Bike: 1999 M900s
Symptoms: A couple of months ago, Stillie was riding my bike to work and got about a mile and a half from the house. It hiccuped once and then cut off almost as if out of gas (which he knew was untrue). Getting it home, it will run for as long as we're dumping fuel or starter fluid into the intake (good on air and spark). Replaced the fuel filter, which was in need of replacing. Still doesn't run. Fuel is getting to the carbs and the bowls do refill when emptied. Inspected the carbs and nothing seems gooey beyond the usual amount of residue. The only thing amiss was a cracked hose.
So here's with the hose identification problem. The hose comes from the little plastic triangular breather-ish-looking box that is mounted on the outside of the frame. The hose is wrapped in a spring to keep it from kinking. It has a filter in the line. It goes to a point mounted in between the carbs. What is it? I can snap a pic tomorrow. This hose had a small crack in it that had light debris along the thickness of the hose, indicating that we didn't cause the crack on disassembly.
So the mystery is that it looks like fuel is getting to the carbs and should go through the carbs, and the only thing amiss was this hose that was cracked. What is that hose and would the crack cause it not to run? What else should I inspect?
The hose is a carb diaphragm vent hose.
I don't think that's your problem.
Quote from: ducpainter on August 07, 2008, 07:05:12 PM
The hose is a carb diaphragm vent hose.
I don't think that's your problem.
Vacuum issue somewhere/somehow?
Possibly the vacuum line to your fuel pump is compromised, or your fuel pump has expired.
Quote from: Speeddog on August 07, 2008, 10:23:07 PM
Possibly the vacuum line to your fuel pump is compromised, or your fuel pump has expired.
That's my thought as well.
The hose that goes to the little plastic pod just has to sit in idle air. So make sure you put it back. If the hose is slightly cracked, it won't actually matter much, but you might as well replace it.
As said before, I'd check into your fuel pump.
If you remove the hose between the pump and carbs gas flows freely from the pump. We discovered fuel in the carbs last night after a quick tear down. Tonight we plan on rebuilding the carbs but I don't think they are at fault. Kind of at a loss here. ???
Doesn't really make much sense...
If the bike has a vacuum operated petcock I'm wondering if the fuel flows when the bike isn't running and was being diverted or shut off when it was.
Even then...it should at least start.
Shooting in the dark here....
Perhaps the fuel pump is jacked, such that with vacuum signal it's shutting off the fuel supply.
I've not heard of this failure mode, but.....
Try running it with the vacuum line to the fuel pump unhooked and plugged so that it's not an air leak to the manifold.
As DP said, maybe the vacuum petcock is not operating correctly.
Very odd.
Ok, so here's the drama as it unfolded tonight...
We brought her to a friend's place who is way more knowledgeable than either of us. He's an SV guy but we like him anyway. He teaches us about carburetion in exchange for Guinness. How could we not like the guy?
We finished cleaning out the carbs. We blew air through everything and reassembled the rest of the bike most of the way, just enough to test to see if it would run. Fired right up. But wait, there's more. It sounded very wrong to me. Stillie looked at me puzzled, "Isn't that how it's supposed to sound?" It sounded strangely.... thumper-ish. ACK!!! Only one cylinder firing!!! Now we have created an electrical problem and it's time to find it. Somehow one of the connectors on the bottom of the coil for the vertical cylinder got bumped off, so after a few dry chuckles and embarrassed coughs, it all came together. Both cylinders roared to life.
YAYAYAYAY!!!!!!
Stillie geared up and off we went. I was so relieved that we fixed the problem, but perplexed at what it was. It really didn't sound like it was a carb issue because they both died all of a sudden. Weird.
We got down the road a bit and he started to pull over and then I saw it. She was so mad that we hadn't fixed the problem that she shot HUGE flames out the ass end. And then she died the same death she did before. She'd start and idle, but she wouldn't take any throttle. Well poo.
So now we do know much more about the problem. Those in the fuel pump camp are probably on the right track more than we were. Yes, the carbs were an issue, but only a secondary problem caused by my delay in fixing it.
