8 speed 79cc revival

xXNightRiderXx

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Ok, I got the wheel off the bike, and it turns out it's the pawls that broke. It freely turns to the rear, and catches to the front when turned by hand. I got the axle off, and need a 12mm allen wrench to remove it. I'll post a photo of the damage when I pull the thing off.
 
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xXNightRiderXx

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Jan 12, 2017
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Ok, I got the wheel off the bike, and it turns out it's the pawls that broke. It freely turns to the rear, and catches to the front when turned by hand. I got the axle off, and need a 12mm allen wrench to remove it. I'll post a photo of the damage when I pull the thing off.
I was wrong. It wasn't the freehub itself at all. It was the threads in the wheel itself holding the freehub to it.
IMG_20210718_225436~2.jpg

IMG_20210718_225346~2.jpg


Time to build myself a wheel that I can actually repair, instead of one that I have to replace every time something goes wrong.
 

xXNightRiderXx

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I found a double wall mtb rim with a welded joint and eyelets, a mtb hub with 6 pawls, no threads in the hub to strip out, and thanks to mbrebel, 12ga spokes measuring 254mm. Not only does this mean I'll be able to repair the thing when it fails, it also means that my bike can accelerate and stop faster because there's less mass to impart inertia to and remove it from. Who knows, I might even be able to go faster.

I think I'll also add a 203mm brake rotor to my rear wheel. Interestingly, my current system is 180mm with a 160mm is to post adapter, and it'll be 203 with a 180mm post to post adapter.

PS: this will be a 36 spoke setup, front and rear.
 
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xXNightRiderXx

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Ok, so here are my plans for the future:

Rebuild the battery box for more efficient use of space and better wire routing.
Port and polish, with another mild head sanding
Build new wheels
Build a tow trailer for my mtb
Craft an engine cover to block mechanical noise
Have a new exhaust pipe with a glass pack muffler made
Buy and install a one wire alternator
Buy and install the bored and reworked carb install from agk
Buy and install the agk flywheel
Buy and install a new spark plug for more efficient burn
Get a vin, insurance plan, and registration
Buy and install a longer intake for more low end power
Avoid losing my bike to inattentive or malicious drivers. (Ongoing)

I shall post photos as soon as each item is accomplished.
 

xXNightRiderXx

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I probably could have made this better. I'm the one who wrote it, and after all this time of not even thinking about it, I'm having a hard time deciphering it. So, I'm going to streamline my wiring representation once I've redone my wiring. And yes, I do need to redo it. It's a rats nest and barely fits into a 1" split loom.

Anyway, I'm going to get some tools and parts month after next, which is after I pay my legal fees. Gonna get those wheels built, and my cylinder head spiffed up. Gonna angle my valve seats, lap my valves, port and polish, and do some more sanding for more compression. Then I'm gonna install that flywheel, then take a center punch, and pop out that blasted governor. I'll be free and clear to do other mods after that. At some point, I may decide to do a cam upgrade and 22lb springs, but until then, it's on the back shelf. Has anyone ever spun these engines up above 8k for an extended period? Maybe close to 10k? If I do a shorter air intake and bigger cam, that's where I'll want to spin it up to. Between 6k and 9k. Alternatively, I'll keep the small cam and a long intake and keep the power around 3k. I would like to advance my cam timing just a few degrees. Any way I can do that without paying for a custom cam?
 
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xXNightRiderXx

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I found a company that has done custom cams for this engine: performancecams.com

$135 for a custom welded profile. What I'm thinking is offset timing, but maintaining the intake opening position and making the closing position a few degrees later, and maintaining exhaust duration, but moving open and close a few degrees later. The idea behind this is the later the intake stays open after bottom dead center, the more the intake velocity can be used to charge the cylinder, and the more compression I can get. The later the exhaust opens and closes, the more the exhaust can be pushed out and replaced with the intake charge. The intake will be opening just before the exhaust closes to take advantage of scavenging. If I'm mistaken, tell me straight up, and let me know about anything that would be better.
 

xXNightRiderXx

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Alrighty! I got a class action payment which I used to purchase an alternator, two #35 20t sprockets, a pulley for the crankshaft, and a set of glass and alloy mirrors that won't shake as much as these damn plastic ones. They even have a much higher range of adjustment to get the perfect angle to properly see behind me.

I have the new hubs on the way, which have 6 pawls, and the teeth the pawls engage are on the hub itself. The freehub body pulls away from the hub, so there are no threads that can be stripped away. Next step: Rims and spokes, 93 octane stickers for the tank, carbide burrs and sanding spirals to do some port work, and a set of valve seat cutters for a 3 angle seat job. With the intake, I won't use the sanding spirals much. I'll just let the burrs run around the intake port (light pressure with the Dremel, no resistance against the rotation of the burr), lightly using the sanding spirals to remove any peaks obstructing the charge. This will produce a rough finish in the intake port to keep the charge atomized without reducing the amount of fuel and air entering the cylinder. Any objections to this method?

