The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: diggers on May 26, 2008, 04:33:00 PM
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I've not long had my 81 R65. I've notice at the traffic lights etc my idle spped is usually about 1750 or so. Sounds and feels a bit fast. Is this so? and how do I adjust it down a bit? I'm a first time bike owner and want to learn some basics, so please talk slowly, using words of only one or two syllables and if you must use long words, try adding an explicit picture! (I think I hear some newbie groans from across the Pacific!) Regards from New Zealand, Indy 500 winner! ;D
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There is an adjuster on each carb, looks like a 7 mm bolt.
If you look at the carb, and open the throttle, you will see a small arm contact this bolt, it is the idle adjustment.
Turning the bolt out will decrease the idle speed, turn both at the same time with the engine running.
Don't turn too much, because you can cause the synchronization of the carbs to be affected if you get this adjustment too far out.
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Cheers Bob! I'll let you know how I go. Hopefully good!
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Idle mixture screw may be out of adjustment, too. For 1981 R65, the Clymer manual states 3/4 turn open from a closed position - that's gently closed, to avoid damaging the seat - as a starting point.
Yes, 1700+ revs at idle is a bit much. Does the bike idle at this rpm all the time? Or just after it's warmed up?
A small adjustment should get your scooter calmed down. Good luck. Perhaps consider investing in a shop manual; they're a great cure for insomnia! [smiley=beer.gif]
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Lol about insomnia! I have a workshop manual, but thought I would do better with a plain english reply from someone in the know! Anyway, you must be the insomniac! It's 11am over here, must be insomniac country where you are! It seesm to be fast idle whether it's cold, hot or anywhere in between.
Cheers ;D
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... It seesm to be fast idle whether it's cold, hot or anywhere in between.
Try the idle screw adjustment first. That ought to calm her down. [smiley=thumbup.gif]
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Hi
Take your r65 out for a ride, appr. 30 miles, to get the engine warm.
Place it on the center stand to ensure that the carbs are horizontal.
Remove the plug from the right cylinder, but keep the plug in the cap and place it with a secure ground or frame connection (there is a hole in the cylinder beside the plug hole which can hold the plug) Be careful with the ground connection if you do not want the electronic ignition fried.
Start the engine, which now will run on the left cylinder only.
Slowly turn the airscrew (the bigger of the two screws at the bottom of the carb. in front of the floater housing) clockwise till you feel the stop.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2F+http%3A%2F%2Flh6.ggpht.com%2Fpetertrolle%2FSDv4KlQ0aPI%2FAAAAAAAAC5s%2FGn6R3LXFdOA%2Fs800%2Fright%2520carb%2520seen%2520from%2520bottom.jpg&hash=5eabd62d2fec97419efd80a3f04f8016487d9055) Not the right, but the left!
Slowly turn the airscrew counter clockwise and listen to the revs of the engine: At a certain point the revs will begin to rise and then fall.
When they fall, slowly turn the airscrew clockwise till the revs have reached maximum.
Your left cylinder is now OK with regard to the airscrew.
Repeat the procedure with the right cylinder.
When both airscrews are rightly adjusted and both plugs are in place, you can set the idle.
Turn the idlescrew on the left carb counter clockwise till it barely touches the little plate (place a piece of white paper behind the carb and be sure to have proper light in order to see the tiny space between the screw and the plate)
Do the same with the screw on the right carb.
Now adjust the slack on the throttle cables by turning the spindles so there is 2-3 mm between the spindle and the end of the cable sheath when you pull the sheath upwards. The lever on the carb must not move when you adjust the spindle or pull the sheath.
Start the engine. If it stalls immidiately after starting, turn both idle screws a ½ turn clockwise and try starting again. Repeat till the engine keeps on running after starting.
With the engine running, turn both idlescrews slowly in very small increments counter clockwise to the lowest amount of revs where the engine runs smoothly without stalling. A fluctuating idle is normally an indication of a slight unbalance between the cylinders, so try to make the idle as steady as possible.
If your carbs are in order, the plugs are clean with proper gaps and the valves are properly adjusted (0.20 mm on the exhaust and 0.1 mm on the intake) the engine should idle steady at around 800 rpm.
And! If at first you don't succeed, try and try again!
My wife find me obsessed but I am getting so good at adjusting the carbs, that I can adjust the engine by ear alone, which I just have had proof of. I bought a Twinmax carb adjuster to make the final synchro between the carbs and found that I had already reached optimum without the Twinmax. Never the less, the Twinmax is definitely faster to work with than the ear and gives you the last percent of perfection.
greetings from a sunny and warm north with excellent riding conditions
trolle
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Yo, Justin... FAQ this item from Trolle. It's golden [smiley=thumbsup.gif]
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Hey trolle, I've just seen your response. It's fantastic. I like the picture to help with the explanation! Thanks for taking the time to help out a newbie. Cheers! ;D