Slow Monster rebuild

[Flip]

Firstly I have to say how much I love this thread and I am sure the bike is going to look fantastic when complete.

However, not wanting to throw the proverbial spanner in the works- I changed my timing belt idler bearings in 2018 and fitted a pair of ExactFit belts which I bought at the same time. The bearings supplied (ExactFit are the UK distributers for California Cycle Works) were indeed spec’d as C3, which made sense to me as they run in a pretty hot place.



They’ve been on without issue (touch wood) for around 8000 miles now but I’ll probably take a look behind the covers in a couple of weeks when I give the bike an oil change etc.

Out of interest (Sorry if I missed it), did you find an alternative source for the double sized fixed bearings or did you bite the bullet and pay Ducati’s price?

In addition from what I gather it is often the clutch pressure plate bearing which wrongly gets spec’d as C3.

[350TSS]

Thanks Flip - nice to be appreciated.
Re the tensioner bearings I think that is why I asked the question as I had a nagging doubt as to whether C3 spec bearings were required - however as Stein Dinse show a picture of non C3 bearings that is what I bought (SKF bearings from Simply Bearings about a year ago for about half the SD price)
The original Ducati bearings have no electrically etched numbers or identification on them at all.
I am in a quandary now, I think you are right C3 bearings are probably the better specification for the application, but I also think that SD probably consulted Ducati as to the replacement types and offered non C3 as the replacement ( because the originals were non C3). If I am wrong then the bearings could overheat and seize and bugger up/break the belts and f*** ** the motor.
If I am right and I leave them there I am no worse off than a brand new Ducati M900 owner.

With regard to the fixed bearings I could find no alternatives and paid Moto Rapido prices less 10% UKMOC discount which was a lot less then SD - about £33 each compared to £48 each from SD.

[Luddite]

I see this bearing question was raised on another forum

https://www.ducatiforum.co.uk/thread...earings.50724/

and you may recognise a couple of the contributers' names there (our own Dukedesmo and Nasher to be precise). Neither has mentioned a need for C3 but perhaps they could confirm what spec they actually used if they are reading this.

[350TSS]

Thanks Luddite
Note: Ducati used 2 types of SKF bearing in production for this application, one was a higher heat spec but unnecessary for this application as it falls within the design criteria of the lower heat bearing - if you feel you want the higher heat bearing let me know. Additional cost is + £20.00
Above quote from Exact fit ebay advertisement for bearings for 999 - a watercooled 4 valver (would probably run cooler but with more revs and a probably a higher load 4 admittedly smaller valves per camshaft vs 2 valves per camshaft) so not quite the same as my airhead.
Pondering overnight I think I will stick with non C3 but check them regularly.

Last night I re-created my ETTC schedule ( previous one lost when my computer went bang). In summary,
Engine work requires 16 hours to completion
Wiring 33.5
Painting 48
Assembly 41.5
Total 139 hours to completion
More than I had hoped but a realistic estimate

[350TSS]

Today's task was to make the means of holding a dial gauge directly above the centre line of the valve stem so I could measure the time (in terms of crankshaft rotation) when maximum inlet valve lift was achieved.
I failed.
I made a means of holding the dial gauge but it was not directly in line with the valve stem (out by about 4 mm)
Tomorrow I will cut off the bridge that holds the dial gauge and re weld it about 4mm towards the centre line of the cylinder.

[350TSS]

One other issue I encountered today which I initially thought was terminal was that the "drop" of my dial gauge is less than the lift on the cam lobe. This means that I cannot measure the maximum full cam lift.
However, I think this is actually a good thing.
At the peak of the cam the difference in movement of the valve opening shim between say - 5 degrees and +5 degrees will be very small and even less so pro rata between -2 degrees and + 2 degrees of crankshaft movement simply because the cam profile has to be less aggressive at the point where a direction change in the movement of the valve train is intended/imminent.

Provided the cam profile is symmetrical (and I think most are because the manufacturing process so dictates), then measuring the lift and the recline (some crank rotational distance from the maximum lift) at the point where the cam is more aggressive provided the results are divided by 2 will give a more accurate result. I think????

