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fast idle adjustment


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I have a '98 R1100RT that I bought last summer with about 17k on it. Shortly after I bought it, I noticed when I activated the fast idle lever it would not return. I had a couple of inches of slack hanging out. I tried blipping the throttle and adjusting it up top to no avail. I looked in the Haynes manual and it said an 18k service would be coming up and that the throttle cables needed to be replaced anyhow along with a TB sync. As I was new to wrenching on BMW's, I just changed the plugs and did the valve adjustment. I started reading this web site soon after I got bike. Anyhow, last summer, (a BMW shop that was recommended by one of the guys here, as one of the best) replaced the fast idle cable, and the various throttle cables and did the TB sync. This winter I noticed that the fast idle lever wasn't working as well as it should. It seemed to have to much adjustment and would not raise rpms too much. Because I've been going through radiation therapy, chemo, and all sorts of other stuff for my cancer treatment, I finally drive the 160 round mile trip up to this BMW dealer. I go up there the other day, and the service writer or manager (really not sure which) took a quick look at it and said he could fix it. He adjusted it, turning the long silver, knurled adjuster this way and that- he told me he liked about a 1/16" of play and then tightened down the locknut and slid the rubber boot over it. When I got home, I thought he might have put the locknut in the wrong position. In the Haynes manual, on page 1.13, in the upper left hand corner, picture 8.10a, there is a pic that shows the locknut locked up against the black swithgear side. This guy has got the locknut up against the long, silver, knurled adjuster. Would someone be kind enough to tell me how to adjust the fast idle, what sort of clearance i am looking for, etc. I do know that I will put the locknut back in it's proper place against the black switchgear. Book says "on 1996-on models cable (choke) freeplay should be zero. I saw one post when i searched that said 1/8" to 1/4". I assume freeplay is measured up top, but am not sure. Thanks.

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For starters, yes he has the lock nut in the wrong position. Unless up against the switch gear mount, it won't lock anything!


ISFA adjusting, here's what I do...


With a warm bike adjust the cable (where you were, under the boot) so when on the first fast idle click you get about a 1000-1200 RPM rise in idle speed.


Now, when the bike is cold, on the first click you will get normal idle speed, rising as the engine warms (while you are riding away), then at some point before your first slow down/stop you click it off, and all is well.

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Hi Michael,


First: best of luck with coming through the treatment (I can empathize completely frown.gif ).


Second: the fast idle cable normally wants to be almost taut--without putting any tension on the system at all when disengaged. That means the play at the left handlebar switch grip should be as close to zero as you can reasonably get it while making sure that it doesn't hang up the butterflys in the throttle bodies--keeping them slightly open when you're idling.


You're also right in that the lock nut wants to be tight against the switchgear housing (that keeps it from automatically turning back in with vibration). When you pull back the rubber boot you can check freeplay by grabbing the cable housing and tugging away from the barrel bolt--it should feel just barely loose but not move back and forth perceptively. You might want to turn the barrel bolt in a few turns and see what movement looks like, then turn it back out until that movement goes away, then lock down the nut against the switchgear and reposition the rubber boot.


18k miles seems a bit soon for new cables but the early versions of the 1998 cables were more prone to failure and hopefully you got the updated ones now so all should be well. However, if you just got new cables be aware that they will stretch a bit more for the next few thousand miles or so and you will need to take up slack in the throttle cable as well as the fast idle cable. Also, the shorter cables from the junction box to the TB's will stretch differently necessitating more frequent synch's for best performance.

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