What to expect

mrelijahgardner

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So I am building my "first" Motorized bicycle. I built failed ones when I was a kid with weedeater motors and stuff.

I went down an Amazon rabbit hole and now I guess I'm building one.

I'm kind of curious what to expect.

I ordered a 100cc kit with a 36 Tooth sprocket. The bike has 26inch tires.

What kind of top speed can I really expect?

I am used to riding motorcycles. I have seen a few videos and I am curious about the clutch. I get popping the clutch to get it started. But I'm curious about taking off. The videos I've seen show people peddling to get to speed then releasing the clutch. Is it not like a motorcycle where you can feather the clutch for a take off?

The bike I'm using only has a coaster brake. Is that going to be adequate? I might look into a front disc brake later on. What other solutions are available to a suitable rear brake

I'm sure I'll have more questions when the boxes start showing up and I start putting it together.
 

noah9988

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Top speed should be about 35. You can feather the clutch a bit but most people aren't able to take off from a stop without pedaling. The engines simply don't have enough power and with the single speed. It's advised that you have another braking system other than a coaster brake. I've never used one but it's recommended to get another form of braking.
 

Sidewinder Jerry

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So I am building my "first" Motorized bicycle. I built failed ones when I was a kid with weedeater motors and stuff.

I went down an Amazon rabbit hole and now I guess I'm building one.

I'm kind of curious what to expect.

I ordered a 100cc kit with a 36 Tooth sprocket. The bike has 26inch tires.

What kind of top speed can I really expect?

I am used to riding motorcycles. I have seen a few videos and I am curious about the clutch. I get popping the clutch to get it started. But I'm curious about taking off. The videos I've seen show people peddling to get to speed then releasing the clutch. Is it not like a motorcycle where you can feather the clutch for a take off?

The bike I'm using only has a coaster brake. Is that going to be adequate? I might look into a front disc brake later on. What other solutions are available to a suitable rear brake

I'm sure I'll have more questions when the boxes start showing up and I start putting it together.
A poor braking system can take you on your last ride. Having at least front/rear rim brakes should be your top priority.

When riding be sure to use good cycling skills. Being a good MB'er starts with being a good cyclist first.

 

weefek

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I've never driven a motorcycle. Obviously a motorized bike is no comparison... but I have ridden a few dirt bikes, but not for very long. Was never much good at it for whatever reason. I think the main reason a motorized bike is so fun is because the bike is so insanely light, which is something I always struggled with riding dirt bikes and I'd assume it's the same for motorcycles.

For most I think it's just fun, something to tinker with, relatively inexpensive, etc. And it certainly is an economic way to get from point A to point B as long as those two points aren't too far apart.

I think 35 seems like a good guess for top speed, you could possibly get higher depending on how well your engine runs and how well it is tuned. And, of course, wind direction lol.

One thing I will recommend if you're handy enough to do it: tear down the engine first and clean/check it. Depending on where it comes from / who makes it , these engines tend to have a lot of easily corrected issues. There's a post somewhere I think "for newbies" or some such thing that goes over all the easy things to check. Especially since you're ordering from amazon. Who knows where the motor came from.

Sometimes there's machining chips in them, sometimes the pistons are installed backwards, sometimes bearings are bad right out of the box, and almost always there is casting slag in areas that there shouldn't be. I'd also recommend decking the top of the jug and the head mating surfaces as they're usually not machined from the factory and usually leak out of the box.
 

weefek

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Also with a shift kit you can start off from a dead stop, but with a 36 tooth sprocket and one gear you won't be able to pull it off without really wearing out the clutch.

It's like trying to start in 3rd in a 5 speed. It's possible in theory but not very good for clutch longevity.
 

Sidewinder Jerry

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Also with a shift kit you can start off from a dead stop, but with a 36 tooth sprocket and one gear you won't be able to pull it off without really wearing out the clutch.

It's like trying to start in 3rd in a 5 speed. It's possible in theory but not very good for clutch longevity.
I've helped several people build shifters. My shifter's lowest reduction is 66.79:1. Unless you're going down hill I'd never recommend starting from a dead stop without pedal assisting. My centrifugal clutch is 12 years old with over 4500 hours of use on it.
 

Barnabyfoxx

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I'd say between 30-35 mph after it's broken in would be a good prediction. I've had 3 of the 66cc engines and all would easily hit 30 mph on the flats. Every one of these engines is a little different though. They each have a personality lol.

Personally, I wouldn't trust a coaster brake on a mb. They work fine on pedal bikes putting around town, but they don't handle the motors well. You don't have to spend big money on brakes, a decent set of caliper brakes and good pads will serve you well. They'll more than pay for themselves the first time you need to really stop fast.

I'd at least pull the jug and head off, rinse the case out and check the ports in the jug for debris and sharp edges. Definitely deck the mating surfaces for the gaskets too. The spring tensioner that attaches to the motor is a good upgrade if you can't set up the bike without a tensioner. Be ready to spend more time tinkering than riding at first, once everything is settled in and happy these are quite fun contraptions to dart around on.
 

mrelijahgardner

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Thanks for the advice on pulling the head. I watched a few videos about it. I guess I didn't realize the build quality could potentially be so poor. Good thing they are simple engines.

I am looking forward to the light weight zipping around. My smallest Motorcycle weights about 400lbs and my daily rider closer to 800. I'll feel like a kid on a minibike again lol.

Are there any recommended shift kits?

I can see this rabbit hole getting much deeper lol. Its a super cheap way to tinker and have fun. I'll even be able to involve the grandkids.
 

Chainlube

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Thanks for the advice on pulling the head. I watched a few videos about it. I guess I didn't realize the build quality could potentially be so poor. Good thing they are simple engines.

I am looking forward to the light weight zipping around. My smallest Motorcycle weights about 400lbs and my daily rider closer to 800. I'll feel like a kid on a minibike again lol.

Are there any recommended shift kits?

I can see this rabbit hole getting much deeper lol. Its a super cheap way to tinker and have fun. I'll even be able to involve the grandkids.
Check with @Pablo, he might have one left.
 
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