So after I tidied up my wiring a bit installing a vizi-tec taillight module, i fired the bike up. Things were going well... Got it up to idle, let it warm up, revved it up and down to 5 or 6k a few times and everything seemed well.
While it was idling, i was checking all my lights and discovered I had forgotten to plug in the front brake switch. no big deal. Plugged it in, went to rev again, and in doing so, it sputtered as I got to about 3k and now it'll die when i try to rev it past there.
Stock mikuni carbs, seems to idle fairly well still. Smell of gas after it dies.
I haven't tinkered with the carb settings any and have left the ignitech with same profile as before (and it was working fine, though not yet dyno tuned).
I don't know much about carbs. I get the principles behind it, but have never tinkered with a set before. From my reading, I am not really sure which problem I have, but it seems like it could be a stuck float? I'm not sure while it will come to idle right now though and die as i roll on the gas.
Thoughts? I need to fix the carbs, can't convert to FCR's until the next winter.
Anybody in DFW want to help me fix this over some beer? I'll provide beer for efforts, and pizza for success.
has the bike been sitting for more than a couple of weeks?
just about 3 weeks (not quite 3). rode it for quite a long time on a weekend in the middle of February.
I pulled the airfilter to inspect and clean it, wiped out some grime from the bottom of the airbox by the drain hose and made sure no dead bugs had made there way down in there. put everything back together, and it started right up on about the 2nd or 3rd push of the starter with the choke engaged.
Quote from: ato memphis on March 04, 2010, 11:08:22 AM
just about 3 weeks (not quite 3). rode it for quite a long time on a weekend in the middle of February.
I pulled the airfilter to inspect and clean it, wiped out some grime from the bottom of the airbox by the drain hose and made sure no dead bugs had made there way down in there. put everything back together, and it started right up on about the 2nd or 3rd push of the starter with the choke engaged.
Is there ethanol fuel in the tank?
no more than the normal Texas amount. I put 93 in recently from Shell.
Interestingly, I let it sit for awhile, and when i fired it back up, no problems... Idled fine (just like before) and would rev up and down pleasantly through the rev range. Sounded great...
...Until it warmed up more.. 10m or so, and it would stall as i gave the throttle even a little bit of a twist...
Quote from: ato memphis on March 04, 2010, 12:21:05 PM
no more than the normal Texas amount. I put 93 in recently from Shell.
Interestingly, I let it sit for awhile, and when i fired it back up, no problems... Idled fine (just like before) and would rev up and down pleasantly through the rev range. Sounded great...
...Until it warmed up more.. 10m or so, and it would stall as i gave the throttle even a little bit of a twist...
I think you have a fuel issue. I could be wrong. I have had all kinds of issues with my track bike after sitting for short (2 week) periods.
For S&Gs drain a float bowl and see what you get.
ok. is this symptomatic of a stuck float?
(not that i have enough experience to rip carbs apart in a flash, but I can find some free time)
Quote from: ato memphis on March 04, 2010, 12:30:30 PM
ok. is this symptomatic of a stuck float?
(not that i have enough experience to rip carbs apart in a flash, but I can find some free time)
I think if a float was stuck open you'd have fuel spilling out the bowl vent or running into a manifold.
If you suspect a stuck float be sure to shut off the fuel.
i don't really suspect that, I think its odd that it fires up and idles normally... and even revs fine, only to misbehave once it comes up to temp.
hmm, maybe fuel filter or kinked line? sits for a while has time to fill float bowl, but once it's dry can't supply fuel fast enough to keep up with demand? just thought i'd guess since i'm dealing with my own fuel issue now.
Quote from: svr on March 04, 2010, 12:59:35 PM
hmm, maybe fuel filter or kinked line? sits for a while has time to fill float bowl, but once it's dry can't supply fuel fast enough to keep up with demand? just thought i'd guess since i'm dealing with my own fuel issue now.
Not a bad thought.
Particularly when you consider the bike was tweaked here and there.
I'll check the lines. We're thinking a kink that allows some fuel to flow (enough for idle) but not enough to fill bowls, thus killing it when i open up the throttle after its been running for a bit?
