Okay, what's white with brown specs?

My Sparkplugs. :roll:

I did about 2 hours of forum searching and didn't see a word about white speckled insulators.

Now, I understand white is lean....but brown specs? :?:

Also, adjusting the pilot mixture screw only effects the color of the plugs at idle, right?

What if the plugs are lean at 5k rpm? Float height?

Cleaned my carbs today. A lot easier then I thought it would be.
set the pilot mixture screws at 2.5 turns, and the damn thing ran like a champ. great idle, and lots more power then it had.
Did a plug chop, and all the plugs were white with brown specs?

 

it is lean, and yes, the pilots do have an impact at higher RPM, just not a lot.

do you have the stock jets and stock air filter?

 

Carbs aren't truly clean, float heights could also be a factor.

You're probably right in the ballpark tuning-wise, but your fuel isn't "atomizing" into small enough droplets; you've got a tiny orifice still plugged somewhere.

 

Yup, stock jets and stock filter.
4 into 1 exhaust.

 

Not sure why I didn't set/check the float height when I had the carbs pulled?
I guess I didn't do it because I assumed the carbs would take so much longer to clean. Took me about 7 hours straight. I haven't checked the valve shims yet either.

It ran really really good after I cleaned the carbs, and set the pilot screw to 2.5.

A tiny orifice on three of the four carbs?

I actually decided to rip it apart when I realized riding normally was stressful because I was never sure how the bike was going to run that day.

 

Specks on white insulators is generally a pretty bad sign. It's usually an indication that the engine is going quite lean under load, with the resultant high temperature in the cylinder and excess of air causing the bike to start burning the aluminum of the combustion chamber and piston crown.

Mid-band lean is probably related to the jet needle height or profile (too low and/or too thick). A vacuum leak could also cause problems here, by letting in too much air and by messing up the behavior of the CV slides.

Are there any mods on your bike (pods, different exhaust, etc)? What altitude are you at? Do the carbs have stock jets and needles?

 

Only mod is a 4 into 1 exhaust.

Did some plug chops at idle....and 1&2 (from left to right looking towards the front of the bike) and 3 & 4 were a light black/brownish.

I just checked my float heights dry.....and they were way off off that 17.5mm spec?
They were hanging WAY WAY down?

 

You gotta check the float heights with fluid, the other method is only a starting point.

 

I'm not sure what's right..... I read that 6 page float height thread, and it's is confusing.

When the floats are hanging right side up.....should the float needle be being pulled out slightly by the tang??

 

I'd agree with Fitz that you want to measure these with fluid, rather than dry. I'll go further and say that that fluid should be gasoline, because other fluids have different specific gravities and you'll end up with incorrect float height.

I still think the service fuel level test (bike level on center stand, clear tube used to check fuel level with carbs on bike) is the best bet. If you replace your float bowl screws with allen screws, you should then be able to remove a bowl and tweak a tang if needed without removing the rack.

How about the other two questions I asked:

1. What altitude are you at?

2. Do your carbs have stock jetting, or do they have a "jet kit" in them?

Cheers,
Paul

 

I'm in central WI, so normal attitude.
The bike is stock other then the 4 into 1 exhaust. 8O

Okay, I just reset the floats to 17.5mm dry and reset the pilot screws to 2.5 turns.
I had the idle screw a little too far in, was idling at 3k....had to back that out a little too.

I checked the float levels before I reinstalled the carbs, using a jig and the clear tube method. All appear to be within spec.

It's idling and starting really good right now, took it for a spin around the block. Seems to have decent power.......kinda sluggish. chopped the plugs after idling in the garage for 30 seconds. Running pretty damn hot.

All bone white.
The ground electrode looks a little white.......appears to be running extremely hot.
no color, no speckles, no nothing?

 

back the mixture screws out to three and see if you get any color


mn

 

That was my thought too....so I just went and did that.

No color.

After I changed the float height, any color at idle I did have, disappeared.
(3 and 4 were decent colored)

I will say that my floats, set dry were around 13-14mm.....rather then 17.5mm. When I checked with the clear tube....they were all within approx. .5mm.
Seems like that would make a huge difference.

 

Again, the main things for mid-band power will be the needles, not the idle jets. I'm back to the vacuum leak theory.

 

White with Brown Specs means you are running too Lean.
You could burning Piston Wall sheen as Fuel.
This condition needs corrective measures to avoid serious problems.

Examine the Ceramic surrounding the Center Electrode under a magnifying glass.
If the Ceramic shows Hairline fractures or erosion ... Don't run it.
You might be at Combustion Chamber temperatures which will liquify aluminum.

Protect yourself!
If you cannot adjust the Mixtures Screws to provide Supplemental Richness to reduce the Explosive Lean Mixture ...
TAKE PRECAUTIONARY MEASURES !!

