BD125-8 ZS190 swap and EFI conversion

[glavey]

• mockup exhaust/confirm fitment
• replace rusty front caliper nut
• JB weld vacuum nipple on fuel pressure regulator
• new nuts for exhaust studs
• hardware for TB - intake manifold mounting
• fittings for fuel pressure gauge
• tap for vacuum port on manifold
• shaved horn button
• clip holding crank case vent hose
• re-route clutch cable

All that and more, tonight on This Old Thread!

User Whiskey has told me that he(I'm guessing, forgive me if I'm wrong) has contacted motorkit.com and they have said that they DO ship to the US. Moreover, they have the gp1 exhaust is stock and he has bought one from them. I run a number of ad-blockers and script blockers on my web browser; it is quite possible that one or more of those could have messed up the checkout page, making it appear as though they didn't ship to the US.

Meanwhile I, or rather my cat had a bit of bad luck. Nollie came in from being outside with a red front paw a couple nights ago. I'll spare the details, but she seems to be much better now. No limping, no hiding, no pain-meowls, just an occasional lick on her left front paw. I paused for about a day when that happened. Purrs > Vrooms.

On to less sad things! When Whiskey told me that the gp1 exhausts were back in stock, I was originally going to return the ebay one I have and use that to subsidize the purchase of the gp1 exhaust. However, today I finally went to the local hardware store and pickup some nuts, bolts, and washers that let me mock-up the exhaust as if there were another ~1cm of pipe added to the piece that mounts to the engine. I bought 5 washers, I forget what fractional size they are, but they're 32mm OD. I stacked those on top of the bit of exhaust pipe that actually goes into the engine and is held in place with the flange. With all 5 washers, the nuts for the exhaust studs only had about 3 threads to grab onto, but that's ok; I'm just mocking up the location of everything and I'm not going to use all 5 washers. I just bought these washers as an inexpensive place holder for these.

With the exhaust in place as it is intended to be used, the passenger footpeg and the whole "arm" that bolts the passenger peg is in the way, but the muffler is (or rather would, if the peg wasn't there) pointed out the back of the bike, not out to the side, and there is about 5mm between the exhaust manifold and the starter motor. With the exhaust installed with the mid pipe turned around, so the end that normally connects to the muffler now connects to the header pipe and vise-versa, the passenger footpeg is no longer in the way and there is still ample clearance between the starter and the exhaust manifold. Unfortunately, the spring clamps loops that hold the muffler to the mid pipe and the mid pipe to the manifold are either rotated and/or too short. So I can either install the exhaust as intended with new rearsets, or flip one bit around, keep the stock rearsets, but have to take the exhaust pipes to a welder and have them make and then weld some more spring hooks.

[glavey]

I'm not sure if this has come across through my posts, but I have quite severe social anxiety. Almost to the point of agoraphobia. That's why I work from home and live with family. I'm already not looking forward to taking the exhaust pipe somewhere to get the o2 sensor bung welded in, adding another thing to do doesn't sound good to me. I'll spare you the rest of the sob story, and just tell you that I'm going to be most likely buying new rearsets and installing the exhaust the "normal" way. Apologies for bringing more sadness into this post.

The hanger that come with the exhaust system is too short to hold the muffler in place. The clamp piece with the rubber in it can be mounted to the loop on the passenger's footpeg, if you choose to flip the mid pipe, but since I am getting rid of the stock rearsets, I'll have to get some metal stock and bend something that can support the muffler from one if not both exhaust hanger tabs on the right side of the bike. No biggie.

One of the nuts on the front brake caliper has started to rust, and I don't like the idea of fighting with rusted-up hardware especially on brakes, so I replaced the rusty nut with a lock nut.

I wanted to use a 90 degree hose fitting for the to-be-made vacuum port on the fuel pressure regulator, but I could only get straight ones. Oh well. I bought a 3/16 hose splicer (back to back hose barbs) and cut it in half, right down the middle. I cleaned up and scratched up the hose barb and the metal part of the pressure regulator, mixed the JB weld, and covered both side holes, and attached the hose barb to the top hole on the regulator. I tried not to use so much of that stuff that I couldn't get the cap/ring back onto the regulator. I'll have to wait 'till tomorrow to see.

