BMW K bikes (Bricks)

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1Back to top Go down    Throttle stop screw on Fri Mar 03, 2017 8:14 am

Puccini


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On the 85 K100, is the throttle stop screw on the end of the shaft from the butterflys also part of the idle adjustment?

Some people say it is and others say it shouldn't be used for that. Only the 4 adjusting screws on the throttle bodies should be used for idle adjustment.

If it is not supposed to be used for idle adjustment, what is the proper adjustment procedure for it?

    

2Back to top Go down    Re: Throttle stop screw on Fri Mar 03, 2017 8:35 am

RicK G

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On the 85 K100, is the throttle stop screw on the end of the shaft from the butterflys also part of the idle adjustment?
No that is an adjustment for the choke or fast idle. The throttle stop is between #2 & #3.

Only the 4 adjusting screws on the throttle bodies should be used for idle adjustment. That's correct.



If it is not supposed to be used for idle adjustment, what is the proper adjustment procedure for it?



To get the correct setting on the throttle bypass screws and the MAF bypass you need to open the MAF bypass so as to let heaps of air in then set the throttle bypass screws with vacuum gauges or mercury manometer once they are set and the idle is at 950rpm (the vacuum reading is not important but they should be all the same) you then screw the MAF bypass screw SLOWLY until the engine falters then out SLOWLY till it picks up (about 1/4 turn) that way the barn door flap opens as soon as the throttle is opened.
If you are getting #4 not playing the game then I would suspect the butterflys are not synchronized. There are many threads that say DON"T TOUCH THE BUTTERFLY SETTINGS, that was all very well when they were near new but wear and tear makes it necessary.
You need to have them off the bike and set the backstop screw so that a piece of magnetic audio tape can just be drawn through the opening then adjust the rest till the same and back off the backstop screw till it hits the stop when the butterflys are closed fully and leave the backstop there as it is NOT an idle adjustment.
Idle speed adjustment is done by opening or closing the throttle bypass screws.




Tip:- don't use the choke/fast idle as a stop/reference point to sync the butterflys ONLY use the throttle stop screw.


__________________________________________________
If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

3Back to top Go down    Re: Throttle stop screw on Fri Mar 03, 2017 8:38 am

RicK G

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The main purpose of the throttle stop is to have a stop so the butterflys are not actually being used for a stop and wearing out the bore of the body.


__________________________________________________
If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

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