Yet Another M900 Build - Page 37

Luddite · 03-08-2021, 01:00 PM

Quote:

Originally Posted by PPuxley

Oh jesus, thats the other way from the Haynes!!! Ive just re-fitted it as Haynes!!

There was a similar discussion a few years back on ducati.ms. For what it's worth, Brad the Bike Boy recommends refitting it as per the Haynes manual for pre-2001 models.

"For (most?) models 2001 onwards (that i have had to deal with) it is reversed, meaning it is fitted the way you would expect it to be fitted. but, in 2001, they went to a different oil pump drive ratio and those pumps spin a lot faster and deliver a lot more pressure.prior to 2001 that seal is fitted the "wrong" way around. replace it as it is now being the most salient point."

https://www.ducati.ms/threads/cranks...cement.475921/

PPuxley · 03-08-2021, 01:03 PM

Quote:

Originally Posted by hh93

You could try resoldering then testing with a multimeter and dunk it in water and out to see if the resistance changes - can take 30 to 60 Seconds to change through. That's deliberate to prevent flashing of the warning light.

Reposting the link to the PDF of Thermister Info so it's on here too:

https://www.teamwavelength.com/therm...y%20or%20glass

Sorry, missed this. What was inside the Ducati level detector was not an encapsulated thermistor it was a small piece of material with a piece of conductor affixed to each end. I can only see encapsulated ones.
Its a bit academic now since I have dismantled the part and set it all up for this optical detector. If I could find the right thermistor I could have a play and see if I could make it work. As used in the original it was a very simple device, immersed it was high resistance, out of the liquid when it was able to warm it became low resistance, allowing it to pass current and light the lamp. There was no ancillary circuitry.

PPuxley · 03-08-2021, 01:29 PM

Quote:

Originally Posted by Luddite

There was a similar discussion a few years back on ducati.ms. For what it's worth, Brad the Bike Boy recommends refitting it as per the Haynes manual for pre-2001 models.

"For (most?) models 2001 onwards (that i have had to deal with) it is reversed, meaning it is fitted the way you would expect it to be fitted. but, in 2001, they went to a different oil pump drive ratio and those pumps spin a lot faster and deliver a lot more pressure.prior to 2001 that seal is fitted the "wrong" way around. replace it as it is now being the most salient point."

https://www.ducati.ms/threads/cranks...cement.475921/

Thanks, Luddite. I've now read that other thread end to end.
At the risk of frustrating everybody, I'm afraid I still dont understand Brad's final words.
"Replace it as it is now being the most salient point."

What does he mean by "as it is now"?

So which way is that?

For pre 2001...with new viton seal replacement......spring towards centre (wrong) or spring towards outside (right)?

utopia · 03-08-2021, 01:34 PM

On my 750 (yr 2000 and with a wet clutch), the paint on the clutch cover had blistered and so I bought a used cover which I repainted and fitted, rather than enduring the extended downtime necessary to remove and repaint the existing cover (or doing it in situ).
I replaced the oil seal in the "new" cover with one supplied by JHP Ducati Coventry which was the new type (part no. 93040911A), fully encapsulated in a brown rubber of some sort ... probably viton I guess but I don't really know.
Anyway, apart from the new seal being rubber-covered all over while the original had a plain steel case, the seals looked to be of identical type .. at least they did to my cursory glance.
So I fitted the new seal the same way round as the old one, ie hollow side facing outward towards the circlip.
Unfortunately the bike has only run a few miles to and from the mot centre since then so I can't really give a long term report but in the short term (8 or 10 miles) its been fine as far as I can tell, ie no strange noises and no oil warning light.
I appreciate that after so few miles the new assembly is not yet fully proven but its been fine so far. I'll try and get out for a few more miles later today or tomorrow and report back.
Also, I checked my original case just now and the old type, (bare steel cased) seal in that is fitted hollow side outward towards the circlip
I'm twitching ever so slightly now in the light of this discussion in case the new type seal should go the other way round but like DD says, the physical appearance of the seal suggests that it operates in the same way as the original and therefore should be fitted the same way round.
Still not absolutely conclusive but maybe that throws a little more light on the subject.
I'll report back.

And yes, I had to butcher the old seal out of the cover too.

ps. the above was written prior to seeing Lud's post re. Brad the Bike Boy's comments.

PPuxley · 03-08-2021, 01:42 PM

Utopia, thanks. Your post is very clear. I think Brad is advocating exactly what you have done. It would be so much easier and quicker to convey meaning if standing face to face and having a conversation!

utopia · 03-08-2021, 01:55 PM

Ha ... thanks.
I sometimes wonder whether folk find my carefully worded posts a little tiresome.
My confidence is restored.

And while on the subject of the clutch cover, don't be tempted (as I was briefly) to fit a gasket where there was formerly a threebond seal.
The little green o-ring that seals the oilway from the pump will not be compressed adequately due to the extra thickness of the gasket.
According to my calcs even a new seal will only get one or two thou compression and if you re-use the old one it wont even touch the sides.
I'm sure you'd spot this yourself but it never hurts to give extra info, eh ?