In case you wanted to know, the vacuum port on these aluminum intake manifolds are threaded in, not pressed in as I thought. I was going to use the vacuum port nipple from the 125's manifold and put it in the 190, but the hardware store didn't have a (what I assume is a) 1/16 npt tap, only 1/8 and up, so I bought one of those and forgot to buy a 1/8 npt to 3/16 hose barb fitting. Oops. Next time.

[glavey]

I bought some new nuts for the exhaust manifold studs to replace the end-cap ones that came with the bike. I'll probably use two nuts per stud so I can make a jam nut and not have to worry (as much) about them coming loose.

I had to get a bit creative and unsymmetrical with the bolts and nuts I used to fasten the TB to the intake manifold. One side of the TB has the idle air mixture screw right behind the bolt hole, so you can't get a screw driver in there to turn a bolt, and the other side has the injector body right behind the bolt hole, with only enough to use a nut, not a bolt. So on one side of the TB, I have a standard hex-head bolt going through the TB bolt hole and threading into the intake manifold. On the other side I have a bolt with a ground-down head coming from the intake manifold through the TB bolt hole and threading into a nut that miracle-has-it just barely fits on the TB.

I had some fittings from a previous project that I can could use on this one. 4x 1/8 npt to 5/16 hose barb, 1x 1/8 npt street elbow, 1x 1/8 npt plug, 1x 1/8 npt bleed valve, 1x 1/8 npt female to female union, and 1x 1/8 npt 4-way fitting. As in the picture, I am going to have the 5/16 barbs on opposite ends of the 4-way, with the bleed valve on the top and either a plug or a street elbow + pressure gauge. I would like to be able to confirm that the fuel pump/regulator is indeed pumping and regulating and that my manifold-pressure-reference mod did something. I will be securing these hose barb fittings with clamps designed for fuel injection hose, NOT plain worm-drive clamps.

I also did a few small things. I don't know if this happens to other riders, but especially on this bike, with these controls, I am constantly accidentally tapping the horn when I move my thumb from the grip to the turn signal controls. I ground down the bit on the horn button that sticks out on the left side. Hopefully I won't unintentionally honk at so many people now. I also put a hose-retaining clip on the swing arm to hold the engine crankcase vent hose in place. However, the swing arm is going to move independently of the hose so I bent the hose clip so that the hose can still slide up and down in the clip, but not come out. Finally, I re-routed the clutch cable through a hole I drilled in the black plastic pieces on the back of the red trellis fairings. The clutch cable won't get as bent and squished between the tank fairing and the handlebars now.

I had a lot of pics to go with these topics, so I spread them out over the posts; the pictures I have posted in one post may not be written about in that particular post.

[Weldangrind]

Despite knowing nothing about it, I presume that a good antidote for agoraphobia is a really good bike. That's gotta make you want to get out there.

[glavey]

That is very true. I'm hoping my interest in this project will overcome my anxieties and let me be more social. Adam Savage once said that he had a young fan approach him to ask a question, but he (the young fan) was unable to get the words out because he was too nervous, but his love for science and knowledge pushed him through his anxieties and let him ask his question. I'm hoping something like that happens to me.

Or, ya know... amazon delivers pretty much everything now-a-days.

I could go on and on about my problems, but that isn't what you came here for.

The only things I have to do/buy (as opposed to potential additions to the project or just nice-to-haves) before I get to wait a month or more for warmth are:

Buy:

• 5/16" ID fuel injection hose, at least 2 or 3 feet
• 5/16" ID fuel injection hose clamps
• 1/8" npt to 3/16" ID hose barb, for manifold vacuum port
• 21/64" (Q) drill bit, for 1/8" npt tap
• dielectric grease
• o2 sensor bung
• 5/16" hose barb bulkhead fitting, for fuel return into fuel tank
• fuel pressure gauge, not absolutely mandatory but I'd really like to know the pressure of the fuel being delivered to the injector
• sealing/spacing washers from mcmaster carr
• rearsets

