The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: BooG on January 14, 2010, 04:51:02 PM
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I tested the compression today with a good gauge, and had 130psi on each side, with no change once I did a wet test with a squirt of oil into each cylinder. The spark seems fine: blue and healthy. The plugs do not appear wet after cranking however. I have cleaned both carbs, all possible passageways have been carb cleaned. As I cranked the bike I could feel the air being pulled into the carbs (I had the inlet pipes off). A squirt of carb cleaner gave me a cough at the cylinder, but no bite.
Are carbs liable to fail like this? Is ultrasonic cleaning the only way to go?
I can't believe I haven't got to the bottom of this yet!! >:(
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Timing?
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I've set up the static timing as best as I can.
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I haven't re-read your other thread, Boog, but have you emailed the Bing Agency?
Anyone nearby that might loan you there Bings as a test mule?
Stumped? Me, too. Monte
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I posted this on Boxerworks, lets see what kind of response is posted .
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sounds like timing.
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Fuel flow from tank?
Fuel in bowls?
Pickup tubes (bowl) clear?
Bowl/float, jets/needles and orifices clear?
Choke assemblies correct?
Unless I'm missing something it sounds like you're not getting fuel to the combustion chamber.
http://s428.photobucket.com/albums/qq8/gruntyman66/81%20R650%20Restoration/Bing%20Carb%20Left/
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Thanks for the posting onto the Boxerworks site! This seems to confirm that it is probably a carb prob as I do get a bite or two when I squirt carb cleaner into the carb, (yes, it did backfire on me!).
I will also check the timing whilst cranking the engine over.
Thanks for the carb re-build photos Mike! Thats the next job with a full ultrasonic clean.
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An Ultrasonic cleaning may not be necessary unless you have access to one. I've had good results with a 50-50 solution of Simple Green and Water. Or carb cleaner (dip) from your local parts store. If you use carb cleaner read the directions and take the recommended cautions and be aware the cleaner may destroy your throttle shaft o-rings. Best to do the job completely if you're going to the trouble. The shaft o-ring replacement isn't all that difficult with care and a rotary tool. You'll need to order the shaft butterfly screws and some blue Locktite. If you choose to use Simple Green, don't leave the carb parts soaking for too long - it will discolor the aluminum. Thirty minutes in Simple Green with maybe multiple baths if needed should be good. Have an air compressor on hand to blow everything dry after a fresh water bath and I like to use a few copper strands of wire to clear ALL the holes in the carb body and parts. Be thorough and methodical. Take notes and draw sketches. The Bing manual is worth it's price. There's many more useful tips if you decide to completely rebuild the carbs with plenty of experience here on the forum. Lots of us have performed this task with success and the personal experience is always valuable if you're not comfortable with the task.
Are you getting fuel to your float bowls?
If not, check that your float needle isn't sticking in the seat.
Probably a good idea to check the simple things first...process of elimination.