Quote from: ato memphis on March 04, 2010, 01:25:08 PM
I'll check the lines. We're thinking a kink that allows some fuel to flow (enough for idle) but not enough to fill bowls, thus killing it when i open up the throttle after its been running for a bit?
Yup....
Checked all the lines. All the fuel lines have some freedom of movement, and aren't pinched.. Definitely no kinks.
Fuel filter is new as of middle of last summer, not very many miles on it sense then (under 1,000mi).
When its cool, the idle and rev feel really really good. Smooth throttle response. After more than 10m of idling though, temps got up over 100c and it went to pot. Roll the throttle and it sputters a bit, back off the throttle and I'm back to idling... rev a bit more throttle and it dies.
I've got a quick turn throttle on the bike, but there's been no change since last time I rode to the cables and such (everything looks normal - throttle and choke); choke seems to work quite fine, just like normal when the bike is cold.
have you drained a float bowl?
not yet
Quote from: ato memphis on March 04, 2010, 02:37:49 PM
not yet
humor an old fossil...
I won't live forever you know. [laugh]
its going to have to wait an hour or so before I can tinker again (i'd like things to cool down a smidge before I cook a hand on the motor), the wife is deadset on a pizza pie for dinner.
Quote from: ato memphis on March 04, 2010, 02:45:08 PM
its going to have to wait an hour or so before I can tinker again (i'd like things to cool down a smidge before I cook a hand on the motor), the wife is deadset on a pizza pie for dinner.
good thing I'm eating steak right now or I'd be jealous. ;D
curses, steak!
Through a bit of seafoam in the tank to see if that could cure some bad gas... Got out there a bit this morning, revs fine for quite a long time, up and down the range, feeling good. Engine temp got to over 80c and things were going good for awhile (I had a fan blowing across it so it wouldn't get much hotter), but then a few minutes later, as I cracked the throttle open it was having trouble running and backfired a lot, all the way up to 5k or so. shortly after that I couldn't get it to rev up any further and it would die as I tried.
Could also be worn needles causing fouled plugs. Pull a spark plug and look at the color. Brown or tan = good Black = bad
QuoteWhile it was idling, i was checking all my lights and discovered I had forgotten to plug in the front brake switch. no big deal. Plugged it in, went to rev again, and in doing so, it sputtered as I got to about 3k and now it'll die when i try to rev it past there.
Check wiring around steering head.
Isolation often wears through, causing misfire, sudden death etc.
Does the fault occur on sidestand & just revving?
on rearstand, happens after bike has been running for 10min or more... Once its gotten good and warm.
Could be fuel starvation rather than flooding I believe. Cory at the shop asked me to see if I had a leak in the intake tract. Gonna look into that.
Do you smell gas in the exhaust? Plugs fouled/fouling? If no, then starvation.
Played a little more today. Seems like it is starved for fuel, rather than flooding as I had originally thought - I'm not sure why I smelled gas the first time, perhaps it was my own? (bad joke.)
From my research, it looks like common problems come from heat/age with both the fuel lines and fuel pump. I'm going to try swapping 'em to see if that's the issue.
any updates here? i'm in the middle of changing fuel lines, filter, going to a manual petcock and just rebuild my fuel pump so i wanna keep up with how yours is going.
waitin' on fuel pump to test (it has shipped, should be here any day now)
Don't know much about these modern bikes, but on my old Brit Iron, this problem was symptomatic of 2 things. A condenser breaking down under heat - which is obviated on these technological marvels - or - a clogged vent in the gas filler cap. (Too much wax.) Now, I don't know if this makes any sense with a fuel pump but suspect an unvented tank might lead to fuel starvation. Vent hose crimped someplace?
i'll check those vents out for sure.
I'm back. Here's what I know it isn't:
It isn't the vacuum petcock.
It isn't the vacuum fuel pump (replaced).
It isn't the fuel lines (replaced).
It isn't the tank vent or drain hose (checked, clear).
It isn't the fuel filter (new).
It isn't the fuel (new).
Today's Symptoms:
Turn bike on. Idles and revs nicely. Things get warmer, bike idles and revs fine. Bike gets warm after many minutes idling, begins to backfire loudly when revving before ultimately dying if I keep trying to rev.
