The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: DadsR65 on April 15, 2023, 06:07:01 AM
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It's been a while since I've been here, but I'm getting my 1980 R65 back on the road after a couple year hiatus. Carbs cleaned and rebuilt, valves checked, all new fluids, new electronic ignition from EME, set timing.
The bing manual says my idle mixture screw setting should be 0.5 turns out. I'm finding that the motor runs much stronger at ~1.5 turns out. It also seems that it doesn't like running on the choke, so I'm wondering if 1.5 turns makes idle too rich? (Both chokes are clean and assembled correctly, I've checked twice.)
It rides great. Good power over the entire range with no stumbles. It's just that cold idle is finicky.
Thanks in advance for any guidance.
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My '81 R65 needs the 'choke' to start when cold, I set the carbs about 9 years ago .
My '82 LS, which I purchased 4 years ago, needs no 'choke' to start, I have not done anything to the carb settings since I got it .
If it starts and runs good and the plugs look good, I wouldn't do anything to it .
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The bing manual says my idle mixture screw setting should be 0.5 turns out. I'm finding that the motor runs much stronger at ~1.5 turns out. It also seems that it doesn't like running on the choke, so I'm wondering if 1.5 turns makes idle too rich? (Both chokes are clean and assembled correctly, I've checked twice.)
0.5 turns out is the correct base setting. 1.5 turns would normally be grossly rich and suggests to me that there is something else wrong. The idle circuit flows a pre-mix of fuel and air. I would look at the pre-mix air inlet jet on the face of the carb and blow that through. There are two air inlets, one for the needle jet and one for the idle jet which is the smaller of the two.
If that isn't the issue, the only time I've had to use as much as 1/4 turn difference from the base setting is when the float levels were out so that's the another thing to check.
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The bing manual says my idle mixture screw setting should be 0.5 turns out. I'm finding that the motor runs much stronger at ~1.5 turns out. It also seems that it doesn't like running on the choke, so I'm wondering if 1.5 turns makes idle too rich? (Both chokes are clean and assembled correctly, I've checked twice.)
0.5 turns out is the correct base setting. 1.5 turns would normally be grossly rich and suggests to me that there is something else wrong. The idle circuit flows a pre-mix of fuel and air. I would look at the pre-mix air inlet jet on the face of the carb and blow that through. There are two air inlets, one for the needle jet and one for the idle jet which is the smaller of the two.
If that isn't the issue, the only time I've had to use as much as 1/4 turn difference from the base setting is when the float levels were out so that's the another thing to check.
Good input, thanks.
When I rebuilt the carbs a few weeks ago, the bodies spent a couple days in Pine-sol, then got rinsed and all orifices dried with compressed air. I also just rechecked float levels. Fuel starts/stops right when floats are parallel to carb body (floats are only a few years old). I'll take a look at the pre-mix inlet, regardless.