run a compression test. If it's low, squirt some oil in the sparkplug hole and try again. If it's still low, you got a bad valve.
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Old 05-18-2010, 07:39 AM   #3
bmwblake
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make sure the metal piece that screws into the head where the rubber between the carb and the head meet is tight. you'll have to remove the carb and the intake rubber to access it.

number 4 in the image below.

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Old 05-18-2010, 11:33 AM   #4
squirrelscoundrel OP
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Thanks for the advice. I appreciate it.
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Old 05-21-2010, 09:03 PM   #5
evildonald
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You are likely using the wrong brand of duct tape!
But seriously, it sounds like an intake valve too tight to me.


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Old 05-22-2010, 04:04 AM   #6
Cigars&Scotch
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On BMW's, You must use metric duct tape. That is the only kind that works.





Cover the ends of the exhaust while running and check for leaks in the exhaust system.
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