Info on Bike:
DynaCoils, Ignitech, Nichols Flywheel, Open Airbox, Sil Headers/Pipes, Mikuni CV Carbs that have been jetted.
Have you verified that the slides are lifting?
Have you looked at the plugs?
I haven't verified that they are once its warm and starts misbehaving. When its cold, I can peer down the intake and see everything seeming to work as its supposed to.
Sparkplugs (NGK) are new since last long ride (before this began).
What are the symptoms to worn jets? Anything like this? I'm trying to guess here.
Quote from: ato memphis on March 16, 2010, 02:20:10 PM
I haven't verified that they are once its warm and starts misbehaving. When its cold, I can peer down the intake and see everything seeming to work as its supposed to.
Sparkplugs (NGK) are new since last long ride (before this began).
What are the symptoms to worn jets? Anything like this? I'm trying to guess here.
The mains don't wear, and needle jets will make it run
rich at low throttle openings/cruise...
but it wouldn't die.
When it dies will it restart?
immediately. and resume idling normally to mock me, but if you whack open the throttle, dead. If you wait a bit, you can crank it up, rev up and down normally, and once its warm it'll die when you try to rev.
So if you go inside to have a glass of water, come back out in a minute after your wife kicks you out of the house for being dirty and smelling like gas/exhaust/solvents, etc, you can start it up and its like nothing is wrong... for a minute. Then its warm and it dies when you roll on the throttle.
I know you said you have new fuel.
Humor me and use some type of ethanol fuel treatment. ;D
the more research i do, the more I'm thinking its not the gas anymore since I've put in fresh Shell 93.
How likely is it that I've got an intake gasket leak at the heads or at the carbs on a 1999? Carbs were pulled off about a year ago for a quick turn throttle to be installed but I've ridden a thousand or more miles since then. Do the gaskets at the head/manifold junction age and leak?
i will humor you though. seafoam ok with you or must i go to autozone and poke about until i find some specific ethanol treatment
Quote from: ato memphis on March 16, 2010, 02:54:02 PM
the more research i do, the more I'm thinking its not the gas anymore since I've put in fresh Shell 93.
How likely is it that I've got an intake gasket leak at the heads or at the carbs on a 1999? Carbs were pulled off about a year ago for a quick turn throttle to be installed but I've ridden a thousand or more miles since then. Do the gaskets at the head/manifold junction age and leak?
I don't think so.
An air leak would have to be very severe to make it quit.
Quote from: ato memphis on March 16, 2010, 02:55:41 PM
i will humor you though. seafoam ok with you or must i go to autozone and poke about until i find some specific ethanol treatment
http://mystarbrite.com/startron/ (http://mystarbrite.com/startron/)
They have a store locator.
I am NOT familiar yet with Ducatis. However, a general trouble shooting test with my old Brit Iron twins was to get it idling and pull one spark plug wire and keep it running by playing with the throttle to see if it performed the same on either cylinder.
Now, I do not know if you can keep a Ducati running on one cylinder. But if you can, this may help you isolate the problem or give you further insight.
Beware, with some electronic ignitions, an ungrounded plug can damage the system. You can usually get around this by 'fettling' a small coil spring between the spark plug and the cap and attaching a wire to the spring. I use a tricked out clippydoo (male only) for this attachment. Then, after starting, grounding the wire by touching it to the engine thereby killing the spark to that cylinder. Perhaps our resident electronics gurus can comment on if this is safe on Ducatis. Howie?
sounds like you're ruling out things because they're new or fresh or you don't think it's an issue without actually doing anything. have you drained the float bowls or looked at the plugs yet? if you drain the bowls crimp the fuel hose between pump and carbs to keep fuel in the line. and catch the fuel as it comes out of the bowls so you can look at it.
you can also hook up a clear hose to the float bowl drain and hold it up the side to see the fuel level as you run it on the stand. this will tell you if there's a fuel supply issue at all.
try refitting the original ignition units if you have them.
