Pipes turning blue

What would cause the pipes to blue progressively from 4 towards number 1. The float levels have been set to spec, the boots are in good shape. I removed them and sealed the gaskets. I tried the propane test for air leaks but got no rpm rise. There seems to be enough fuel as a full throttle test showed it pulled like a train to 9K in the first 3 gears before I ran out of guts. Speedo was buried. The pipes are stock as is everything else. The carbs are clean and the float valves have been replaced with the "deluxe parts from our favorite parts guy. Cold or hot it fires right up, with a little en-richer if cold. There is just a slight stumble as it come off idle under load but nothing bad. Syc was done with mercury sticks and I was seeing dark blue with the color tune.

 

Lets see the plugs Place on brown paper bag and take a picture and post here. Think your lean still. I know the color tune looks great when blue. I would run the mixture screws out just a little more. Width of a dime. Your real close though but would bet the plugs are still showing white or very light tan insulators.

 

The pipes are turning blue because the INNER pipes are either cracked or rusted through. SINGLE-wall pipes turn blue all the time, look at any early BMW or British bike. Your once double-walled stock pipes have become single wall pipes somewhere.

It happened on both my SR500s, in those cases the inner pipe cracked from vibration. In your case if the bike sat for a long time the inner pipes may have rusted through.

 

So he's not actually running lean?

 

What's your cruising gas mileage?? Just curious.
I also want to see some pipes cut in 2, dissected to see the cracks.
The blue will polish out, but then it would re-blue if cracked.

 

Check the timing.

The pipes will blue if the timing is retarded.

If it's in time and not lean I say leave it!

I think blue pipes look cool!

 

Cracked inner liners makes sense. Both mufflers have taken pretty good hits and this bike was sitting for about 3 years before this resurrection. It may be running a little lean but the performance is good so it shouldn't be enough to blue the pipes. The PO had plugs in it that were 2 heat ranges (5s) to hot so reading the plugs wasn't to helpful. It has a new set of NGKs (7s) of the right range in it now with about 150 miles on them. I'll pull them and post a picture tomorrow.

 

running while leaned over on a kickstand?

 

Imo definitely check the plug colour. Seeing as you would be running in the low to mid rpm range mostly maybe pick up your needles a notch or shim them slightly if no adjustment is available. It looks to be running a little lean to me going by the colour of the pipes.

 

I've been thinking of raising the needles a notch. My 81 1100SH responded real well to a .020 shim under the needles. When I had the Hitachi's apart I looked at that but wanted to know what the collective thought was. So 2 questions. How do you shim these needles and how far?

 

conventional wisdom from back in the day was .020" and I believe it still is.

Those pipes are definitely that way because the inner pipe isn't protecting the outer one from the heat any longer.

When it happened on my SR500 a broken hunk of the inner pipe fell out.
I would suspect these are rusted through rather than cracked.

 

I plan to pull them this weekend and check them internally. I have access to a great piece of bore scope equipment and will check the exhaust system and the cylinders. The more I look at the pipes the more I'm agreeing. They also have some bluing just up stream from the muffler connection. I pulled the plugs as suggested but don't think there is to much to see. They only have about 150 miles on them.




As far as raising the needles, what is the best way to do that? Make .020 shims that fit between the slide and the plastic retainer?

 

I'm no expert, but those plugs say WAAAAAY too lean.

 

Yep way too lean

 

Just too lean. Adjust your mixture screws out and see if you can get those insulators to turn tan. Just as a note: Blue pipes are caused from heat in the exhaust as well as blown out inner pipes. Get the plugs tan and use some blue away if you can find some where you live. The motorcycle shop here in Mpls has some if you can't find it. My pipes were blue and gold color unitll I got the mixtures right. I have not had any trouble since. Good Luck

 

actually those plug only have 140 miles on them and if you look at the chart they not that far off. As a matter of fact those plugs look like mine and my pipe aren't blue

 

Your right not far off.
They have the tan eyebrow a little richer and it will tan up nicely.

 

Those Plugs are WAY too LEAN!
Critically, way too Lean!
Your Pipes went blue because the Mixture is too HOT.

