1974 Ducati 900GTS Desmo Resto-Cafe

Post pictures of your twin cylinder Bevel Drive Ducati (pre-1985) along with a description here.
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l_aysan
Cucciolo - the Lil Pup
Posts: 4
Joined: Tue Jul 05, 2011 6:13 am

1974 Ducati 900GTS Desmo Resto-Cafe

Post by l_aysan » Tue Jan 19, 2016 7:13 pm

This will be kind of a build thread for my engine ... I hope this is the right spot for it! let me know if its not

I've got another build thread over at DoTheTon (same thread title)






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------ THE HISTORY -----

-My father bought this bike as the 2nd owner back in the early 80s ... It started out as a "860GT" which was a non-Desmo engine and slightly different tank and seat (more square like)

- he dropped a valve seat in the late 80s and out the bike in storage. (And the engine was toast.)

- we did a frame up rebuild in 2001 ... Found the GTS tank, seat, stainless fenders and other associated parts. The engine was still a non-Desmo engine at that point

- I rode it for 5 years had an absolute blast! At that point a number of electrical issues began popping up and a strange whining noise coming from the engine.

- I took the Desmo engine and Bosch ignition system out of a 1978 900SS and installed it in the bike.

- 3 years ago something let go inside the engine and I stored the bike till this winter for the rebuild. (I didn't know the history of the engine so I was always suspicious of how long it would last)


------- THE PLAN ----

- ENGINE: rebuild the engine - fairly standard rebuild maybe some goodies from Steve. depending on how trashed the engine got.


- ELECTRICAL: I had another flare up of electrical issues in the period leading up to the demise of the engine ... Worn handle bar switches, fuse box problems and burned out ignition. So I need a new fuse box and bar controls. I'll see how my budget is doing after the engine rebuild.

- TAIL: I plan on chopping up an extra regular (steel) rear fender and changing up the tail light to something a little more interesting.

Something like this:

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Or modify the seat a little for an embedded look:

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- GUAGES/DASH: I've had non stop problems with the original speedo and tach.... I'm running a dash and gauges out of the 900 SS; but still running into problems fairly consistently. And I'm not a big fan of the way the dash looks without the fairing surrounding the sides of the dash

- SUSPENSION: seals need replacing up front ... tired shocks out back. Again; once the engine is torn down and assessed I can budget how crazy I'm going on this end

----- ON WITH IT!! -----

Tear down Time!
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Torn down ready to pull the engine.

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Time to lift the bike off the engine .... Strapped the engine down to the table and pulled the bike up with the hoist

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I pulled the side covers and heads off. I forgot to take pictures of the heads but luckily whatever let go isn't up there. The cylinders have a bit of scaring.... I'll have to get them measured to see what's up.

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I thought the problem would be something in the clutch that let go .... But it's all there also.

So it must be something in the bottom end.

Regardless it needs a full rebuild so it doesn't matter....

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Heavy scaring on the Pistons .... May not be salvageable
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Heavy metal flaking in the oil passages

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This weekend I'll be splitting the engine and getting into the bottom end.

I'd appreciate any help you guys have!! I build the original 860 engine (non-desmo) engine ... however I've never dove into a Desmo.

(I've got the manuals and spare parts books)

Stay tuned!

wdietz186
851
Posts: 601
Joined: Sun Sep 10, 2006 4:40 pm

Re: 1974 Ducati 900GTS Desmo Resto-Cafe

Post by wdietz186 » Fri Jan 22, 2016 5:40 pm

Looks like the crank took a dump. I suggest a stiff drink and being seated before you price a rod set. Pistons and the like are pretty steep too. You will likely need some trans bits too as the heat treating was kind of iffy back then. Rebuilding it isn't rocket science but do pay attention when you take it apart. Note where, and the thickness of the billion or so shims on the shafts and gears. Pictures and drawings are a big help. Oil can stick the shims to bearings and other surfaces so double check that nothing is stuck to the pieces when you pull things apart.

l_aysan
Cucciolo - the Lil Pup
Posts: 4
Joined: Tue Jul 05, 2011 6:13 am

Re: 1974 Ducati 900GTS Desmo Resto-Cafe

Post by l_aysan » Sun Feb 07, 2016 12:59 pm

wdietz186 wrote:Looks like the crank took a dump. I suggest a stiff drink and being seated before you price a rod set. Pistons and the like are pretty steep too. You will likely need some trans bits too as the heat treating was kind of iffy back then. Rebuilding it isn't rocket science but do pay attention when you take it apart. Note where, and the thickness of the billion or so shims on the shafts and gears. Pictures and drawings are a big help. Oil can stick the shims to bearings and other surfaces so double check that nothing is stuck to the pieces when you pull things apart.
Yeah its the bearing of the vertical cylinder .... bringing it to a shop this week to get it checked out. I've got an extra crank shaft ... but i dont know its good or not.

And thanks for the advise! I've been very careful during the split to make sure all the shims go back into the right spots.



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The knock is coming from the vertical cylinder connecting rod.



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The Big Split

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Lots of metal chips and Whatnot

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Pressing Bearings out

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Cleaning ... cleaning ... cleaning

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Decided to give this VHT Wrinkle paint a shot!

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Sprays on smooth then it takes a couple hours to get the wrinkle effect ... pretty neat

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right after i sprayed it

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after about an hour (should wrinkle up more but i had to run!)

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Dug out all the spare parts and spread them out to see whats up!
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Most in good shape ..... this head came out of another 860GT engine the valve seat dropped and tore up the head/piston/cylinder. Still keeping it incase
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I'm bringing the crank/cylinders/pistons to a machine shop to get them checked out the cylinders to see if they need re-sleeving etc.

I also need to get the crank split to change the bearing and check out the crank to see if its garbage or not ... I've got another one tho! so I'm not to worried!

I looked at what I have for bearings and I need pretty much everything.

- Does anyone know where I can get a list of all the bearings that are used in this engine?

- A machine shop in Toronto, Ontario for the crank etc?



- Stay Tuned!

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