warm idle at 1300 rpm. The bike moves and it's smooth, what should I do?

[cy7878]

I know from my searches that the warm idle on a K100 should be about 950 plus/minus 50.  My bike starts w/o needing the choke at 1000 and warms to around 1300.  It runs smooth and idles fine without any hesitation or problems.

Most of what I read point to air leak.  Today, after a 40 mile ride, I check the cable for play and click, changed the small rubber caps on the vents, and tried to turn the idle screw.  The idle screw is fully out and didn't slow the idle down. There seem to be the right cable play and I can hear the "click".  When I sprayed carb cleaner on the manifold bushings, I can get a slow in idle for a few seconds. 

Since the bike runs fine, I'm thinking it's not worth the tear down to get to the hoses and bushing.  What would folks here do?

[wmax351]

Sounds more like a mis-adjusted idle screw. Warm it up, then turn counter-clockwise to drop the idle to 950 or so.

[Grim]

The air leak would have to be beyond the butterflies on all cylinders if its idling smooth. Do the propane check to rule out a leak but if its smooth I'm doubting you will find one.

 If you don't find leaks then I would start by checking that cables are operating free for the choke and throttle. There should be a very slight bit of slack noticeable if you pull up lightly on the cable housing where they connect on the throttle bodies if they are fully releasing at idle. Check at both ends. if there iss too much slack the end could have come unseated and hanging on the Ferrel.
 One cable joins between 2 and 3 and the other joins next to the throttle position sensor on #4 on my K1100. I think the K100 is going to be the same.   

If that checks out then its possible all the idle balance screws are too far out. If you know how to balance the cylinders Id start by running each idle bypass screw in 1/8 turn and see what happens.

[Inge K.]

A misadjusted TPS could also prevent the b.flies to close completly.

Inge K.

[Grim]

TPS could do that but unless it has been messed with I'd look for other causes first. If the TPS is the same set up as my Bosch based Toyota or my old VW there is a procedure that must be followed to set it correctly. Their is a circuit that must activate at idle. You will need a VOM, feeler gauges and the procedure from a manual to set it.

[cy7878]

Thanks for all the replies. I checked the choke and throttle cable.  The idle screw fully counter clockwise turned actually began to turn away from contacting the level.  It's as low as it goes. 

How do I check the TPS?  Actually what is the TPS? 

Thanks again for the replies.

[WayneDW]

The TPS is Throttle Position Switch (or Sensor) sometimes called an Idle Switch.  Located at the rear of the throttle bodies with a wide wire plug coming out of the top.  It's purpose is to reduce backfires.
When I missadjusted mine it held the idle high as you describe. 

It is bigger than a golf ball, smaller than a baseball, kind of a triangle shape.  There is a screw on the right and left of it for adjusting it.  The screw on the right is hard to get to, I use a small ratchet with a phillips bit in it or an offset screwdriver.   After you loosen the screws you can rotate it all the way closed and you will notice the idle screw should close as well (if that indeed is your problem).  You may leave it this way and the bike will run fine.
The manuals go through how to adjust it correctly which is just barely off of totally closed.

Another possibility is that your "choke" is missadjusted which would also hold the throttle open.

HTH.

here is a thread on how to adjust the TPS:
http://www.motobrick.com/index.php/topic,1522.msg20927.html#msg20927

BTW, with my old ears, I have to use a copper pipe as a stethoscope to hear the "click".

[Inge K.]

A picture usually helps...............

[Grim]

Here is another thread with the same complaint.
http://www.motobrick.com/index.php/topic,4164.0/topicseen.html

Somebody also suggested the idle screws are out to far. they provided a nice diagram of what your looking for.

[cy7878]

Here is another thread with the same complaint.
http://www.motobrick.com/index.php/topic,4164.0/topicseen.html

Somebody also suggested the idle screws are out to far. they provided a nice diagram of what your looking for.

Thanks.  Been watching that on too.  My idle screw is definitely not doing much.  I can back it all the way out and idle won't slow one bit.  I won a fleabay auction on the throttle bodies with a TPS attached which I can play and mess with to see how the linkages actually work so I don't screw up my smooth but fast idling bike.

[Grim]

Screwing them clockwise should restrict air flow.