What we do know is that the bowls are for some reason being drained faster than they can be filled. So it's either a vacuum issue with the pump demand or the pump is in the process of giving up the ghost. I'll keep everyone posted. And thank all you fuel pump nay-sayers for making me feel like an ass for doubting you!
And are there any other gems of wisdom or alternate theories anyone cares to offer?
Pump rebuild info here:
http://ducatimonsterforum.org/index.php?topic=4274.msg65213#msg65213
And here:
http://ducatimonsterforum.org/index.php?topic=6218.msg106761#msg106761
And here:
http://www.fokust.com/gallery/fuel_pump
This is really simple/stupid but I have to mention it, because it's caused similar symptoms for me, twice. (And, in my defense, my Duc tech once)
Thank doG the PO warned me about it, so that after 15-20 minutes of running my battery down and scratching a hole in my head, I remembered him mentioning it.
If I'm not really careful when I put the tank down, I'll get a crimp in the line that goes from the fuel filter down to that vaccum/petcock thing. Sometimes, it's bad enough that once the float bowls run dry, it simply won't start. But if it's just partially crimped, it will start and idle fine, but the second I get on it, it coughs and groans like Granda Simpson smoking a doob. Lift the tank, the crimp is removed, runs fine, and will start again and run for a few minutes. Tank down, not so much.
Just a thought, check it out. Believe me, I know how bad it sucks chasing your tail when the simple answer is staring you in the face and shouting "LOOK AT ME, DUMBSHIT." ;D
Quote from: dlearl476 on August 09, 2008, 11:09:24 AM
This is really simple/stupid but I have to mention it, because it's caused similar symptoms for me, twice. (And, in my defense, my Duc tech once)
Thank doG the PO warned me about it, so that after 15-20 minutes of running my battery down and scratching a hole in my head, I remembered him mentioning it.
If I'm not really careful when I put the tank down, I'll get a crimp in the line that goes from the fuel filter down to that vaccum/petcock thing. Sometimes, it's bad enough that once the float bowls run dry, it simply won't start. But if it's just partially crimped, it will start and idle fine, but the second I get on it, it coughs and groans like Granda Simpson smoking a doob. Lift the tank, the crimp is removed, runs fine, and will start again and run for a few minutes. Tank down, not so much.
Just a thought, check it out. Believe me, I know how bad it sucks chasing your tail when the simple answer is staring you in the face and shouting "LOOK AT ME, DUMBSHIT." ;D
I like the theory, but would it have happened twice in a row with multiple reseatings? I know that we were VERY VERY VERY careful when we were reseating the tank, but I'll certainly take a good look at this. I do have a rather large battery crammed in there, but the lines coming from the fuel tank are at the back and the battery is at the front. I will inspect the length of it, though, to ensure it is open the whole way.
Quote from: Ducatista on August 09, 2008, 06:36:46 PM
I like the theory, but would it have happened twice in a row with multiple reseatings?
On my bike, it happens every time I lift the tank and put it back, unless I physically guide the hose away from the vaccum petcock thing. Especially since I installed a new line when I did the FCRs. At first, I had the fuel filter clamped too tight in the clamp and it' wouldn't turn. AFAIK, it needs to, so that it can rotate and let the hose lay correctly, without a crimp. Another thing to look at, if your filter IS clamped tight like mine was, that could be an issue as well, putting a crimp right there when you put the tank down.
Quote from: dlearl476 on August 10, 2008, 10:02:10 AM
On my bike, it happens every time I lift the tank and put it back, unless I physically guide the hose away from the vaccum petcock thing. Especially since I installed a new line when I did the FCRs. At first, I had the fuel filter clamped too tight in the clamp and it' wouldn't turn. AFAIK, it needs to, so that it can rotate and let the hose lay correctly, without a crimp. Another thing to look at, if your filter IS clamped tight like mine was, that could be an issue as well, putting a crimp right there when you put the tank down.
I'll take a peek. Thanks for the hint!
So I ordered the parts for a fuel pump rebuild. I'll let everyone know how it goes and hopefully I'll take enough good pics to post up in the how to section.
