Jetting Question

[motoman]

Sorry guys...was just trying to be of help with some known facts. Am also a certified welder of 30+years. More O2, less heat, acetelene for fuel makes the heat, mixed in correct porportion with o2. Too rich, unburnt fuel causes the discoloration, in this case blue. Too much oxygen(lean) causes gold dicoloration. Both which can be removed easily.(even the fuel /air ratio)

[xj11john]

Well,

I'm not going to argue, but do some research on it trbig, I say we are right. Also your plugs being very light definetly means you are lean.

here is a quote from the Yamaha Road Star Clinic forum in responce to the same question with quotes from "Geezer" and "DocShadow"

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Quote:

Re:Pipes are bluing - 2006/02/08 14:33
You definately need to change your jetting. Most Japanese bikes are lean from the factory to pass emissions in the U.S. Some will tell you that you don't need jetting unless you change the air cleaner, that's "bull" I've owned quite a few bikes over the past 25yrs and haven't seen one yet that didn't benefit from jetting, that includes jap and american. The reason for the "blueing" is because the bike is running slightly lean which causes it to run a little hotter, causing the pipes to turn color. As far as the "popping", jetting will stop some of it, but if you want to just about eliminate it, install an AIS removal kit, the kit runs around 15 bucks, is very easy to install and that eliminates the emissions garbage from the bike. You can find posts on the forum about it.

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DocShadow



Moderator

Posts: 683

Karma: 17
Re:Pipes are bluing - 2006/02/08 18:35
I've heard of the occasional ProPipe cone turning gold but not blue.

If you look at your header pipe behind the shields you should see either a blue or gold colour. Gold is rich and Blue is lean. So I agree with geezer on this one.

However, blueing at the cone is a slightly different situation and I need to respectively differ from geezer.

Blueing far down the pipe where the exhaust would usually be cooler results from an overly rich air-fuel mixture. A rich mixture ignites inside the cone, causes a flame to hover and a large blue spot will appear on the outside of the exhaust pipe.

Popping on decel would also indicate unburnt fuel, which would be especially noticeable if you have you still have the AIS connect.

It would help if you post your carb setup.

Doc
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heres the link
http://roadstarclinic.com/component/...id,13/id,4365/


This is an interesting topic, don't ya think?

[xj11john]

Here is another quote that makes both sound right?!

"In case your pipes become blue too quickly or over and over again, it can be a manifestation that the air-fuel mixture or timing is not right or accurate. To overdo the mixture and make it overly rich can turn the pipe or muffler blue. This is because the unburned gas ignites on a baffle or hot spot. Too lean mixture or timing can cause pinging. It can also turn an extremely hot exhaust into blue."


heres that link.
http://searchwarp.com/swa27402.htm


Ok I'm done,
good luck

[LoserShoes]

Well, I would just say if you are running so severly rich as to have a seperate band of discoloration away from where the pipe meets the head, you would have many other idicators for the problem, such miserable gas mileage.

I am a journeyman welder, and colors in chrome are the same shades you get when tempering metal. The colors come from differing thicknesses of oxides.

When you remove the blue, you are also removing chrome, and will eventually remove it all down to the nickle plate.

Steve

[trbig]

Well, I honestly thought this was going to be a quick easy thread, but now I am thouroughly confused and bumfuzzled. How about I just show a pic of the &^%$ things and we discuss from there?


The pipes are blue right until after the bend, where they start turning gold-ish. So tell me.... Lean or Rich??

[trbig]

OK... here's one better. Here's a picture of one of the plugs. A slight tinge of tan on the insulator... slight black on the base like it's supposed to, but obviously running hot for some reason due to the pipes blueing.





Tod

[trbig]

&%!$@#&!$#*&!$# Sorry about the huge picture

[Firehawk]

Whoa! I knew something had to be wrong, cause I had thought that the outer two cylinders were different from the inner two!

Pretty much why I posted, was to do some double checking. And thanks.

And yes, I can return it.

[Dark Horse]

Originally posted by motoman
Sorry guys...was just trying to be of help with some known facts. Am also a certified welder of 30+years. More O2, less heat, acetelene for fuel makes the heat, mixed in correct porportion with o2. Too rich, unburnt fuel causes the discoloration, in this case blue. Too much oxygen(lean) causes gold dicoloration. Both which can be removed easily.(even the fuel /air ratio)

Sorry Motoman, but more O2 = more heat. The oxy-acetylene flame is the hottest known chemical flame. When burning rich (excess acetylene or "Carburizing" flame) the temperature at the point of the inner cone is 5300 deg. F. Neutral flame = 6000 deg. and the lean burning (excess oxygen or "Oxidizing" flame) burns at 6300 deg. F.

I am also a "Certified Welder" with 30+ years experience as well as an American Welding Society Certified Welding Inspector and AWS Certified Welding Educator.