Do:

• run fuel hoses: tank->filter, filter->pump inlet, pump return->tank, regulated pressure out->4-way fitting (pressure gauge and bleeder), 4-way fitting->injector
• drill and tap hole for manifold vacuum port, install fitting
• run vacuum line from manifold to fuel pump/pressure regulator
• dielectric grease on most connectors
• drill hole for o2 sensor bung, get said bung welded-in
• drill hole for, and install bulkhead fitting on fuel tank
• temporarily install exhaust with sealing washers
• fabricobble exhaust hanger
• sync timing between engine and ecu, might not be possible without engine running
• install rearsets
• eat
• sleep
• poop
• wait

[Weldangrind]

Glavey, I'm really starting to look forward to your latest posts.

[glavey]

Thanks, dude! I appreciate that. I just placed an order for most of the small things I need, less the dielectric grease, rearsets, and sealing washers. I'm gonna try and force myself to purchase some items like the grease and a tap wrench locally. Hardware stores and the like are easier to me because they have much more... structured and predictable social interactions; as long as you know the technical terms for what you want to buy, things tend to go smoothly.

I'm going to have to wait, as usual, to drill/mount/install the fuel return fitting on the fuel tank until warmer weather. First, I have to drain all the old fuel out, eliminate as much of the fuel vapor in the tank as possible (drilling into metal = risk of spark, fire, explosion, and free hearing test), figure out where on the tank is a suitable location that is unobstructed by the tank fairings, as flat as possible, near the fuel pump, and if possible around or above the 3/4 full level (the fitting I am buying is sold as a "...Hose Barb Fuel Tank Fitting", but I would still feel more comfortable with my family jewels merely inches from a gas tank with a fitting that is only some of the time submerged in fuel and thus, hopefully less likely to leak and make things go boom).

I'l also have to find out how I"m going to hold the nut on the inside on the tank while tightening the fitting; the normal fuel filler hole has a metal plate underneath it with holes much too small to fit my hands through. I could always take the fuel level sensor cap off of the bottom of the tank and hope my hand or at least a wrench fits up there...

Even once I get the package, I'm pretty limited to what I can do without the fuel tank and warm weather. At most, I'll be able to run the high-pressure line from the pump/regulator to the 4-way with the bleed valve and pressure gauge to the injector, semi-finalize the exhaust location so I know where I can put the o2 sensor bung, get said bung welded in, and drill/tap/install fitting for vacuum port on intake manifold.

I tried to renew my lic plate tabs today, but I would have had to stand in line in front of the "please take a number" for half an hour before I could even sit down to wait for my number to be called. I think there was 80 or so people ahead of me. That's a big fat NOPE. You would think they wouldn't be so busy on a Tuesday during work hours.

That's about it for today.

[RedCrowRides]

-Just as a footnote, I too suffer from mild agoraphobia ,it's a real thing and I totally sympathise with the struggles it causes. Thats kind of the good thing about a bike, it's not the fear of outdoors for me at all, it's the "people" part of it. ,so at least I can still ride since it does not ( usually ) require much social interaction , so less anxiety for me.


That said, i have developed 2-3 good friends that don't ( usually ) stress me too much so overall my being into motorcycles has helped me a lot, i think it will help you too ,just take it slow and dont get overwhelmed by going to a major Bike gathering right off, lol!

[glavey]

The bike has helped me get out of the house quite a bit, even though I usually go ride around 75% of the time with no real destination, just riding around the town for an hour or so and come back.


When I do stop somewhere, even if it is just at a gas station or a barely-busy thrift store, because of my bike's unusual size and style, more often than not I get asked about it. So far all of the encounters have been positive.


Oh geez, a bike rally/group ride. That is FAR in my future if it ever even happens. I'm not this bad anymore, but I used to get a headache and have to change my shirt from sweating too much if I played a multiplayer video game.

