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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Westone on May 03, 2013, 05:49:11 PM

Title: Choke operation
Post by: Westone on May 03, 2013, 05:49:11 PM
Hi,
The choke on my '88 K75 seems to have 3 positions: off, midway, full on. In the midway position it stays put until I move it. in the full on position it won't stay put, it will slowly gravitate to the midway position. Is this by design or does it need adjusting? Or better yet, maybe it needs fixing. I been looking for a reason to get my hammer out.
Title: Re: Choke operation
Post by: Scott_ on May 03, 2013, 06:07:50 PM
Sounds perfectly normal.
It is actually a throttle advance, NO choke baffles.

Full on, does not stay put. It's only designed to be used when cold starting. Then release to midway(where it stays put) to allow it to warm up. Then off when it's warm.
Title: Re: Choke operation
Post by: TimTyler on May 03, 2013, 06:16:30 PM
It should stay in each of the three positions.

Pop the cap off, unscrew and remove the switch lever, and clean and lube the guts. Your cable might need replacing too.
Title: Re: Choke operation
Post by: rbm on May 03, 2013, 09:52:19 PM
Under the fast idle control lever is a semi-circular detent plate. There is a sprung bearing in the control lever that engages holes drilled in the plate, which in turn retains the position of the lever. I have owned two K-bikes and each has a different detent plate.  One plate has two holes and the other has only one.  The former provides three positions for the control -- off - mid - full.  The latter only provides two positions -- off - mid.  I can try to set the full position with the lever however the setting will not be retained and the lever always returns to mid position.  I find this frustrating.  I much prefer the three position detent plate.

To be certain, remove the fast idle lever and examine the detent plate underneath.
Title: Re: Choke operation
Post by: TimTyler on May 03, 2013, 10:06:36 PM
...  One plate has two holes and the other has only one...

OK. Didn't know that! Makes sense now.
Title: Re: Choke operation
Post by: Lawrence on May 04, 2013, 11:08:58 AM
My 1985 K100RS lever holds only in the second position.  However, that has never been anything I've found troubling.  If it's really cold when I fire her up I simply hold the lever at the end of its rotation until she fires up, then I allow the lever to move to the second position for a short time.  As noted, it's not a choke at all, but just a means of holding the throttle plates open slightly.  Once underway, it has no bearing on how the engine runs as far as I can tell.