CB1100 Idle speed instability problem

[736cc_imp]

When batteries are disconnected or replaced, standard operating procedure on 1st re-start is to allow the vehicle to idle until fully warmed up to allow all sensors to cycle. Connecting a battery, and throwing a cold car into drive going down the road immediately a definite no-no.

[SportsterDoc]

When batteries are disconnected or replaced, standard operating procedure on 1st re-start is to allow the vehicle to idle until fully warmed up to allow all sensors to cycle. Connecting a battery, and throwing a cold car into drive going down the road immediately a definite no-no.

Not being facetious, but does it matter if the engine is still warm?

[dave]

SportsterDoc may have just solved the high/low idle mystery! I checked the hose clamps on the throttle bodies today and all eight were loose! Two of them I turned the screws about three full revolutions before achieving an acceptable tightness! I rode the bike about 100 miles after tightening the clamps and it ran perfectly! Most of the miles were on the freeway, but I came to a full stop and put the bike in neutral no less than twenty times today, and each and every time it immediately returned to a perfect 1050 RPM idle! Before I can declare my idle issue is completely cured I must put more miles on the bike, and do some in town, slow speed, stop and go riding, and for a thorough test, I need to perform the in town riding in elevated temperatures. I will perform addition tests ASAP (hopefully next weekend), and report back. I urge any of you guys who are experiencing the idle problem to check your throttle body hose clamps, as SportsterDoc has been recommending.

[pdedse]

SportsterDoc may have just solved the high/low idle mystery! I checked the hose clamps on the throttle bodies today and all eight were loose! Two of them I turned the screws about three full revolutions before achieving an acceptable tightness! I rode the bike about 100 miles after tightening the clamps and it ran perfectly! Most of the miles were on the freeway, but I came to a full stop and put the bike in neutral no less than twenty times today, and each and every time it immediately returned to a perfect 1050 RPM idle! Before I can declare my idle issue is completely cured I must put more miles on the bike, and do some in town, slow speed, stop and go riding, and for a thorough test, I need to perform the in town riding in elevated temperatures. I will perform addition tests ASAP (hopefully next weekend), and report back. I urge any of you guys who are experiencing the idle problem to check your throttle body hose clamps, as SportsterDoc has been recommending.

Dave, that's awesome! Very happy for you!! Did you do the TPS disconnect and clean prior? Or just the tightening of the loose clamps?

[Guth_imp]

SportsterDoc may have just solved the high/low idle mystery! I checked the hose clamps on the throttle bodies today and all eight were loose! Two of them I turned the screws about three full revolutions before achieving an acceptable tightness! I rode the bike about 100 miles after tightening the clamps and it ran perfectly! Most of the miles were on the freeway, but I came to a full stop and put the bike in neutral no less than twenty times today, and each and every time it immediately returned to a perfect 1050 RPM idle! Before I can declare my idle issue is completely cured I must put more miles on the bike, and do some in town, slow speed, stop and go riding, and for a thorough test, I need to perform the in town riding in elevated temperatures. I will perform addition tests ASAP (hopefully next weekend), and report back. I urge any of you guys who are experiencing the idle problem to check your throttle body hose clamps, as SportsterDoc has been recommending.

If this indeed proves to be the case, I might just have to pull an admin power move and change his user name to "CB1100Doc".

[max]

That is a very interesting and useful find, Dave, thanks for keeping us posted.
max

[pdedse]

SportsterDoc may have just solved the high/low idle mystery! I checked the hose clamps on the throttle bodies today and all eight were loose! Two of them I turned the screws about three full revolutions before achieving an acceptable tightness! I rode the bike about 100 miles after tightening the clamps and it ran perfectly! Most of the miles were on the freeway, but I came to a full stop and put the bike in neutral no less than twenty times today, and each and every time it immediately returned to a perfect 1050 RPM idle! Before I can declare my idle issue is completely cured I must put more miles on the bike, and do some in town, slow speed, stop and go riding, and for a thorough test, I need to perform the in town riding in elevated temperatures. I will perform addition tests ASAP (hopefully next weekend), and report back. I urge any of you guys who are experiencing the idle problem to check your throttle body hose clamps, as SportsterDoc has been recommending.

If this indeed proves to be the case, I might just have to pull an admin power move and change his user name to "CB1100Doc".

If this proves to be the case, you can pull another admin power move and change my user name to "CB1100sUkr" (having sold mine!). Haha...oh well.

[Houtman_imp]

SportsterDoc may have just solved the high/low idle mystery! I checked the hose clamps on the throttle bodies today and all eight were loose! Two of them I turned the screws about three full revolutions before achieving an acceptable tightness! I rode the bike about 100 miles after tightening the clamps and it ran perfectly! Most of the miles were on the freeway, but I came to a full stop and put the bike in neutral no less than twenty times today, and each and every time it immediately returned to a perfect 1050 RPM idle! Before I can declare my idle issue is completely cured I must put more miles on the bike, and do some in town, slow speed, stop and go riding, and for a thorough test, I need to perform the in town riding in elevated temperatures. I will perform addition tests ASAP (hopefully next weekend), and report back. I urge any of you guys who are experiencing the idle problem to check your throttle body hose clamps, as SportsterDoc has been recommending.

That is great news Dave , I know you probably would not like to do this but see if you loosen them again would the poor idle return ?
If you do this take a screw driver with you to tighten them while on the road after your "test"

[dave]

Dave, that's awesome! Very happy for you!! Did you do the TPS disconnect and clean prior? Or just the tightening of the loose clamps?
[/quote]

Thanks pdedse. I wanted to change only one variable at a time, so I did not clean the TPS connection. However, because I had unplugged the TPS and reconnected the TPS just to see if the connection could be unplugged without removing the tank, I did perform the TPS reset. Hopefully unplugging and reconnecting the TPS was not the root cause.

[SportsterDoc]

Dave, yours may be the only vacuum loss issue, but it is worth checking.

Also, more than one issue may be involved.

Enjoying the rain in Simi Valley, CA (visiting my 91 year old dad).
Hopefully mudslides will not interfere with return to Las Vegas, tomorrow.