[glavey]

I played around with turning over the engine with the electric starter motor while there was no spark plug, exhaust, or intake installed so I could get the maximum speed the engine could turn over. The ECU needs to know when the engine is cranking vs running, so I can set the max cranking RPM a bit above the actual engine cranking speed. Above that RPM, the ECU will assume the engine is running, stop giving the engine extra "startup" fuel, and begin after-start enrichment and warmup enrichment if needed.

I had the intake manifold and TB just hanging from some string on the bike's frame. I needed the injector and the MAP/IAT/TPS to be connected, otherwise the ECU displays a code on its equivalent of a check engine light. I connect everything up along with a 1990-ish vintage inductive timing light I bought some time back. Turn the bike on, wait for the ECU to do its priming pulse and fuel pump prime, and hit the starter button. No tach signal. Doh! I had the kill switch on. Turn the kill switch OFF, and try again. WOO HOO! It was quite nice to see that RPM gauge on my laptop move for the first time.

First thing I noticed was that the decompression valve on this engine lets the starter turn quite fast, albeit with no restriction. Second thing was sparks! The only good kind of sparks in a vehicle; from the spark plug. Big, bright, blue sparks. It appears that the ECU is "talking" to the CDI, the CDI is firing the coil, and the coil is making a spark occur at the spark plug tip, at least in open, atmospheric pressure air. Third noticed thing was my old timing light wasn't working; no flashy-flashy. I forgot to try turning around the clip-on lead, so I'm not sure if it is broken or not but no matter, I have another timing light that connects directly to the ignition coil. Fourth thing I noticed was that the tuning software recorded an ECU reset right after I let go of the starter button, not good.

A reset, in this instance, is the ECU not having enough either voltage delivered to it, or not enough current available to it, resulting in a voltage drop. I looked online and it seems like a starter solenoid isn't an uncommon thing to cause reverse voltage spikes or just bad electromagnetic interference (EMI). I can test this theory by not using the solenoid, but just bridging the two starter contacts, completing the starter motor circuit, but not energizing/de-energizing the solenoid's coil. I can also add a diode across the solenoid's coil to limit the inductive kick-back like I did with the relays. I'll test that in the coming days.

I managed to snag a datalog of the test start. The tuning software saves datalogs in a excel-style spreadsheet. You can view them in any software that can open .xls files. Viewing the files this way is quite... raw and dry. An alternative is to use the software that mega/microsquirt users use to view logs; MegaLogViewer MS. The "MS" version is the free version, that's the one I used to view the logs. It can graph any of the variables the ECU logged, and compare them in the same graph to any other variable. If you buy, I think it is the HD version of the software, you can import your tuning file from your tuning software and the log viewer will show you where in the VE table, spark table, AFR table, etc. the engine is at any specific point in the logs. I took a screenshot of the few seconds I logged while the engine was turning over.

[glavey]

A few more electrical gremlins tonight. First was one of the wires going into the left hand control cluster had come out of its crimped terminal in the connector. There was only about 2-3mm of insulation cut off of the end of the wire; no wonder it didn't stay in the terminal. I had to solder the wire into the terminal since it was already crimped and trying to open it would have destroyed the terminal. After a quick solder and heatshrink treatment, the wire is back in the connector and once again the passing light switch works.

Next, I did some testing and probing and disassembling to determine how the starter solenoid was wired. In case you wanted or need to know how the wires are connected in the right hand control cluster, I took a picture. Switched +12v -> starter button -> solenoid -> clutch switch -> ground. That seemed like a rather odd way to wire the clutch safety switch. I elected to remove the clutch switch all together and do: switched +12v -> starter button -> solenoid -> ground. I also added a diode across the solenoid coil's leads to limit the voltage spike from the coil de-energizing. Now, one lead of the solenoid is permanently connected to ground and the other is provided +12v from the starter button. I'll just have to be careful not to hit the starter button while the engine is already running. As for the clutch switch, I always start the engine with the clutch pulled in anyway. Worst is I try to start the bike with the transmission in gear and the starter very briefly turns then stalls, I feel the bike trying to move forward a wee bit, I let go of the starter, put the transmission in neutral and/or pull the clutch in, and try starting it again. I still have to add a diode to the main relay.

