BD125-8 ZS190 swap and EFI conversion

[Weldangrind]

Polydactyl on just one paw or more?

[glavey]

Both front paws.

[Weldangrind]

He'll be able to take a round out of a dog if necessary.

[glavey]

Apologies for waiting almost a month between updates, but I've hit a mental project exhaustion tipping point. Details at the bottom of the post (kinda whiny/needed-to-vent/oh-man-I-need-a-therapist)

Post 1/2

Ever since my bike was delivered the throttle tube was quite loose on the handlebars. Something like 1-2mm of play between the ID of the tube and the OD of the bars. By comparison the throttle tube on my scooter is quite snug. I decided removing the slop from the tube is worth while since it will give me finer throttle control.

I removed all the bolts holding the right handlebar control cluster together and disconnected the throttle tube from the throttle cable. I measured the OD of the handlebars and the ID of the throttle tube to see which is the culprit... The throttle tube! It was about 2.4mm diameter too big. I decided to wrap the handlebars with a very thin, slippery fabric to fill the void. The best thing I could find was a synthetic almost tyvek-like fabric. I wrapped the handlebars and trimmed off bit by bit until the throttle tube fit on snugly while still being able to snap back to closed if I let go of the throttle tube.

As the bike is now, the clutch handle has a very uneven feel. The friction zone of the clutch is RIGHT where you start to feel "real" tension on the handle, not just the spring tension holding the cable taught. So from the point where the clutch is not being held in, up to right before you are in the friction zone is just spring tension, but as soon as you enter the friction zone all the way to the clutch handle being completely pulled in, there is tension from the clutch pressure plate springs as well as the clutch return spring.

It has been difficult to develop muscle memory for the clutch friction zone with the tension changing based on the distance moved. I want to install an additional return spring for the clutch to give the handle a more consistent feel. The extra spring I have from the exhaust is too small and I don't want to go out to the hardware store and pay $5 for a single spring. I'll need to fabricate something at a later date.

My whole body misses having a balance shaft.

The last couple times I was out on a ride, I heard some metal rattling while riding. It wasn't like a too-lean engine knock, it wasn't the valves (though they did seem a little louder than normal), and it didn't change with engine speed, but with road speed and condition. Something made of metal is loose or something loose it hitting something metal. Quite possibly one of the unused wiring harness connectors flapping around in the breeze and jamming out to the good vibrations from the engine and the wheels. I still have yet to properly secure the wiring harness as much as I would like it to be. For another time.

I checked the valve clearances again since the valves seemed just a wee bit too loud. The intake had gotten tighter than .003" and the exhaust was at .005". I adjusted both to a .004" go/.005" no go clearance. That seemed to work, though there was little difference is noise of the valve train.

The baffle I made in the previous post did work at quieting down the exhaust slightly. Subjectively, it went from an 8 (0-10; quiet to loud) to a 7 or 7.5. Audible, noticeable, measurable difference, but not quite enough for me. Also, I could tell it was one of the more restrictive ways of quieting exhaust; 3/4 to WOT was in the 10 AFR range without jet changes.

Yep I did it again. Another thing to try and quiet down the exhaust. I'm obsessed at this point. It is either this or (gulp) back to the restrictive as hell OEM exhaust and goodbye wideband.

I first laid eyes on the muffler while searching, oddly enough, how mufflers are manufactured and difference quieting techniques. I found a link to a muffler that just looked like any ol' pit bike muffler. However this one was marketed as "quiet". I had never seen an after market muffler marketed as quiet. Most try and push that they are loud and brash. Tbolt's website doesn't provide a picture of the inside of the muffler or of the silencer after it has been removed. I needed to see how the silencer was built to determine, from pictures only, if the muffler would be quieter than the one I have with the baffle installed.

I searched ebay, amazon, and aliexpress for "pit bike muffler" and scrolled through all the listings my brain could handle and clicked on the ones that had a similar looking exhaust. Finally I found a listing that showed the silencer after it was taken out of the muffler. Perforated tube with end rounded off and closed, roughly 30% open area, 1/2 covered by a fiberglass muffler packing sheet. In my mind, that silencer would make that muffler quieter than what I have now.

