Project Ducati 998 Superbike Part 5: Testing upgrades on the track
The gold threaded rod is left hand thread on one side and right hand thread on the other to make for quick adjustments to ride height. This piece is essential to set rear ride height which can ultimately effect rake, trail, center of gravity etc.

 

One last strange problem that I’m still pondering: during high load situations such as 5th or 6th gear at full throttle and 9,000+ rpm the engine would suddenly feel as if it ran out of fuel. This bike has no fuel level indicator or low fuel lamp to verify this though. If I rolled off and back on the throttle gingerly the engine would pick back up and I could continue provided I wasn’t at 100% throttle. This problem only occurred after 6 or so laps of each session, but was very repeatable. I genuinely though I’d run out of fuel when it first occurred. When I inspected in the pits, the fuel pump was still submerged and there was probably 1/3 of a tank of fuel left. I topped off and went out next session and the same issue occurred late in the session. Even brimming the tank I would still get this problem before the end of the sessions. I’m not sold on this being fuel level related. It could possibly be heat related. The ECU on this machine is an ancient Magneti Marelli 59M which are notoriously unreliable. After some research it is apparently common that a failing ECU will cause igniter faults that strangely result in 0 volts going to the fuel pump. Being a 25 year old Italian machine with Italian electronics, there are no check engine lights or OBDII ports. There’s only ancient software that’s very difficult to find and purchase.  To rule out the really easy stuff first however, I think I’m going to stuff the tank with some mesh to reduce the sloshing of fuel that could cause symptoms like what I was experiencing. This will take some more testing. Ideally I’ll get my hands on some old Italian software and report back. As always, testing continues.

No fuel gauge here. The tachometer and water temperature gauges are standard. The STACK electronic oil pressure gauge was added by yours truly.

 

Not bad looking for a 25 year old race bike

 

Here you can see the Triumph 675 peeking through in the background. It didn’t turn a wheel in anger on this day.

And lastly, because all of this testing is done on a racetrack, the results should be lap times. Unfortunately I haven’t splurged on a fancy Aim Solo 2 GPS lap timer or data logger just yet, so a good friend with an iphone is my only reference. Lapping in the 1:58s means this Ducati is quick, and not just for an old turd, quick even by modern bike standards. I’m hoping next time to be able to ride the Triumph 675 and Ducati on the same day and compare lap times and splits to see how they stack up. Stay tuned.

Source
Aim Solo 2 DL
NolaMotorsportsPark
Part1
Part2
Part3
Part4

 

 

10 comments

    1. Thanks Mike. Hopefully the warmer weather comes around early next year. Part 6 will see some upgrades to the bike as mentioned here as well as a new Solo2 to get some quantitative data to share. Looking forward to next time out!

  1. “making my own fully floating discs out of the factory semi floaters. […] These are certainly the best brakes I’ve used on a race bike regarding initial feel, braking power and fade resistance”

    You certainly should give the details of this conversion. It sounds fascinating.

    1. Tan, take a look at part 4 of this project.
      For more details on that. It’s linked in the bottom of the article here. Thanks for reading!

  2. Love this serious. Clearly challenging bikes to run one’s self. Very curious fuel dilemma. Hopefully not causing a leaning out issue. Vapor lock?

    1. Thanks Miguel! Ducatis in general are not difficult to run, but it does help to understand how they work. They definitely don’t have quite the “set it and forget it” nature of modern japanese machines, or even of my Triumph for that matter.

      Interesting you mention the vapor lock, because I kind of though the same thing initially. However with vapor lock the bike is essentially starved of fuel unless the cap is opened. I did replace the fuel cap as a precaution, and because fiddling with a key in a 25yr old lock cylinder at the track is a complete pain in the ass. I used to clear out vent lines by blowing compressed air through the vent line, but I no longer have access to compressed air. I’ll try with a little air pump at home before the next outing to be sure. Thanks for your input!

      1. Ha most definitely they require specific knowledge and tools. So I appreciate you revealing the details of their nuances. My old SR500 is a much better candidate for hammering away and learning on, for now!

        On the vapor lock thing, I had it happen to my ’13 F800GS BMW a couple times despite being relatively new. Hot day, full tank, but issue was low RPM and it would die completely. Very annoying. Popping the cap and not over filling the tank seemed to remedy it. (I suspect overfilling interfered with ventilation in my case)

        I’ve been reading a lot about fuel system and supply issues lately. As I am pretty sure low fuel pressure at max revs cost me a car engine last summer. Unfortunately – no data.

        1. The simplicity of an SR500 is certainly to be appreciated. I’ve had vapor lock issues in the past, but not on this machine specifically, and it was a very hot day, so you may be correct. I’ve blown up a car engine or two from low fuel pressure under high turbo boost before also. I never had any quantitative data either, but the engine felt very fast for a split second then made bad noises lol. Pretty clear.

  3. Just came across this page as I have a 998 myself and am looking to upgrade the brakes. I always thought the braking was great until I tried a friend’s newer Ducati (and another friend’s Kawi for that matter).

    As to your fuel issue, I don’t know if you’ve sourced the problem, but I regularly have vapor lock issues at the track. I need to pop open the tank before I can start the bike, but once I’ve done that the bike starts up fine and has never given me issues on the track, even during long track sessions. Love to hear what your “fix” was.

    1. Mike I’d love to say I have a fix to
      share. I don’t believe vapor lock is the issue, as it doesn’t remedy even after I open the fuel cap.

      I’ve got a sneaking suspicion it’s electrical. The worst part is I can’t duplicate it as the bike isn’t registered or road legal. So I get to the track and after 30min or so I get the problem and the bike won’t start for my next session. Hugely annoying.

      I’ve since removed the fuel pump and filter again to double check everything and verify fuel pressure. I have another day planned in a couple of weeks, so we’ll see if the issue persists. Next step I think is making a new harness and finding a new ECU.

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