Header pipe color mismatch

RobMan

RobMan

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Just when you thought I had run out of breath I come up with something else. After taking the bike for a short run today I noticed the header pipe on the right side was turning a bit of a wheat straw color close to the head which if memory serves is normal for a properly tuned engine but when I looked at the left it was barely starting to turn color. Pulled the plugs and the right looked good to me but the left was bit more sooty looking. After looking things over I believe I may have found the problem with the throttle cable slightly out of sync and the left side opening after the right. Tightened the right adjuster almost a 1/2 turn and appears to be in sync. Appreciate any feedback especially if my theory is flawed. Pics of the plugs and headers but a little blurred.

Right Side


IMG_5441.jpeg

Left Side

IMG_5443.jpeg
 
Those are the single wall repops?

They should color balance pretty quickly. I had the same on my GL with the Delkevic exhaust.

I don’t know what 1MM of cable travel translates into as far as butterfly opening, but it surely wouldn’t help in leaning the mixture out.
 
It will be interesting to see how the pipes respond to the throttle cable adjustment. If nothing else, it's nice that the pipe color helped you identify the cable being out of sync.

I hope you're not trying to start a trend of header chops along with the plug chops — plugs are expensive enough!
 
RobMan said:
After looking things over I believe I may have found the problem with the throttle cable slightly out of sync and the left side opening after the right. Tightened the right adjuster almost a 1/2 turn and appears to be in sync.
Click to expand...
Probably reading you wrong here. You would want to tighten the left adjuster by turning it out to get them opening at the same time. Or, loosen the right cable adjuster by turning it in.

I guess you mean tighten in the sense of turning the adjuster in (righty tighty) to produce more slack on the cable?
 
Blue with a single wall pipe is too hot, Yellow-isch is ok, no color is ok / too rich. If one side is yellow, it is leaner then the non-colored side, so far the logic.

I would first check for air leakes at the intake, the next thing I would check is the ignition timing. If those things are ok, I would move top the carbs.

But before you go to the carbs, you should determine which area (and fuel system) are responsible for the color.

0-1/4 throttle, check your mixture screw
1/4 to 1/2, needle position, and since the needle is connected to the side, check you slide hight at 1/4 to 1/2
1/2 to full throttle, check you main jet.

But before you start with this, check your float levels first (or be certain that it is good).

Since you are starting to ride the bike after rebuild, and watching the videos on your thread, I get the impression that you are a very gentle rider, so I would guess it's the 0-1/4 throttle area, which it's the easiest to fix.

In this area, the slide opening is very sensitive, so, yes, if you have a mismatch of the cables, it could lead to this imbalance of color.

To find the area, I would recommend plug chop's in the first two area's.
 
jensen said:
Blue with a single wall pipe is too hot, Yellow-isch is ok, no color is ok / too rich. If one side is yellow, it is leaner then the non-colored side, so far the logic.

I would first check for air leakes at the intake, the next thing I would check is the ignition timing. If those things are ok, I would move top the carbs.

But before you go to the carbs, you should determine which area (and fuel system) are responsible for the color.

0-1/4 throttle, check your mixture screw
1/4 to 1/2, needle position, and since the needle is connected to the side, check you slide hight at 1/4 to 1/2
1/2 to full throttle, check you main jet.

But before you start with this, check your float levels first (or be certain that it is good).

Since you are starting to ride the bike after rebuild, and watching the videos on your thread, I get the impression that you are a very gentle rider, so I would guess it's the 0-1/4 throttle area, which it's the easiest to fix.

In this area, the slide opening is very sensitive, so, yes, if you have a mismatch of the cables, it could lead to this imbalance of color.

To find the area, I would recommend plug chop's in the first two area's.
Click to expand...
Thank you for validating my thinking on this and your troubleshooting suggestions. I suspect I am a gentle rider compared to some others but I am trying to overcome my inclination to lug the engine after riding a Sportster for so many years. I run the engine fairly hard (for me) typically at 4-5K briefly accelerating to higher RPM's when road conditions and local law enforcement permit. I will start by checking for an intake leak to rule that out and then take it for another test ride to see if the cable adjustments makes any difference. After that I will take a look at the mixture screws to see if I can fine tune it a bit there. I am going to avoid going back into the carbs unless I really have to.
 
stl360+450 said:
Probably reading you wrong here. You would want to tighten the left adjuster by turning it out to get them opening at the same time. Or, loosen the right cable adjuster by turning it in.