Quote from: Ducatista on August 11, 2008, 07:50:44 PM
So I ordered the parts for a fuel pump rebuild. I'll let everyone know how it goes and hopefully I'll take enough good pics to post up in the how to section.
I would've suggested an electric pump, but it can be a hassle to find a good mounting point. Good luck with the rebuild, it should be simple enough.
However, definitely buy a manual fuel shutoff valve if your bike has the vacuum operated petcock. Those things are prone to fail and if you haven't checked it yet, it might be part of the problem anyway as someone suggested. The only good thing about the vacuum petcock is that it is automatic until it fails.
I would suggest getting one of these: http://www.motionpro.com/motorcycle/partno/12-0036
No love on the fuel pump rebuild. She's still not running well. She still won't take any throttle.
Does anyone know what the little round thingy is underneath the tank? Not the fuel filter. This is the view with the tank up and looking towards the tail right in the area of the hinge. I'm touching the part in question. Could it be the culprit?
(http://i147.photobucket.com/albums/r286/Desmogirl/DSC_3015.jpg)
It`s the petcock.
When malfunctioning, fuel just flows pass it, doesn`t shut off due to vacuum diaphagms bad inside.
So we found something odd. The breather tube that goes from the tank to the mysterious canister under the seat was full of water. I'm pretty sure that ain't good. What would cause this? We're still at the point where if it has been sitting for awhile, it will run fine. As soon as you take it up and down the street, it dies under power. :-\
We did verify correct assembly and installation of the rebuilt fuel pump. When you disconnect the hose and hit the starter, fuel does indeed come spurting out.
Quote from: Ducatista on August 25, 2008, 07:59:20 PM
So we found something odd. The breather tube that goes from the tank to the mysterious canister under the seat was full of water. I'm pretty sure that ain't good. What would cause this? We're still at the point where if it has been sitting for awhile, it will run fine. As soon as you take it up and down the street, it dies under power. :-\
We did verify correct assembly and installation of the rebuilt fuel pump. When you disconnect the hose and hit the starter, fuel does indeed come spurting out.
I'm not that familiar with the emissions system on these bikes, but I wouldn't think water should be in there unless it drains the air box and water got in the air box. Other than that, I don't know where water would come from. ??? But I don't think that is your problem.
I don't remember if this has been mention yet, but did you check to make sure the tank is venting properly. This sounds exactly like a venting problem that someone I know had recently.
Quote from: Jobu on August 25, 2008, 08:22:15 PM
I'm not that familiar with the emissions system on these bikes, but I wouldn't think water should be in there unless it drains the air box and water got in the air box. Other than that, I don't know where water would come from. ??? But I don't think that is your problem.
I don't remember if this has been mention yet, but did you check to make sure the tank is venting properly. This sounds exactly like a venting problem that someone I know had recently.
The tube doesn't go near the airbox. I've tried running it until it dies and then popping the cap, and there is no suction sound and the bike will not restart until it has been sitting for awhile. I'm not saying that's not the issue, but those are the symptoms I've observed so far.
Quote from: Ducatista on August 25, 2008, 08:35:01 PM
The tube doesn't go near the airbox. I've tried running it until it dies and then popping the cap, and there is no suction sound and the bike will not restart until it has been sitting for awhile. I'm not saying that's not the issue, but those are the symptoms I've observed so far.
Well, you can try running it with the cap open the entire time, that will rule that out, but I don't think that is the problem.
You need to make sure the needles in the carbs are properly raising. This could cause a problem. There are couple of ways to check this. The easiest way is to take the air filter out and reach in and push the black slide in at the top of the carb. If the slide returns, the diaphragms are good. These are probably fine, but good to rule it out.
As a test, bypass the vacuum petcock, perhaps it's partially plugged or stuck nearly closed.
Quote from: Speeddog on August 26, 2008, 12:41:12 AM
As a test, bypass the vacuum petcock, perhaps it's partially plugged or stuck nearly closed.
Just replace it with a manual one.
Quote from: Jobu on August 25, 2008, 09:20:50 PM
You need to make sure the needles in the carbs are properly raising. This could cause a problem. There are couple of ways to check this. The easiest way is to take the air filter out and reach in and push the black slide in at the top of the carb. If the slide returns, the diaphragms are good. These are probably fine, but good to rule it out.