OK, I've decided to buy the muffler as a last-ditch attempt to quiet the exhaust down to a reasonable level and keep my neighbors friendly, or at least tolerant and non-hostile. I can be pretty sure that any listing for this specific type and look of muffler will have the silencer made as shown in the pics from the above link, so I searched the three sites again and found that I would have to wait for at least a few weeks to get one; no US sellers had them in stock. So it would have to come from overseas; the place where all of our electronics are made, the place where they drink a lot of tea, or the place where everything is trying to kill you (affectionately, China, UK, and Australia). I chose the slow boat from china; no rush, save money.

Also, a plus for this particular muffler (for me at least) is that the ID of the exhaust inlet is 38mm. Most chinese after market mufflers are 51mm and come with a conical 38-51mm weld-on adapter. The OD of the exhaust pipe I have is 36mm. I thought I would need (and bought) slip rings that go on exhaust pipes to effectively increase their OD, but I didn't need them. Just some sealant around the pipe before final assembly worked fine.

14 business days later...

It's smaller than I thought it would be. The silencer looks just like it did in the listings I found. Cool, I got the muffler I wanted.

Removing the old exhaust was quite easy thanks mostly to the outside of the exhaust being coating in a chrome like plating. That made twisting off the old muffler and scraping the old sealant off quite easy. Luckily the mounting hardware I made for the old exhaust would 90% work with the new muffler. I had to mount the hanger supplied with the muffler backwards so the part that is supposed to be facing outward and have either a nut or a bolt in it, would be facing inward, pressed against the muffler bracket I made. Not the prettiest solution, but it works. I need to put 2 or 3 washers between the space in the clamp halves so I can torque down the mounting bracket's bolt without worrying about snapping the clamp.The new muffler fit perfectly and stays in place even without springs thanks to the muffler clamp.

With a cold engine and full choke, I started the bike with the new muffler. Yes! this is the sound level I wanted! Loud with a brap under load but calm and civil while cruising. A bit louder than oem with more pop and no buzz or raspy sound. Yeah, trying to explain changes in sound with words is difficult.

After the inaugural run with the new muffler I noticed a few wisps of exhaust packing being pushed out of the muffler. It seems as through this muffler wasn't made with any or enough sealant between the end cap and the main muffler part (the part that is that weird brown/slightly purple/burned bronze color). I have more than enough packing material to repack this muffler if need be. For the time being, I am not worried about tiny bits of the packing material making an escape, unless somehow the whole of the material came out in one giant moto-snot-rocket. Then I would just laugh.

[glavey]

Post 2/2

I was actually planning on having to use the OEM exhaust, so I also bought the cheapest integrated brake light at the same time as the muffler. I think it was only $10. The reason behind needing the integrated brake light is, as the bike was with the fender-elimination I did, the turn signals were RIGHT in the way of the muffler. The only way to use the OEM exhaust with turn signals was either to put the stock license plate/turn signal holder back on or make/buy a integrated tail light.

I chose the integrated taillight that I bought for a few reasons;

1. CHEAP!
2. Easily modifiable. Many of the reviews stated that the lens cover fell off after just mocking up the light to their bike. Perfect! I won't have to worry about breaking the entire light housing by taking it apart with screwdrivers and the hammer of encouragement. All of the LEDs are through-hole; easily removed and replaced/upgraded.
3. Subjectively, it seemed the least... immature? Some taillights had sections shaped as eyes or wings. Not my taste.

The quality of construction is what you would expect by buying from the lowest bidder in china. Very dry solder joints, Poor wire-to-PCB soldering, drilling holes right through the PCB for mounting in the housing. But it works.

Some of the common complaints of this product were LEDs snapping off at the legs, supposedly because of harsh vibrations. I could party cure the reinforcing of the LEDs and at the same time reduce or eliminate the chance of the PCB corroding from trapped moisture/water. I just needed a lot of clear nail polish. You read that correctly.

I've used clear nail polish as a protective coating on electronics before and it worked great. It's cheap compared to the "professional" products and it doesn't require dangerous chemicals to remove if repairs are needed. I poured about 1/2 of a bottle of nail polish on each side of the PCB and spread it out over the whole board, making sure to coat all exposed copper traces. On the other side I made sure all of the LEDs had nail polish brushed up against them as mechanical reinforcement against vibration. The pictures show the end product of the coated taillight.

