900GTS

If you need technical information or help with your BOSCH ignition squarecase Ducati 900SS - Darmah engine - post your FAQs, comments & questions here.
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UngaWunga
Cucciolo - the Lil Pup
Posts: 3
Joined: Thu Apr 16, 2009 9:19 am

900GTS

Post by UngaWunga »

I'm looking at a 900GTS this weekend. High miles, needs some work, all the usual for an older bike.

I'm pretty good a fixing up bikes, but this would be my first Duc. Anything particular to this model I should look out for? I plan on checking out the usual and try to do a compression test.

I do plan on cleaning it up a little and using it as a daily commuter bike.

Thanks
UngaWunga
Cucciolo - the Lil Pup
Posts: 3
Joined: Thu Apr 16, 2009 9:19 am

Post by UngaWunga »

And the big question... if the engine does need a rebuild, what's a ballpark figure for parts? Rod bearings, pistons, rings, crank bearings.

Thanks
ducsi
Cucciolo - the Lil Pup
Posts: 5
Joined: Fri Mar 27, 2009 12:45 pm
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Post by ducsi »

Hi,
I'm building a GTS right now, look for the pickup cable, does the engine run ?

roland
mizike77
860 GT / GTS
Posts: 272
Joined: Sun Jul 06, 2008 9:37 am

Post by mizike77 »

Where is the bike? I looked at a 78 900gts on thursday.....
Lumpy
SD900 Darmah
Posts: 329
Joined: Sun Mar 25, 2007 5:49 am

860GTS

Post by Lumpy »

I`ve owned an 860GTS since 1984. I`ve re-built her since then. Things to watch for are all pretty standard weak points of Duc`s. If it has Electronica ignition it`s prone to failure, as is the standard Duc regulators however better aftermarket units are available cheap. Engine stop relays can be problematic. I`ve also heard on more than one occasion that they are prone to dropping valve seats. Reason being the heads were designed as desmo and not designed to take the hammering of valve springs. I went to put new seats in mine and found the seat recess in the head cracked on the front exhaust valve. I replaced the heads and these days she runs desmo`s.
The biggest issues with my engine were built into it at the factory. both thrust washers were installed on one side of the crank allowing the rod to chew into the crank cheek, lots of machining swarf still stuck into the ignition rotor. Gear box was so tightly shimmed that the shims had turned blue from heat and wildly inaccurate bevel gear shimming. The reason I pulled it apart was due to .6mm end float on the crankshaft, not because she failed. The factory seal was still on the crankcases so this was all factory inaccuracy, she had survived till the ripe old age of 40,000 k`s before re-build. Good news is she always got me home, may have been on one lung a few times but always under her own steam. Wish I could say that about my 82 SS, she came home on a ute a while back with shifter problems. But my relationship with her is comparitivly fresh.
Compression testing I feel is not always the be all and tell all we like to think it is. Given to that top end rebuilds, ie pistons rings and re-bore comparitivly cheap and easy as opposed to the bottom end. If I were looking at splurging my hard earned on an old Duc I did`nt know i would be looking at oil change frequency, oil quality and signs that it had been maintained in an orderly fashion. Sometimes this can be evident by butchered screws and nuts, dry chain or worn out sprockets, head stem bearing play or fork seals that have leaked for long periods.
Gear box and bottom end re-builds are where the real cash lurks and can be hard to pick up on. Duc`s are a comparitively noisey engine mechanically anyway and if your not familiar with them issues in this area can be hard to pick. If possible take some one who knows their Ducs with you to check her over. No rocket science there.
On the bright side since all this was sorted she`s been more fun than a champagne enima. I`ve always maintaned that if your not mechanically inclined or willing to tinker don`t by a bevel drive. There was an old saying I heard some time back. There are 2 great days in a Ducati owners life, the day he buys it and the day he sells it. Personally i don`t agree but I`ve seen a few who would vouch for it.
In sumary, oil oil oil, regular loving maintenance, and take a Duc savy friend if your new to the marque. Get a good one and you, like many others on this great web site will be a believer.............
UngaWunga
Cucciolo - the Lil Pup
Posts: 3
Joined: Thu Apr 16, 2009 9:19 am

Post by UngaWunga »

Thanks, but I've been saved. The ad disappeared before I could call the seller. Price was low, but the pictures were fuzzy, so it might be a good thing that it went away.

Thanks for the info.
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