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**The CyberPoet** · 08-16-2005, 03:18 AM

The obvious one:

Have you checked your gas tank for the presence of rust? If that's what's clogging up your carbs, cleaning the carbs only solves the symptom and the main problem remains to rear it's ugly head again...

CyberPoet's "What to do if you find rust in your motorcycle or boat gas tank" page at MotorcycleAnchor.com, fine American made motorcycle security anchor products

Good Luck!
=-= The CyberPoet

**Guest** · 08-16-2005, 03:23 PM

There's not any rust in my tank, but there is something there. We don't know what it is, but it's the same stuff that we just found in my bowls. It's fine enough that it's getting past both of my fuel filters. But you have to remember, I just cleaned all that stuff out of my carbs. The little bit of stuff in the tank shouldn't make a difference so quickly.

**The CyberPoet** · 08-16-2005, 03:29 PM

I would place a paper in-line filter into the fuel lines to help prevent this, as well as draining/cleaning the tank and figuring out what it was... remember that most sediment wants to fall to the bottom of the tank, close to the petcock. Could be anything from lawn debris to the remains of petro-eating algae living in the fuel.

Cheers
=-= The CyberPoet

**S�sser Tod** · 08-16-2005, 04:39 PM

Obviously it shouldnt, but it is doing a big difference. If everytime you clean the carbs the bike runs fine, that means that they were dirty.

That also means that all that crap is comming from somewhere, and that place would be your gas tank.

Why don't you clean it? I mean, it is a lot less work than cleaning the carbs every week.

**Guest** · 08-16-2005, 09:42 PM

I've cleaned the tank as best as I could. Thought I had it all last time, but evidently I was wrong. I know it's not helping the problem with there being crap in the fuel, but that's not the only problem. I just cleaned out everything, to the point that you could have eaten of them, and it's still doing it.

Tried putting my old tank on today, which I know for a fact is super clean on the inside, took the carbs apart again just to make sure they were clean (which they were), fresh gas, and still the same problem. I'm at a loss....

**kiba** · 08-16-2005, 11:00 PM

If it's not coming from the tank, then it might be the lines themselves. How old are they? Mine are about 3 yrs and if you rub them, a bit of rubber will come off so I'm going to replace them soon. Or one of your fuel filters might be failing and coming apart.

/kiba

Edit: I would of mentioned the diaphram in the petcock, but he said he swapped tanks...

**Guest** · 08-17-2005, 06:11 AM

That's thw weird thing is my lines and the filters themselves are pretty new, only a couple months old. I think we might be on to something tho....

We took it to another friend of ours and let him ride it and see what he thought. He said that while going down the interstate and it starting screwing up, he reached down, put the tank on prime so it would dump more fuel, pulled the choke back about half way to limit some of the air getting in the carbs, and said about half of the problem went away. I've heard a few people in shops here say that the DJ jet kits are usually still too lean when you install them. Something about the air and humidity and elevation and something else, I don't really remember. We're going to try to put bigger main jets in it and raise the float level a little bit, see if that helps it any. Crossing my fingers at this point....

**ThAzKat** · 08-17-2005, 06:23 AM

Originally posted by The CyberPoet

The obvious one:

Have you checked your gas tank for the presence of rust? If that's what's clogging up your carbs, cleaning the carbs only solves the symptom and the main problem remains to rear it's ugly head again...

CyberPoet's "What to do if you find rust in your motorcycle or boat gas tank" page at MotorcycleAnchor.com, fine American made motorcycle security anchor products

Good Luck!
=-= The CyberPoet

DITTO, first thing that crossed my mine! If the carbs have been cleaned and the true monster comes back then there is another issue and not the carbs.
Clean out the gas tank
clean your petcock
change the diaphragm in the petcock
And get a new mechanic

Just Kidding
edit: I should have read through!
lets see Clean tank, clean carbs, new lines
check the petcock and make sure there are no pinches in the lines or weak area's that can collapse while the bike is running under vaccuum

**The CyberPoet** · 08-17-2005, 07:49 AM

Re: Um... Problems?

Originally posted by kiba

If it's not coming from the tank, then it might be the lines themselves. How old are they? Mine are about 3 yrs and if you rub them, a bit of rubber will come off so I'm going to replace them soon. Or one of your fuel filters might be failing and coming apart.

Recommended replacement cycle: fuel lines and vacuum lines every 4th year for most locations... sooner if there's any sign of degradation involved.

Originally posted by RoadRacer61

Now, it's starting to do it around 5000 or so, but not all the time. You can clutch it, rev it to clear it out, and sometimes it will get better, sometimes not.

Q: Has it been on an exhaust gas analyzer or dyno (which normally have them built in)? This will give you the definitive answer to where it's going too rich or too lean.
Note that turning on the choke (actually an enrichment circuit) does not restrict the air coming in -- it dumps more fuel into the mix.

Given the info you've posted so far, this is my best estimates:
(A) It has not been on an exhaust analyzer lately. Midwinter results in Louisville would be far different than early summer results in Daytona (although the elevations are only 800 ft apart, there would be radical changes in humidity rates, temps, plus your area may use special fuels in winter that contain MTBE which will throw-off the exhaust readings once you go back to regular "summer gas").
(B) The lines or the filters have seen better days. Replace the fuel & vacuum lines, as well as the fuel filter(s).
(C) The petcock vacuum diaphram may be acting up and need replacement, although based on the symptoms of which RPM's the problem is occuring in (and the fact that switching to prime didn't immediately clear them all), I'm inclined to downplay the likeliness of it.

Good Luck!
=-= The CyberPoet

**Guest** · 08-19-2005, 01:40 PM

Ok, I figured it out, and I actually kinda feel like an idiot now

. I took it to one of my buddies shops here in town and hooked it to an exhaust analyzer. It showed that it went REALLY lean as soon as you gave it any kind of throttle at all. To me, that narrowed my choices down to 3 major things.

1. The float levels were too low and as soon as you gave it throttle, it was sucking the bowls dry.

2. My inline fuel filters were causing a restriction and not letting enough fuel flow.

3. My petcock was screwed and cansing bad fuel flow.

Any way you looked at it, I had a fuel flow problem, not a carb problem. (at least this was my guess at the time). I knew my floats were ok, since we just did a rebuild on the carbs and checked all of that stuff. Number one eliminated. Decided to remove my fuel filters and ride it to see if that was part of my problem. When I took the first filter out, I thought "man, this thing is a lot longer than when I put it in..." So I looked at it closer. Turns out, the heat from the engine and the added pressure of the hose clamp had caused the ends of the filter to stretch out and collapsed the ID of both the inlet and outlet. There was less than 1/8" ID for fuel to flow. Now how are you supposed to get enough fuel to run up top with a little hole like that? So I replaced the fuel lines again, this time with a 3/8" ID line and no filters. Bike runs like a champ now!

**katana bob** · 08-19-2005, 02:11 PM

glad you found the problem, but put filters back in asap or you'll be pulling those carbs again in no time.

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