Add a Top Cylinder Lubricant to your Fuel.
Enough to slow-down the "Flash-Bulb Type" of Fuel Ignition you have going-on in there at the present.

This is a good time for you to introduce yourself to:
Marvel Mystery Oil.

http://www.marvelmysteryoil.com/index.php/site/faq/



Specific Gravity Test for Float Height Settings.
Blue = Windshield Washer Fluid > (A non-flammable, pleasant smelling, cleaner; requiring little or no ventilation)
Amber = Gasoline. Stinks and goes "Boom"

 

When I was trying to find a vacuum leak on my bike I was spraying carb cleaner all over the boots I couldn't find a leak until I got spray above the mixture screws. The fluid got sucked right in, even filling the space above the screw head. I pulled out the screw and the little rubber o-rings were gone, might be worth a look.

 

I tried to determine if there was an air leak with a propane torch, but I didn't notice any change in RPM.

I've just pulled the carbs completely apart, and re-cleaned everything.
All of the parts are there. Even with the pilot mixture at 3 turns out, no color.

I suppose absolutely bone white is better then specs, right? 8O

Re-checked all jets, and openings. taking a break now.......but will be reassembling soon.

Still wondering if I should return my floats to the 13-14mm setting they were originally?

 

Air leaks that great would be the Intake Manifolds themselves.
Where they fasten to the Head; leaking under Vacuum.
Manifolds split where the Hose Clamp affixes to the Carb Neck
(or missing clamps)

You might want to check the Size of the Jets
Consider using a Bigger Pilot FUEL Jet.

 

"Specks" only occurs when the engine is lean under load. That's where you have the combination of heat from high power combustion and excess air that leads to aluminum burning. At idle, there's not enough heat to burn aluminum, so you just get white, or maybe glazed, insulators.

 

I get it now. Thank you for the info!

I just went through the entire rack again. Cleaned everything.

Reset the float heights again.
When tested with fuel and clear tube......the levels are nearly level with the bowl seam. Back to adjusting them again.
Which way do I have to go? + or - 17.5mm?

My bike has always ran fairly lean.......not sure what to do?

 

I wouldn't think float height's your problem if your that close to the gasket, and the bike is level.

However, if you can't get good color on the plugs at idle, then jet needles wouldn't be the only problem either.

Just so we're clear: as I understand it, currently, you're getting white insulators at idle on all four plugs regardless of where the pilot screws are set. Is that correct?

If that's the case, that would mean it's either something wrong with all four carbs, or something they all have in common.

Things they have in common include the air box, air filter, and, to some extent, intake vacuum, due to the YICS passage.

Did you check for vacuum leaks at the throttle shaft seals? Also, what condition are the carb diaphragms in? Did you seal them with silicone grease when installing them?

One thing you could try would be to pull the air filter, or run with the carb boots off, to see if you can see the slides moving up when the throttle is quickly opened. If they're not moving, or not moving much, that might explain the mid-band leanness. Of course, running without boots or air filter will be even leaner, and would open the engine up to contamination by airborne dirt, so should only be for a quick check.

 

I made a jig for the carbs to hold them level off the bike.


I'm getting zero color......after I installed new plugs and tweaked the carbs.

...well, I haven't ran the bike since discovering that the new plugs were purely white. Just ripped the carbs apart, cleaned and put them back together.....took a short ride to test, then discovered the albino plugs.

I hadn't checked for leaks at the throttle shaft seals.
I'll put that on my to-do list tomorrow.

Ummmm......seal them with grease? No?!?

 

Chacal's got a whole writeup on carb cleaning in his parts forum. One of his tips is to use silicone grease (not petroleum grease) to hold the lip of the diaphragm in place when installing the slide. The silicone grease makes sure the lip stays put, and also helps seal the diaphragm. You can get silicone grease in the plumbing section of most any hardware store.

This grease is also good for the O-rings in the carbs, especially those on the pilot screws, that are prone to get torn up a bit.

 

I'm going to do that tomorrow. thanks again.

I just can't figure out why I'm so lean?

 

think he is talkin about the carb diaphragm when you install them to use a silicone grase to lock theboot lips into place in the groove so as to avoid a vacuum loss and introduction of MORE air to your lean problem. Just a guess

 

I hope that's the problem.

I did probe around with an unlit propane torch......with no conclusions.

 

Recently, I have encountered Air Leaks at:

Manifold Gasket between Manifold and Head.
Factory O-ring fails and allows air at higher rpm's.

Manifold to Carb.
Manifold is split because wrong Hose Clamp is used of misplaced.
Cleanly lacerates the Manifold at the Head side of the Manifold.

 

I'm going to closely examine both sets of boots....and grease the diaphragms.

