#4 cylinder rich

[Drumagician]

I tried the plug wire swap, went for a 15 minute ride and here is what I found...
The #1 plug looked a little black; I would still consider ok, but more black than before; could just be how I rode it that time.
The #4 plug looked slightly less black than before the swap but still surely rich and much much darker than the remaining plugs.
The confusing thing is that it ran noticeably worse than before.
My plug reads seem to tell me its a carb issue but why would it run like crap.
I swapped wires back and it ran ok again.
I guess I have a fire and carb problem.

[dbeardslee]

just put new wires and caps on and they ohm'd out good but I will check.

My plug wires are a part of the coil and cannot be disconnect.

I was rereading the thread, and was a little confused by these two seemingly contradictory posts. Did you graft new wires into your coils? If you didn't, you might want to think about it. 30 year old high tension wires can loose voltage through the sheath - particularly if they get wet.

That being said, it appears that the problem largely stayed with #4, which would indicate carbs. I'd take another look at the float height and float integrity on #4. I'm thinking your primary problem is in the carbs, but the ignition is sounding a little iffy too.

When you adjusted your mixtures, did you use a colortune plug or a different method?

[Larrym]

Multiple Bogies???

The #1 plug looked a little black; I would still consider ok, but more black than before; could just be how I rode it that time.
The #4 plug looked slightly less black than before the swap but still surely rich and much much darker than the remaining plugs.

My plug reads seem to tell me its a carb issue but why would it run like crap.

I tried the plug wire swap, went for a 15 minute ride and here is what I found...

Finding out something and reporting it is the right step cause it gives us all something to work with. (Guides my little pea-brain along the troubleshooting process...)

The confusing thing is that it ran noticeably worse than before.

Mwuahaha... (In a GOOD way!) Likely that when you X-fered the plug wire that the #1 cylinder was getting an intermittent spark. I mean originally I figure you were running on three good cylinders and only one (#4) was a problem child. (Ran like an three cylinder 750 CC and that ain't bad, eh???) When #1 dropped out due to the intermittent spark along with #4 running so rich that it barely fired even with a good spark then you had only two good cylinders. (Thats when most folks really take notice and say, "What the Flock is going on here??!".)

I swapped wires back and it ran ok again.

Uhhh...these bikes aren't s'posed to run "ok". Eets a SUPERBIKE man!
Prob'ly went back to running on three cylinders again which is what you're already used to. (On Four fully functional cylinders there's definitely more "Joy" when you twist the throttle grip...)

I guess I have a fire and carb problem.

That's a good working theory for right now. It's what I would believe if I was seeing the same things you are.



I'd suggest that the spark problem be investigated/corrected first. That way when you find out what's wonky with #4 carb you'll have a strong spark to confirm that you got it right. (That "test run" should be quite interesting: Joy and Terror in equal portions.)

[Drumagician]

I agree with you guys. My method of tuning is by ear; its not that hard. #4 carb will be coming off soon. I'll let ya'll know what happens.

[geobiker]

Needle Jet?

While you have the #4 carb apart, remove the needle jet (emulsion tube) and check to make sure none of the holes are plugged or that possibly, a previous owner put an incorrect needle jet in that carb.

I fought a richness problem for a long time on my 79F (Standard) where 2&3 were very rich and 1&4 were good. Turned-out that my bike had SF (Special) carbs on it with two different style needle jets. Carbs 1& 4 had the series 266 X-2 (16 hole) needle jets and 2&3 had the series 301 X-2 (10 hole) needle jets. For whatever reason, possibly the Mac 4-2 pipes on my bike, it likes the series 266 jets. I obtained some used 266 series jets for carbs 2 & 3 and now all the plugs are clean and uniform in color.

Now I'm not saying you need to change your needle jets, but I would make sure that the one in 4 is of the correct type and that none of the holes are plugged. It is possible this may be the cause because the needle and needle jet control the bikes operation over a pretty wide range of operation.

Another thought is that although you set your floats at the same level, they may not actually be floating at that level. I would double-check to make sure that the float in 4 doesn't have a pin-hole leak. Also, you could do the check, by attaching clear tubing to the bottom of each carb to make sure the fuel level in all 4 carbs is the same. There is a thread on how to do this.