You need to add some Richness to the Mixture OR ...
You are going to SCRAP that Engine.

Critically Lean:
Mixture Combustion Heat will eventually destroy the Piston Crown.
Mixture so lean Oil sheen is burned as fuel.
Piston Skirts will begin to heat and score the Cylinder.

You MUST have SOME color on the Center Electrode Ceramic.

If you run like that you are going to KILL the Engine.

 

Wingnut, I agree with Rick, them are dangerously lean. They should look more like this photo.

 

The mixture screw will only control fuel mixture up too about 2000rpm. However it does need to be richer. screw the mixture out 1/4 of a turn & shim the needle a bit at a time until you get the tan on the plugs.
You don't want a rich mixture at idle and still be lean at cruise.

Oh hold on!!!

Have you striped and cleaned the carbies? How good is the fuel flow to the carbs? does it poor out?

Make sure you do a thorough job and strip the carbs completely bare and pull the emulsion tubes and make sure that there spotless to. It could be crud in the carbies that isn't allowing proper fuel/air flow through them. Its a stock bike right? i can't remember if you said that.

Ive learnt allot about carbies in the last two months, most of it thanks too the great guys on this site!!!

Edit: dam pod filters, there :twisted:

 

I agree they look to lean to me. In answer to the question "are they clean?" They have been down to parade rest. The emulation tubes are spotless. All passages have been flushed and inspected. Like I said it pulls like a freight train all the way to red line. All right here's the plan. Pull the exhaust system and inspect the pipes with the bore scope. Bore scope the cylinders just cause we can. Pull the carbs back off and adjust the needles up .020. Check the float levels again. Put it all back together and adjust the idle mixture screws out 1/4th of a turn each. Re-check for air leaks using the propane method. Any other suggestions as to how to richen it up. Maybe up the jet size? I have access to the leftovers of a Dyana jet kit.

 

If it pulls like a freight train ... I doubt you have any trouble with float levels.

You have a Mixture Problem.
Either not enough fuel; or too much air.
If you are running a stock bike with airbox:
Increase Pilot Mixtures
Look at Placement of AIR Jets
Check to see if the Main FUEL Jet is correct.
Look for air leak sources.
Although ... you are LEAN ... right across the board.

Colortune?
Get off the "Early Blue" and "Get-out" of the Blue on the Rich end.
The Mixture is too LEAN.

Pods:
RE-Jet
You need a Hotter set of Pilots and Mains

 

Are you running stock air box and exhaust?? If you have pods you will be way lean with stock jetting.

If you are stock you can raise the float level just a touch and that will give you more fuel at higher RPM's. But for low speed and just running around town. I think you are on the right track with the 1/4 turn and see what happens. Put the Color tune back in and adjust just so the mixture goes from cobalt blue to Blue/Amber and bring it back just a tweak. These engines like lean but they don't last long like that. Good luck and hope to see some more plug pics soon.

Just as another note: you will notice the engine will run much cooler when you get the mixture right. You will be able to clean your pipes and they won't blue again.

 

Wow. This has been VERY educational for me. Great thread. Wingnut I think you're almost there. A little richer and you'll have a perfect engine.

 

Stock air box and exhaust. That's one of the reasons I'm having a problem figuring this one out. I'll let you know what I find. Thanks for the suggestions

 

OK just to make sure I'm not chasing my tail here. Are these jets the stock size and in the right places. This is a shot of the air jets.



the jet at the top of the picture which is on the engine or suction side of the carb is marked 195. the jet on the inlet side is marked 50. Not shown but on the inlet bell both jets, right and left sides, are marked 36.



The main jet is a 110 & the pilot jet is a 40

I bore scoped the pipes and found no cracks or holes in the inner liners. Can't show you the pictures of that as its a PIA to get the images from the equipment. That leaves the lean issue as the cause of the pipe blueing. New throttle shaft seals and new idle mixture screw orings are inbound. Those are the only things I did not replace when going through the carbs.

 

Are you sure you are running the correct plugs?

