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Our bikes - 1975 Ducati 860 GT Fire me up (by Guy ‘Guido’ Allen, Apr 2021)
The old Ducati looks great, but age has caught up with the ignition system Yep, we've added a Ducati to the shed. It's an 860 GT, October 1974 build for the 1975 model year. This was to follow on from the success of the more elegant 750 Sport and, thanks in part to the radical and oh-so-seventies styling by the legendary Giorgetto Giugiaro, it hit the proverbial brick wall in the showroom. A hasty redesign was organised (essentially softening the harsh angular lines) and Ducati two years later launched the Darmah series as an alternative. While the the lines may have offended some back in the day, they seem less hard on the eye now. If you've been watching the classic motorcycle and car markets, you will probably have noticed that seventies toys are hot at the moment. This example came from old mate Ian Falloon, a well-known motorcycle author and whose idea of acceptable motorcycle presentation is something dead original and clean enough to perform surgery on. It's the second bike I've relieved him of – the first was a MkIII Norton Commando. So much for the background. The Ducati turned up looking immaculate and running, but there was a hint all wasn't well in the Italian section of the shed. These things run very early Ducati Electronica solid state ignition, which were okay in the day, but had a reputation for two issues: One was they could be a bit of a cow to start; The other was the ignition curve made a massive 20 degree jump in its advance at 1200rpm. The latter was suspected of making life unnecessarily hard on other components of the engine, including the bottom end. A check-over raised the suspicion the spark being delivered wasn't all it could be, particularly on the rear cylinder. This bike had been restored to as-new, which means all the factory components and their foibles. Given it was heading towards 50 years old, you could forgive the now well and truly outdated ignition system for becoming tired and emotional. We decided to bite the bullet and replace, while putting the original bits aside for any future owner who absolutely had to have factory-correct. There are choices out there for bevel Ducati replacment ignition systems, and on Ian's advice I went for Elektronik Sachse – a German make. Cruising owner sites, it seems to have a solid reputation, while offering a choice of several ignition curves. While the kit provided the engine trigger hardware and control unit, it also required updated ignition coils and leads. The cost for that lot was Au$650 (US$500, GB£355) shipped to Australia for the Sachse kit, plus another Au$130 for the coils and leads from Trispark in Australia. A substantial cost, but rather that than start each ride wondering whether the heart-attack will arrive before I've finally succeeded in kick-starting the thing! A quick read of the installation instructions made it a pretty easy decision to hand over the job to someone else. From where I was sitting, there were two potential issues: getting the timing wheel in and out (see the pics to understand why) and ensuring the new unit was properly 'embedded' with the existing electrical system. A chap called Peter Shearman of Dukelectrix did the honours. He's located a little way out of Melbourne and had already worked on the 860, cleaning up the wiring loom and getting it fully-functional. As part of this job, he upgraded the ignition circuit to something a little more robust. Here's a visual run-down of the job... Complete Sachse kit Left-side engine cover is removed to expose the clutch and ignition trigger. Removing the trigger wheel required a puller. Original pick-up plate exposed. New pick-up plate in place. Old trigger wheel and drive gear. Separating the old trigger wheel and drive gear was a surprisingly big job, as someone had previously been over-enthusiastic with the Loctite. New trigger wheel is attached to the drive gear by just three screws. New trigger wheel in place. Peter made up a couple of brackets, including this one to hold the new coils. The coils tucked away in their new home. The old ignition system has been packed away. The Sachse system offers several ignition curve options. We've gone middle of the road at number four. And the result? There's no question it's now a much easier proposition to start. That was aided significantly by Peter finding and clearing a blocked idle jet on the rear carburettor. At this stage we're looking at easier starting and presumably a more reliable ride. That will do. Next up is we're going to tackle a couple of minor leaks as part of the shake-down process – watch this space. More on stylist Giugiaro here at Unique Cars magazine ------------------------------------------------- Produced by AllMoto abn 61 400 694 722 |
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