OK Carb Guru's

[DMPLATT]

Here's the scoop. About 3 weeks ago or so, I decided to check my air filter. I've only had this bike for about 2 months. The air filter was dry as a bone. I cleaned and oiled it. After that I noticed it was just a TAD harder to start in the morning (choked). Other than that it seemed to run good. I started an oil leak after that, so I check the air filter again and find liquid sitting under the foam filter. I assume it's oil, however I remember a strong Gas smell. (The oil leak was the clutch cover).
After another post about this, I clean it in gas, then Dawn and let dry. A few days later I again noticed the liquid under the foam filter and I'm certain now that it IS gas. I cleaned the filter yet again, carefully washing it free of the gas I used to get the oil out.

With me so far? Sorry this is long winded.

Ok, during this time my bike (when warm) went from idling at about 1500 RPM, to about 1100-1200 RPM. This went on for about a week. Well, when I was getting ready to go on the Florida Ride, I pull the plugs. # 1 & 2 where ALMOST white, and # 3 & 4 where ALMOST black (Mostly tan with a little black).

One guy on the ride said when he was behind me it smelled like I was running NASCAR fuel. I have NO leaks and the bike runs very well (I'm new to the bike - so maybe it's not at it's peak).
On the ride home from the Florida ride, about 100 miles of nice country riding of about 70 MPH, I just checked the air filter and DO have a strong smell of gas. I'm sure it's evaporated since I haven't ridden today. I pulled one of the Lean looking plugs and it looks fine, slightly tan - yet probably just a tad lean.

Finally the question: Could the new plugs I put in about 1 1/2 months ago be bad? The factory manual just says when a white or black plug exists - change it. ?????

I can't understand the strong smell of gas in the air filter? I'm not leaking any where else. However, I noticed on the bottom of the air filter cover, there is a small round boss that is bent and deformed. I also notice a small round hole for this in the bottom of the air box and it has a small metal "Clip"? Not sure if I'm obstructing something? Maybe I bent this boss upon my initial air filter ordeal, then piched something when Re-installing it? It's bent beyond repair, but I never force things like that. It could have been bent before, maybe I didn't get it seated?
Anyway, I can't get this boss seated or straightened. It doesn't seem to be fitting properly. I'm thinking now, that when i first did this, I remember the tab from the front of the air box NOT being seated. I wonder if this is why it runs a little lower on the rpms?

Thanks and sorry for the long winded post. I just want to tell everything I know. (Yeah - I'm suprised myself)
Thanks.

[Anonymous]

If you have gas in your air filter, it's probable that either your floats are too high on the rich cylinders, or that your float needles are sticking on one or more cylinders. This will cause fuel to overflow from the bowls in to the airbox.


-Shane

[earlfor]

Dave, airflow is through the airbox, into the carbs and then into the cylinder.
It is not possible for fuel to flow into the airbox when the engine is running.
Therefore, your problem occurs when the engine is not running. If your vacuum petcock is working properly, it is not possible for fuel to flow into the carb bowls when the engine is off and no fuel can build up in the airbox.

So........fact........your fuel petcock is faulty.

Now, even though the petcock is faulty and allowing fuel to seep into the carb bowls, if your float needles were seating as they should, they would stop fuel from continuing. Possibilities...........your float needles are worn and need replacing, or you have the float height on the 3 and 4 carbs set so high that the float is being pressed against the top of the float chamber before the needle seat is activated to close the valve.

My suggestion..........remove the carb rack, reset the float heights on all carbs and then with them upside down and the float tang resting on the float needle and closing the valve, check for fuel seal by blowing into the fuel line that feeds the carbs. You should not be able to blow air through it.

Earl

[DMPLATT]

Thanks for the replies guys.

Next question. How Urgent is this? I can live with it til it gets worse, as long as I'm not causing major engine damage?
For me, except the slight idle variation, it runs exceptionally well. It sh$ts and gets enough for me. :twisted: :twisted:

[earlfor]

I would disconnect the fuel line from the petcock whenever I shut the engine off then. If there is enough fuel to saturate the air filter, there is certainly enough to drain into the crankcase oil. I consider that a serious problem.

Earl

Thanks for the replies guys.

Next question. How Urgent is this? I can live with it til it gets worse, as long as I'm not causing major engine damage?
For me, except the slight idle variation, it runs exceptionally well. It sh$ts and gets enough for me. :twisted: :twisted:

[DMPLATT]

Thanks Earl.
What's weird is that after sitting for a day, The gas has evaporated. It only seems to be there after a run???? It doesn't leak when just sitting?

I just remembered something else. When I had an oil leak, I took a stiff wire and poked down thru the bottom of the air box (thinking I was cleaning out a vent tube). Could that have damaged something?

I'm curious as to what is at the bottom of the air box? The manual doesn't really specify and I can't see?

[earlfor]

"What's weird is that after sitting for a day, The gas has evaporated. It only seems to be there after a run???? It doesn't leak when just sitting?
********* Fuel doesnt flow from the carb to the airbox. It flows downstream with the engine running. The airbox can only be soaked if there is a fuel leak.