Take a look at my gallery. The plugs shown have 1000 miles and are 1 range hot

 

NGK heat range 7s are whats in it now and in the picture. PO had a set of 5s in there when I got the bike. Think he knew it was running lean and was trying to drop the plug heat range. He didn't know NGK is back wards for heat ranges than almost evey other plug manufacturer

 

Those are the right positions for the AIR Jets.
The FUEL Jets are OK ... too.

If you have the ColorTune Plug:

Start IN
Adjust OUT looking for Blue
Get into the FRONT-END of the Blue
Continue THRU the Blue until the Blue just starts to go-away ... Rich.

Try that.
Get off the Blue.
Get out of the Blue end on the Rich side.

 

Thanks Rick I'll give that procedure a try. In my usual way I have over reacted to the words "If you keep running it that way you will destroy that engine" So I've pulled the rack and am waiting for new throttle shaft seals and orings for the idle mixture adjustment screws. I had not replaced them so I want to cover all my bases. I'm pushing this project cause the 1100 is down for paint and a new saddle cover. Not having a bike to ride this time of year just kills me!

 

Parts arrived and I changed out the throttle shaft seals. In addition I shimmed the needles up.020. While I was waiting for parts I re checked the valve clearance. # 3 was a little loose so it was brought back into spec. Tried the color tune and still can't get the response to the adjustment the way I can on the 1100. I attempted to start at the Blue and turn out 1/4 of a turn at a time to get to the orange but could never get there before I ran out of adjustment. Idle mixture screws started at 3 turns out and I'm probably close to 4.5 now after playing with them. Sync went really easy which I believe is a byproduct of the new seals. I put about 20 miles on it today and then pulled a 60 mph throttle chop. Plugs are still snow white!!! I'm out of ideas. A totally stock bike with shimmed needles and carbs that are sterile clean inside and out should not be doing this, Tomorrow I will have access to another carb set. I'm going to mount them and see what happens. One question. Is the 041 pilot jet larger than the 040 or the other way around. Would you start with up sizing the pilots or the mains first?

 

If you have the stock air box, make sure you have the correct clean fiter, get your jets back to stock (whatever the book says) then I would bench sync' again & start with the idle jets at 2 1/2 turns out.
Make sure the in-line fuel filter is new & getting a good flow from a mechanics tank, then vac' sync'

 

I would start by understanding the Pilot Jet "Sensitivity"

A Quarter of a turn when you close to having the Bike dialed-in means ...

You could be ... 0 ... Too Lean ... / / / / ... Too Rich ... 1/4 Turn.

Between Too Lean and Too Rich is "The Sweet Spot"
The "Sweet Spot" is about as wide as a Nickel (or two ... depending on Pilot FUEL Jet Size.

 

Found the problem

It was the foam seal on the air filter. The seal had rotted on the right side of the air cleaner effectively removing the restriction of the filter. That's why the #4 & #3 were the first cylinders to show the lean condition. They had a straighter shot at the unrestricted air. #2 & #1 were running lean but not as bad as they were on the opposite side from what was the same as a hole in inlet boots. Sort of like running pod filters but only on 2 cylinders. I guess this goes back to the other thread kicking around right now about inspecting everything on these old machines before you try to put it on the road. This bike looked so good that I didn't go after all the things I should have. I had looked at the air cleaner and the element was clean and intact. Didn't notice the seal was bad until I had a light in the airbox and had one of the inlet boots off. Up side is the carbs on this one are finished. New everything and all polished up and pretty. Now how to get the blue off these pipes if I can. Thanks for all the help and ideas.

 

Congrats on the fix! I don't know what it's called but I have seen people in here mention a product that removes the blue from the pipes.

 

Wingnut, saw some stuff at a biker shop on Friday called Blue Job. Suppose to take the blue off chrome pipes.

 

"OK people, ... we need a name for this product that people will remember!"
"How about ... Blue Away ... that's catchy!"
"No. People will think it explodes."

"Lets call it ... Blue Job ... We're all about cleaning pipes!"
"Perfect. And, raise the price a little, too."

 

LMAO -once again Rick I love your sense of humor....