Hi All - I did post this in Tech, but had no responses today - hope this doesn't bother anyone too much, just want a wider viewing range to help me get it back on the road After recently fixing my electrical problems with new reg/rect, main relay and some new heatproof wires, I tidied everything up, put all the bits back on and treated the 748 to a new battery, Finished up with all this last night and seeing it was nice I thought there was nothing more to do than go for a blast.... which ended in a 3 mile walk, 1 of which was pushing the bike! before I left the house the last thing I did was check the fluid levels etc, all were good, and the last oil change I did was probably little over 1000 miles, and seeing as I have/had a trackday coming up I thought I would do a service before that, changing the oil, filter, brake fluid etc (all stuff I have waiting in the shed ready to use!) anyway, cutting to the chase, took the bike for a spirited run, it was going great, plenty of pull, water temp good, no oil light etc. after about 35 mins of riding I cam into a nice string of corners, down a hill, cracked the throttle open, bike felt like it was choking, oil light started flickering, I shut the throttle down, then the oil light came on solid, I then flicked the switch and killed the bike, pushed it about a mile to my mates house then walked a further 2 miles in my leathers (as he wasn't in) to a main road for someone to pick me up :-( I was bloody sweating! Im guessing the bottom end has gone, but any suggestions would be welcome, im going to pick the bike up tonight and drop the oil, which I fully expect to be full of metal :-( the bike only has 14,500 miles on it, 2k of which has been myself, I have done 3 oil/filter changes in that time, 1 when I got it, 1 before a trackday and one after a trackday. when I got the bike it was losing oil, which I discovered was because the oil filter was not tight when I bought it... so im guessing its had oil starvation in the past and this is the result finally happening!? Gutted. truly Gutted.
If the main bearing fails on the nearside it normally causes the side casing to crack, but having experienced it the oil pressure doesn't drop. The offside bearing doesn't usually give trouble as it has an easier job. It could be conrod (bigend) bearings and I assume that would show as low oil pressure, again I have had a set get very worn but there was no sign of dropping oil pressure. It could also be the oil pump The best thing to do first is drain the oil and see what comes out, that might help identify the problem. What year is the bike? Just a few comments\suggestions, hope this helps
Thanks, Dropped the oil last night,,,, no metal! So I'm going to fill it up, start it and check the pressure, assuming faulty switch, failing that, pull the engine out and get in to have a look!
an encouraging sign - no metal. Were there any accompanying noises as engine got tight before you chopped it off? Could be crankshaft oil gallery blanking plug unscrewing but this is often accompanied by aluminium 'toenails clippings' in sump.
The fact that it seemed to lose power just as the oil light came on doesn't sound good. I'd seriously consider seeing how freely it turns over by hand, take the plugs out, put it in gear and turn the rear wheel, if it doesn't feel right I wouldn't even consider trying to start it.
A quick look at the belts might not go amiss before you consider removing the engine. It's good there was not metal inside, when was the oil last changed. When my main bearing went there was surprisingly little metal in the oil. The loss of power is the most puzzling because all the other things like bearing failure don't tend to result in that from my little experience. Sometimes the plastic cage goes on the bearing and if that has happened it might throw the timing out enough to have the bike start misbehaving. Just a few extra thoughts
Thanks for the responses guys, Then oil was changed around 500 miles ago - Castrol race stuff, as were the belts, I just wonder if it have maybe jumped a tooth in the timing? maybe I didn't tension the belt enough? still does not explain why the oil light came on though, but might explain the power loss! there was a couple of little bits of metal, but just teeny tiny particles, nothing like you would expect, I half expected the oil to be really metallic aswell, but nothing at all like it. I will whip of the belt covers and see that the timing all matches up tonight. is there any way I can have a look in the engine without splitting it (like the sump in a car) ?
If you remove the cylinders you can see a lot of the insides and it's not that big a job, don't even need to remove the engine from the frame. Good luck.
I am pretty sure if you jumped a tooth on the timing belt it would do some top end damage and it would seem fairly terminal (noticeable) when it happened. It's also pretty hard to jump a tooth as the sprockets are quite deep and you can get a fair bit of slack in the belts without any ill effect. As above a top end strip would help, the engine splits sideways so it's quite a big job to do a full strip down. Its worth having a look at the water pump side by taking off the side cover to see if you have any play in the flywheel which would indicate possible main bearing trouble. Any movement indicates wear usually. You do in theory need a cranked spanner to get the heads off so you might want to investigate that when you are looking at the engine. The heads can be got off by various means but re-torquing them is harder without the right tool.
Morning All, So, I had a chance to look at the bike last night, Pulled the plugs, checked down the bores, all looks good there, Put the bike up on the stand, put it in gear, spun the back wheel, everything sounded ok (no valve clattering etc) Tested the oil pressure switch was physically working (plugged it in/turned the ignition on/earthed it/pushed a small allen key inside it to function the switch) obviously I don't know if it functions at the right pressure, but seeing as its a sprung switch im not doubting it works as the light goes on and off when you press/depress it. I also pulled the inspection cover off the flywheel bearing, no play there and what you can see of the balls and the race its very clean. I drained the filter I took out of it and put it back in, put about 3 ltrs of oil in it to bring the level up to max, turned the back wheel again in gear to spin the engine up, the oil level dropped to min as it was circulated, so from this im guessing the oil pump is fine as it filled up the filter. I then topped the oil up again (around .25 of a ltr) put the plugs back in, and started the bike, oil pressure was good, bike sounded sweet - (my god it sounds immense with the airbox off!) however, as soon as the bike warmed - not to working temp, but heads warm to touch - up, the engine stared to give a nasty 'knock' so I killed the power! so, engine strip it will have to be, im still confused by the lack of metal in the oil, but I have maybe caught it early enough that its not too bad? could it be the little ends and not the big ones? again, any suggestions are welcome!! thanks.
symptoms still sound right for gallery blanking plug in which case you could be ok with a straight rebuild but second run won't have helped.
cheers chris, the blanking plug - does any one have an exploded diagram of the engine or can anyone direct me to one?
Ducati parts catalogue can be downloaded online from Ducati,com. It might help if you just want an idea of what the engine looks like inside. It is split into sections though. Might be worth an ebay hunt for a Workshop manual on CD or something. I got one once for a few quid, it was pretty good but I lost it in a PC crash a few years back. Never known a little end to go from my limited experience, I don't think it's a known problem. I have never come across it It might be worth a look here http://www.ducati-john.co.uk/ducati-points.htm
Much information on this link especially Shazaam's post. I think the OP on this thread is an SS engine but i believe the theory is all the same. Is this Oil Galley Plug Backing Out? - Ducati.ms - The Ultimate Ducati Forum
Here's a pic of the oil galley plug (large screw in crank), they sometimes have a tendency to undo and get milled away against the casing - when they finally fall out the oil feed to crank fails with disastrous results, you should find 'toenail' shaped aluminium bits in the oil if this happens. They can easily be staked in place to prevent this but you need to split the cases to get to it.
Might have missed it but I can't see anywhere that you have taken out the pickup filter on the R/H engine casing?
I ended up selling the bike with the duffed engine to a guy who was building an 853 and he gave me back a good 748 engine as a P/X, which I am now selling . been looking at 848 and 1098's as a replacement...
