I'd agree that dropping the gap is not the best way to diagnose a weak spark, but it can be surprisingly effective in pointing in the right direction. Coincidentally, in the past month I've run into 2 different situations where plug gap had a significant impact on the running of an engine; both were characterized by by a rev limiter like cutoff in power near peak torque output. One was a 2 stroke race bike that had been ported, bringing the BMEP to a point where the existing electronics just couldn't fire across the stock gap. The other was a Saab that wouldn't run over about 4,000K under any load. In both cases, regapping the plugs helped confirm the source of the problem. Checking for carbon tracks is a) hard to do on properly anything not scrupulously clean and b) only an indicator of a bad component, not a weak ignition system. I completely agree, that bench testing is the only way to reliably check an ignition, but unfortunately not always available.

There's also the chance that you're going to take the plugs out and find that they're set too wide to begin with. Out of the box plugs can come with a standard gap over .045 - definitely big enough to cause problems with a weak Ducati ignition.

I'm not saying that this is the problem, but I'd completely iron out the ignition before moving to the fuel pump. Don't forget the old mechanic's adage: "most carburetor problems are electrical". Still every bit as true with OEM EFI systems today.



Sam

eddie... what about a dyno tune....no guess work there

OK, keep in mind I'm not a mechanic and I'm new to Ducati's. I took the 907 out again today (great weather) for a 60+ mile loop. In the past tests I was very gentle with the throttle giving me the 5500-5800 rpm hiccup. Today I was a little more aggressive and noticed the hiccup between 4000-6000 rpm. It seems that more of a handful of throttle the sooner the engine cut out. So, I do believe it has something to do with the fuel pump, ie, the screen being clogged. Its just so much fun to figure this out

you are on the right track now

I've done a search and looked through post but cannot find anything on how to remove the fuel pump. Is it removed from the top at the filler hole? Is there a post on how to remove it? Thanks.

Remove from the top. Take out the 8 or so screws and remove the filler door assembly. Make sure the battery is disconnected and have a fan blowing at you just in case. I can't remember if the wires are long enough for you to pull the pump out and then disconnect. Anyway there is a one or two places to push in a plastic tab to release the pump and screen from the mounting bracket inside the tank. I believe you have to disconnect the supply hoses before you can remove it. Good time to replace the filter also. Sorry, it has been a while.
du907

sorry double post

Could your tank vent be restricted? I've had something similar happen on my ktm. The vent tube became pinched but not completely closed. It would draw a vacuum in the tank after running so long at high rpms. Slower speed travel with traffic lights did not allow the vacuum to build. It only happened under extended hard acceleration or after going a distance 1/4 -1/2 mile at high rpms. After pulling over because of the stall, it would restart within a short period once it had time to draw enough air through the nearly closed vent tubing.

Have you seen this topic ?
viewtopic.php?f=3&t=4188

Day 3 test. Got up this morning and removed the fuel filter and fuel pump. The screen basket on the fuel pump looked to be in good shape but did have varnish on the bottom of it. I soaked it Sea Foam and finally got a good flow through it. Cleaned the fuel filter and put everything back together. Went for a 140 mile ride and the symptons were still there. Hard on the throttle then it would cut out and stall. Gentle on the throttle and not above 5500 rpm it ran fine. If its electrical what should I check? I don't think it would be the coil since it restarts right away.

I got a shop manual with the bike but its for a 906. Of course the 906 has the fuel pump under the tank so it was learn as you go today. I think I'm slowly becoming a mechanic



This is the former owners place. Good friend, I miss you Don.

Eddie, when I got my 907 last year, it ran sickly, one I got it running. I replaced the the fuel screen, pump ( because it had intermittent problems. locked up evry 20 seconds or so) fuel filter, and had the injectors ultasonically cleaned. The report on the injectors was that one had 40% of the flow and the other 60%. After cleaning, both were at 97%. I bought an FIM chip and got it running very strong. Almost 10K miles later, not a problem, except for a voltage regulator. I do run some Techron thru the tank every couple of thousand miles though. I think you still have a fuel problem. Just my 2 cents.

Ed,
Had a similar problem
with relays, turned out to be the fuse carrier in the relay was a loose fit, intermittent not firing,see this link, there are pictures of relays, maybe they are the same !
I got mine from Ducati dealer here in scotland.

Gerry


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