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Discussion Starter #1
Hi

I was on a track day today. It was my first real trackday on the 900ss, the last time it started raining after just 15 minutes of riding.

At the end of the day I was accelerating on the main straight when the transmission failed. There was a grinding sound like when having a missed shift and the bike stopped pulling forward. The engine was still idling ok. When I pushed the bike to the pit it felt like the tranny was trying to lock up at every revolution but I noticed I could still shift gears and found neutral after which I could push the bike around with no locking, just a grinding noise from the gearbox. I had to leave the bike there as I rode it to the track, but will fetch it tomorrow.

I tried to google but didn't find much anything about similar failures of 900-ss transmissions. It seems this is not a typical fault but a pretty rare problem.

Has any of you had a failure of the transmission? I think the teeth of a pair of sprockets (maybe 4th or 5th gear, I'm not exactly sure which gear I was on)are probably broken on the transmission, telling by the symptoms.

I think I'm gonna split the engine during the fall and winter and replace the transmission and while I'm there, probably replace the oil galley plug and cylinder head bolts too to make the engine more reliable.
 

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I am aware of hardening problems on (I think...) 1st and 6th gear cog pairs? Never heard of one eating itself though? :eek:

They are easy enough to strip down :)
 

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Not to get off topic, but what is up with the oil galley plug you mentioned? A known problem?
 

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Not to get off topic, but what is up with the oil galley plug you mentioned? A known problem?
I believe hes talking about the oil galley plug on the crank. They are known to back out. If you go into the engine take the plug out and put thread lock on it and stake it on 4 corners so it wont back out. You take a center punch I know theres a picture on here of what it looks like when done.

Bad luck, sorry for the trans issue. Easy to do I just finished rebuilding my motor myself. Good luck
 

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Has any of you had a failure of the transmission?
The transmission on my '95 900SS CR didn't fail quite the same way yours did Pajazo but I've found that the gear teeth are chipped on some of the gears in mine. I think I prolly caught it just in time though.

I'll be replacing my entire transmission with a minty low mile one out of a '94,replacing the aluminum oil galley plug with the updated steel one,and installing a set of APE heavy duty cylinder studs as well.
 

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Discussion Starter #7
uploadfromtaptalk1347726966505.jpg
This is what I found when draining oil
uploadfromtaptalk1347727006114.jpg
The engine removed. Next job is to wash it and take it apart.
 

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The transmission on my '95 900SS CR didn't fail quite the same way yours did Pajazo but I've found that the gear teeth are chipped on some of the gears in mine. I think I prolly caught it just in time though.

I'll be replacing my entire transmission with a minty low mile one out of a '94,replacing the aluminum oil galley plug with the updated steel one,and installing a set of APE heavy duty cylinder studs as well.
Good luck with the studs if yours haven't already been replaced. I did mine myself. I don't know what Ducati use as a threadlock - but it was the threadlock from hell! :mad: Be prepared to apply a bit of heat to the base of the studs (and lots of penetrating oil) - and be REAL careful - the damn threadlock has a tendency to pick up the alloy threads from the cases - you'll get the studs out - and there's no thread left to screw the new ones in - it's still attached to the studs! :eek:
To make it worse on mine - I had two broken ones (broken before dismantling). :mad: One below the case surface, which was a pig to remove. But even the unbroken ones were really nasty to get out!
 

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Discussion Starter #9
Pistons are scored but the cylinders seem fine. The pistons seemed to stick a bit to the bottom of the cyl bores when removing them.
View attachment 118230

The head
uploadfromtaptalk1347971468984.jpg

Anyone know if these studs are reliable or not? They have an "M" marking at the end.
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uploadfromtaptalk1347971596628.jpg

The oil pump gears show no visible damage.
uploadfromtaptalk1347971691135.jpg
 

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I know of a 20k bike with pitted gears. Mine has 42k and the trans seems to work fine. Also, my 95 900ss had studs that broke. In 1996 the studs were changed. If your studs look silver and shinny, they are the older ones. If they have a black coating, they are the improved ones.
 