PPuxley · 03-08-2021, 02:02 PM

Quote:

Originally Posted by utopia

Ha ... thanks.
I sometimes wonder whether folk find my carefully worded posts a little tiresome.
My confidence is restored.

And while on the subject of the clutch cover, don't be tempted (as I was briefly) to fit a gasket where there was formerly a threebond seal.
The little green o-ring that seals the oilway from the pump will not be compressed adequately due to the extra thickness of the gasket.
According to my calcs even a new seal will only get one or two thou compression and if you re-use the old one it wont even touch the sides.
I'm sure you'd spot this yourself but it never hurts to give extra info, eh ?

Need to take a look at that. My gasket came away clean, it looks like it had been oiled both sides. So I was going to put back having totally degreased it, probably with a smear of 3 bond. Looks like that may be a bad idea so will probably now go with just 3 bond. But I will have a proper look to see what compression I'm getting on that o ring

Luddite · 03-08-2021, 02:37 PM

Quote:

Originally Posted by PPuxley

If I could find the right thermistor I could have a play and see if I could make it work.

If you want to experiment there are quite a few NTC thermistors specifically for fuel sensors on eBay e.g. https://www.ebay.co.uk/itm/Fuel-Leve...-/353526434180

Quote:

Originally Posted by PPuxley

At the risk of frustrating everybody, I'm afraid I still dont understand Brad's final words.
"Replace it as it is now being the most salient point."

What does he mean by "as it is now"?

I agree, it's not very clear but, in the context of what he says elsewhere, I'd say he means replace it as it was originally installed, rather than as per the later, post-2001, instructions.

PPuxley · 03-08-2021, 03:43 PM

Quote:

Originally Posted by Luddite

If you want to experiment there are quite a few NTC thermistors specifically for fuel sensors on eBay e.g. https://www.ebay.co.uk/itm/Fuel-Leve...-/353526434180.

Thanks, again.
Actually Ive now found a video of someone fixing an almost identical thermistor sending unit with a 1k ohm NTC thermistor, using the old housing and just installing the new component. So cheaper and no wait for the part from China. Incidentally, at about 18 secs in , that is exactly what I found in my bust one

utopia · 03-08-2021, 04:54 PM

.... back to the clutch cover gasket ....

Ah, for some reason I was assuming that your assembly had no gasket fitted when you stripped it.
I guess there's no way of telling whether your gasket was fitted originally or whether a previous owner has added one where there was formerly none.
You may find my measurements useful then (though remember this is for a wet-clutched yr 2000 M750 .. for what difference that may or may not make).
The essential dimension is the depth of the counterbore which houses the o-ring on the crankcase side. In old money, this measured 0.042 ins on my engine.
Thickness of the o-ring was 0.068 ins (new) or 0.062 ins (used).
Thus std o-ring compression is 0.026 ins (new) or 0.020 ins (used).
The new Exactfit gasket that I bought (before realising the problem) measures 0.024 ins (0.6mm).
Thus a new o-ring would only get two thou compression and a re-used one would have four thou clearance (assuming zero compression of the gasket).
I've also assumed zero thickness of an applied film of threebond after assembly, though in fact I doubt this is precisely correct.

Now that I think of it, I can't remember how I determined that the mating face for the o-ring on the cover side was in the same plane as the gasket face .. but the above is based on that premise.
And I ended up deducing that where a gasket was originally fitted, the counterbore on the crankcase side would be shallower. I would be interested to know what measurements you find on your engine.

In the pursuit of minutiae, it may or may not be worth considering that the fitment of a gasket places the oil seal (and the bush) a fraction further out on the end of the crankshaft.

PPuxley · 03-08-2021, 04:59 PM

Utopia. I was just going to break out the blutac, put some in place of the o-ring do the casing up and measure what thichness that was and see how it compares to the o-ring

PPuxley · 03-08-2021, 05:12 PM

Thanks for the tip for putting that large O-ring into the clutch housing, (whoever it was) , using the parts of the clutch to pull it in square. I went so far with just the two parts then introduced some spacers to pull it further. Needs regular checking as you dont want to go too far.
I assume it should fit flush to the outside, which leaves about a 2mm lip of the seal protruding on the inside

PPuxley · 05-08-2021, 10:40 PM

Waiting for a replacement 6th gear before I can close the cases, I did a bit of hand painting on the new outer casings

Ive received an assortment of shims from Snells so did a bit of sorting these out and working out whats going where. And remeasured the crank float

hh93 · 06-08-2021, 06:11 AM

That's one veteran Workmate

PPuxley · 06-08-2021, 09:15 AM

Quote:

Originally Posted by hh93

That's one veteran Workmate

Ha! yes it is.

