Had to pull over on the highway 3 times today.... :(

[skids]

So, did you try running the bike on prime?

[sparkfly88]

When it started to sputter and feel like it was loosing cylinders...yeah, I would try reserve first, then prime.

No change

Then when I got to where I was going( it did it right before my destination) I let it sit for a work shift...

Started it up and it was STILL doing it.

So I gimped it to the fuel station, and it was fine.

[TomB]

So, I think its a fuel level issue...
So, it seems to only pitch a fit when Im a little lower on fuel

You may have something there. A full tank gives a greater head, if you have kinked fuel pipe or other partial blockage a greater head of fuel will push through more fuel compared to a low fuel tank.


.

[Stoners420time]

?

I had some problems like your speaking of, my fix was to replace the fuel line's with car brake line's, tight bends but it does not look bad and it run's great at all speed's. good luck tho.

[sparkfly88]

Okay, so today I changed out the lines and filters.


Now then, when I had the tank off, I checked all operations of the petcocks.
Sucked on the vac line, fuel comes pouring out on both sides, in all modes, at the same flow rate.
Ditto with the prime on both.

SO, I put the new lines, and new filters on.

Put tank up on bike, installed lines to carbs.

Flipped to prime.

Started bike.

One filter filled INSTANTLY almost completely filling it.
The other, barely did, maybe a third of it filled, just enough to contact filter media.

I took the bike for a ride down the road, and came back.
Filters were at the same levels.


SO...

What gives

[skids]

Maybe the floats for those two bowls were already full which cuts off fuel from the line. You rode the bike, dropped the floats and the air was flushed out...

[sparkfly88]

Sorry, i mean the filters were at the same levels...meaning they didnt move.

One was still full, the other barely had any in it

[skids]

PS, this does not apply to you if you had problems previously in the prime position, but I have an xs11 (standard) that has occasional issues with fuel starvation at about 60 mph and I have to switch the left petcock to prime to alleviate the problem. I am guessing that the spring is a little too stout for the diaphragm in the petcock (yes I stretched it a little once when I rebuilt the petcock). With mercury sticks you can see that columns of Hg drop some when the throttle is open and constant...at least on my bike. That could cause the vacuum operation for fuel flow to malfunction.

[TopCatGr58]

Hey Spark,

Are the filters on their side or vertical? Having some air in the filter doesn't mean that it isn't flowing fuel. The filter doesn't slow down the fuel flow, and sometimes once the fuel gets to the outlet, it can just flow THRU the filter without necessarily filling UP the filter chamber.

You can test it by just pulling the line downstream from the filter and open the line and see how much/fast the fuel flows from the hose, you'll probably find that it flows just as fast as the other side.

T.C.

[sparkfly88]

Well, I rode to work and back today.

Then adjusted my idle which was too high and colortuned it.

After all of this, I look at the filters, and they have basically matched each other.

I'm at 51 miles for this tank. Let's see if around 80 it has a fit about the fuel level again.

And yes topcat, they are sideways.

[sparkfly88]

Well, I passed 80 miles with no incident.

See how long this lasts.

[sparkfly88]

So returning to this problem...

Yesterday at 96 miles my bike started bogging down again...I think on 2 cylinders....I'd turn it to reserve, or prime and no change would happen.

So I gimped it to the fuel station and pumped 3.66 gallons into it. ( right up to the neck till it bubbles )

That put me at 26.9 mpg for that tank driving to and from work around town and one highway trip of 10 miles or so.


Now it seems I'm missing a cylinder at low rpm...
I have the feeling my fuel saga yesterday caused a float to get stuck. I hit my carbs with a rubber mallet but no change.
Both fuel filters are filled to the brim which is nice.


Time to go in AGAIN

[sparkfly88]

Tomorrow I'm gonna a pull it into one of my bays at work and tear it down yet again.

I got home today and figured out it is my number 2 cylinder this time.

Pain in my neck!

[sparkfly88]

Well I disassembled my bike, AGAIN and went through the carbs AGAIN

I didn't see anything out of the ordinary...gave em a good blow out with parts cleaner and high pressure air at the shop.

Reset all my floats to a more accurate level, which looks WAY better than what I had before.


Synced, colortuned, synced.

Purrs like a kittin on crack

[Pizzaboy]

Is it possible, you have the broken wire coming out of your pick up coil on the left side of the engine? Are you absolutely sure its a fuel problem and not an ignition problem? Just my thoughts as I was reading your misfortune.