Exhaust header glowing

[Jazzcam]

Over the winter months here in pa, I decided to do a thorough "cleaning" and refresh.  perfect opportunity to check valve clearances, spline lube etc.  Upon reassembly, I'm brining it up to operating temp to sync the throttle bodies and notice the header on cylinder three glowing.  Cyclinder two isn't far behind.  I recheck valve clearances on exhaust side, replace injectors and now all three cylinders are glowing at idle. 
This is my first time attempting to sync TBs and I seated the brass bypass screws then turned them out 1 1/2 turns.  NEVER would I have messed with the butterfly adjustments.
I haven't been able to dial the TBs in perfectly, but even if I get number two where I want it the pipes assumably will still be indicating a lean mixture. 
I hate to admit defeat by taking the bike to someone.  Over thirty years of riding and no one has ever wrenched on my rides but me. 
Any suggestions will be appreciated. 

[Laitch]

I recheck valve clearances on exhaust side, replace injectors and now all three cylinders are glowing at idle. . . .
Any suggestions will be appreciated.

I've never noticed my bike's header glowing during the day; I ride at night and nobody has told me my bike's header was glowing. Maybe they've been waiting to see what happened next so they could put it on YouTube. Based on that lack of direct experience, I'll observe that when a chimney pipe starts glowing it's because it's laden with deposits that are igniting from the heat, creating even more heat. How many miles on the bike?

Have you checked cylinder compression? All the values relatively close?

[Jazzcam]

The bike has roughly 145,000 miles.  Never checked compression.  I'll give it a go.  Gotta say, I've never noticed the headers during the day either, but my daily commute was bringing me home after dark for two years.  You'd think I would've noticed that. 
After the valve adjust and parts it really feels strong (on the center stand).  Everything I've read says to adjust valves and then sync the throttle bodies.  Is it reasonable to assume it's rideable and that the only time this occurs is at ideal.  The sync is only an idles sync anyway, but maybe I just haven't tinkered enough with it.  The adjuster screws were turned out quite a bit before I reset to 1 1/2 turns out.
Thanks for your reply!

[Laitch]

The bike has roughly 145,000 miles.

Is that all?  :clap:  Well, you've made a good-looking rig out of it and you're bound to get this sorted, too.

[Scott_]

Ok, if I understand what is happening, while you have the bike on the center stand and running you see the pipes glowing....

So, what happens if when you are doing this, you place a fan(and turn it on...lol) in front of the bike to "simulate" air flow as if you were riding the bike--hence some cooling.

[Laitch]

So, what happens if when you are doing this, you place a fan(and turn it on...lol) in front of the bike to "simulate" air flow as if you were riding the bike--hence some cooling.

Good idea.

That engine might be running too lean. You might need to put some more time in on it before you take long rides. I think short rides would be ok—just avoid riding through leaves and tall grass. Scorched earth will trouble the neighbors. Pipes on a commuter bike shouldn't glow unless that's part of their design.

[Jazzcam]

@Scott-yeah I tried the fan thing and it indeed cooled the pipes quickly and to "normal color." 

@ Laitch-yes lean.  The plugs are slightly white.  And I'm assuming just at idle, but not sure.  For all I know It could've been doing this all last season as I didn't ride at night to notice it.
I'll fiddle some more with the sync, but just worried about burning valves.  The closest service dept is an hour from here, but just hate the thought of that! 

Thanks gentlemen.  I'll let ya know how I fair. 

[Jazzcam]

Well, I folded and took the bike to the nearest shop that services BMW.  Within an hour they diagnosed the problem as the throttle plates have been messed with and are causing cyclinders 2&3 to run quite lean.  No flow bench there, so buying another used set that have not been tampered with is my best option. 
I wouldn't have attempted to adjust those, so had to be the PO.  Just don't understand why I started having trouble recently.  I've put thousands of miles on this bike. 
Anyway, should be back on the road in a few days if all remains constant and the planets align.  I'll let ya know how it goes.

[TimTyler]

Don't assume that the BMW shop has done anything besides take an educated guess.

How many miles have you owned the bike?

Do your throttle bodies butterfly screws still have blue paint on them, indicating that they have not been messed with?

You could remove the throttle bodies and visually inspect them. See if there are deposits or something else keeping the butterflies open.

Even without a flow bench I've heard stories that you can tune them using a thin piano wire. I assume that you adjust them in the "barely cracked open" position by threading a thin piano wire through with equal resistance on all three throttle body butterflies.

[Martin]

www.k100-forum.com/t1526-how-to-balance-the-throttle-bodies-solved  Rob Lentini on the K100 forum has a procedure for adjusting throttle bodies.
Regards Martin

[Scott_]

I've checked and tweek'd mine with my carbtune, similar as setting the idle flow balance, just at a higher rpm and a specific order to the work.
After 100K miles of airflow and throttle plate movements, they were a little off but not terrible.

[Jazzcam]

Hello good people of motobrick.  I feel like a jack%&*@ as I thought I had followed up on this issue here on the forum.  I realized I had only hung my head in desperation. 
The used set of throttle bodies proved successful.  The butterfly adjustment had in fact been disturbed.  I guess it's possible that I bumped the plates hard enough during a thorough cleaning, thus leaning out that one cylinder.  It just wasn't enough to cause it to run badly. 
I should have attempted the adjustment myself with my original TBs as the replacements leak around the rubber seals and it's cold natured to the point that even in summer months I start the bike, then head back in the house to grab my gear before attempting to ride!  Thanks for all your help and patience gentlemen!  Maybe this thread will help someone else someday.
Sincerely,
Mikel

[Laitch]

Maybe this thread will help someone else someday.

Thanks for following up!

[kris]

Jazzcam,
If I'm not mistaken BMW wants you to start and ride these machines. The warm-up is on the fly. Don't tear into it when cold, obviously. But a running warm-up is what is recommended and what I do. Give that a shot.

[johnny]

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