I cleaned, glued together, and reinstalled the clutch switch after I got some very high and erratic resistance readings across it. Even though I'm not going to be using it, I like to keep it in working condition in case I need it in the future. There really wasn't much in the switch, a few pieces of plastic, a spring and two terminals doubling as the switch contacts.

I am trying to have ALL grounds that can be routed or moved terminate at a single location so there is no voltage difference between the ECU ground and any of the sensors' ground. If there are too many more grounds to terminate, I may need to buy an isolated terminal to connect them all. The wire I previously installed on the left side of the bike that connected the engine to the frame didn't match my star-grounding strategy, so I moved it to where all of the other grounds were terminated, and connected the other end to the bolt that holds the rear brake fluid reservoir to the frame. You can see in one of the pics, the brake reservoir just to the right of the bolt hole that will hold it and the wire lead in place. It's getting mighty crowded on that side of the bike.

I'm going to go eat chili until either my stomach says "UNCLE!" or my bowels say "NOW!"

[glavey]

This is going to be a multi-post post, I have many pics to share. Pics attached to one post may not reflect what was discussed in that particular post.

I finally got a package from amazon that allowed me to move forward with a few of the remaining things left to do; FI hose, clamps, fuel pressure gauge, fuel tank return hose fitting, Q size drill bits, and o2 sensor bungs.

The vacuum port on the intake manifold was drilled, tapped, and threaded in without much fuss. The soft aluminum really made the process go faster. I chose to install the vacuum port on the opposite side of the manifold that the circular detent is on for two reasons; 1, the walls of the manifold were much thinner where the detent was and 2, the vacuum hose from the fuel pressure regulator was coming from the side of the manifold opposite the detent. Now the hose fits on there perfectly.

I drew on the exhaust where I need the o2 sensor bung welded in. Now I have to find a way to drill a 22mm hole in a pipe with a slippery chrome coating on it. The first way to do that, that comes to mind is to get a square-ish piece of wood a little larger than the diameter of the pipe and cut/gouge/sand out the shape of the exhaust pipe on one side of it, so the piece of wood can sit on the pipe and not twist around, but can still rotate around the pipe (I know, I really suck at explaining things). Then you drill a hole through the middle of the piece of wood, perpendicular to the cut out of the pipe. Now clamp the piece of wood to the pipe with the exhaust pipe in the cut out portion and the hole exactly where you want the hole in the pipe to be drilled. You now have a guide/bore for your drill bit to follow so it won't walk all over the place on the nice shiny slippery chrome.

I soldered on a diode to the main power relay. I have had a bottle of liquid electrical tape for some time, but never used it more than once or twice before. This seemed like a good time to test it out because I only stripped the insulation off of the wires on the main power relay, I didn't cut them and re-solder them back together, so I couldn't put heat shrink on the wires. I also didn't want to just wrap the diode up in the red electrical tape I've been using. I brushed on the thick, noxious smelling paste and let it sit for about 3 hours and then put another coat on. Once it dried completely, it seemed like a formidable adversary against moisture ingress, abrasion, and high voltage arcs.

I, yet again went shopping in my garage for some scraps of metal that might be able to the muffler up and away from the swing arc of the swingarm. I found a pair of angle brackets very similar to the ones I used to make a fender eliminator. I bolted one side of the piece of metal to the holes in the exhaust-side rearset, where the passenger pegs used to be, and the other side, 90 degrees bent, has the muffler support bracket bolted to it. The picture should show what I mean much better. In that picture I am using 4 of the exhaust-spacing-mock-up washers to emulate the height/depth the exhaust will go into the cylinder head. There is about 1/8" between the exhaust pipe and the starter with the exhaust system installed as it is in the picture. With the exhaust as it is now, I'll have to go out and get some exhaust spring hooks welded on at the same time I get the bung welded in. Oh well, I'll just face it. I don't think spreading a post over multiple postings is against forum rules. Mods/admins, if it is, please let me know.