"I just remembered something else. When I had an oil leak, I took a stiff wire and poked down thru the bottom of the air box (thinking I was cleaning out a vent tube). Could that have damaged something?"
***************The only thing in the bottom of the airbox is a small drain. Poking a wire through it would not cause any problem.
( I havent a clue how poking a wire through an airbox vent could be considered a solution for an oil leak.... ??????????? huh...say what! :-) )

Earl :-)

Thanks Earl.
What's weird is that after sitting for a day, The gas has evaporated. It only seems to be there after a run???? It doesn't leak when just sitting?

I just remembered something else. When I had an oil leak, I took a stiff wire and poked down thru the bottom of the air box (thinking I was cleaning out a vent tube). Could that have damaged something?

I'm curious as to what is at the bottom of the air box? The manual doesn't really specify and I can't see?

[DMPLATT]

( I havent a clue how poking a wire through an airbox vent could be considered a solution for an oil leak.... ??????????? huh...say what!

Uhhh, I'm Polish?? Just kidding. (No offense to any Polish people)...

After I oiled the filter (lightly) I noticed a couple oil leakes. Also after a HARD run I noticed a few drips coming from the vent tube. I was thinking it might be coming from the vent, so I wanted to make sure it the vent tube was clear. Later I found the clutch cover a bit loose and that took care of the main leak.
Honestly, I can't trace the vent tube, so I don't really no where it goes. Ron asked me if the vent tube was running into the air box. I'm not sure what he meant.

Is there more than 1 vent tube? Like 1 at the bottom of the air box, and another one coming from the engine?

The other strange thing is that I'm getting great fuel economy. Somewhere in the 45 to 48 mpg. Yet I do have some vibration, and after reading these forums, I think I need my carbs balanced.
I'll check it again tonight after I get home and see if there IS gas again in the airbox.
Also, with the idle dropping from 1500 to 1100, can I just adjust the idle screw until I can get the carbs balanced? I'm thinking this would be ok?

Thanks again. I'm seeing carb rebuild in my future......

Oh and NO gas in the oil.......

[DMPLATT]

Ok Earl,
I either have been smoking too much crack lately, or a complete idiot. Or maybe both. Maybe I hadn't let the air filter dry? Maybe It's moisture from the rain? I had ridden in the rain a few times last week?
After about a 50 mile run after work there is no gas in the air box. The idle was still low, about 1000 to 1100 rpm and it wanted to die at stop lights. I adjusted the idle screw back to 1500.
Curious as to what the strong fuel smell that someone behind me mentioned? Un burnt fuel?
It runs great, but there seems to be a bit of vibration. I'm confused about balancing the carbs. Does this actually change the mixture? In other words, I have 2 plugs looking a tad rich, and 2 plugs a tad lean. Balancing out would correct this?

Thanks.
Scotty has vaccuum gages and has offered to help, whenever I can get up there that is.

[KEITH KRAUSE]

If you want to know how your float valves are sealing, try this. Install a clear fuel line. When you shut the bike off put it on the sidestand or centerstand, but put it on the stand that you've been using during this problem. Your fuel line will be full, with maybe a small bubble near the top. Check the bike a while later and see if the level has dropped. Then check again in the morning. If the level has dropped, your valves or valve seat o-rings are not sealing or the floats need adjusting.
Make sure the clear fuel line is CLEAR. Old clear fuel line turns the same color as fuel and you can come out in the morning and think the line is still full, when it's really completely drained. If any doubt, turn the petcock to prime as you're watching the fuel line. If it's dry, you'll see the fuel rush down.
Do this check a couple of nights.
As for the petcock, remember, even if the petcock is good, the fuel still in the line and in the carb passages can drain down past the float valves and get in the crankcase and in the airbox. A few ounces after each long shut off can equal a lot of fuel in the crankcase or airbox after a while. This will smell a lot and the fuel will get past the rings and enter the crankcase breather. From there it will drain down the crankcase vent line and into the airbox. Also, with this problem, you would not notice a loss of fuel mileage.
Your plug reads could also be a poor carb synch, dirty carbs, etc.

[DMPLATT]

Well, after going thru this in my small pea sized brain again. I've come to the conclusion that I must have gotten water in the air box and assumed it was gas.
The seat on my GS 750E goes up the tank a bit. Right below that is where the air box intake is. When my bike sat in the parking lot at work a few days last week, we had some torrential down pours. I also hit a couple squals on the way home. I must have gotten rain in thru the air intake and since the little boss on the bottom of my air box cover is bent and I don't think it seats in the bottom of the air box, it must not have let water drain out? Could this be logical?

This would also explain why I had 2 plugs that looked a bit lean last Friday night? My dad used to tell me that a little water in the gas cleaned the ole plugs up. So I'm assuming that a little water in the ole air box would do the same?

That would explain everything except the "Nascar Fuel" smell Orval said I had when he was behind me???

Oh well, it doesn't bother me and as long as I can keep everyone behind me...... :twisted: :twisted: :twisted:

Unless anyone has any insight, I'm thinking problem (or NON problem) solved?????