Originally Posted by markjenn
Believe me, I'm a believer that FI is better than carbs too (the 950 is off my wish list until the FI version appears), but the key words in your sentence above is "well tuned".
Maybe this FI stuff is more plug-n-play that I think, but my understanding is that it takes a fair amount of work to rig a system with all the sensors working properly, and then develop a reasonable fuel map for a given application. The whole thing reminds me of someone disliking Microsoft Windows and deciding that want to write their own OS. It's just a bunch of drivers, a disk manager, a memory manager, and UI right? Well, in concept, that's true, but the devil is in the details. And to continue the analogy, if you don't like the BST, then the FCR might be the Linux you're looking for.
You should understand that, either due to luck or my low demands/expectations, I have zero complaints about my BST. It seems to carb perfectly for me in all temps and elevations up to 6K feet or so. So I don't see much of a problem that needs solving. But I don't attempt to loft the front end over 8" logs going up hills dodging typerwriter-sized rocks either. It's my adventure bike, not my dirt bike.
Again, I think this is a very cool project and so I don't mean to discourage you. If you like to tinker with this sort of thing, that's extremely cool and I'll be highly interested how it goes. But if you just want a 640 that works better, I think you could get to that goal a LOT cheaper and faster by buying a FCR kit and fiddling with jetting - there is a broad range of experience with FCR setup on our bikes.
I actually thought about the FCR, but I thought I might give the EFI thing a try. Comparing the BST to Windows, and the Megasquirt to writing a new OS is a bit overkill, but maybe your a computer guy? Personally I ditched Windows and got a Mac,but again tough comparison. The reality is that it seems like a fun project. As far as doing it cheaper, well I think $400 is a good estimate for the time being, but I will keep track for the fun of it.
What would you expect to spend on a FCR used? $150? Worst case, the bike runs like crap, and I put the BST back on.... no big deal. Best case is that I gain a few HP in spot that was lacking, and maybe pick up a mile per gallon. The BST is working fine after the re-jet and slide drilling(Thanks Creeper),but I'm in need of a project.
The VT winters get pretty long, so I'll just call it entertainment.
Lots of great No Bull answers to common EFI questions if your interested