I guess you mean tighten in the sense of turning the adjuster in (righty tighty) to produce more slack on the cable?
Click to expand...
Poor description. By tighten I meant I took some slack out of the left cable by by about a 1/2 turn to more closely match the right side while going back and forth looking at one throttle stop and feeling with a finger on the other.

I currently have a 4into1 throttle cable but I really am not that impressed with it but it may just be me. They advertise it as fitting K1 through K7 although the parts manual shows P/N 17910-297-751 for the K1-K2 and P/N 17910-292-751 for the K3-K5 so wondering are they interchangeable?
 
Took the bike out for a short run yesterday after adjusting the throttle cable. Start up seemed better with both cylinders kicking in almost simultaneously where before one cylinder (the left I believe) took a couple of seconds to kick in. Let it warm up a bit and then went for about 5 miles. Ran well and perhaps my imagination but throttle seemed a little more responsive. Hopefully I can take it on a longer run in a few days and check the plugs and the pipes and see how they look.
 
Went for a 20 mile mile ride today, about 85 degrees and low humidity. Couldn't see much change in header pipe color but pulled plugs after the ride and this is what I got. Now the left plug almost looks a little to hot compared to how it looked before adjusting throttle cable when it showed a bit of black carbon. Right plug looks OK to me. The only change done was throttle cable adjustment and weather is a little warmer.

Left Plug Right Plug

IMG_5447.jpgIMG_5448.jpg
 
Those look pretty good to me. There's enough color on the left that I would be happy. You could check to see if the carb balance is still good, but I think you're pretty much there.

You're gonna have to find something else to fiddle with!
 
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stl360+450 said:
Those look pretty good to me. There's enough color on the left that I would be happy. You could check to see if the carb balance is still good, but I think your pretty much there.

You're gonna have to find something else to fiddle with!
Click to expand...
Yep I agree! Now go put some miles on that 450!!!
 
Put about another 100 miles on the bike since my last post and noticed the right exhaust pipe was getting a little more color while the left appears to be staying about the same so decided to check for any vacuum leaks again while the engine was hot. I didn't find any leaks around the insulators but I remembered I didn't check the throttle butterfly shafts previously so I sprayed a bit of carb cleaner on the outside shaft area of the right carb the idle increased slightly about 50 RPM or so by ear. Hummm. Funny thing when I checked the left side carb, instead of increasing the idle actually drops a bit. I also sprayed cleaner on both inner throttle shaft ends but didn't seem to affect the idle on either carb. The plugs both look good with the right running a bit warmer than the left but not bad.

I have reset the Pilot screws back to 1.5 turns out and am playing withe adjustment but noticed an error in the FSM on adjusting them.

Idle Adustmnet.jpg

Just for a sanity check it should read

"When the pilot screw is turned in, the mixture becomes lean,
and becomes rich when the screw is turned out."

Correct?
 
These were the aftermarket DSS headers? I noticed both sets of the Delkevik pipes on the CX and GL had a lot of uneven color for a bit.
 
RobMan said:
Put about another 100 miles on the bike since my last post and noticed the right exhaust pipe was getting a little more color while the left appears to be staying about the same so decided to check for any vacuum leaks again while the engine was hot. I didn't find any leaks around the insulators but I remembered I didn't check the throttle butterfly shafts previously so I sprayed a bit of carb cleaner on the outside shaft area of the right carb the idle increased slightly about 50 RPM or so by ear. Hummm. Funny thing when I checked the left side carb, instead of increasing the idle actually drops a bit. I also sprayed cleaner on both inner throttle shaft ends but didn't seem to affect the idle on either carb. The plugs both look good with the right running a bit warmer than the left but not bad.

I have reset the Pilot screws back to 1.5 turns out and am playing withe adjustment but noticed an error in the FSM on adjusting them.

View attachment 57789

Just for a sanity check it should read

"When the pilot screw is turned in, the mixture becomes lean,
and becomes rich when the screw is turned out."

Correct?
Click to expand...
Correct for the DOHC 450 carbs, yes.
 
EzPete said:
These were the aftermarket DSS headers? I noticed both sets of the Delkevik pipes on the CX and GL had a lot of uneven color for a bit.
Click to expand...
Yes single wall DSS headers. Thanks for the info on the CX and GL that this is probably not unusual. :)
 
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