900 ss rear cylinder races away

Post your 'Carburettor & Fuel System' FAQs, comments & questions regarding Ducati motorcycles here.
Post Reply
philg100
Cucciolo - the Lil Pup
Posts: 7
Joined: Sun Dec 30, 2007 9:04 am

900 ss rear cylinder races away

Post by philg100 »

Hi Trying to set up carbs as per the carb sync process posted here and can get somewhere near an initial balance if I hold the revs at 2000 or so but I cant get it to tick over, just as i think i am getting there the rear cylinder loads up and the revs climb to about 4000 rpm. Any thoughts??
philg100

User avatar
abmartin
SSD900 Darmah
Posts: 358
Joined: Tue Apr 10, 2007 5:08 pm
Location: New Brunswick, Canada

Post by abmartin »

I use the following method to set up the carbs:

1. make sure that there is plenty of slack in each throttle cable;
2. start and warm up the bike;
3. either turn in or out the throttle stop screw in each carb until you get a balanced idle. You can tell that this has been achieved when slight turns out of each screw cause the idle to increase. The balance point is occurs when turning the screws in causes no change in the idle but turning one or the other out increases it;
4. ensure that each throttle slide strikes the throttle stop screw. If this doesn't happen create more slack in the appropriate throttle cable and begin the procedure again;
5. now that the idle level is synchronized, do the same with the throttle slide lift. Adjust each throttle cable until the slides strike the throttle stop screw simultaneously when closing the throttle. There should be audible clicks as they strike the throttle stop and the slides should lift simultaneously;
6. finally adjust the idle mixture screws. I just screw mine in or out with the motor running until it runs best;
7. go for a ride and enjoy the bike.

This method may dismay the purists but it has worked well for me. My bike has always been able to keep up with other performance machines while returning over 50 miles per Imperial gallon or 5.6 litres per 100 kilometres.
1979 900SS
Fredericton, NB
Canada

Post Reply

Return to “Carburettor & Fuel System Shop”