Motorized bike build

5 minute(s) of a 23 minute read

3-27-20
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So I had my first ride yesterday, it was glorious but short lived.

Filled up the tank with gas and 2stroke oil. Tried several times and the bike wouldn’t start. Figured it was an electrical issue. Tested the components and they seemed fine. Opened the side of the motor and noticed the magneto wasn’t spinning when it should’ve been. That will cause a problem.

The clutch was out of adjustment so the motor wasn’t actually spinning. Adjusted the clutch and I was off!

The bike drove great, took a few tries for it to start but it was soon up and running. Took it about 3/4 of the way around the block when there was a loud bang and the rear tire locked up. Had to half carry the bike home.

This isn’t good. 

Neither is this.

All the engine mount nuts had vibrated themselves loose which caused the engine to shift and messed up the chain, at least that’s how I think it went. Not a huge deal, I replaced the super long front mount rods with the stock ones, and added a locking nut to each one so they are doubled up. It seems like the chain is a lot more loose now so I’ll have to tighten it up some. Hopefully will be back on the saddle today.

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3-28-20
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Finally have it up and running! It took a bit of fiddling to get there. I checked if I could remove a couple chain links, although it seems like a decent amount of slack I had no room to remove any links. I readjusted the idler and added a second one to keep the chain from slapping around. It took some adjustment to keep the chain from hitting various parts but it seemed to work.

I did notice while riding at a constant speed the engine noise would go up and down at a rate of about 2 Hz, in time with the idler pulley bouncing up and down almost like it was bogging. Could be due to a resonance related to the stiffness of the pulley spring, I’ll try swapping it out with a stiffer spring at some point.

It was quite fun to ride, although I was worried about something breaking so I stayed in the subdivision. A couple items to note/improvements to be made:

Even with the softer mounts the bike vibrates quite a bit, especially at higher speeds/full throttle the whole bike is buzzing. After a long stint of riding my hands were tingly. I’ll probably wear gloves from now on, especially during long rides.

It takes a couple tries to get the motor started, don’t know if it’s because it’s a brand new motor or what.

There’s a decent amount of resistance even with the clutch fully in, maybe because of the two idler wheels. Will have to investigate. This makes the multiple starting attempts a pain as I have to get the bike up to speed.

The clutch handle that comes with the kit is pretty jankey, the handle has a lot of play and is cheaply made in general. With its placement I can operate it and the front brake with one hand, but I’ll eventually upgrade to a better handle.

The brakes are pretty decent, the rear is sort of weak but in combination with the front disk the bike stops well.

The kickstand is inadequate with all the additional weight, unless it’s perfectly positioned the bike falls down, will have to look up alternatives.

The seat doesn’t have a ton of cushion and hurt after a while. It looks cool but I’d want to swap it out for longer rides.

The bike looks pretty cool even though the paint is getting worn from all the assembly and disassembly. All the neighbors walking around smiled and waved.

Going to keep riding and improving it. One of my coworkers just built an electric bike from components he found online, we will do a race at some point in the future. :D