Log in

View Full Version : Ducati backfire through exhaust on start up



750sf
21st June 2009, 15:15
I have a ducati 89 900ss with the weber carb. When I start it it makes a hell of a bang through the exhaust. Its loud enough to get the AOS called out and is also embarrasing. Has anyone out there had a simalar problem with there ducati? Keen to find a solution.

98tls
21st June 2009, 16:43
Had an 89 myself,the Webers a nasty thing though not necessarily the problem in this case.Might be something useful for ya here,http://au.wrs.yahoo.com/_ylt=A0oGkzHRuT1K_kQAeYAL5gt.;_ylu=X3oDMTByZ3RtN3J 1BHNlYwNzcgRwb3MDMgRjb2xvA3NrMQR2dGlkAw--/SIG=12eq4acdm/EXP=1245645649/**http%3a//forums.ducatipaso.org/viewtopic.php%3ff=2%26p=26189 or hopefully someone else on here comes along with some useful info.

CookMySock
21st June 2009, 17:52
My hyo 650 vtwin does the same. I was told not to touch the throttle AT ALL on cold starts. Full choke only - no throttle. Sometimes it will still give a wee pop, but not the hellava BOOM that you are talking about.

Steve

wysper
21st June 2009, 17:58
My SV650 has done that on occasion too. I am not sure what causes it.
Doesn't do it every time, and hasn't done it for a few months now either.

I was thinking it might be fuel related?

98tls
21st June 2009, 18:16
To be honest mate i would myself just log onto one of the many Duc forums,as with any brand specific forum the members are pretty clued up,with my one i had a few problems with both the carb and the electrics.I have no doubt many of the old hands on one of the Ducati forums could get you sorted double quick.

CookMySock
21st June 2009, 18:20
My guess is it's the unburned fuel/air being ignited by the wasted spark when the exhaust valve is open. It's a fooken massive KA-POW thats for sure. I clear the area behind me on all cold starts.

Steve

YellowDog
21st June 2009, 19:27
If it sounds cool and makes everyone look at your beautiful bike: What's the Problem?

idb
21st June 2009, 19:34
It could be any number of things - timing, carburettor wear, starting technique...