03-08-2021, 01:34 PM	#544
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,545	On my 750 (yr 2000 and with a wet clutch), the paint on the clutch cover had blistered and so I bought a used cover which I repainted and fitted, rather than enduring the extended downtime necessary to remove and repaint the existing cover (or doing it in situ). I replaced the oil seal in the "new" cover with one supplied by JHP Ducati Coventry which was the new type (part no. 93040911A), fully encapsulated in a brown rubber of some sort ... probably viton I guess but I don't really know. Anyway, apart from the new seal being rubber-covered all over while the original had a plain steel case, the seals looked to be of identical type .. at least they did to my cursory glance. So I fitted the new seal the same way round as the old one, ie hollow side facing outward towards the circlip. Unfortunately the bike has only run a few miles to and from the mot centre since then so I can't really give a long term report but in the short term (8 or 10 miles) its been fine as far as I can tell, ie no strange noises and no oil warning light. I appreciate that after so few miles the new assembly is not yet fully proven but its been fine so far. I'll try and get out for a few more miles later today or tomorrow and report back. Also, I checked my original case just now and the old type, (bare steel cased) seal in that is fitted hollow side outward towards the circlip I'm twitching ever so slightly now in the light of this discussion in case the new type seal should go the other way round but like DD says, the physical appearance of the seal suggests that it operates in the same way as the original and therefore should be fitted the same way round. Still not absolutely conclusive but maybe that throws a little more light on the subject. I'll report back. And yes, I had to butcher the old seal out of the cover too. ps. the above was written prior to seeing Lud's post re. Brad the Bike Boy's comments. Last edited by utopia; 03-08-2021 at 01:36 PM..

03-08-2021, 01:42 PM	#545
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Utopia, thanks. Your post is very clear. I think Brad is advocating exactly what you have done. It would be so much easier and quicker to convey meaning if standing face to face and having a conversation! __________________ Golf-My favourite game. While my wife plays I'm in the workshop.

03-08-2021, 04:59 PM	#551
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Utopia. I was just going to break out the blutac, put some in place of the o-ring do the casing up and measure what thichness that was and see how it compares to the o-ring __________________ Golf-My favourite game. While my wife plays I'm in the workshop.

03-08-2021, 05:12 PM	#552
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Thanks for the tip for putting that large O-ring into the clutch housing, (whoever it was) , using the parts of the clutch to pull it in square. I went so far with just the two parts then introduced some spacers to pull it further. Needs regular checking as you dont want to go too far. I assume it should fit flush to the outside, which leaves about a 2mm lip of the seal protruding on the inside __________________ Golf-My favourite game. While my wife plays I'm in the workshop.

05-08-2021, 10:40 PM	#553
PPuxley Registered User Join Date: Apr 2021 Location: Reading Bike: M900 Posts: 600	Waiting for a replacement 6th gear before I can close the cases, I did a bit of hand painting on the new outer casings Ive received an assortment of shims from Snells so did a bit of sorting these out and working out whats going where. And remeasured the crank float __________________ Golf-My favourite game. While my wife plays I'm in the workshop.

03-08-2021, 01:55 PM	#546
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,545	Ha ... thanks. I sometimes wonder whether folk find my carefully worded posts a little tiresome. My confidence is restored. And while on the subject of the clutch cover, don't be tempted (as I was briefly) to fit a gasket where there was formerly a threebond seal. The little green o-ring that seals the oilway from the pump will not be compressed adequately due to the extra thickness of the gasket. According to my calcs even a new seal will only get one or two thou compression and if you re-use the old one it wont even touch the sides. I'm sure you'd spot this yourself but it never hurts to give extra info, eh ?

03-08-2021, 04:54 PM	#550
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,545	.... back to the clutch cover gasket .... Ah, for some reason I was assuming that your assembly had no gasket fitted when you stripped it. I guess there's no way of telling whether your gasket was fitted originally or whether a previous owner has added one where there was formerly none. You may find my measurements useful then (though remember this is for a wet-clutched yr 2000 M750 .. for what difference that may or may not make). The essential dimension is the depth of the counterbore which houses the o-ring on the crankcase side. In old money, this measured 0.042 ins on my engine. Thickness of the o-ring was 0.068 ins (new) or 0.062 ins (used). Thus std o-ring compression is 0.026 ins (new) or 0.020 ins (used). The new Exactfit gasket that I bought (before realising the problem) measures 0.024 ins (0.6mm). Thus a new o-ring would only get two thou compression and a re-used one would have four thou clearance (assuming zero compression of the gasket). I've also assumed zero thickness of an applied film of threebond after assembly, though in fact I doubt this is precisely correct. Now that I think of it, I can't remember how I determined that the mating face for the o-ring on the cover side was in the same plane as the gasket face .. but the above is based on that premise. And I ended up deducing that where a gasket was originally fitted, the counterbore on the crankcase side would be shallower. I would be interested to know what measurements you find on your engine. In the pursuit of minutiae, it may or may not be worth considering that the fitment of a gasket places the oil seal (and the bush) a fraction further out on the end of the crankshaft.

06-08-2021, 06:11 AM	#554
hh93 Member Join Date: Jul 2018 Location: Lincoln Bike: M620ie Posts: 116	That's one veteran Workmate