In the carb rebuild, we checked their function and they slid smoothly and returned as normal.
Quote from: Speeddog on August 26, 2008, 12:41:12 AM
As a test, bypass the vacuum petcock, perhaps it's partially plugged or stuck nearly closed.
In our testing, we took off the hose on the other side of the fuel pump, and fuel gushed out. If the petcock was stuck partially or fully closed, we wouldn't have gotten so much fuel spurting out. Please correct me if I'm mistaken!
Quote from: Ducatista on August 25, 2008, 07:59:20 PM
So we found something odd. The breather tube that goes from the tank to the mysterious canister under the seat was full of water. I'm pretty sure that ain't good. What would cause this? We're still at the point where if it has been sitting for awhile, it will run fine. As soon as you take it up and down the street, it dies under power. :-\
We did verify correct assembly and installation of the rebuilt fuel pump. When you disconnect the hose and hit the starter, fuel does indeed come spurting out.
If there was water in the emissions cannister the hoses under the tank are reversed.
Maybe you're feeding water into the vacuum line?
Ok, so I have a case of bad gas... uh, I mean... the bike had bad gas in the tank. It hadn't been in there long before the failure, in fact Stillie had just gotten gas (*ding ding ding*) when the problems started happening. So we drained what was there and it was bright dehydrated-pee yellow. YUCK!!! So poured some known good gas in. Cough sputter wheeze, and she roared to life after several tries, working the bad gas through. So then we get ambitious. We take her for a spin on this little bit of good gas. She dies after awhile. There's still a bit of gas in the tank. Hmmmm... we didn't run out of gas. So we disconnected the spark plugs, unhooked the tubes, and drained some out. VERY INTERESTING. This bad gas floats. No water, just the smaller bit of yellow ickness floating on the top. So now comes the fun part. We get to purge the entire system. The bad gas floats, so every time we run low, this problem will occur unless we get every drop out from head to toe (or tank to carbs, as the case may be).
So the primary problem was the bad gas, the carbs were indeed thoroughly gummed, so that was secondary and needed to be done anyway.
This is the theory, at least.
Anyone know what kind of bad gas floats?
Quote from: Ducatista on September 02, 2008, 05:58:08 PM
<snip>
Anyone know what kind of bad gas floats? <snip>
Not to be a wise guy, but "not gas".
Water is heavier and would sink to the bottom, so is Diesel, but they would mix.
Have kids? Was someone playing "Gas Station". My mom has a not even Super 8 (yep, another fossil) of me playing gas station with dad's new Merc!
Is all well after a thorough clean out?
Quote from: Bigbore4 on September 02, 2008, 07:15:49 PM
Not to be a wise guy, but "not gas".
Water is heavier and would sink to the bottom, so is Diesel, but they would mix.
Have kids? Was someone playing "Gas Station". My mom has a not even Super 8 (yep, another fossil) of me playing gas station with dad's new Merc!
Is all well after a thorough clean out?
Well, the clean out is going to happen tomorrow. I'm keeping my fingers crossed that it will work!
It is whatever came out of the 89 octane pump the last time Stillie filled up. No kids except the furry kind. It also burns... kinda... but not well.
I can't imagine what the yellow floating stuff is. If you figure it out, let us know. I would save a sample and contact whomever the gasoline company is if you believe the stuff came out of the pump. Anyway, after cleaning out the tank I would use some Techron or Sea Foam with the fresh gas.
I thought you had already drained the tank and refilled it to no avail ??? That should have been one the first things suggested.
Oh well, at least you figured out what the problem was. [thumbsup] And definitely add some kind of carb cleaner/fuel additive as Howie suggested.
Quote from: Ducatista on September 02, 2008, 07:32:24 PM
Well, the clean out is going to happen tomorrow. I'm keeping my fingers crossed that it will work!
It is whatever came out of the 89 octane pump the last time Stillie filled up. No kids except the furry kind. It also burns... kinda... but not well.
Did that do it?