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The head
View attachment 118231

Anyone know if these studs are reliable or not? They have an "M" marking at the end.
View attachment 118232
View attachment 118234
I've still got my originals around - somewhere hidden... so I found this link for you... MK1 Superlight engine mods found so far - Page 2

I am not sure what the new ones look like because I have not bought any yet and they could be different depending where you get them i.e. silver or darker or black, but I believe mine to be original ones which are bright silver and which have snapped and have an "M" stamped on the end. Have a look at following article: Good Studs vs Bad, Head Studs that is - Ducati Monster Forums: Ducati Monster Motorcycle Forum
Which pointed to this... Good Studs vs Bad, Head Studs that is - Ducati Monster Forums: Ducati Monster Motorcycle Forum Click on the link to get at the pictures...

Pulling apart my '94/ '95 M900 Engine and look what i found,

For people not sure what they are looking at,

Picture 1 shows the old Silver cylinder studs on the vertical cylinder that had a tendency to break, not elastic enough. The Horizontal has the good bronze coloured ones.

Picture 2 and 3 are what is printed on the end of the stud, where you should be able to see. M bad, O good. Contary to what Ian Falloon says in his Resto book. :

Some mechanics really can be lazy, only replacing the Horizontal cylinder studs because to replace the Verticals means dropping the engine. >

Lets see what else i find :p
Good luck! But change your studs - the APE ones look good!
 

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Discussion Starter #14 (Edited)
The fifth gear sprocket had lost teeth and was splitted.
uploadfromtaptalk1348239987681.jpg
There was probably some kind of a manufacturing fault with the fifth gear as there is hardly any visible wear to the other gears. The 1st gear dogs have a bit rounded edges but there was no problem with the engagement of the first gear.

The oil galley plug was loose but not chipped by the crank bearing. I think it was just a matter of time before it started chipping.
uploadfromtaptalk1348240005420.jpg

Does anyone know if it is OK to bore out the cylinders to 94mm? The engine has 93 year stamps on it, so I think the cylinders are not nikasil coated. Then I could use JE 944 pistons with the original cylinders which are now a bit scraped by debris from the broken gear.
 

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Discussion Starter #15
I got all the cyl studs out by tightening three nuts against each other to the stud and then turning from the lowest one. The studs were really tight, some loosened by a sharp tap of a hammer to the end of the stud.
uploadfromtaptalk1348249747969.jpg
uploadfromtaptalk1348249766403.jpg
 

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The fifth gear sprocket had lost teeth and was splitted.

Does anyone know if it is OK to bore out the cylinders to 94mm? The engine has 93 year stamps on it, so I think the cylinders are not nikasil coated. Then I could use JE 944 pistons with the original cylinders which are now a bit scraped by debris from the broken gear.
My 1981 Pantah 500 was Nikasil coated. I believe ALL the belt driven OHCam engines are.
 

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Im thinking the big gear has some sort of defect, cracked, broke a chunk out which stripped the teeth off the smaller gear?

Not a common problem in the SS??

On the upside you get to strip & rebuild your engine PROPERLY sorting any future galley plug & stud issues :D
 

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Hi,

bummer with the trans failure...

You will need to replace all gears with even slighly rounded engaugement dogs. If not this will only cause problems later. Check your shift drum aswell... It should have sharp edges on the peaks. The bottom of the peak should be flat, otherwise you will have problems with missed shifts. This may not make sense now but when you have the drum in your hand you will understand what I mean. If not post a pic and I will let you know if it is ok.

The cylinders will need to be replated. Millennium Technologies does great work so you should give them a call. I would recommend that you look at pistal or weisco pistons as I don't like the JE pistons (personal opinion... though they are cheap). It would also be a good idea to get the crank balanced while it is out and you are putting in new pistons...

Good luck with your build :)

Gray
 

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Discussion Starter #20
uploadfromtaptalk1349886065821.jpg
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A few pics of the broken gear teeth found inside the engine. To me it looks like fatique fractures developed to the root of the gear teeth, a few teeth broke of and initiated the breakup of the gear pair.

I got a cheap transmission from a 97 monster from ebay. It seems to be in very good condition otherwise that on the input shaft side sprocket of 3rd gear there seems to be small fissures that can just be seen with bare eye.

uploadfromtaptalk1349886731478.jpg

I wonder if these are anything to be worried about? I can only find them on the 3rd gear gear pair, but the pair which broke on my bike was 4th. I have the option of replacing the 3rd gear pair, but the ducati gears are not cheap. The fissures are not very noticeable by the bare eye, but they show much better in the photo.
 
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