Might EFI my 1976 RD400 this winter

[rd400canuck]

Wow that is a very cool bike and setup! I had no idea anyone had gone about it with an aircooled RD. I wonder if he is using the stock ignition. He's running a missing tooth setup so I'm assuming he's controlling spark unless the ECU he used isnt able to get ign pulse through coil with an opto isolator like I can with the Microsquirt but since Im doing ign curve as well I'll use the VR sensor of the Vape.

It said he tuned by the seat of his pants and logging during rides. Thats what I was planning on doing but I wouldnt even dare tune a ignition curve by the seat of my pants. Thankfully the dyno im building will be able to hold steady rpm and plot torque curve as I mess with spark and fuel.

Annoys me though... every time I see someone EFI'ing a two-stroke they always point out they are using O2 sensor but never acknowledge the unburnt oxygen that might be effing up the readings. I have an O2 that I will use but I wont trust it. Actually I have an idea on how to avoid the scavenging cycle unburnt fuel issue.. once I flesh it out I'll pass it by you guys. One thing at a time! Im finalizing in my head how exactly I will build frame to hold the pump between the swingarm and have the bike's stock chain drive it.

[m in sc]

jump on fb and reach out to him. 

[rd400canuck]

I got rid of FB ages ago.. too much drama with my bonkers family.

I found this calculator for gear pump hp. I put 3000 psi and 17 gpm and it says 31 hp.

http://www.metaris.com/hp-calculator.php

Can I assume this means I can run a 31hp engine on it? If so I think it's a safe pump for 1 powered cylinder at a time like I was planning. I think the most I'll see is 20hp from 1 cylinder.

[sav0r]

Wow that is a very cool bike and setup! I had no idea anyone had gone about it with an aircooled RD. I wonder if he is using the stock ignition. He's running a missing tooth setup so I'm assuming he's controlling spark unless the ECU he used isnt able to get ign pulse through coil with an opto isolator like I can with the Microsquirt but since Im doing ign curve as well I'll use the VR sensor of the Vape.

It said he tuned by the seat of his pants and logging during rides. Thats what I was planning on doing but I wouldnt even dare tune a ignition curve by the seat of my pants. Thankfully the dyno im building will be able to hold steady rpm and plot torque curve as I mess with spark and fuel.

Annoys me though... every time I see someone EFI'ing a two-stroke they always point out they are using O2 sensor but never acknowledge the unburnt oxygen that might be effing up the readings. I have an O2 that I will use but I wont trust it. Actually I have an idea on how to avoid the scavenging cycle unburnt fuel issue.. once I flesh it out I'll pass it by you guys. One thing at a time! Im finalizing in my head how exactly I will build frame to hold the pump between the swingarm and have the bike's stock chain drive it.

We only ever used O2 on carbureted motors, generally we recorded it at around 100hz. This was used to adjust the carb on track as well as after sessions, depending on the type of carb. But the recorded numbers are only relative to yourself. You will have to establish a baseline. The scavenging cycle may push your readings up or down, but assuming the scavenging cycle is consistent (it should be) you just scale your table accordingly. It doesn't matter what readings you actually get as long you can establish where they are when the bike is running properly. For a production vehicle the approach would be different, you'd aim for an ideal reading. You don't have to worry about that because you are doing this once. That's where the dyno is going to be invaluable. I also bet you get slightly different readings cylinder to cylinder. I know my EGT's are never the same left to right, even with everything theoretically the same.

[rd400canuck]

Thanks for the feedback, savOr :)

Thats pretty much my plan.. I'll be doing carbureted and stock ignition timing runs on the dyno and plotting EGT, CHT and O2 readings.. as well as torque produced. I ordered a 30kg load cell to plot that as well. It'll be invaluable data to have and compare against.

I just wish I had it as good as the 4-stroke guys with their O2 readings cause they get to know exactly what air/fuel ratio they are burning but I think with the outputs I have I should fair pretty good.

I have access to a 12x12 or 16x16 fuel and spark tables but I think since this bike can't reach 8000 rpm 16x16 tables is overkill. Plus 12x12 will be less of a headache to work with. I'm thinking about recording everything I do so everyone can follow along on youchoob and give me feedback and ideas on how I might do things differently. This is all a first for me so the more brains I have access to, the better.

[rd400canuck]

Been collecting parts...  just need to find an old propane tank to use as a reservoir.

[Striker1423]

Why not run something like a Ski Doo O2 sensor? They run them on their E-tec machines as well as EGT sensors. Sure they don't burn as much oil anymore, but they're designed for 2t use and indeed see some oil.
https://www.powersportsid.com/ski-doo-exhaust-oxygen-sensors/

[85RZwade]

And are parts from/for the KTM/Husqvarna injected 2-strokes useful to this project?

[rd400canuck]

Hey... weekend is almost here :)

I was looking into O2 sensors for two-strokes but the more i read the more it seemed like that are just regular heated O2 sensors... some two-stroke bungs are longer to keep the sensor out of direct exhaust flow, tho. I wont be drilling a massive hole into my stock pipes and welding anything to them... dont want to damage the chrome and it'll just look ugly. I have an idea on how to get exhaust gasses without having to do that... and if I dont go that route I will build an O2 sniffer and just stuff it in the end while I do my testing.

I think those O2 sensors in the E-Tecs last because those machines barely burn oil at all. Im guessing their oil injection systems send oil right the the cylinder walls and crank negating the need to use loads of oil because most of it will tumble out the exhaust. I think, anyway. I'll look that up sometime.

Did you see the price of those EGT's on ski-doo website?  ha! ha!   $100.94 - $182.64   effing crazy, what a scam.

I'm not even going to drill into my header pipes for the EGT's. I found a couple on fleabay that are rusted to hell. They will be used for testing. I wouldnt dream of ruining my stock ones.. the chrome is perfect. Once I get the Dyno working and sorted I will make loads of runs at each throttle % and rpm and log all the data. That will be enough for me to work with I imagine.

I was out in the garage... removed the rear wheel and fender to make room... sizing things up at this point. I think I have arrived at a good plan of action of how the dyno cradle will be built and sit back there. I found out these gear pumps use gears and chains with #40, #50 etc sizes and lucky me none of them fit a 520 chain. I ended up with a #50 because it has the same pitch but it's way too thick so Ive been trying to grind it narrower and evenly. pain in the rear :(

[sav0r]

Yeah we always just ran regular heated sensors. We'd buy them from AIM Technologies because they came ready to plug in to our data acq., but as long as the unit outputs in the range you can handle, just about any unit will work. We did foul them up fairly often, so cheaper might be better.

The first few we tried were not heated, and they fouled VERY quickly.

[rd400canuck]

Ya i imagine a non heated would fould up fast. My idea to get exhaust gases from the combustion chamber involves tapping into the little passage above the exhiast port and feeding it to a small chamber housing the O2 sensor. The outlet from the O2 chamber will be smaller than the inlet. My thinking is this will keep the pressure high enough in it so no intake charge can be pushed back into it. The combustion chamber pessure should be pretty low at that part of the stroke on its way back up.

[rd400canuck]

Hey guys,

Anyone know if I can weld stainless steel fittings to mild steel (propane tank) without having to buy 308l wire?  I'm hoping regular steel wire will do the trick even if it aint pretty. Damn stuff is $50 a roll and I'll probably never need it again

[m in sc]

it'll do it.

[rd400canuck]

it'll do it.

Youre a good man but thatll be one hell of a drive!

[m in sc]

It'll do it. Not me. But send it down i have stainless wire i'll tig it up.