So I'm not having much luck awakening the old 916 from her winter slumber. Belt change, new plugs, fuel filter, lines and freshly charged battery having no effect. Checked tank vent lines for pinching, everything looks ok. Fuel pump primes and stops, starter engages, engine turns over... fires and runs briefly before dying. Every time. Rather than go through a rigorous, methodical process to pinpoint the problem... I'll just post a quick video so you can see/hear what's happening. I realise the problem could be any number of things and I'm giving you all nothing to go on, but does anything obvious jump out here?
First thing I noticed is that you're trying to start it with the fast idle button. That opens the throttles slightly and produces too much compression for the starter. You can hear the starter struggling to turn the motor over. As you're cranking give the throttle a blip and let it fall back to idle.
I would test the battery as follows: 1. Connect a multimeter, set to Vdc, to the battery terminals. Check the voltage, should be 12.5 -13. 2. Turn the key to the on position and see what happens on the multimeter. It should drop very slightly, maybe by 0.5v max and then hold steady, even with the lights on and the fuel pump running. 3. Press the starter button and watch what happens. The starter should spin but the voltage reading on the MM should still remain above 12v. If the battery behaves as it should you know it’s not that. If however, the battery voltage starts to drop and continues slowly dropping when doing 2 above or if the battery voltage falls below 12 when doing 3 above then I would advise getting a new battery as it’s past its best. There is a massive demand placed upon the battery when starting the bike, the starter motor takes a massive amperage draw and if the battery isn’t in tip top condition then whilst the starter motor is sucking the life out of the battery there’s little left to charge the coils resulting in a weak spark and poor or no starting. The battery may appear fully charged to you and your charger but in actual fact is not holding that charge as it should. It’s a simple test that costs nothing to do, takes 1 minute and will either rule in or rule out the battery before you start disappearing down various rabbit holes.
Load test battery as described. May be stupid question! Is the filter you changed in the right way round? Stupid question but stupid here has done it! .
I noticed your red charging light is not active. Blown bulb probably. But this light is useful on a 916. Very useful. It comes on with ignition and should go off when its running. Also, open fuel cap in case you have a pressure lock. I vaguely recall in the dim past mine doing something similar and someone on here told me to do that and it was a trapped pinched pipe somewhere.
Thanks lads. Will get the multimeter out today. This is a US-market strada, so no actual switch to turn off the lights. Martin- have always used fast idle in the past for cold starts... did try with it off and blipping while cranking with no luck. Fuel filter is indeed correct way around. I can see fuel circulating in the tank as the pump primes, although the sound of the pump has changed from last year. Smoother, less of a whine... Bootsam- this bike got its regulator changed at some point in it's life. I believe that takes out the ability for the charging light to work.
Mine has had several RR's in my 20yr ownership. She eats them like I eat choc biscuits. There is a wire to connect that will still show on dash. I cannot remember which tho. Its easy to overlook it and not reconnect it. But with the amount of RR mine has chomped, it serves as an advanced warning to me.
Ok, multimeter results as follows: 12.8V at rest 12.3V with key on 10.2V while cranking Looks like a new battery may be required(?)
to be honest, cranking speed sounds good to me, even on your third attempt and although not dismissing there might be an issue there, i'm not sure it's at the heart of your starting mystery.
It doesn't sound like your pump is producing much pressure. It seems to run to easy. I'd bet my bottom dollar one of the pressure hoses is leaking. Could be the pressure regulator that duff as well although they seem bomb proof. My fuel pump sounds quite strained after a couple of seconds.
Was hoping for a more drastic change on cranking voltage of the battery as an obvious answer. Yuasa battery only 2 years old and well maintained. A fuelling problem was my initial thought as well. Just the fact the pump sound has changed quite a bit from the last time I rode it is strange. What triggers the relay to cut the pump off? Once it hits 3.0 bar pressure? When doing the fresh filter install, I jimmied the pump out of it's seat as per LT Snyder's manual to check the mesh underneath was clear. Big chip of red tank paint sitting there but otherwise relatively clean. Might pull the fuel plate again and double-check lines. Exterior lines are fine. Not going down rabbit hole though... definitely not doing that...
Dump the battery. Almost certainly on its way out but agree with Chris probably not the current problem (pun). Coil connections been checked?Nothing disturbed when working under tank? Just thinking out loud.
For $100, you're right. Probably worth it. Full disclosure: when changing belts, I ended up being a couple teeth out on both cylinders. Thread here: https://www.ducatiforum.co.uk/threads/belt-change-rescue-mission.85508/ If I bent a valve (gulp), would the resulting drop in compression hinder starting?
If you bent a valve it's game over. Did you try and start it with the belts misaligned or did you just turn the engine gently and found it binds? The former will bend valves, the latter doesn't.
I just read your other thread about the belts being out. Doesn't sound good. I think a compression test should be your next step.
But why would it start then die if there is no compression. Got to have compression for it to go bang!
There was no binding turning it over slowly with an engine turning tool. After removing belts and resetting cams to timing marks, engine now at least starts... briefly, that is.