I started to diagnose and troubleshoot the reset problem with the ECU and the starter. I disconnected the starter from the solenoid so that only the solenoid coil would be powered and the reset did not happen. I disconnected the fuel pump and wideband relays and the lighting circuit. The only things powered were the ECU and the main power relay. I still had the power lead from the motor to the solenoid disconnected, so I bypassed the solenoid and just touched the starter wire to the lead coming from the battery. BIG-ARSE sparks and an ECU reset. I think I'm on to something. Many more sparks and resets later, I am ~90% sure that the inductive surge from the starter when the power to it is interrupted is causing a huge voltage spike on the ground-end of the wiring on the bike. A voltage spike to ground, if received by the ECU, will almost surely cause it to reset.

[glavey]

Let's say the ECU needs a nominal 12 volts to operate. The voltage on the +12 wire into the ECU must be at least 12 volts higher than the voltage on the ground wire going into the ECU. The ground wire could have 1000 volts (referenced to earth) on it and if you connect 1012 volts to the +12v wire, the ECU will operate as it should, provided there is no reference to earth ground anywhere on the ECU. If the ECU's ground voltage is pulled up too high from things like stray inductance, a magnetic field collapsing, rapid high power switching, etc, then there won't be enough voltage difference the +12v and the ground at the ECU to let it keep functioning properly and it crashes and resets.

So I need to suppress that inductive spike. This is a bit beyond my knowledge set, since I can't really "intercept" the ground signal like I can on a relay; the starter motor is more-or-less permanently attached and grounded to the engine, so I can't exactly put a diode in-between the motor and the engine. I started a thread on the arduino forum asking for assistance with suppressing the inductive "kick" from the motor. I already have a few things I can try.

That thread on the arduino forum also made me realize that I think the wiring on this from-china ECU is probably its weakest link. ALL the wires are too small gauge to carry enough current and not have dramatic voltage drop and too short to isolate electronically noise components, power hungry components, and sensitive analog components from each other. You can see how small the ground wire is in the picture.

For this EFI kit to work WELL and RELAIBLY, I will most likely have to crack open the case and hopefully be able to solder on some thicker gauge wires, proper grounding wires, and sensitive analog signals shielded all the way to the ECU box (notice I said work well and reliably, not just work. I am sure that this kit will start and run and engine, but it will at some point probably have an electrical gremlin or two that will be very difficult if not impossible to squash without opening the ECU.)

I am going to try to keep the wiring coming from the ECU as close to "stock" as I can so I can test the kit as anyone else who purchased it would have it wired. If it turns out that I cannot reliably control the engine with the stock wiring, I will dive right in to the ECU case and crack it open like a walnut. I don't want to open the ECU just yet, I haven't even tried to start the engine with it yet and I don't want to condemn the ECU because I just thought I would have a problem with it.

The fuel tank fitting, of course, requires drilling a hole in the gas tank. Drilling a hole in metal causes heat, hot sharp shrapnel, and possibly sparks. Gas tanks have... gas in them. Gas + oxygen + spark = the kind of boom you want INSIDE your engine, not outside. I drained out all of the gas from the tank and took off the filler cap. Now I'm just letting the remaining gas and gas fumes evaporate and leave the tank. With the temperature so low, that may take a while. I'm going to have to get all of the vapor out of the tank because I realized that I really do need the tank on the bike to know where I can route the fuel hoses and where to put the pressure gauge so it can be viewed with all of the fairings on. So I can't run the hoses, install the return fitting, or position the pressure gauge before I get the tank nice and empty.

I was able to sync the timing between the engine and the ECU despite the reset issue. One thing that made it much easier was a printed pulley/crank/flywheel degree ruler. This site lets you enter the circumference of the wheel you want to degree and gives you a printable degree ruler you can tape/glue to whatever you need. I temporarily stuck it to the magneto so I could see the degree markings through the peep hole on the engine. Of course, I could only do this at cranking speed, not idle. I had to remove the intake manifold and keep the spark plug out so the engine could turn as fast as possible. With the spark plug in, the timing jumped between 10 and 20 degrees BTDC because on one rotation of the crank, the motor had to compress a cylinders worth of air, slowing it down a lot, and on the next rotation of the crank, the exhaust was being pushed out, so very little slow down there.

