Topic: Why are my plugs STILL black??!! Help

[nino400F]

So, ripped the carbs apart,

New mains 105,

new pilots 40,

Needle at the 4th position from bottom notch dropping needle closer to float bowl giving a leaner condition from 1/4 - 1/2 throttle

New DPR7ES-9 plugs (slightly hotter than D8EA)

Will put them on tomorrow and go for a run, then will post pictures of plugs.

In theory it should be running lean as my 4-1 exhaust is not stock and everything else is other than the leaner needle position.

Crossing fingers!!!


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[nino400F]

So, ripped the carbs apart,

New mains 105,

new pilots 40,

Needle at the 4th position from bottom notch dropping needle closer to float bowl giving a leaner condition from 1/4 - 1/2 throttle

New DPR7ES-9 plugs (slightly hotter than D8EA)

Will put them on tomorrow and go for a run, then will post pictures of plugs.

In theory it should be running lean as my 4-1 exhaust is not stock and everything else is other than the leaner needle position.

Crossing fingers!!!


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I also reset the float levels to 26mm on the nose FYI (they weren’t that off)


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[nino400F]

New DPR7ES-9 plugs (slightly hotter than D8EA)

Will put them on tomorrow and go for a run, then will post pictures of plugs.

In theory it should be running lean as my 4-1 exhaust is not stock and everything else is other than the leaner needle position.

To ascertain what your plugs are experiencing, you need to run chops at specific throttle positions. A general “go for a ride” and then examine plugs will not tell you what is happening “when” relative to your carburation.

Also, I doubt very seriously if a simple 4:1 system change will alter your throttle much unless it’s a top of the line product like MotoGPWerks or Hindle. Even then, probably not noticeably.

Yes I agree and I would like to do that, but how do I hold at three quarter throttle to see something without redlining and blowing motor? Or do you mean to hold at a certain RPM range? Or when I am driving it have different plugs with me, and cut the bike off after running with throttle up?


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[nino400F]

That may be an idea


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[nino400F]

Okay. So here is current setup

4-1 exhaust (MAC) with upswing reverse megaphone
Stock airbox
Paper filter

40 pilot
105 main
Needle in 4th position from bottom
Air screw set to 1.5 out from bottom
I bench synced the carbs to 1/16 an inch on engine side using the drillbit method
Triple checked floats at 26mm on the dot
New DPR7ES-9 plugs

Went around the block without doing proper plug chop at different throttle positions just to see how it was doing and didn’t want to try to read plugs at night.

Got back home and 1-4 look ok, 4 is actually sooty on one side and tan on the other, 1 is tanning with not much soot.

2-3 look like they are on there way to fouling. Black soot around except the head of the electrode is still a bit white from new..

I am at a WTF moment here.





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[scottly]

No clear tube test. All bowls have good fuel in them. What is the clear tube test? How to do it? What result am I looking for? What’s the point?


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The clear tube test shows the actual fuel level in the float bowls, which may vary from the measured setting. The test is done by fitting a piece of clear tubing to the bowl drains, and holding it next to the carb body. The fuel will enter the tube and rise to the same level as that inside the bowl. The level should be 2-3 mm below the top of the bowl; 2mm would be richer than 3mm.

[nino400F]

No clear tube test. All bowls have good fuel in them. What is the clear tube test? How to do it? What result am I looking for? What’s the point?


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The clear tube test shows the actual fuel level in the float bowls, which may vary from the measured setting. The test is done by fitting a piece of clear tubing to the bowl drains, and holding it next to the carb body. The fuel will enter the tube and rise to the same level as that inside the bowl. The level should be 2-3 mm below the top of the bowl; 2mm would be richer than 3mm.

Ok that’s on the menu tonight


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[nino400F]

No clear tube test. All bowls have good fuel in them. What is the clear tube test? How to do it? What result am I looking for? What’s the point?


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The clear tube test shows the actual fuel level in the float bowls, which may vary from the measured setting. The test is done by fitting a piece of clear tubing to the bowl drains, and holding it next to the carb body. The fuel will enter the tube and rise to the same level as that inside the bowl. The level should be 2-3 mm below the top of the bowl; 2mm would be richer than 3mm.

How would this work with 657B carbs as the drain screw when you pull it out there is no nipple to put a tube on?


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[robvangulik]

Hard to imagine needing 105 mains, with stock intake set up.  I don't recall what stock is.  78s?

Seems Mike Nixon removed the carb chart he once made available over at the motorcycle project site.

Cheers,

The subject is a 750, has been so for the last week.........

[TwoTired]

The subject is a 750, has been so for the last week.........

Ok, never mind.  I thought a 400f was being discussed.

[Bankerdanny]

Easy mistake to make Lloyd based on the poster's name and the lack of a signature with model info.

[jgger]

Ok it took me awhile to find it on my computer, but here is the clear tube test they have been trying to get you to perform.

[nino400F]

Thanks for that Jigger, I found a similar diagram in my Clymer but my problem is my 657B carbs don’t have a nipple to put the hose on. It is just a screw that you pull out, then you have a hole. I may be able to rig something up, maybe a small piece of pliable plastic tube, but it needs be be a good seal I would imagine.


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[jgger]

Go to the auto parts store and get a package of those small plastic vac. line connectors and just screw them in where the drain screw goes. Hook a length of clear tubing (as in the name of this process, pretty cleaver huh?) and have at it. The bike needs to be on the center stand. There ya go......... Bob's yer'  uncle!

[scottly]

Another trick is to take a length of clear vinyl tubing and heat it up in the center with a cigarette lighter, then slowly stretch the tubing into an hour glass shape. Let it cool, then cut the tubing in the narrow middle. You will have two tubes with a tapered end that can be "threaded" into the drain plug holes.  

[nino400F]

Those are both good ideas, yayyy I get to go to the Auto store tomorrow! Guaranteed I won’t walk out of there without a new tool and a lighter wallet LOL


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[scottly]

Vinyl tubing at Ace Hardware is pennys per foot.