[manwithredbike]

If it was any help, I could pull the belt covers off mine and spin the motor to line up the timing marks and count the belt teeth between timing marks. Could send pics to go with it. The bike's laid up and partially in bits anyway.

[Darren69]

That will get you in the ball park using the timing marks then you can 'dial' the cams in more accurately by using some adjustable cam pulleys.

[350TSS]

Thanks Phil for the kind offer, I do not think I need you to take the trouble.
My plan of action is as follows:
First I will set the adjustable camshaft pulleys in the middle of their range of movement, there are no timing marks on these pulleys at present so I will compare the keyway position on the old pulleys with the new ones and make corresponding marks on the new ones.
I will determine true Top dead centre by using the stop method, inserting something in the plughole which will stop the piston at some point before TDC and noting what the degree disc says then turning the engine backwards until the piston stops again. TDC is halfway between the two positions where the piston stops.
Having established true TDC (as opposed to a possibly inaccurate TDC indicated by the marks on the flywheel) I will make sure that the jack shaft pulley is completely aligned with the timing mark on the crankcase. I have already found there is about a couple of degrees of slop on the pulley so the pulley nut will be done up when the engine is at true TDC and the marks are aligned.
The next issue is that I have no static marks on the inner belt pulley caps because I have binned them.
This is where my process gets a bit flakey.
Studying pictures of the original assembly the vertical cylinder inner cam belt timing mark is at about 09.30 on the big hand of an imaginary clock if the clock face is aligned between the centres of the upper and lower pulleys. This is where I will set my newly marked adjustable pulley as I put the belt on. A similar process for the horizontal cylinder.
Unlike the 4v design there is no danger of the valves hitting each other if the timing is wrong because the single cams are ground so that the valves do not collide. I will turn the engine over slowly to establish there is no possibility of a valve vs piston collision.
The next task is to establish the position of the crank shaft when peak opening of the inlet cam occurs and to do so for both cylinders.
Assuming that my DTI cannot measure the full range of valve movement I will have to determine where the DTI stops turning but the valve is still descending and record the reading on the timing disc, then rotate the engine backwards about 600 degrees and record where the DTI starts to move as the valve closes. Peak valve lift will be halfway between the two.
I will compare the results for both cylinders with the specification for the camshaft fitted and adjust the adjustable pulleys accordingly.
It will probably take me about a week.

[manwithredbike]

Your method is def much more interesting and a proper challenge!!

[350TSS]

Sorry Slob I did not spot your post on page 73 (number 1098 spooky) until this morning. The simplicity of your design of DTI bracket appealed and decided that it would be easier to make a Mk2 version than to modify the Mk1 to make it functional.
Here it is

the DTI has a spigot on the bottom beneath the gauge itself which fits inside a 10mm nut welded to the horizontal plate. The nut was drilled and tapped 4mm so 2 x 4mm grub screws can secure the DTI in position.
I was almost hoping that making the DTI probe touch the rocker nearer its pivot point would allow the travel on the DTI to record all movement of the valve, but it doesn't. I think I may get in a big muddle trying to work out crankshaft rotation in degrees forward and backwards.

Next job was to make a stop to hit the piston before and after TDC. I think I would prefer an aluminium head on it so that it does not mark the piston and, in any case, I had no 12mm bolts the right thread also I do not have a die that could replicate the plug thread, 12mm x 1.25mm.
So I decided to utilise an old spark plug. getting rid of the ceramic bit was taken care of by a hammer but left me with a plug of ceramic from the top of the nut to the electrode. and it would not come out either way. Eventually, I worked out that the steel bit of the plug just above the nut had been swaged over the ceramic and once this was ground off it came out easily. I drilled it through 7mm and turned up some 10mm aluminium bar which was then araldited in.
Finally, I marked up my adjustable cam pulleys and even managed to get the vertical belt on and tensioned before the temperature in the garage drove me indoors.
test teclado

[Dukedesmo]

Originally Posted by Luddite

I see this bearing question was raised on another forum

https://www.ducatiforum.co.uk/thread...earings.50724/

and you may recognise a couple of the contributers' names there (our own Dukedesmo and Nasher to be precise). Neither has mentioned a need for C3 but perhaps they could confirm what spec they actually used if they are reading this.