Quote from: alibaba on March 17, 2010, 08:01:29 PM
I am NOT familiar yet with Ducatis. However, a general trouble shooting test with my old Brit Iron twins was to get it idling and pull one spark plug wire and keep it running by playing with the throttle to see if it performed the same on either cylinder.
Now, I do not know if you can keep a Ducati running on one cylinder. But if you can, this may help you isolate the problem or give you further insight.
Beware, with some electronic ignitions, an ungrounded plug can damage the system. You can usually get around this by 'fettling' a small coil spring between the spark plug and the cap and attaching a wire to the spring. I use a tricked out clippydoo (male only) for this attachment. Then, after starting, grounding the wire by touching it to the engine thereby killing the spark to that cylinder. Perhaps our resident electronics gurus can comment on if this is safe on Ducatis. Howie?
A Duc actually runs pretty well on one cylinder. The plug wire should be grounded before starting. From the symptoms ato is having the problem is affecting both cylinders. I think ato will find the problem if he does what brad black says.
Quote from: brad black on March 18, 2010, 01:38:57 AM
sounds like you're ruling out things because they're new or fresh or you don't think it's an issue without actually doing anything. have you drained the float bowls or looked at the plugs yet? if you drain the bowls crimp the fuel hose between pump and carbs to keep fuel in the line. and catch the fuel as it comes out of the bowls so you can look at it.
you can also hook up a clear hose to the float bowl drain and hold it up the side to see the fuel level as you run it on the stand. this will tell you if there's a fuel supply issue at all.
try refitting the original ignition units if you have them.
I pulled the carbs yesterday (drained floats first, gas ran out fine). There was no visible gunk in the carbs in the bowls, on the floats, or whatnot, but I blew compressed air through the passages to unstick the things I could not see. They are reassembled and ready to go back to the bike.
I tested the vacuum petcock using a mightyvac and pumping into a gas can and it performed fine. Pumped when the mightvac supplied vacuum, quit when I released the vacuum.
So later today I plan on putting the carbs back on, and seeing where we are at now with Ignitech. If it still malfunctions, I'll throw the stock ignition boxes on and give that a whirl.
Gday AM
I wonder if the fuel flow is keeping up with the engine. Since the fuel pump is new I wonder if its worth bypassing the petcock. Can the seals/diaphrams in a faulty petcock be affected by heat/age and restrict flow when they are 'on the way out'. Actually, Ethanol and other additives in fuel may affect the diaphrams and seals over time.
I had to modify the vacuum petcock on my NC30/VFR400. It ran fine until I used sustained high revs. As the petcock's internals aged it began to starve the motor at higher revs. Removing/rearranging the seals and diaphrams turned the petcock into a gravity type. Is there a similar mod for the Ducati one?
Since everything around it is new, I'd bypass the petcock, go gravity feed to the new fuel pump, and see what happens.
Y'know, I had the same idea while a buddy was over in the garage with me yesterday, and he said "vacuum petcock. seems overly complicated. What's wrong with a simple on-off valve".
So I logged on here and began looking about. It seems others are using a Motion Pro 5/16" petcock as a suitable replacement. Fair enough. Its only $15, I'll order it up.
That's great. Another cheap option for OEM parts.
Mines a simple on-off petcock (OEM 1995), but if it dies I know what to replace it with. Can only imagine what a new OEM petcocks worth.
Similar story with the OEM fuel pump. The Mikuni rectangular pump is nearly a hundred bucks cheaper (here).
I hope its just the petcock.
I'll stay tuned to see how you go.
I know this is an old thread but I'm having the same issue and wonder what the problem turned out to be... did replacing the vacuum petcock with a manual shut-off solve the problem?
uh, i'm not sure. See, i pulled the carbs and cleaned them, replaced the vacuum petcock with manual, replaced the fuel pump with a fresh replacement, replaced all lines, tossed out old and now-clean carbs and put on flatslides, had intake manifolds ceramic coated and reinstalled with fresh gaskets, made a carbon fiber battery box... and the problem seemed to disappear. I suggest maybe only one of those things was the issue.
Clearly my non-carbon fiber battery box is the culprit! [laugh]
exactly. i highly suggest killing the gnat with dynamite.