The fitment of the light wasn't as good as the OEM brake light. The old brake light aimed along the lines of the fairing; it pointed and shone at an upward angle, where the eyes of a driver behind you would be. The new light points at the horizon/no upward angle. All of the lights are still very visible from the "flat" angle, but it is obvious that this light was originally made for another platform and someone at some time discovered that it fit the grom well enough to sell it as a grom taillight. In the pictures of the new muffler on the bike, the top right picture shows how the new taillight is angled horizontally

I had to super glue the bolts that anchored into the back of the light housing - just approaching "snug" would make the bolts turn in the housing. I also had to use some washers around the bolts and the rubber mounting pieces on the bike. Sorry, I didn't get any pictures showing exactly what I mean here.

I also included pictures of the stock/OEM brake light PCB in case anyone wants/needs to repair/upgrade/modify theirs. Quality is about the same as the integrated taillight.

As I was working on installing the taillights, I noticed that one of the rubber feet for the seat had broken free and was just resting next to the battery. The LITTLE conical tip that is supposed to hold the rubber foot in place in the seat had sheared off. Not surprising really, this "rubber" can be ground away with one of your fingers.

The rubber feet on the seat are ALL that keeps the seat from just sitting and rubbing on the battery and the frame, I needed to fix this before I could ride the bike again. I didn't take too many pictures of this process, I wasn't in a good mood when I discovered that I now had a compulsory repair on my bike. I needed to use a bolt to hold the rubber foot in place, but the hole in the seat is only open on one end - there's cushioning and covering blocking the other side. You can kinda see in the right-most picture of the seat repair, I had to grind and drill a smallish slit into the side of the rubber foot mounting point. I got a washer and a bolt in through the side-slit (that sounds dirty) and managed to get screwdriver to hold the bolt in place while I tightened a nut down from the outside. After a test ride, the foot stayed where it was supposed to.

I wasn't planning on replacing the shifter arm so soon, but a fortuitous deal happened to cross my path. I got this even though it doesn't explicitly say it will not work with grom-sized engines. One of the reviewers stated that it did fit his grom. Oh, and just so you know if you are looking for a similar shifter arm; all of the stock images for the IMS folding shift lever (at least on amazon) are the same, you will have to look at reviewer pictures to see what the shifter arm really looks like.

The shifter arm is between the two arms I have now in length. The shortest one is the one I have been using. It is difficult to get into neutral as well as really "feel" shifts with this one. The largest one has very poor quality welding. I can just see that arm snapping off after 100 shifts.

The new shifter arm does fit the splines on the shift shaft! But, without modification it cannot move at all once installed on the shaft. Both top edges touch the left side engine cover. With some chamfers ground it to the top edges, the shifter works perfectly. I also included a top-down shot showing how the shifter arm lines up with the foot peg, in case someone was thinking about getting this same shifter arm.

I have made some progress on the short shifter circuitry. I got 99% of the design into software so it will be easier to plan out how every chip is laid out relevant to every other chip. I've attached a copy of a schematic for most of the circuitry. This is my first time using this particular piece of software, so I'm not sure I'm doing anything correctly. The files I have attached should be treated as a rough draft and a guide, not as a finalized design. I take no responsibility for the out come of your actions with or without the use of the files I am providing (It might go boom and it's not my fault).



Whiny/needed-to-vent/oh-man-I-need-a-therapist stuff starts... ... Now!

I'll save you from having to become my therapist for this post; I'll keep things short...ish (I tend to write a lot in my posts).

I know I've mentioned my anxiety in previous posts, but I don't know if I said that I damn near have an anxiety-induced panic attack EVERY time before I ride my bike. At first I thought it was the more-or-less straight open exhaust and muffler screaming LOOK AT ME!! (not to mention making your chest pound from the sound pulses, which feels exactly like a panicking heart beat). As you can read in my previous posts, I tried to quiet down the exhaust by repacking it and making an additional baffle/silencer. The repack did nothing, the baffle helped marginally, anxiety temporarily reduced, but the exhaust was still to loud for my tastes/mental state (honestly I'm not sure if there is a difference between my personal tastes and whatever reduces anxiety the most).