I'm also thinking of turning the engine around and using an idler sprocket system to reverse the jackshaft rotation. This will allow me to mount the engine level and get optimal cooling, leg clearance from the exhaust, and oil level. I will also be able to route the exhaust down and back, keeping it away from the saddle and my thigh. Not sure how easy that will be, however, I'm sure I can do it, since cars and cameras did it. I'll just be using nuts and bolts instead of welds.
 

xXNightRiderXx

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No objections? Alright then, I'll get goin on this. The pulley, hubs, mirrors, alternator, sprockets, and chain have all arrived, but it turns out that I left the stock jackshaft plate in the weather too long, so the shaft and most likely the bearings are all rusted and shot now. Time for a new one. Screws were falling out of it anyway. There are 3 things I will need to do to make this stage successful:

1: I will need to fabricate a mounting bracket for this alternator. It's a beast of a thing compared to the size of the engine. The steel I use will have to be at least 1/8" thick to support the weight, and one bracket will go onto the truss rod mount and twist to mate up with the alternator. The other bracket will bolt onto the engine side cover and bend around it, preventing the bracket from rotating. There won't be any adjustment for tension here, so I'll need to make the belt a little bit tight at first. It'll loosen up in the first couple hours of operation, and then I can tighten it with an idler pulley mounted somewhere.

2: purchase a new jackshaft plate to relocate the clutch. This is so I can turn the clutch with the two sprockets I bought, making room on the crankshaft for the pulley.

3: build the new wheels with a minimum of 92% max tension in the spokes. Because they're 2.6mm spokes, I will also need to drill out the hub flanges to 2.8mm and countersink the holes. This is why I bought MTB hubs. They can handle that extra load on the spoke flanges without breaking. The hubs I bought seem to be based on the older Industry 9 hubs, which are top of the line when it comes to durability and speed. High speed sealed bearings will help reduce the rolling resistance, maximizing acceleration and top speed. These wheels will also be lighter than the mag wheels, and so carry less inertia, making it easier to slow them down.

As far as turning the engine around, it's not feasible. To do so would require shifting parts around in a way that would create greater load on one side of the bike, where currently, the load is spread in a diagonal. That one sided load concentration would increase the risk of bending the frame under the torque of the engine. Cars and cameras did it in a way that would keep the load in a diagonal distribution, where I have no such option if I'm to keep using the cassette. Yes, I understand that on most builds, the load is concentrated on one side, and it works fine, but that diagonal force distribution spreads the load throughout the frame, rather than one side of it, maximizing longevity. That's my aim.

I will be replacing all of my chains, and likewise replacing my cassette. The cassette shows wear, and the chain has slipped off the inner chainring and jammed into the nuts, likely causing damage and stretching the chain. The chainrings show no wear. I will search for an ebike compatible cassette, since they are built a bit more rugged and will resist wear better. All of my chains have become dirty, and have probably worn a bit, so I want some known reliable chains and will lubricate them using a dry wax based/Teflon based lubricant. This keeps the dust off, preventing wear so long as I keep it out of the weather. If I take it out in the rain, I'll lubricate them using the proper lubricant.

I will also be disassembling my clutch and lubricating that as well, keeping all lubrication away from the bell and pads. Until I get more power, I'll stick with the 42-11 cassette. Once it starts outpacing the low gear range, (e.g. 2 seconds or less before full sync) I'll swap it out with a 36-11 cassette. That will ensure that I can reach higher speeds per gear and maintain clutch sync time. It is currently at 3 seconds.

Once I get everything all together and working well, I will disassemble the bike and repaint the frame with a metallic red paint and a gloss clear enamel, after fully stripping all paint off the frame using a citrus based stripper.

Thankfully, my seatpost is long enough that it prevents the seat tube from being crushed, though I will probably replace it with a slightly longer one just to be safe.
 

xXNightRiderXx

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My hubs have arrived, and I've got to say, they're even better than I expected. I'll be running 14ga up front, and 12ga on the rear. Cuts down on cost and machine work. I've already got 36 holes to drill out for the 12ga, I don't need 72. As it is, I'm lucky I have a friend that has a drill press, so I can get a nice, straight cut. If he doesn't have a 2.8mm bit, I'll be getting my own hss double cut bit. I'll also be using a pair of wooden 1x2 blocks to prevent damage to the finish of these hubs.

Time to buy the rims and spokes, and a couple pieces of scrap steel plate.
 
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