it was the festival of italian motorcycles today, and i'd given up on going just because this piece of shit was pissing me off. but then someone convinced me to do something about it so i spent 4 hours last night putting it all back to original throttle body wise. balancing the throttle bodies is such a pita with the old style link rod.
put the p7 ecu back into it and cut out the fim additional memory board which i don't need anymore because i can do anything i need to the eprom files. i went with a 009b based eprom just in case there was any oddness from the fim based stuff. put in the fuel map from the eprom i developed back when i was riding it, modified the spark map and break points to try to give it the increased advance below the desired idle speed to help it when it's cold and a constant advance section just above idle to stop it creeping and changed the air and coolant temp trim tables.
the eprom i had before was a lot leaner at low throttle than the 009b, more so than a direct comparison would indicate as the 009b air temp trims were generally 5% ish richer than the um011 based eprom, which i'd modified anyway.
i figured the sections that were around -30% could be what was giving me the total shut down feeling i was getting at low throttle when i first got it going again. so i changed them to be no greater than -15%, just to see what difference it'd make. turns out, with how it is now, it's a touch rich. but nice to get a feel for it, and how to fix an issue.
years ago i'd shut the fuel off on overrun from 2,500 rpm upwards, but i found today that if i pulled the clutch above 2,000 rpm ish on overrun it'd die - mustn't be able to catch itself in time. i'll raise that to 3,000 rpm. it really jumps when the fuel comes back on, and i think part of that is the spark map.
i found that, when the fuel comes back on, it's really jerky if you let it just run down through 2,000 rpm. gets a lot better around 1,500. i tend to run spark maps with 10 degrees per 1,000 rpm, but that's a lot more than the 009b had originally at 2,000 rpm and 0 throttle, so i'll change that to see if i can smooth it out.
the idle fuel i made the same as the 009b, and i reset the ecu trimmer to 2.5v (the midpoint) and it wasn't too bad (kind of) mixture wise. it's idling higher than 1,100, and i really hate high idling bikes, even though it helps - having increasingly more throttle opening and idle speed makes an increasing reduction to the dirtiness. it's still a bit offensive to sit behind - kind of like a 748sp i'd say from memory. it's around 3.5 - 4% co, maybe trying it a bit leaner may clean it up a touch more. i'm still not happy with it, but don't have any real ideas on how to make it better.
i wonder if the extra overlap from the cam timing changes have an impact. doesn't with anything else with these cams - 748 to 996 - but maybe the 851 is a bit more precious. maybe s4/st4s inlet cams would help it.
when i had it running with the p8 and the axone diagnostic hooked up it came up with a crank/cam sensor phase error. never seen or heard of it before, but then we rarely needed to have p8 bikes running with diagnostics connected, and most of the ducatis got fim based eproms back in the day. all the dots line up cam wise, and i've done the cam timing confirming that all is as expected. but the dp aluminium flywheel doesn't have any tdc marks so i can't make an eprom with 0 advance and see how it shows with a timing light. it didn't change how it ran back in the day when i fitted the flywheel, so i expect that was all the same as it was before lump wise.
but, it's a lot better. nice enough to ride, just needs a few tweaks.
i unbolted the brake splitter under the lower triple too last night and rolled the splitter around to let any air move up and through. zip tied the lever in overnight and it was better this morning, much less sponge than before. they used to be great.