I bought a new designed-to-be-quieter muffler, it further reduced the exhaust note to something I can tolerate if not learn to love. The first ride after installing the new muffler was great. The second ride wasn't as good.

I'm still making stupid beginner mistakes during every ride. I need more seat time to get used to and learn... everything. But every time I even think about going out for a ride my insides tighten and I get increasingly panicky. I has become a chore to push myself to go ride. A passion absolutely should not be like that.

Another facet of my mental state is the realization that owning/riding/working on a bike has been one of the things my brain decided it just needed to experience. Let me elaborate;

All throughout my life I have never had (except for one, kinda) a real lasting hobby/interest/passion. I ravenously attack any new interest I happen to find with more planning, research, question asking, and mental focus than I am capable of. Notice I said, "more... than I am capable of." I will forget to go to the bathroom, eat, and notice that I am tired. One of the many symptoms of ADD. Oh yeah, I'm 95% sure I have undiagnosed ADD. Where was I? Right, Any new interest will usually last no more than a month. The attempted EFI conversion I did in this thread was the longest a single project has held my interest. Well the spark has stopped um... sparking (my mental interest spark, that is). I can never predict when my interest in a particular thing will stop or what will cause it to stop, but like death, taxes, and stupidity; it is unavoidable.

This post is going to likely mark my (long) pause in this project. Depending on how long from now it is when I decide to start messing with the bike, I may either continue this thread or start a new one. I'll still try and check on the thread and answer questions. In the event that I do decide to sell some or all of the bike, I'll try my best to give the forum here first dibs on items. All of you have been so kind to me. Thank you.

TLDR - I cannot enjoy something that I have to push past horrible feelings to get to. I got bored. I'm looking for a new hobby to sink my mental teeth into. I'm making excuses. I love you all.

Later Dudes.

[Weldangrind]

I can appreciate what you're saying about projects, but my affliction is dissimilar. My problem is too many concurrent projects and not enough focus/time/prioritization. I'm working hard on that aspect of my social style right now, although I admit that I just started another project.

[EvilWayz]

Im sure this post is dead, but where did you get your efi kit from? Or did you buy it piece by piece?

[JerryHawk250]

You can find these kits on Aliexpress. https://www.aliexpress.com/item/3278...ddresstype=600

[Drozzikid]

Can u send me a link for that kit please or if anyone knows anything about arduino???

[Drozzikid]

Please help me out I purchased the rojo system with ecu on throttle body but that's here nor there I just wanna know what u did about stator/generator???? For charging and lights and runny Ng efi fuel pump all time ???? Only stator I know of is the one from ooracing but in the states we can't get it so I'm wondering what u uses?????

[Drozzikid]

Please shoot me email at danielppoleet@gmail.com

[klausfelix12]

If it turns out that the software truly doesn't support wideband, I'll just skip right over using the Chinese ECU and software and use the genuine microsquirt and tunerstudio.

I am sure I could eventually get a decent tune on an engine with just a narrowband sensor for ECU feedback.

I have seen a few videos of people with this same kit or one very like it get an engine running and rideable but this is my very first foray into EFI conversion and tuning.

So I want the experience to be as good easy as I can make it so I won't have a sour taste left in my mouth from a bad first experience with tuning.

I already have 90% of the bike taken apart and will probably drop the engine sometime between tomorrow and Wednesday.

Trying to drop an engine, even one this small, without an platform jack is... painful. I'll probably end up using a combination of trolley jacks, jack stands, and rope to drop the 125 and lift the 190.

Unless something unexpected happens, I probably won't document the engine swap part too heavily as it's quite straight-forward; take stuff off of your bike until you can remove the engine.

Disconnect anything that is connected between the engine and the frame or wiring harness, remove front sprocket, remove the right rear set to get access to a bolt, remove engine mount bolts that's where I am right now.

Drop hopefully not literally the engine, new engine install is reverse of removal.I think there is one or two wires that I have to move/swap, if you were going to stay carbureted, you'd be 95% done.