Hi All,
This is a quick beg for help. My 2000 m750 is going into the shop after a few weeks of issues which I outlined in this thread: http://ducatimonsterforum.org/index.php?topic=41447.msg740715#msg740715 (http://ducatimonsterforum.org/index.php?topic=41447.msg740715#msg740715)
My last full tank of fuel was 93RON and everything seemed to be going just fine, but today I started it up and BAMM - Backfire - Backfire - Backfire.
This is 6:30am in a quiet residential area so I let it die, which it rarely does, and wheeled it down to the end of the street to start it up. Better to wake up the neighbors down there.
Well, it started rough and kept backfiring until it was warm. I hate to run it like this, but I have no other option than to bring it to work and then on to the shop.
I'm not looking for a permanent fix, I think only the shop can provide that now. I would like to get it out of the parking garage without scaring the shit out of the people in my office though and if I can drive it to the gas station warm and put in a higher or lower octane I'd feel better about it.
Is this caused or in any way due to my lower octane fuel, or would lower octane help prevent backfire?
Octane would not be a direct cause of your back firing. You might want to drain the fuel from your float bowls and look for water/debris. If you look at the right side of the bike you will find two plastic tubes. follow them up and where they connect to the float bowls you will see screws with, I think, 8 mm. heads. Loosen them and the fuel will drain out. Catch the fuel in a clear container and look at what you have. You might want to look at the spark plugs too. Also check your fuel and vent hoses for kinks.
Thanks Howie, I will drain and peek just to be on the safe side and to learn how to do it. Meanwhile, I brought the bike into a place I trust and learned that I've been doing everything wrong. At least according to the shop owner. He's been strictly Ducati for over 18 years and has some classics in his show room as well as 2010's.
The former owner told me to rarely if ever use the choke; the wrench told me to freely use the choke and let it rev a bit.
The f.o. told me to warm it up using the throttle as much as possible and if necessary use the choke; the wrench told me that's a sure way to foul the plugs and cause backfire.
The f.o. told me to run Aussi RON 91; the wrench told me his best kept engines drink only 95 and 98RON.
For what it's worth, I trust this wrench and I'm not only going to try it, I'm going to "do it" and if I have issues, I'll go back to him for advise.
On a side note the other local Ducati shop (a big store that deals in Ducati as well as others) gave me an estimate that came in a tad under $900 and included a carb rebuild and sync, new plugs, wires, tank flush, compression test, etc. And the $900 was the bottom est.
All told I spent $110 and that included the tools and supplies to change the oil and plugs myself.
I'll let you know in a few hundred km how it's going.
My experience is each bike varies a little when it comes to using the choke. You definitely want to use some choke until you have a stable idle. I use maybe a third to half choke on a cold start in normal weather and back off as needed, usually only a few seconds, full choke in winter and no choke when the ambient temperature is really high. Your tech is correct that too lean a mixture from not using the choke will cause mayhem. That is why the choke is there. Your 750, if stock, has relatively low compression. I wouldn't use the 95 unless you hear ping, on the other hand, if it is not E10 (gasahol) it won't hurt. Oh since you can, avoid E10.