• o2 sensor and exhaust spring hooks welded in
• install return hose fitting in tank
• plumb fuel hoses
• solve or minimize reset issue
• permanently mount exhaust
• wait

That's it. The last 10% is the longest 10%.

[glavey]

Two steps forward, one (big) step back; that's the current situation with the ECU resetting itself.

To eliminate the possibility that the USB cable was somehow receiving interference from something electrical on the bike, causing the software to detect a reset, I made a bluetooth adapter to use in its place. I had a spare serial-to-bluetooth adapter from a previous upgrade on a 3d printer and a very common chinese buck converter (feed in any voltage up to the chip's limit, it will output a stable, selectable voltage. I just had to buzz out which wires were transmit, receive, power, and ground. Luckily the aliexpress ECU outputs serial data at 3.3 volts, the same voltage that the bluetooth adapter uses so I didn't need to use a voltage-level shifter. Now I just need to package it up, neat-and-tidy in some small box or something... I'll find something.

The adapter works with my laptop's internal BT communicating with the tuning software, on two of my cellphones, but not on a usb-bluetooth dongle I use for my main PC. Oh well, I intend to do the majority of tuning on my laptop. However, even with the wireless connection to the ECU, the resets were still happening...

My initial assumption that the ECU reset was caused by the starter motor were wrong. I discovered that if I turn the engine over using any method (e-starter, kickstart, socket/ratchet on the crank bolt) while the kill switch is in the RUN position, the ECU resets itself. When the kill switch is in the STOP position, it grounds the signal coming from the trigger coil; when it is in the RUN position, it has no effect on the trigger coil. So, it is the trigger coil itself that is causing the resets.

My first thought was that one of the two wires coming from the trigger coil is grounded, when usually in EFI systems both wires go back to the ECU. The manual for the microsquirt states: "...The Microsquirt measures the voltage from the sensor and converts it into a temperature, position etc. reading. If that sensor is grounded to anything other than the Microsquirt itself, then that input voltage will be altered by any external voltage drops. ...Tach input (e.g. crank, cam sensors) will be even worse - they can show false or missed teeth and cause syncloss due to the ground voltage difference..." The aliexpress ECU does not have a ground wire for the trigger coil to attach to. Without an rpm signal, an ECU is worse than a paperweight. I decided in order to give the aliexpress ECU the best shot at working, I had to crack open the case and solder a new wire to a good ground point. Opening the case was quite easy. 6 small screws and some lightly adhesive conformal coating was all that held it together. My first reaction was... Dang, these motoEFI guys (the tuning software and the ECU firmware are both have their names in them) even had a custom PCB created. I absolutely thought that the board inside the case was going to be a clone of one of this or this. Nope, looks like they (motoefi) have put on the PCB only what is needed to run a one cylinder engine on a particular configuration without many of the extra features like knock sensors, vehicle speed input, flex fuel, etc. Also, the I'm guessing... mosfets? they are using to switch the injector and the fuel pump aren't connected to any heatsink. One of them has a very small piece of metal adhered to it as an added thermal mass and the other one had nothing on it at all. The soldering is IMHO, just passable - the solder joints look very dry (lack of flux), maybe even hand-soldered. The main IC had its name scratched off, as did one of the suspected mosfets.

After having taken a good look at the ECU PCB, considering options, trying to filter/condition/shield the signal from the trigger coil, and many other things, I have decided to stop using the aliexpress ECU if I cannot get this issue solved with minimal extra cost or effort. I still have a few ideas in my head that I think might do something, but if the problem is what I think it is, I and possibly other people who buy this kit will have to buy a $25-$70 circuit board that will condition the trigger coil signal and/or a oscilloscope to see what output the trigger coil is giving in their particular case and filter it as needed. Either way you are spending time or money or even both. Sorry dudes, but at least in my case it looks like the ECU from aliexpress won't work without monetary or time investment that is equal to buying a real/genuine/brand-name ECU. I hate to stop using the ECU before I even get to try and start the engine, but as I said above, without an RPM signal, an ECU is worse than a paperweight. The other hardware and sensors from the seller seem to be working fine. This kit may still be a viable option if you just need everything except the ECU, as I did. I had a heck of a time searching the internet for a small-engine-sized throttle body. There were only a few sellers and most of them had odd/different mounting points where the TB bolts to the intake manifold. Ecotrons is an option, but their small engine EFI kit is $600, the tuning software is, in my experience, difficult and unintuitive to use, and I doubt you could purchase all the supporting hardware minus the ECU for less than the aliexpress kit.

