I have a 2001 750s project. It starts and runs ok when cold but bogs down and flames out the exhausts when warm. I have had both barrels off to replace leaky o-rings at the base of the cylinder already. I took the valve covers off the horizontal cylinder this evening and was not greeted with a pool of oil on my foot from the cover. I ran the engine briefly with the covers off and i still didn;t get oiley. I took the cover off initially to get the oil temp sender out to test it but it doesn't have any oil on it, i therefor assume that the ECU doesn't know what temp the oil is and not adjusting the fuel map properly? The engine is 'clanky' as well, i presume this is again lack of oil in the head. I haven't looked in the vertical cylinder head cover yet to see if that is dry as well. The oil pressure light comes on with the ignition and goes off when engine is running. The bike has not been used in this condition, just started and left to tick over. What could be causing the lack of oil in the head - i assume i could have clogged the oil way in the block that lines up with the bottom of the barrel. Would there be an easy way to unblock this hole without whipping the head and barrel off please? Cheers Kevin
Did it make a noise before you took the barrels off? If no, then in all probability you have inadvertently caused the issue e.g. incorrectly positioned/misplaced one of the "O" rings on the barrel/crankcase joint, too much 3 bond on the barrel crankcase joint causing it to squeeze into the oilway and block it. The barrel will have to come off again to investigate. If yes, then there is something wrong that needs invvestigating which I am afraid means the barrel has to come off as I do not think there is any known method of doing anything worthwhile without removing the barrels. Sorry
Thanks for the depressing reply lol It has run badly since i bought it and i didnt really run it much before stripping it down due to the copious quantities of oil dripping from the base gasket onto the exhaust. Looks like a strip down is due then. Could you confirm which way up the dowels with the precision hole go please? Any places sell just the o-rings i need please or is it just the normal online ducati genuine parts places please? Kind Regards Kevin
I am afraid I cannot help re the dowels, this may help, although for a 600 it is basically the same engine Re the O rings I am definitely a fan of using bearing factors (Simply Bearings etc) or any other source for generic parts, bearings, seals except where it is a real PIA if the spec is wrong. For O rings under the barrel I think I would pay the Ducati tax and get the proper ones. The last thing you want to do is have to strip it down for a third time. That is stretching the joys of ownership a bit too far for me.
Thank you for the reply and the video. Am I right in assuming that the rocker covers should literally be filled with oil, and if the engine is running oil should be pumped out of the valve cover (if valve cover is off)? I'm going to hopefully get time today to take cam cover off the vertical head and I severely hope oil piddles out everywhere. Kind regards Kevin Ps if I'm ordering base orings from ducati I may as well buy them all from there as tbf they aren't silly prices. I just begrudge the postage and having to buy a pack or 5 or 10 orings where I only need a couple. I've got spares if anyone wants one or 2.
Do you mean rocker cover (2 rectangular-ish covers per head located fore and aft on top of the head casting) or cam bearing holder (1 on each side opposite the belt covers)? If rocker cover, then the chamber within should be freshly wet but not drowned with oil. The oil feed (I think) comes from the pump through crankcase drillings through the pressure switch and the bronze bush on the end of the crankshaft up into the cylinder barrel (past the O ring on the cylinder base) through the drilled dowel at the head joint into the cylinder head and via drillings into the cam bearing, then along the inside of the camshaft to splash onto the rockers and the opening and closing adjusters. Others will doubtless correct me here. Do not attempt to start it with the cam bearing cap removed as the camshaft will only be supported at the belt end and it will end badly
Thanks again Yes I do mean the 2 rectangular covers. How does the oil temp sensor work on the horizontal cylinder (on the front valve cover) if it only sees a splash of oil please? I would have thought it would be an 'air temp sensor' if it was dry? I've ordered orings, base shims etc from ducati this morning. I so don't wanna strip it down if it isn't a problem. The front horizontal valve cover dripped some oil out, but I cudnt see any in the back rocker cover hole. Cheers Kevin
Not that familiar with injection bikes but if the oil temp sensor is on the exhaust (lower) side it would be sitting in a puddle of oil before it drains back through the barrel to the sump. If on the inlet side I have no idea how it works.
The oil temp sensor is on the valve cover at the front of the engine (exhaust valve?) it's the cover that has a bracket on for the oil cooler mounting point. The sensor is bone dry.
Yes, that is the inlet side. If the sensor is not sitting in the oil it is not measuring the temperature of the oil, it can only be measuring the temperature of the rocker cover or air space beneath it. Depending on how the switch is calibrated that may be a sufficient proxy for the temperature of the oil to provide a) a warning or b) perhaps to inform the ECU of when to adjust the mixture strength
Yes, it's the engine temperature sensor for the ECU to set the fueling according to the signal it gets from it. It is not measuring oil temperature. I'd be more concerned about why oil isn't getting to the head.
I've been scouring all over the internet and i can only find 1 post that says 20cc should be in those valve covers. Oil did piddle slightly out of the exhaust cover - not loads but possibly in the realms of 20cc?! I'm hopefully going to get the cam cover off tomorrow to see how much oil is in there. Thank you for the advice you two. I've bought an FDTI chipset diagnostic cable but it doesnt appear to work with the 750s. If oiling is OK then im going to try a fixed resistance instead of oil temp sensor and see if this affects the fuel map. The sensor is 4.7k ohms at approx 8 degrees C. I'm gonna put sensor near a heat source and check for resistance at various heat levels to see if it is working. I'll update things tomorrow. Kind Regards Kevin
If you want to check the sensor output this spec sheet might be useful. They are known for going bad.
Thankyou. It's still concerning me it's classed as a "fluid temperature sensor" even though mine seems to be running dry. Has anyone lifted one of the valve covers off just after engine has stopped to see how much oil comes out? I'm thinking it is that sensor or lack of oil on that sensor because resistance seems OK at ambient temp but when engine gets warm it runs badly and rich, it sounds like a mapped Ford focus rs popping / farting and flaming.
Yes, about 50ml collected in the exh valve cover. The sensor is meant to run in the oil and due to it's location never can do. It gets heat from the valve cover it is screwed into and from oil thrown at it when the engine is running. The ECU isn't interested in the oil temperature only the engine temperatures that it has been calibrated for. It is the same as those fitted to the Fiat Punto Mk2 8V 1.2 engine and many other Fiats. Replacements can be got for around £20-£25 if you want to try swapping it.
Thankyou I've just stuck my sensor in the spout of my boiling kettle and it's got a resistance of about 205 ohms (which is right going by your attached sheet). I'm assuming the hotter the oil, the lower the resistance and it drops fuel delivery down on the predetermined fuel map in the ecu (same as water temp sensor on liquid cooled cars etc). Back to looking for oil this aft I think. I'd be happier if I cud get jpdiag to read ecu to see what's going on. Cheers Kevin
I have run the engine briefly with horizontal valve covers off (not cam cover) - there was not a drop on the floor after 2 mins so I shut engine off. After looking at the horizontal cylinder without the air box in, looking through the inlet valve cover I can see the floor eg open passage between inlet and exhaust valve chambers so there won't b any oil pooling in inlet valve cover, only oil dripping onto exhaust valve cover. The vertical cylinder looked wetter in the inlet valve cover - not piddle wet through but signs of oil. I therefor think oil ways are blocked on horizontal cylinder and barrel will have to come off . I'll start stripping it in upcoming week. Thanks for the input so far. Cheers