The floats are set properly, and the carbs are surgically clean.

We'll see what happens tonight after work when I put them back on.

 

http://xjbikes.com/Forums/viewtopic/t=1 ... rt=60.html

After reading that thread, I realized that I'm running 110 main and 40 pilot jets.

With a 4-1 exhaust, should I be using 114 & 41(41.25?) respectively?

 

I would.
I'd much rather run rich and cook the Mill or burn a valve.

 

...an order will be placed....
new jets, petcock, and valve cover gasket......

Came home to a garage that smelled like gas.....apparently my petcock is leaky....since I had it off the bike.

 

greased the diaphragms......reinstalled the carbs.

Could not find an air leak with propane. all plugs were white. Bike ran really well......but bone white.

Must spend bike down time checking the valves, replacing petcock and jets.
I also ordered a colortune.

Thank you everyone for the help. I'll probably post again once I tweak all of these things.

 

Did you change the o-ring in the Mixture screws already?

 

Change them?
The existing ones looked pretty good? :?:

 

any progress on this?

 

I'm waiting on a set of metric feeler gauges so I can check the shim clearance accurately. I checked them with a set of standard ones....and most were around .114 and .165.....only one was way off. 0.89-ish 8O

So, I'm going to take care of that FIRST......swap the stock jets for some bigger ones (110 to 114 and 40 to 41).

I'm also going to treat my tank, replace the crispy valve cover gasket and rebuilt the petcock while the bike is "down".

At least, after all of that I can narrow down any air leaks that may be causing my bike to run so lean.

 

Do a Compression Check; first!

Don't spend hard earned money on a new saddle and tack for your horse until you know it ain't gonna up-and-die on you.

You might need the money for a new horse.

 

Won't tight valves skew my results?

I also don't follow your horse references...... :lol: 8O

 

Checking compression cold, as long as there's SOME clearance between the cam and shim, the clearance shouldn't affect your readings... if anything you'll read a tiny bit higher because you'll be getting maximum open displacement of the valve.

Now, if there were zero clearance, then your results could be way off, since the valves might actually be hanging open throughout the cycle.

 

Horse analogy explained:

Don't spend money ordering parts and having things done ... until you see the results of a Compression Test after having run the Bike so Lean.

Critically Lean Burns flash and consume every flammable source of Fuel.
The Oil Sheen on the Cylinder Wall gets used making the Cylinder Wall and Rings vulnerable to premature wear, scoring and other issues related to engine problems that can and often do become severe and costly.

 

I checked the shims before ordering any jets....found two out of spec.
Exhaust on #1 and Intake on #3. Replaced them last night, and installed a new valve cover gasket.
The original gasket was a huge pain to get off completely....I assume it's 27 years old.
I'm starting to realize the PO didn't take care of the bike at all.

Since I put in an order, I got the new jets (114 & 41)....since the jets were stock (110 & 40) and I have a 4-1 exhaust. Also got new drain screws and a petcock rebuild kit.

The carbs are sitting at home with new jets waiting for the float heights to be checked, and be reinstalled.

I'm going to RTV the intake boots, and I've been soaking the other boots in armorall.

Also going to pick up a vacuum gauge to sync them properly.....then colortune. I should test the compression too....so I'm not chasing my tail!

I hope all of this solves my lean issues.

Hopefully, my throttle shaft seals don't need to be replaced?

 

UPDATE:

Well, put the carbs back on.......started up easily. Sounded better.

had to choke it quite a bit to keep it idling.

Took it for a quick spin, about 30 seconds into the ride the RPMs jumped way up, so I hopped off at a stop sign and tweaked the idle screw.

Rode around for 5-10 mins. The bike has a lot of power now.....plenty of get up and go.
Still sounds like it's popping/gurgling on decel......and a little hesitation on take off.

Came home, and checked the plugs after letting it idle for 30 seconds.

1- bone white
2- bone white
3- slightly brown on one side
4- brownish on one side (more then 3)

Ran out of time.

Vacuum check, compression and colortune this weekend. Hopefully that will help.

 

Sounds like progress! Congratulations.

 

Getting there.
I suppose it's a slow process that everyone goes through at first?
(now I have brand new bike to start tuning ( :roll: :lol: ) luckily it runs a million times better then the SECA )

After the vacuum sync and colortune.......I should be able to narrow any issues down.

If my pilot screws are ineffective at coloring the plugs/properly colortuning, I can assume I have an air leak, right?

Right now, it just runs like shit.
Will getting everything tweaked properly solve this?

 

So how did the colortune work out for you?

 

You hit the nail on the head.....DETONATION....this is a very bad thing

 

Match your condition to the illustrations on this chart.

http://www.ngksparkplugs.com/tech_suppo ... aqread.asp