Might EFI my 1976 RD400 this winter

[rd400canuck]

Little update.  Working on new pump coupler set up and probably starting the frame that will hold the pump and load cell. Built something to funnel the exhaust outside. Works extremely good.

[rd400canuck]

Heres the final setup minus the frame. Im uncertain this wont vibrate like hell.. too many places in it for movement. I gave the engine side of it a dry run on the bike and it seemed to have some issues with wobble.. and at 2700rpm it prolly be dangerous. I think i should have a short as possible solid setup welded to a sproket minus the joint. Testing will show if this will be safe or not.

[m in sc]

run a much longer chain, set it out back behind the bike and mount it solid, and support it w an extension on the other side of that sprocket as well. that's a dangerous disaster waiting to happen. needs to be double shear supported.   

[sav0r]

The oldham coupler isn't intended to run in shear. Do as Mark says, but you will still need at coupler or eventually you'll damage the bearings in the pump. The coupler should be pump side. The sprocket supported with two pillow blocks.

[1976RD400C]

I'm not sure I'm grasping everything you're trying to do there but being a hydraulic repair tech for 40 years I see a few issues.

You should have an adjustable relief valve in the system. That flow control valve can be set but as the pump rpm goes up the system pressure is going to increase. It is going to be tricky to adjust that properly as the engine speed and power increases. It could easily jump up over 3000psi when it is running at peak power if you are not careful.

Any torsion bar needs to be right at the flange where the pump mounts, not at the back of the pump. If it's at the back it will put a side load on the pump shaft and try to bend it.

If you make a separate frame to hold the pump it has to be very securely bolted to the frame of the bike or the whole pump frame assembly will try to rotate as soon as the pump has a load on it.

[m in sc]

or pull the wheel out and fixture it in the swingarm as well.

hes right, you need a relief valve. Im no fan of adjustables (we actually sell relief valves at work), and for safety sake, you want to run it a few hundred psi under what the max is as a failsafe, as a bare minimum, but a bleed off at a set pressure 'back to tank' will do what you need as well. ie, run both if you can. .02

[85RZwade]

I have been following along with interest, and maybe I missed something, but where is all this hardware going to live on the motorcycle? Maybe I need to go back and re-read, but you are planning to ride this machine when you're all done, right? It seems like you're going to need a sidecar rig for all the plumbing 

[sav0r]

You're pretty far off.

[rd400canuck]

Thank for feedback guys.... this is certainly a learning process for me.

After the initial frame I built got pulled inwards and bent I was thinking that I could just couple the pump right to the counter shaft. If I didnt have to make it so the pump was ale to rotate a little it'd be far easier but i do so I can measure torgue with the load cell. The pump isnt going to actually rotate obviously... but it cant be hard mounted and solid.

After I welded up yesterdays idea I knew right away it was a very bad idea. Last night I decided to go back to chain and build a beefy frame to hold everything solidly in play while allowing the pump to be able to press down a moment arm. This was actually my orig idea but took another route after thinking too hard lol.

So im going to do what SC is saying... I will have a shaft with a sprocket on it that will be held on each end with a cushion bearing to keep sheer forces at bay. One side will have the shaft extended out a couple inches and I plan to use a coupler there to couple to the pump shaft. The rear of the pump will be supported by a centered shaft I have welded up to a bracket and bolted on the back that will sit in another cushion bearing. The moment arm will be bolt to the front of the pump and will press on a load cell. Everything is going to be bolted onto a beefy frame I will weld up.

Ive seen a number of these hydraulic pump dyno setups on the net for small engines and they all work perfectly with the needle valve. They just turn it in by hand until the engine bogs down from redline and the torque is graphed as a curve that way.

I will use an Arduino that will have the rpm feed into it from the ignition... i have written code that will control a geared motor attached to the needle valve that will turn the valve until it reaches the requested rpm. Ive got a 3 : 1 pulley set and a toothed belt. So for every turn of the geared motor the needle valve will turn by 1/3. Ive already written most of the code that will control the motor and tested it a little. It has a ton of torque and I can code it to turn full speed which is 60 rpm or I can increment it small enough that it is almost imperceptible. I'm fairly certain that will give me the control the Arduino will need to control the engine rpm.

Im heading to get some parts... keep you guys posted.

[rd400canuck]

This is my idea. 3 cushion bearing assys, 5 inch shaft to hold sprocket and extend out one bearing into a coupler that the pump shaft will fit into the other side. 

Or... should I connect one side of the spider joint coupler I have to the 5inch shaft and put the other half right on the pump shaft?

Let me know what you guys think.

[m in sc]

this looks good to me.

[sav0r]

Yep, that's right.

[rd400canuck]

ok thanks for feedback.... got everything i need and will get to work this week. pics to come.

[rd400canuck]

Ok.. herres setup #3. I should have done this in the first place but was too busy getting fancy. Should have the frame done this week or weekend.

edit..   worked a little on the frame... ignore the welds please lol... having a little trouble getting used to fluxcore.

there is the cogged pulley on the needle valve that will be controlled by the geared motor... the 3rd pic is the setup that will control everything. the black one is a stepper motor that will control the throttle percentage when i am steady state and acel enrichment turning.

[rd400canuck]

Hey all,

just letting you guys know I havent given up on the dyno and efi project... life has been getting in the way lately. Should be able to get back to it in a couple weeks.

Also, picked up my new ride last week.