Might EFI my 1976 RD400 this winter

[Striker1423]

Got my Vape from EC :)

I just wanted to ask... where is the ECU that controls spark curve? It seems its right in the coil assy to me. And if so... now I'm wondering when I get my Microsquirt to take over ignition duty will I have to replace the VAPE coil for one with no ECU in it?

On the vape I do believe the ecu is in the voltage regulator. The coil is just a coil. However, as you can see the VR is filled in at the factory with the goop. But, my understanding of the VAPE is it is static timed? Or am I wrong... Mark? lol

[rd400canuck]

Ah ok that makes sense Striker... Im not sure why I was thinking there was an ECU on this setup with an iggy curve in it. I think I was thinking it was like the HPI that has an ECU and curve programmed into it. Ok so it's basically got a flat curve... thats fine actually.. I only wanted the VAPE for the 150w it puts out...The Microsquirt I purchased with control the spark and I'll be able to program in a curve.

[m in sc]

I cant speak to the ones with the integrated curves, not even sure if they are available any more. the ones i have are all static. theres no ecm to speak of. the vr and ignition are not actually connected in any way. 2 of the ones i have are running with a zeel box to control curve and rev-limiter.

the hpi i have has a curve and does have an ign box it runs thru, but its tiny.

[rd400canuck]

I cant speak to the ones with the integrated curves, not even sure if they are available any more. the ones i have are all static. theres no ecm to speak of. the vr and ignition are not actually connected in any way. 2 of the ones i have are running with a zeel box to control curve and rev-limiter.

the hpi i have has a curve and does have an ign box it runs thru, but its tiny.

The HPI works pretty good.. I had it on my RD40 for a week before I took it off.  I'm looking forward to dialing in a curve when I get the Microsquirt to take over ignition duty.

[rd400canuck]

Hi again,

Anyone have any input on Speed Density over Alpha-N fuel map?

The SD route will only see a minor vacuum... 80-100 and it'll be jumpy as well with only two cylinders. I know I can out a fuel filter on the vacuum line to act as a buffer to smoothen the pulses out tho.

But AN looks like I should think about trying it, too. I'm going for a 12x12 fuel table... im thinking 16x16 will be overkill for a bike that wont go past 8000rpm and just be more of a headache to tune with so many cells to dial in.

I'm still pouring over any material I can find on the pros and cons of the two.. thought Id hit you guys up while I'm at it.

P.S.
Did I mention I got my Vape from EC? What a high quality piece of kit it looks like, really impressed with the craftsmanship in it. Am looking forward to getting this thing on the bike.

[rd400canuck]

Got the vape on and running. I just gotta go over it all again and make sure nothing is lose. Already blew a fuse with a dangling wire. Thank god for chucks how-to.. it walked me right through it.

Id better ckeck the timing properly...i had to back the idle screws out more than an entire turn to get it idle at 1200rpm. The mid seemed a little stronger and the top end seemed a little wooly. Im think i have too much advance in it.

[rd400canuck]

Hi guys... I seem to remember an equation that would figure out how many degrees of rotation of crank take place when the piston crown drops say 2mm.

Anyone know it?

edit.. just checked timing and it's at 2.1mm so am gonna leave it as is (unless it's supposed to be 1.8mm? or is that for 350's?). I dont think the bike was warmed up fully when I test drove it yesterday and it felt weak up top. I went for another good run today and it seems to behaving exactly as it did when the points where on it... just feels smoother somehow. I absolutely love the VAPE ignition. I'm not sure if it's because its the cold air, only 8c/46f here, but the bike was really running well.

[Striker1423]

The bike's absolutely run better with a VAPE. Easier to start, better throttle response and all.

[rd400canuck]

Well.... it must be the VAPE then. One thing I noticed after i set everything up and started it for the first time it was really revving high and I had to turn the idle screws out an entire turn to get it to settle at 1200rpm. Seems to me if the timing is the same it would idle the same. I wonder if I never had the points set up properly in the first place.

I have some EGT probes on order and have a CHT here as well. Next thing I will do is install the microsquirt and go make some runs and log what the temps are so I have that data to compare against after I switch it over to EFI. I bought an O2 sensor and controller but I'm on the fence if I want to drill into my stock pipe and well a bung to it.

[Striker1423]

If timing is too retarded the bike will idle real low. Will lack character when riding too. If the timing is advanced, the idle will smooth out a bit and it will punch harder when ridden. The sweet spot prevents a loss of power or a hole in your piston.

Dis you verify it with a timing light per Chuck's write up?

[rd400canuck]

Yup, I checked it with a timing light and it is 2.1 mm.

Not really sure why I had to turn down the idle so much... all I can think is that I had the points ignition messed up somehow but I didnt really notice any issues with engine characteristics.

One other thing I noticed is that it didnt seem to surge at all now when I close the throttle and coast to a stop. There was always a little of it when it dropped to around 3000rpm and lower but it seems to be gone. It just seems smoother everywhere now.

[Striker1423]

High idle could have been a slight air leak too. But, if it isn't idling funny anymore, then I'd run it. Especially if the air screws cause the engine to change characteristics.

[rd400canuck]

Well... i have all winter perhaps i should tear the motor down and check everything. Ive been driving it for 2 summers now since full revuild. Cant hurt to make sure everything is within spec. Not like i can do any tuning of the efi until late spring anyways.

Anyone know any good resources on two stroke ignition timing? I want to know as much as possible before i start tuning in an igntion map.

[sav0r]

Does the MicroSquirt accomodate a dedicated cold startup map?

[rd400canuck]

Does the MicroSquirt accomodate a dedicated cold startup map?

It does.

as far as cold starting is concerned I have ordered an automotive solenoid air valve to let in some extra air for higher revs during warm up. I'll just tune the inlet until i get it revving at 2200rpm or so and itll close once warm enough.

I can actually tune how high it will allow rpm to go if it is not fully warm. Doubt I'll use that feature though as I know to take it real easy on the bike if i dont give it enough time to come up to temp.