The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: shelhead210 on September 02, 2010, 06:46:47 PM
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My R65 stalls at stop signs and quick stops when cold. I can put it in nuetral, start it, and shack back and forth and it will die. This only happens cold. Carb float problems? Any help would be greatly appreciated.
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What year bike do you have, as the 'choke' or enrichening cables changed with the '81 model year bikes .
How much, and how long do you use the 'choke' on a cold engine ?
Without any other information, my first guesses would be the possibility of the 'choke' cables not being adjusted correctly, other possibility is the small part that is screwed to the carb body, where the 'choke' cables attach to, may have a deteriorated paper gasket .
There's also an o-ring on the shaft that the 'choke' cables attaches to .
With the average age of these bikes, rubber o-rings and gaskets are due for replacement .
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It could also be a float /float needle issue. If fuel level in the bowl is either much too high, or much too low, the sloshing fore and aft of the fuel can either temporarily flood the engine or cause it to suck air. The could exacerbate a less than well adjusted situation with the air/fuel mixture or with partially blocked enricher jet.
On ANY carbureted bike, one can stop fast and watch the RPMs drop and then recover, due to the sloshing of the fuel in the carbs, but if things aren't set within reason, the bike can stall before it recovers.
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I'm with the sloshing fuel-float adjustment opinions on this performance issue. Saw this question posted on the Airhead's Forum today prior to checking in here.
Monte
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Whats it ticking over at when its warmed up???
Lou
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If it only happens when it's cold I wouldn't worry about it. I think it's normal to use the throttle to keep a bike from dying at a stop, if you don't still have the choke on. One of the joys of air cooled motors. I wonder how many of us do things like that (hand on the throttle) without noticing it any more.
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Thanks for the responses. It's an 84' with 24k miles. I'll start it up on full choke, let her idle for 20 seconds (summer weather), drive 1/4 mile to a stop sign and then it wants to stall. I adjust the throttle to keep it going, take off from the stop sign, switch to 1/2 choke, drive 1/4 mile to the next stop sign, same problem. After that it is fine, depending on how cold it is. I have the idle set at about 1100 RPMs. I'm suspecting the air/fuel mixture. I do have the manual which explains how to adjust it, but I don't think it is very well worded. It wasn't always this way, but I am getting used to it. Maybe it's time to adjust the valves and resync the carbs. Riding season is over now.
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Riding season is over now.
Riding season is just really getting started here in the low deserts of south central Aridzona !!!!!!!!!!! [smiley=happy.gif]
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I'm with Ed Miller. I think this is normal behaviour for many airheads.
The enricher is a relatively crude device and I'm not sure its meant to provide a stable tickover only to start the bike. They do seem to vary between different bikes though over the years. Some ride on the choke for a while as you have described and and some shut the choke off after 20 secs and then ride off.
Mine will not tickover at the correct speed for at least a couple of miles with the choke off. If it did I would suspect the idle mixture was set too rich.
The idle mixture should be set when the engine is fully warmed up so it's reasonable to expect it to be too weak for a normal speed tickover for several miles.
I compensate with the throttle and call it character.
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I start my bike on full choke (first start of the day only) then go straight to 1/2 choke for the 30 yard ride to the corner, then turn the choke off. Maybe you could try using your 'choke' less?
I also don't expect my bike to idle for long when cold, but I set my idle speed at only about 800rpm, not the 1100rpm often quoted here as normal.