The exhaust silencer and the filament came in!
The exhaust silencer, as compared to the one that came with the exhaust system, has a larger diameter outlet pipe, a cap on the inside end of the exhaust inlet, and holes drilled along the length of the pipe. The holes are, I'm guessing, about 1/4" diameter, at 12, 3, 6, and 9 o'clock. You can move the exhaust inlet cap closer or further away from the wide part of the silencer for less or more noise and power respectively. I went for a ride today with only the last four holes in the silencer letting exhaust gasses through. During warm-up with the choke on and at idle there was little to no difference in the perceived volume of the exhaust as compared to the silencer that came with the exhaust. However, at higher rpms the silencer was without question choking the engine. I knew the loss in power would happen, I wanted to see what the worst performance with this silencer would be and then hopefully get to a point where restriction-to-flow and decibel levels are good enough.
Oh and if you want to know the size of silencer to get for the exhaust system I have, the exhaust tip Internal Diameter is 48mm/ 1.8". The tip is angled so don't get a silencer that is much longer than about 71mm/3".
I recorded a very short clip of the engine idling and revving after I got back from a ride. The microphone in my phone does not do the low-end bassy portion of the audio justice, but you can hear how the engine and exhaust don't have the steady put-put-put other engines do. The video bogieboy posted sounds very much like how my bike idles. I suspect my phone was doing some compression/processing to the audio to make it sound like it did.
When I took that video, I noticed that what I suspect are the valves are getting a wee bit loud. Before I go out on my next ride (in another week, cold weather) I need to at least check the valve clearances. I think I remember I put them both at .006". I posted the number I used, I'll go back and look. Whether or not they are still at or near .006", I think I will try them both at .005 and see how much that quiets the valve train. While I'm doing that, I can give the engine its 100 mile oil change. I expect slightly metallic oil from the break in period, hopefully not silver paint or chunks and bits of... anything.
Three more things I would like to get done on the bike are:
1. Deal with fuel tank vent hose leaking/dripping fuel. The stock fuel tank vent on my bike - the one on the top of the tank with the hose barb bent 90 degrees will, with or without a hose and/or filter attached to it, sputter/drip/spray fuel. I am starting to suspect a purposeful or accidental restriction in the hose barb on the fuel tank. The fuel would be able to splash/roll up there and if the tank happens to have a positive pressure inside it, it will push the fuel through the restriction into the hose barb and not let it back in the tank because more fuel/fuel vapors are being pushed out. I don't think there are any baffles inside the tank around the venting hose barb. There are however, MANY baffles around the fuel filler area. I am thinking I might either buy/make a gas cap that has an integrated vent tube thingy (the kind that are quite common with dirt bikes, like
this one) OR just drilling a small, maybe 1/16" hole in the fuel cap that I have now - enough to equalize pressure, but not invite dirt, dust, debris, and bugs into the tank all while keeping all of the fuel inside the fuel tank.
2. See if the
$15 grom shock mod can me done on my forks. I already bought the hardware and the fork oil. Even if the mod doesn't work, I'm still going to get rid of the factory "oil".
3. Connect and wire the dash wart to the speedometer. I finished designing and making a housing for the AFR gauge, wideband status LED, and a voltmeter. More on that down below.
I have noticed that the area on my exhaust that is directly beneath the starter motor has what looks like.. not rust, but something like a water stain. The Only what I could think of the exhaust starting to corrode in that specific area is if somehow... (wild guesses about sciencey stuff that I barely understand coming up, be warned) when the metal of the exhaust and the starter motor get to a hot enough temperature, they do something like... emit particles? atoms? ions? The exhaust could, I think, be at a different voltage potential than the engine block (I am including the starter in the engine block) because of all of the particles of air that are striking the exhaust while the bike is in motion. That difference in potential voltage might allow what ever the hot engine block is emitting to adhere to the metal of the exhaust and cause it to tarnish.
Or maybe it's magic pixies and unicorn farts. That was just an exercise in letting my brain go as far as it wanted to with a certain train of thought.
Whatever the cause of the tarnishing, unless it gets worse, I'm not worried about it.
I started making the housing for the gauges by making educated guesses on the contour of the top of the speedometer. I tried taking pictures straight-on and using them as references for modeling, but that didn't give me a good-enough result. I do have the capability to 3d-scan an object with an old xbox kinect and use the resulting model as a reference, but that would require me digging out the kinect camera as well as a lot of work post-model-capture to clean up the model to a usable level. I decided to go the old fashion route of guess, make, check, curse, repeat. In one of the pictures you can see some of the contour test prints as well as items I printed to get my printer calibrated to a new roll of filament, including a throttle-hand wrist rest.
I ended up with an off-to-one-side, bolt-to-the-speedo cluster. The face of the cluster is angled about 20 degrees higher than the speedometer so it is easier to see and maybe less likely to reflect the sun into my eyes. The AFR gauge face, arduino, power regulator, voltmeter, and status LED all get stuffed inside from the outside throuth the AFR gauge face hole. The power and signal wires come out the right side and the whole thing gets zip-tied/bolted/otherwise attached to the speedometer housing through 8 holes drilled in the cluster (and soon to be drilled in the speedometer case). I didn't intend for this case/cluster to be water or weather-proof. I will probably silicone or hot glue the AFR gauge face and the voltmeter housing in place and plug-up the wire exit hole, but I am going to leave the holes for the zip ties/bolts/whatever unplugged, as-is. I want the case to be able to breathe and vent air and moisture.
I attached a lower-quality .stl file of the cluster if anyone wants it. Also,
here is a link that will let you look at the part in your web browser as well as download a high-quality copy in many different file formats.