Not 100% certain now but, I think I used C3 bearings in both the Monster (for the movable pulley) and 916 belt tensioners, based on the reasoning of the heat due to speed/constant running and that they are not lubricated. I still have the original (to me) fixed 'special' pulley bearings of unknown age/mileage but at the last check (last year) were fine.

Otherwise the Monster has done 14k miles on the ones I swapped and the 916 - 50k miles although is on it's second set of bearings - that said when I swapped them at, IIRC 30k ish miles they were fine and showed no signs of wear. I mainly changed them as I fitted larger fixed pulleys (to allow for head skim/tuning/shorter belt run) and so did the adjustables at the same time as part of preventative maintenance.

[Dukedesmo]

With regards to adjustable pulleys; I bought a set for the Monster and took the engine to Nelly at Cornerspeed to set them up properly but it didn't require them as the standard pulleys had the timing spot on anyway so I didn't use them as I felt that it was just something that could go wrong whilst giving no benefit - that said it looks like your pulleys are alloy so lighter whereas mine were steel and so no weight saving to be made.

IMHO it's worth checking the timing with fixed pulleys as you could be in the same situation as mine?

I did change the timing on the 916 (using offset woodruff keys) but mainly because of the head skim changing timing but also, on a 4v there is more chance of them being out and more benefit to be had by altering as the intake and exhaust can be done individually (separate camshafts) whereas the 2v you can only adjust the overall timing.

[350TSS]

A frustrating day today, the horizontal cam belt got put on and tensioned using an estimated position for the timing.
The camshaft pulley nuts got loctited and torqued up, I had a bit of a concern as to how to hold them whilst applying 60Nm to the jackshaft nut and 72Nm to the cam nuts. Without the flywheel on (which I still have not located) the only way, I had to hold the engine was via the nut on the jackshaft at the other end which obviously meant all the torque was being transmitted by the belts themselves.
I then tried my piston locker that I made yesterday but it didn't work for two reasons, first I do not think it was quite long enough and second because at 7mm thick, I think it got in the way of the valves. Even gently turning the engine over with it inserted I felt a slight resistance which quickly freed off. I obviously inserted it on the wrong stroke and I think the inlet valve nicked it.
private image upload

So I set TDC with the dial gauge through the plug recording where on the timing disc the gauge began to move as the piston rose, then reversing the engine and doing the same on the other stroke and then splitting the difference and setting the timing disc to TDC. Amazingly the jackshaft pulley and the timing mark on the crankcase were perfectly in line.
Now with a true TDC I started the process of determining at what point the inlet valves on each cylinder reached peak opening. I started with the vertical cylinder and measured 3 times and I got reasonably consistent results at 443, 444.5 and 447 degrees after TDC.
Moving to the horizontal cylinder the results were all over the place, the first measurement was at 453 and then I had two results at 384 degrees ATDC.
I think I know what was going wrong with the last two, the DTI is mounted about 20 degrees to the horizontal and the return spring on the probe is lazy (ancient hand me down DTI) and the probe simply was not following the valve lifter accurately. For the vertical cylinder, the DTI probe obviously had the advantage of gravity. By this time I was getting tired and cold and frustrated, I will re-measure tomorrow and hopefully find out the difference between the two camshafts in terms of advance and retard.
I still obviously have to determine what is the right time for the camshaft to be at peak lift and at present cannot find a spec sheet for an M900 with a V2 head.
I need inlet opens and inlet closes timings.
An American website lists this information as IO 43 and IC 85 and I spent quite a bit of the cold day in the garage trying to reconcile these numbers - to me they are meaningless?????

[Luddite]

Originally Posted by 350TSS

I need inlet opens and inlet closes timings.
An American website lists this information as IO 43 and IC 85 and I spent quite a bit of the cold day in the garage trying to reconcile these numbers - to me they are meaningless?????

Is this table any use to you, Richard? I've got it saved in my photos and I refer to it for all things 'valvey'.