My 650 Special has a Cagiva Elefant engine and PHF36 carbs with no air filters, and Conti megaphone "silencers". Before I got it, the bike had never run in this configuration as far as I can see. It goes quite well but is a little rough with slight mis-firing in the mid-range. I have increased the main jets from 130 to 132 (H) and from 132 to 134 (V). Needles are in the bottom slot (furthest out). Slides and needles are standard. Float level is perfect. The plugs are pale grey in normal running conditions, so I am assuming that the lack of air filters and zero back pressure from the Conti pipes results in a weak mixture. I also get some occasional popping in the pipes on the over-run. Anyone have experience of this, and suggested solutions? I don't want to be trying various different slides and needles without some guidance on how much to change and what to go for. Any help greatly appreciated!
Or maybe that is just the way a 650 Ducati from the 1980s runs. I'll get some miles in and see how we go. The standard Pantah 650 carb setup is if anything slightly leaner. Talking to myself here - I guess if I wanted company in this forum I should post some semi-literate cant about Brexit and/or Trump.
LOL yep - plenty of comments and opinions here but not much factual information sometimes. I have a 650 pantah engine with open bell mouths 36mm dells and a conti exhaust. Loud and awesome!! I will take a look at the jetting I currently have in it. I think I have the idle jets about right as it is easy to get a clean sharp tick over on about 1 1/2 turns and a good progression up to about half throttle opening. I don't think I have the mains right as it will not pull cleanly when I open her up. Pretty sure I have bigger mains in than the 132 you have. I will take a look at the weekend and report back. I have few main jets in the garage so may even have a chance to put bigger ones in. I think between us we could fine tune both our vehicles. Best regards Keith MM ps long shot but where are you based ? I'm in SE London.
Excellent stuff - many thanks! I am in the Cambridge area. Sounds like a very similar setup. Here are my carb details: Slide: 60/3 Needle K18 Pilot jet 65 Needle valve 250 Needle jet 265AB Choke jet 75 Float level 18mm Needle clip is in bottom slot. Starts fine, ticks over fine. Backfires on over-run and does not run cleanly at low to mid throttle opening. Plugs looking too pale grey for my liking. Haven't tried running flat out yet!
Any progress on checking your carb internals? I would be particularly interested to know what main jets you have and what needles...
I ran a totally stock 650 Elefant briefly and I always remember thinking that it possibly should’ve been pulling cleaner through mid-revs but never got to grips with it as you two are attempting. Some researching at the time revealed that carburation was a little compromised as standard. I wish you the best of luck, I waved the white flag when I couldn’t get replacement inlet rubbers at the time. As said, refreshing to see this type of thread on here. Here is a thread that ran for quite a while, but dealt mostly with later Elefants :- https://www.ducatiforum.co.uk/threads/cagiva-elefant-750-1987.5627/
Thanks for the very useful feedback - just waiting for better weather to get some miles in, then I think I might well stop trying to get the bike to run like a well-mannered computerised injection clone. It's a 1980s Ducati; as long as it does the biz at full throttle, corners on rails, sounds fabulous and looks beautiful, why should I complain....
Interestingly (well, interesting to me anyway) the carbs seem to be settling in on their own. Bearing in mind the bike was built for an exhibition, the (1985 Elefant 650) engine probably never ran since last used, probably in the late 80's. After a few miles, the plugs were white and it ran as if very lean. Now the plugs are pale brown and the bike is running much better, even though I have not made any adjustments. Most running is "on the needle", ie 1/4 to 3/4 throttle. Funny old things these 1980's Ducati engines - they obviously have a soul.