After I try all that I can to get the aliexpress ECU to accept a trigger coil input and mapped out which wire goes to what thing, I'm going to need to re-run and maybe re-wire most of the EFI harness. At the time I wires the bike, there were no thoughts given to keep high power wires and sources of noise isolated and apart from low power signal wires, the wires from the ECU were to short to have anything but a rats nest. I'll also have to try and keep electrically noisy parts like the regulator/rectifier, wideband controller, ignition coil & lead, fuel pump, CDI, and relays to one end/side of the bike and the sensitive stuff on the opposite side/end. I'll also need to get proper water-resistant connectors and wire whose gauge size is suitable for how much current it will carry. And a crimp tool. And wire shielding sleeves. And heat shrink tubing. And a "real" fuse/relay box. And blackjack. And hookers. Time to save up...

So much for that teeny tiny little left to do/buy list.

I'm actually starting to wonder if I will get this done before warmer weather starts to appear...

[glavey]

Seeing the internals of the microsquirt as compared to the aliexpress ECU gives me much more confidence about switching to it. The build and soldering quality are much better and most importantly to me, it has a hardware filtering circuit for the trigger coil built-in. The wiring loom also has much longer, higher quality, labeled wires.

The only place that wasn't electrically noisy and had enough space to hold the ECU was where I had installed the fuse box originally. I moved the fuse box to right in the 90 degree corner of the frame, where the front-half meets the back-half, right below where I mounted the relays. The ECU didn't completely fit without modification - I had to cut off the four mounting tabs on the case and secure it with zip-ties. I swear zip-ties have helped me more in the last few months than duct tape has throughout my whole life. There really isn't much space between the bottom of the seat cushion and the top of the frame bars where I mounted the ECU. I had to butt the ECU right up against the little pillar the holds the screw for the battery hold-down, I had to cut off the little plastic pieces that on the real grom hold spare fuses.

I'm going to try my best to separate the power wires from the signal wires; I'm going to run wires for the lighting, fuel pump, R/R, ignition coil, wideband controller, and injector on the right side of the bike, and keep all of the lower voltage sensitive signal wires on the left side. I'm going to have to find a way to move the R/R to the right side of the bike, as it is now it's right where the sensor harness will be.

I had previously purchased an automotive ignition coil, GM "truck" coil (acdelco part# d585, gm part#10457730) to use when I installed the microsquirt. Well, the time is upon us and it was installed. The old ignition coil was RIGHT next to the TB and probably would have caused interference. I installed the gm coil on the right side of the bike, using the nuts on the frame that originally held up the air filter. The coil hasn't really moves that much farther away from the TB, but the whole bike's frame will be in-between the coil and the TB and sensor harness.

I took the wiring harness that came with the bike and un-did all of the electrical tape and soldered all of the points where they used a crimp to join wires. If done properly, crimping wire ends together works very well and will be very reliable. However, this is a Chinese bike, and we all know that the wiring on these bikes is sub-standard. I didn't bother to remove the crimps, I just flowed solder over all of the wires and the crimp together. Taking the wiring harness to pieces also lead me to find out that the connector that plugs into the 125 engines and tells the dashboard what gear you are in is, except for the neutral wire, is just one miniature wiring harness. The wires go from the connector on the 125 engine, to one of the dashboard connectors, to the dashboard. So, if anyone swaps in an engine without a gear indicator and doesn't want that connector just flapping in the breeze, you can take the harness apart and remove the mini-harness completely and tuck the wires from the dash behind the headlights.

The next amazon order will be things for the wiring harness; insulated battery post, heat shrink, waterproof connectors, crimp tool for said connectors, and braided metal sleeving.