"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
10/23/2020 at 12:26 • Filed to: None
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"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
10/23/2020 at 12:26 • Filed to: None | 3
| 5 |
Carburation . It’s a thing. It works, sometimes. My 1997 Ducati 900SS is one year shy of the “third generation” of SuperSport which had lumpier, more complex bodywork and fuel injection . Neato. My SuperSport makes do with a pair of Mikuni constant-velocity carbs. Pretty standard stuff for a streetbike, very finnicky and sensitive to precise vacuum with tons of tiny little orfices that have to be perfectly clear for the bike to run and god help you if someone swapped out the intake or exhaust on your bike. In the Ducati 900SS w orld any issues with the factory Mikunis are met with a simple solution: buy a set of Keihin flatslides (pictured below). The flat-slide Keihin carb benefits from better airflow and more precise fuel metering using pro-active vs re-active mechanics and is like getting a whole new bike in terms of responsiveness and top-end ponies. The problem? Keihin FCR kits range from $1300 to $1500 new and typically sell used just shy of a grand.
Graphic: Yee haw
A grand on carbs. That’s steep. It’s steeper when you consider the fact my steed was $1500 to begin with.
So what do? Keep living with mediocre and, in my case, broken Mikunis? Nah. There’s a third option.
Graphic: Yee haw
This is the throttle body setup from a Ducati 900SS FE, Monster 900, ST2, and probably a couple other models. I just bought one on ebay as well as the matching intake runners. This will be bolt-on fuel delivery for my old 900SS. But there’s still the question of controlling it.
The factory FI Ducatis have a little ECU box that controls ignition and fueling all-in-one but requires a crank trigger wheel that is lacking on my older engine, and the retrofit requires some pretty substantial butchery of the engine casings and delicate machinework.
But my bike doesn’t have a spark issue, it has a fuel issue. And fuel doesn’t require precise timing like spark does and, in fact, many aftermarket fuel injection systems such as FiTech TBI systems don’t require any sort of crank position input, just working on a speed-density basis getting engine speed off of the coil negative.
I could do that.
My plan right now is to use a Speeduino to run the fuel system using Alpha-N fueling strategy and a wideband O2 to assist in dialing the system in and, if supported, cruise in closed-loop.
Should be fun.
Obligatory video series on my progress will be coming probably next month.
Highlander-Datsuns are Forever
> Jake - Has Bad Luck So You Don't Have To
10/23/2020 at 13:16 |
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I’m guessing that’s not an L24 under the hood of that yellow G-nose datsun.
Snuze: Needs another Swede
> Jake - Has Bad Luck So You Don't Have To
10/23/2020 at 13:17 |
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God speed!
Also, I need to look at Speeduino. I had the idea of making a little Arduino based EFI system back in college. I thought it would be particularly useful for controlling a direct injector for a 2 stroke as a way to cheaply and efficiently clean up the gazillion 2 stroke bikes in developing countries .
DipodomysDeserti
> Jake - Has Bad Luck So You Don't Have To
10/23/2020 at 14:43 |
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Are there no other slide carbs you could throw on there that aren’t so pricey ? I’ve been very pleased with the VM36 on my Yamaha. Have ridden it at 1k and 8k feet in the same day without any tuning issues. Very simple and robust design. I also have Mikuni round slide carbs on my CB175 and that thing will fire up and run after months of sitting. The CV carbs on my 450 were always a pain in the ass.
I’d be reticent to add electronics and complexity to an aging Italian bike.
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Jake - Has Bad Luck So You Don't Have To
> DipodomysDeserti
10/23/2020 at 15:35 |
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That’s just what FCR41s go for these days
MiniGTI - now with XJ6
> Jake - Has Bad Luck So You Don't Have To
10/23/2020 at 17:45 |
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Just make sure y ou have at least two other functional vehicles before you tear it up.