Post valve adjustment idle/mixture adjustments

[gtem]

Hi all,

I just performed what I suspect may be the first valve adjustment that my XS1100F has ever had in 23k miles, judging by the need to swap every single shim for a thinner one. I'm back in spec everywhere now, buttoned it back up, fired it up to sync the carbs. Sync'd the carbs using my carb-tune-pro. Noticed the idle was quite a bit higher (around 1700 instead of the 1000 I usually like it at), which per my understanding may be the expected outcome after loosening up too-tight of valves? I backed off the throttle stop to get the idle back to a normal range. When revved I can detect a bit of rev hang, I suspect my idle mixture needs some adjustment as well now after the valve adjustment?

What is the general logic, now that my valves are opening presumably a tad later/less than before? Would I be richer or leaner now at idle?

In other news, she's about ready to roll for the coming riding season. Scored a OE rear turn signal relocation kit to fit my new larger Chase Harper bags, and I'm going to be trying out this Plexistar 2 fairing I scored for $70.

Thanks for all the help in advance as always!

[Radioguylogs]

I haven't noticed any appreciable change in carburation after valve adjustments, but mine were not as big of an adjustment as you experienced.

[gtem]

My first suspicion was a manifold/air leak, but some quick testing with starting fluid sprayed around the carb boots etc didn't bump the idle speed one bit.

[DiverRay]

My normal for an adjustment is valves, idle mixture, and then sync. I've been doing this for a few years, and usually do the mixture by ear. The tachometer on the bike will not show changes as easily as an old dwell/tach unit does.

[DEEBS11]

Setting valve lash will not effect jetting. Synchronizing carbs will often raise the idle. When it was out of sync (and the lash was off) the motor was not tuned properly and you adjusted your idle over time to compensate. Now everything is back to spec.

[cajun31]

Hi all,

I just performed what I suspect may be the first valve adjustment that my XS1100F has ever had in 23k miles, judging by the need to swap every single shim for a thinner one. I'm back in spec everywhere now, buttoned it back up, fired it up to sync the carbs. Sync'd the carbs using my carb-tune-pro. Noticed the idle was quite a bit higher (around 1700 instead of the 1000 I usually like it at), which per my understanding may be the expected outcome after loosening up too-tight of valves? I backed off the throttle stop to get the idle back to a normal range. When revved I can detect a bit of rev hang, I suspect my idle mixture needs some adjustment as well now after the valve adjustment?

What is the general logic, now that my valves are opening presumably a tad later/less than before? Would I be richer or leaner now at idle?

In other news, she's about ready to roll for the coming riding season. Scored a OE rear turn signal relocation kit to fit my new larger Chase Harper bags, and I'm going to be trying out this Plexistar 2 fairing I scored for $70.

Thanks for all the help in advance as always!

You can generally smell excessive gas fumes when the bike is running at idle fully on the Idle jet circuit. I work in my garage and if the fumes seem excessive then I get my color tune out and check the idle mixture screws one cylinder at a time. I have never experienced a problem or rather change due to a valve adjustment.

[Larrym]

Thingz wut make me go Hmmmm..... (ー_ー)ゞ

If imma getting the right understanding of the responses that there ain't no real dramatic connection between adjusting the valves and changes in the idle speed/synch/jetting like wut DEEBS11 sez? (O_o)

Then I agree. No difference when I did mine. Can't really connect the dots in a way where there IS a connection either. (´･Ω･｀)

I WILL inform you that I will accept the "Quick-n-Dirty" synch's done in the garage to balance the vacuum readings after a cold start, "choke on" fOaR a few minutes, and turning the choke OFF when's the bike will finally NOT DIE when the choke is turned off. (¯―¯ ٥)

Have at it and balance vacuum levels to yur hearts content. (^_^)

Under NO circumstances would I, personally try and/or accept any idle mixture screw tweaking on an engine that ain't been actually RIDDEN less than 10 miles (5 miles out-n-back...) and everything (intake, engine, exhaust, etc....) genuinely at the "operating tempurature" it's R E A L L Y s'posed to be. ♥( ˆ⌣ ˆԅ)

BUT... again I don't see a correlation between doing a valve adjustment and it meaning anyone got's to go drag out the gauges and revisit synching the carbs. (◔ヘ◔)

I DO have a question which may/may NOT have a bearing on yur situation. ( 　ﾟ ,_ゝﾟ)

"When the bike is COLD (as in has sat fOaR an entire 24 hour day...) can you start the bike simply by pulling the choke out (full or half) and hitting the starter button once? "

Yes/No?

[gtem]

As an update to this, I had played around with idle mixture a bit (they were set to 1.5 turns out, I went down to 1.25 before going back to the 1.5 it had been set to). The bike is running fantastic. The real takeaway for me (a real "no duh") and a lesson I guess I had to re-learn, is that any sort of carb fine-tuning especially something like idle mixture *NEEDS* to be done on a *FULLY* warmed up/up-to-temp engine. My mistake I think was thinking just a quick run around the block would be good enough and so the slight throttle hang was down to just a too-cold motor/carbs running a bit lean, as far as I can tell. Running great now, excellent throttle response, revs come right down, idles smoothly right where it should.

[bikerphil]

Yes, our air cooled engines take about 7 miles of riding to become fully warmed up.

[Ccitis]

Mine had a large valve adjustment too. No mixture changes, just a sync after. But yes, a cold engine will cause issues. I tend to run mine a touch on the rich side I would say... it seems to like that.

[cajun31]

Mine had a large valve adjustment too. No mixture changes, just a sync after. But yes, a cold engine will cause issues. I tend to run mine a touch on the rich side I would say... it seems to like that.

I do too but I adjust mine utilizing the color tune because the drop method is based on listening to the engine speed and I have never been good at that.

[pete_s]

Sounds like your throttle cable is hung up under the tank or at the carbs as there should not be any mixture change after a shim change.

[gtem]

Thanks for the input Pete but if you read my latest post you'll see it's al been resolved. No cables hanging up, that is a thing I checked from past experience.