If you haven't removed the needle jets, you need to remove the main jet and the vacuum slide. The jet can then be driven from the bottom of the carb, out the top, using something soft. (I have used a #2 wooden pencil with good results). Clean it good if required. The holes are real tiny so I actually use a magnifying glass to look at them and make sure they look clean. When you put the needle jet back in, reverse the process. There is a groove in the bottom side of the jet that has to align with a tang in the bottom of the carb.

Good Luck!

[Drumagician]

Good info, thanks.

[natemoen]

An easy and effective way to check the floats for holes is to boil a pot of water and then after its boiled pour the water into a clean glass and then submerge the float in the hot water. If there are holes you will see a stream of bubbles coming from the hole. If you just stick it in tap water you wont find the holes so make sure you use boiling water.

If you want to change out your plug wires on your original coils here is the link to the tech tip http://www.xs11.com/forum/showthread.php?t=137 its pretty easy I did it on my coils before I changed over to Mikes XS Green Coils which is another option if you dont want to change the wires out.

To wet check your floats to see where they are all actually floating when installed here is the tech tip http://www.xs11.com/forum/showthread.php?t=76 little more time consuming but its a good thing to look at.

[motoman]

Back to basics again............pick-up coil wires......specially the white one......It will run fine with an intermittent cyl. loosing spark and you won't really even feel it but plugs will show something amiss......again, JAT, but worth the couple minutes it takes to pull on each one agressively. Chased my tail thinking carb issue till 3-Phase found wire seperation under insulation a couple days ago.......just saying....also this caused a very slight stumble 2-4000rpm range.

[Drumagician]

[QUOTE=motoman;296327]It will run fine with an intermittent cyl. loosing spark and you won't really even feel it but plugs will show something amiss......QUOTE]

I don't realu understand whatyour saying here; can you rephrase or elaborate?

[motoman]

Remove left side ignition cover(four allen-head screws), the small wires going to pick-up coil. Take hold of each one individually with both hands and try to pull apart at different sections of each small wire. If insulation stretches at any point, wire is likely broken inside. this happens over time since vacuum advance rotates back and forth continiously causing wire flexing and movement. If a suspect break is found, don't soldier as this will cause wire to become brittle on either side of solder joint and it will break again. A very tiny crimp connector without the insulator installed with a tiny piece of heat-shrink slid over and heat shrunk will fix the problem. Not saying that is the issue, but may be well worth checking before jumping back into carbs. May or may not save you chasing your tail with the carbs.

[Drumagician]

motoman,
I don't understand how a broken pickup coil wire would make the #4 cylinder not fire correctly.

[petejw]

hi Drumagician,
i was just checking out your sig,
your running 45 pilots instead of 42.5
and have a float setting of 25mm which
is on the rich side,
the bike will bog under acceleration, be hard to start on the
enricher when cold and idle really rough.
i see that your running pods but even still id
go back to stock settings of 42.5 pilots and 25.7mm
float height and ride the bike and see how it runs,
with the correct float height you shouldnt need to up
your pilot jets.

[motoman]

Drumagician, without engaging my brain(mentally lazy)thinking the ignition process out and what does what and when,( others here like 3Phase, TC to mention a couple can give a quick correct answer) this is a common issue that won't necessarily keep the bike from running, but can and will immulate a carb/fuel problem. Again, JAT and an easy check to eliminate another possible secondary ignition issue.

[Drumagician]

To all thise interested, I cleaned the #4 carb and put it back together. My richness issue went away thank god. My guess is that the main air jet was somewhat clogged. I don't realy know of any other air passages that could be clogged and effect all throttle positions. I have also had a stumble/hasitation off idle to about 2000 rpm since day one, even before the rich #4 cylinder. When I cleaned the #4 carb I also replaced all my pilot air jets to a 210 from a 180 and this greatly improved the stumble. Now my only remaining issue is a slight hesitation when cracking the throttle when riding steady; can't realy nail it to any rpm; seems to be sparatic. I did recently raise my jet needles one notch and that is when this issue started. i suppose I will need to lower them back down even though I like the performance currently (minus the stumble). I think I will try to go in between the set notches by using some washers. Almost there everyone!

[bikerphil]

Glad it runs better. I hope you are running inline fuel filters. I have found with these early type carbs that I always end up going back to the center needle clip position after experimenting. This is if you have stock needles.