The amount of knowledge on the IPCRC is truly amazing. A half dozen people know their stuff about fuel injection and are supplying a lot of great suggestions and pointers. The thread is a wealth of knowledge for me. If only I had more time to devote to this project at the moment. In the next month I have a bunch of travel and work obligations that will take me away from converting my bike. I’ll still get some things done but not as much as I want. Maybe in the next month I can get some preliminary designs completed and make a parts list.
Looking at the NT-700 microfiche, the throttle body assembly (16400-MEW-L01) looks very promising. It includes the throttle bodies and injectors in one unit. There wouldn’t be any room to tune the volume between the throttle bodies and the valves though. Someone on the IPCRC suggested I try to match the volume of the cylinder to the volume between the valves and the throttle bodies to help compress the air as it enters the engine. I could also do that with a turbo or super charger, too. However, it would be very difficult to tap the exhaust and there aren’t any belts to draw power from. An air ram would almost be better although it would be a wee bit ridiculous to put an air ram on a PC. Never say never though…
Anyway, if the angle of the cylinders is different between the NT-700 and the PC-800 (I suspect it is based upon other engine drawings), it won’t fit quite right. Also I suspect the throttle bodies are smaller diameter on the NT-700 as it is a smaller engine. If anyone reading this happens to have an NT-700 kicking around and wouldn’t mind measuring the throttle body internal diameter and also checking distance between centers on the throttle body and angle of the throttle bodies, that would be a HUGE help. To buy that assembly would set me back $5-600. Not exactly something to buy lightly!
I’ve been thinking more about using the MegaSquirt kit to do the fuel injection timing. It seems very flexible and has a large community of active developers and tinkerers. The unit I was thinking about using though seems like it might not be released (MS-II Sequencer). However, it seems like the MSI, MSII, or MSIII should work. Especially with the “Extra” firmware. Then I get a bunch of other fun management potentials (nitric oxide injection, spark management, etc). This page seems to have a descent rundown of what’s what in Squirt-land. It also seems that Wikipedia is useful to better understand all of the available squirts. One of my buddies has experience using MSII. He bought it from DIY Autotune who he says is a good company. There are mods and kits to make the MSII do nitric oxide injection. Also can do methanol injection with the NOx to give extra oomph. That would be a future project… And hella fun. Although I probably would need a new engine after that 🙂
Looking at the schematic for the spark system for the PC800, it appears we already have the necessary sensors to feed information to a MegaSquirt for cam sensing. That is VERY good news as there isn’t anywhere to attach an external sprocket and sensor on the PC’s engine. Hopefully I can adapt the MS to take the ignition pulse information.
All the extra room under the gas tank that I’ll be left with is opening up some interesting possibilities… I’m thinking about installing a comm unit, some radios (CB, FRS, a few amateur bands, etc). It would also be great to have that extra space for auxiliary switches and dodads. I’ve been wanting to install auxiliary gas tanks in the trunk. A few switches on the faux gas tank would allow me to have transfer pumps and whatnot to trim out weight distribution in those rear tanks and also feed that gas into the primary tank or from the primary tank into the rear tanks. Who needs an aircraft when you can cross-feed your fuel tanks on a PC800?