Never too late to learn something new. Hope I learn something else today.

Bob Udy
Assistant Professor, Welding Technology
Salt Lake Community College

[motoman]

With the lack of lead in fuels now, it's somewhat a different thing reading plugs. The carbon around outside indicates a possible rich mixture. If you cleaned them, ran it at a normal cruise speed, pulled clutch to a immediate stop without any idle, pull a plug and check it. Your pipes look identical to what mine were on my 81 Venturer when I got the bike back some 15yrs. later. It was badly neglected, even though it was ridden all the time. Oil came out like sargums syrup and filter was folded around from being so plugged. It smoked out pipes and would drop 2 cyl. at 70mph after only 45 moles on Interstate.(very sad, as this bike looked and ran like new when I sold it) Rather than a top-end rebuild, I put in another 81motor with only 30,000 on it and clean as a pin inside and out(compression was 143psi on all four). Since hacving carb bank off, removed float bowls and all floats were almost 1/4" to high, wonder it didn't run fuel everywhere. Pilots were stock, mains were 110's all across. droped floats to 23mm, left jetting as was since I am at 5000ft., carb boots on replacement motor were in pefect cond. indicating bike was kept inside. Have ran this over 4,000 miles since Nov. without a sputter, one 500 miler and bout every day locally. After cleaning pipes before installation, they still look like new, no color whatsoever. May lower float levels a bit at this elevation with the combination of crossover sucking a little air occassionally and still a little rich is causing a blue spot at about riders pegs. The crossover having a minor leak combine with a little rich is making for some good igniting there apparently. Plugs at thread base have a tad black around them indicating the same, and that's with stock airbox with a Uni-Filter (foam, same as my moto-cross bike). At this point a tad rich is better than too lean for sure. Hope all this gives some sort of idea where to start..........bettin' float levels for a start tho..........

[motoman]

Yeppers Dark Horse..........re thought that after I sent and knew I was gonna get 'chimed on'. Thanks for verifying what I already should've known. In the case here with header pipes the blue is from heat from unspent fuel vapors still trying to ignite as they exit head. I used to assume the same as most here all these years and had it all explained to me by a expert bike mechanic last year. There are alot of factors involved and the blueing at the head can most of the time be attributed to too rich a mixture for a starting place. The gold color can mostly be a staring place for too lean a mixture. Both indicating there's a problem somwhere, unless it is not a quality chrome, which is not the case with the Yammys, as I have looked at these header pipes very closely and they are a very high quality chrome. Dang Japs are using a very quality process. Ther're is other factos which can cause it like timing, fuel quality,etc.

[trbig]

These carbs have been completely gone through and floats leveled @ 2 months ago with inline filters for the lines feeding them. The carbs are XJ stock (112.5 mains & 47.5 pilots) connected to an XJ head with the bigger valves, on an XS motor that has higher compression than an XJ. Understand all that?? lol. At this point, I am not sure which way to go. I am going to agree at this point that maybe it is running rich. I had alsways thought that the blueing was from lean... but when I start it in the garage, it the fumes smell pretty rich. Bigger valves sucking in more mixture than the XS motor was meant to maybe?? My fuel mileage isn't great... but it's not terrible either. @ 27-30 mpg on cruising at 70-75mph.
I have some pod filters on the way which is supposed to lean me out a couple sizes or so. I will put them on without any changes to the carbs and see what happens.
On a side note... I went to my local motorcycle shop to order the main jets I THOUGHT I needed, and he had the correct main jets for these carbs.... MADE OF PLASTIC!?!? Anybody ever heard of that? I chose to just have him order me brass, but I didn't check on a price for the plastic ones. If they are cheap enough, it might be a good way to fiddle and find the proper mix a little cheaper than the brass, then order brass when you find what you want. I am sure they work fine, but I just dont trust plastic in there for the long term.

Tod

[trbig]

Well, so much for the plan of buying the plastic jets to figure out where I need to be. I got 4 brass main jets today for 2.50 a piece, and the plastic/ nylon jets are close to 4 bucks a piece! Maybe use brass to figure out and go back plastic!? LOL.


Tod

[trbig]

OK guys, I need your advice. I guess we determined that I had been running lean due to the blue pipes. I got my pod filters in today and installed them. I took it for a ride and WOW.... the sound is so cool! But, when I get on it, it does fine until 6 grand then falls on its face and starts crapping out BAD.... won't even make it to 7 grand. I still have the stock 112.5 main jets and 47.5 pilots. Also, at low rpm (@ 2500 or so) cruising town, it pops and sputters and backfires. Accelerating slightly, it goes away, but slight decel to steady... it's there.
Did I go from too rich to way too lean by just adding the pods? Could the general census have been wrong and I was lean already.. now starving for fuel? Please help.... scratching my head here.


Tod

[Ken Talbot]

Time to have a look at the plugs when the problem is happening - the colour will tell you what's going on