• Xr650r batteryless

  • If you'd like to help with compatibility for your engine, please post a few pictures and any technical documentation or manuals you may have.
If you'd like to help with compatibility for your engine, please post a few pictures and any technical documentation or manuals you may have.
 #243  by theailer
 Mon Jan 07, 2019 1:18 pm
Hi. Really interested in your efi project. But will it work on a 650 thumper with no battery, only a small capacitor and a kickstart?
 #248  by alby1976
 Wed Jan 09, 2019 4:46 am
I am rebuilding an Xr400r, and have a battery pack that I will be fitting.
It is a rechargeable AA pack, and it fits nicely in the bottom of the airbox, still with kickstart.
It should be capable of supplying enough current for fuel pump priming until the engine is running.
You should be able to something similar, not sure if a normal capacitor would be enough, as it will slowly discharge when not in use, but then again, it might work, it just might take longer to start.
Don't think that the fuel pump has been decided on yet.

Al.
 #249  by theailer
 Wed Jan 09, 2019 7:19 am
I was thinking it might be possible to prime the pump by just kicking it over once or twice. And then the third or so kickstart would start the bike. I don't have an ignition lock with key, only the kill switch for the motor. But that could be fairly easily installed.
 #250  by alby1976
 Wed Jan 09, 2019 8:54 am
I got an ignition key switch from a TRX 400, as it has 2 circuits, 1 normally open, and one normally closed, and switches both, which is perfect for what I need.
Can't remember offhand if the factory kill switch opens the circuit or earths the spark, I'm leaning toward opens the circuit.
Will have to check some wiring diagrams to know.
But your idea of kicking it to give power to prime was what I had in mind when I said that it might work, just be harder to start.
Less mucking around I guess.
I am very much looking forward to installing the EFI.
 #251  by Travis Nano
 Wed Jan 09, 2019 9:31 am
Unfortunately kicking won't be enough to get the pump up to pressure and stabilized. You'll really need to invest in a battery. A 12v battery with lithium-ion chemistry may be a good idea if weight is the main concern. They're becoming more common and less expensive.

The other issue is making sure your stator is capable of producing enough current at idle. I'll have minimum requirement info soon.
 #253  by theailer
 Wed Jan 09, 2019 9:50 am
I've put a spal fan on one of the radiators and that have no problem running at idle with with the headlight on as well. I think the alternator is capable of 75ish watts.
I guess a small 1Ah battery might fit under the saddle. I know some dirt bikes with Fi and kickstarters are able to prime the battery with just the kickstart, but that might with very special equipment.
 #254  by theailer
 Wed Jan 09, 2019 10:07 am
The following is a snippet from the marketing of a kawasaki 450f 2012:
No battery needed; the engine can be started with only three rotations of the crankshaft using the electricity generated by a single kick of the starter
The system delivers electricity to FI system in sequence: first the ECU, then the fuel pump, and finally the injector for quick, easy starting
 #256  by Travis Nano
 Wed Jan 09, 2019 10:29 am
Do you have any technical documentation on the pump and original FI system I can take a look at?
 #258  by Travis Nano
 Wed Jan 09, 2019 10:58 am
Ah! I think I just needed another sip of coffee. I thought you were looking at a full carburetor-to-EFI install with a regular pump and all.

Based on what I'm seeing, the NEFI ECU itself won't have a problem being powered by your system. There may be some changes to software needed to properly work with the XR's battery-less setup, but I don't see us encountering a problem with at least powering the hardware. I am curious about possibly unusual voltage transients though.

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