So if both engines that used to run perfectly now don't, and you haven't touched both of their timing belts since they were last running, its not the engine and something on the bike itself. I would have agreed with timing being 1 cycle out, but can't be unless you had the belts off both of them ? Compression will also be fine if the cams are 1 cycle out, its just the spark will be on the wrong stroke. It should be suck - squeeze - bang - blow, but you might be sparking on suck, not bang You've already ruled most of the things out by swapping stuff between V and H cylinders. If its not the timing then this all points to the loom: broken wire, poor or damaged connection, or sensor.
I did have the belts off both so being 1 cycle out is a possibility. So how do I check the suck - squeeze - bang - blow is happening in the correct order and that the cams are correct? Surely if the bottom pully is lined up with the mark on the crankcase, and the H cams make the inverted “T” (like in the previous photos from Peter), the engine can’t be 180 degrees out, right??
are you getting battery voltage at the coil + on the cylinder thats playing up when the coils is conected? you may well get continuity untill you put it under load.
it's not 180 degrees out,its one revolution out. One revolution is 2 cycles (piston down and up), so 2 revolutions required for a 4 stroke between sparks.That timing mark on the crank will line up on both revolutions. Sorry if you already knew this,not trying to talk down to you, just not sure how better to describe it. As a tip for the future, I always make a point of not turning the crank once the belt is off, and if I have to I always turn it an even number of times. Sounds like this may well be the answer.
Don’t worry about talking down to me. I’m a noob at this so your description is very valuable to me. Just to be clear... and that we are talking the same thing, 2 revolutions of the crank = 1 revolution of the belt pully right? I (mistakenly?) thought the pully did only one revolution of 2 crank cycles. Thus the pully mark lined up with the crankcase mark MUST be at TDC of the intake stroke. The second TDC is 180 degrees the other side of the mark on the crankcase. If I’m incorrect, that would explain everything,but how do I tell which cycle it is on? By the thumb over the spark hole and feeling for air coming out halfway through the first stroke? Ignore the yellow arrow in this first photo. This is the mark I am talking about. See how there is an inverted T shape in the cam centres. I don’t understand how the engine could be out 1 cycle with the pulley lined up with the pulley mark (indicated by the second yellow arrow) and the inverted Ts on the cams. Thanks so much. If this is right I will be a very happy camper indeed. Ignore this photo... I can’t seem to delete it.
I didn’t know that you had changed the belts - did it start to play up immediately afterwards? take the belt covers off, rotate engine to TDC firing on horizontal cylinder and take pictures of belt run on all sprockets for us.
if you marked the pulley or used the marks on them no matter how many times you may have inadvertently turned any pulley with the belts off, if use the marks you cant be one turn out on any pulley
Isn’t it always TDC firing on horizon cyl where I have indicated with the yellow arrow ... where the mark on the pulley and crankcase line up? Oui? Non?
Good to hear. I thought so but nice to have a more educated second opinion. Will do fresh photos when I get back to the bike but they will look the same. I’m in Rio for a wedding at the moment so it will take me a while to post them.
Alexaussi Looking at your 3rd photo ( which I assume is related to the engine you are having problems with) This looks absolutely correct. For clarification : ( it took me ages to fully understand this as I'm slow on the uptake, so thought I would try to help you ) When the crankshaft pulley mark is aligned with the mark on the crankcase and the cam pulleys are aligned as yours are showing in the photo. The piston is at T.D.C on the Firing stroke. I found the Ducatitech videos very helpful, the link is for a 749 but same principle
For further clarification: The lower pulley runs at 1/2 engine speed, so 2 turns of the crank to 1 turn of the timing pulley. When the timing pulley mark is lined up with the line on the clutch cover the engine is at the timing position. i.e. The horizontal piston is at top dead centre at the start of the firing strowith both valves fully closed and the vertical piston is half way down the inlet stroke with the inlet valve fully open. At this point all camshafts on the MTS engine will have the leg of the T facing away from the cylinder (this is not the case on 749/999 and 1098 engines). The 3rd picture shows the cams correctly timed. I don't think the problem has anything to do with the cam timing but as has been suggested already some obscure electrical problem.
Yes everything I have read here and the video point to the valve timing being correct (but I will still post some photos later when I get in front of the bike to confirm). First on my list is to check the wiring integrity between the coils / injectors and the ECU. Is it worth buying an oscilloscope to troubleshoot these kind of problems? Anyone have an old DDS for sale?
The more cooks the better IMO. The more ideas the more things I can check. It’s only a matter of time before I find the answer.
This is one of the things I was advised to check when my 999 dropped onto one cylinder. I was also advised to use a test bulb rather than a multimeter as this puts more load on the wire, so is more likely to show up any breaks. In my case it turned out to be the ECU but you've already ruled that out
Just a thought - you've swapped round just about everything else but no mention of the MAP sensors. Worth a try surely.
