choke on carb

[manxr65]

the last few day i've been using the bmw and ive not been using choke to start from cold , is it because the weather is hot or could the carb need cleaning out .
how do you remove the 4 studs to get into the choke

[Bob_Roller]

The warmer it gets, the less you need the 'choke', with the high overnight temperatures here in Phoenix this time of year, I don't use it for about 5 months out of the year .

All you need to do, is to remove the four countersunk screws that hold the cover on .

Good chance that there is corrosion on the threads, especially with you residing in a damp climate, with possible salty sea air as well .

[Barry]

Even in our modest summer with the temperatures we've been having recently you shouldn't need to use the choke during the daytime. I haven't used any on the way home from work for weeks now.

At 7.30 in the morning the engine will always catch without choke but may not keep running. Too much choke will flood it so what I do is apply full choke and give the starter button the lightest stab just to turn the engine over and pull up a little fuel through the starter jet. With choke fully off it will then start on the button every time.  Is this progress ! Give me an old fashioned tickler any time.

[GrimReaper]

I always have to use the choke even its too hot here in Vegas.As Barry said it catches but does not keep running.I use full choke for 10 seconds,then half for 10 more.
 All of my bikes had a choke(2 kawasakis and 3 BMW)and no one can start in the morning w/o it.
   On our Sunday morning BMW meeting i saw everybody use a choke after 2 hours at the local cafe.
  Bob what is the trick of not using the choke.The weather here is not so different from Phoenix

[Bob_Roller]

No real trick to it, just turn the fuel on, hit the starter, engine catches, increase throttle to about 1500 rpm for 10-15 seconds, then ride off .

I think I may have my idle mixture set to the rich side, that probably helps 'cold' starting .

[Barry]

I use full choke for 10 seconds,then half for 10 more.

I think there is a lot of variability in the amount of enrichment provided by the choke on different bikes. I believe Bing changed the number of holes in the disc over the years and maybe improved operation. I'd certainly love one that worked properly. As it is when I need to use full choke to start a cold engine it is instantly apparent that the mixture is way way too rich and the engine will not run on full choke for more than a few strokes. I have to get it off very fast by that I mean as fast as my hand can move from the clutch to the choke lever even in winter.  I have wondered whether making the starter jet size the same on R45s and R65's was something of a compromise on BMW/Bings part.

I used to have concerns about carbon build up on the spark plug base rings indicating a generally too rich running mixture but have since concluded from observation that the carbon build up is entirely the result of starting on full choke.

[Rob Valdez 79 R65]

I normally have to turn on full choke whatever time of year it is.  Then half choke after just 10 seconds or so, like SinCity.


Mr. Manx, if you do take your choke covers off, you will most likely need new gaskets for them.
Also, be aware that the choke disk can go in the hole "up-side down" (wrong side facing out), which will leave you wondering "Why won't my bike start?".
Take pictures as you take things apart, or at least make drawings with extensive notes.

Only work on one carb at a time, so you have the other to use for a reference, if needed.


While I have your attention, would you consider adding yourself to our Google Map?
http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1270420008

That would be very cool to have a pointer on the Isle of Man!!!