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Choke (on carburetted 1300) 2 months 2 weeks ago #32643

  • scotch
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Hard starts can be a result of something as simple as the fast idle roller not completing it's travel down the back-side of the fast-idle cam. (the "Steep-Slope")  It's imperative that the roller is not in contact with the cam when the Choke is FULL ON.  This ensures the throttle-plates are closed to the idle position.  This is essential in keeping the vacuum at the throttle-plates as high as possible so the idle circuits can "come on line" quickly.  Additionally; the choke-air restrictor has been very effective in getting the engine to start quickly by increasing the vacuum in the choke system.  Choke-fuel draw is almost immediate.   However:  
There have been comments about having to play with the choke lever once the engine fires-up. "Choke Jockeying".  I agree !   If nothing else it's just annoying ! 
I have found a cure which eliminates the "jockeying".
The "fix" is easy !  It starts with 3 socket-heads that replace the Philips screw that's use to secure the Choke Plunger lifters.

 

 

It requires a point similar to the OEM screw.  Easily done in a drill-press with a file.

 

With a jamb-nut, the new screw replaces the OEM Philips

 

Turn in the new bolt until is stops in the "V" of the choke-rod,  then back it off about 2 turns.  This was an arbitrary setting that I found I didn't have to screw around with  There will be a need to make minor adjustments to these screws in order to Sync the lifters.  Something that could not be done previously.   Secure the bolt with the nut.  NOTE:  This new bolt does NOT secure nor is intended to secure the lifter to the choke-rod. The lifter now "Floats" on the choke rod and does so without any issues !  Now,  The plungers lift later with choke application and close sooner as the choke is reduced.  The delayed lifting of the choke plungers does not have an adverse effect on the fuel or air availability within the choke system. It merely changes the ratio of choke fuel/air relative to the position of the fast-idle roller and cam, along the primary (long) slope of the cam.    
 Each morning for five days I tested this modification with a cold start.  The engines starts immediately as expected but the dramatic affect is a choke application (actually the reduction of) that is linear and predictable with an appreciable stability in the RPM's.
  No more "jockeying" ! 
1980 KZ 1300 sr# KZT30A-009997
Always High - Know Fear !
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