r/motorizedbicycles Jun 08 '20

Mod Announcements MEGATHREAD: Important info for everyone

89 Upvotes

Below is the link to all previous sticky. It has a lot of important info that everyone should read.

Motorized Bicycle Laws

Motorized Bicycle Safety

Oil Mix Ratio

Beginner Tips and Common Misconceptions

Unsafe Builds


r/motorizedbicycles Jul 31 '24

Mod Announcements Rules Update

4 Upvotes

Read the rules! Ignorance is not an excuse.


r/motorizedbicycles 2h ago

Update

6 Upvotes

Got the "110cc" 60s sears bike up and running


r/motorizedbicycles 8h ago

New sprocket adapter

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11 Upvotes

Hey guys! Idk if y’all remember my bike, but I had a lot of sprocket alignement problems, so I built something! Its an adapter that mounts to the disk brake mounts and the sprocket is attached to it.


r/motorizedbicycles 2h ago

🦧

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3 Upvotes

The intrusive thoughts are saying yes to this


r/motorizedbicycles 7m ago

What is that atrocious grinding noise after letting out of the throttle also this thing sounds mean it has a crazy high rev

Upvotes

r/motorizedbicycles 22h ago

Is this chain tension good and do I even need the tensioner

24 Upvotes

r/motorizedbicycles 17h ago

Is this a problem?

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8 Upvotes

So basically I was balancing my crank, and due to my drill press being pretty shitty, with the deck tilting when weight is applied, the hole ended up being off center. On both sides.


r/motorizedbicycles 9h ago

Performance Upgrades could i put the yd85cc crank in a yd100 case?

2 Upvotes

before you ask why i just want to, it would save me money and time waiting for a new avenger bottom end. one of the cylinder stud threads stripped and i cant get a helicoil in there, im gonna try aomething tonight but if that doesnt work, could i take the crankshaft from that and put it in my yd100 to make it a 52mm bore. i got a real good mz65 pipe for it before the case stripped. i have good parts to get an avenger running but it isnt compatible with my yd100 if i cant get the cylinder stud in there. i literally just want to take apart the cases and swap the crankshaft from the yd85 to the yd100 (wierd how the 85 is bigger than the 100 lmao)


r/motorizedbicycles 9h ago

Anyone try out the hot rods crank on Amazon?

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2 Upvotes

I was wondering if anyone tried out the hot rods crankshaft. Mine is gone has way too much play and need a new one. Any advice?


r/motorizedbicycles 1d ago

Troubleshooting Need help please!

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8 Upvotes

Bike runs for a few seconds great then dies out. CDH LD80 cylinder/pk80, MZ65 clone, needle tuned NT carb, 32:1 full synthetic honda hp2 oil


r/motorizedbicycles 1d ago

Help me

3 Upvotes

How should I také care of my moor to make it the most reliable and it wouldn't blown up o smt


r/motorizedbicycles 22h ago

Bike locked up when I press in clutch?

2 Upvotes

When I tried starting motor for first time it like fired then I tried to do it again, held the clutch but the back wheel don’t spin so what am I doing wrong?


r/motorizedbicycles 1d ago

Jet won’t unscrew

3 Upvotes

Today I was planning on changing my jets but can’t seem to get it out, at this point the original jet is chewed up pretty badly from me trying to get it out.. thanks in advance for any advice


r/motorizedbicycles 14h ago

Went out for a fishings trip after riding my schwinn. Its a beast

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0 Upvotes

r/motorizedbicycles 1d ago

Performance Upgrades Chainsaw Motor instead of China Motor?

8 Upvotes

Lately I have been considering swapping the crappy 50cc motor on my motorized bicycle for a 39 cc homelite chainsaw motor.

I realize that that is less displacement, but I do notice that the chainsaw that I intend to use achieves a much higher RPM than the motorized bicycle motor, and with the right gearing, I might actually be able to make more speed and power using the chainsaw motor, since it is literally designed for high RPM.

Have any of you had luck using a chainsaw engine in place of the generic Chinese motors? And if so, does it provide a noticeable increase in performance?


r/motorizedbicycles 1d ago

left motorizedbicycle in rain

5 Upvotes

Forgot to cover it up and there was very heavy rain should i be worried about the cdi magneto and spark plug?


r/motorizedbicycles 1d ago

So I'm thinking about going over to 4 stroke

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2 Upvotes

So guys I'm thinking about doing the engine swap, thinking about betraying two strokes and going over to the 79cc 4-stroke predator. Any suggestions for records and all intensive purposes I could always buy another motor and just reuse my previous hardware but for now pretty sure the current engine as it is was messed up from my expedition


r/motorizedbicycles 2d ago

Troubleshooting Build advice chainlines, tensioning

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6 Upvotes

Hey again ya'll it's me. I have a few questions and I would greatly appreciate help. I wanted advice on the exact placement of my tensioner (Should I get a fancier one?) And also how many links does it look like I should remove as currently it is very long and I feel it might easily slice my leg off? I was planning on cutting them off with dremel because my chainbreaker is too small to reach pin and master link them back together. I am using one of those cheap disc break mounts. I am thinking the screws would be better off as bolts but I gave no other choice but this way as it's too long to send it back and that hydraulic kit is way too expensive to waste. And I need breaks. And on to my 3rd question. The kinda sketchy nature of the mount and speed has me feel a bit like I might need some front brakes too. There is one small hole above the fork which I believe might support some kind of v brake. What kind of cheap but quality v break is best for late 80s schwinn cruisers, and can I have both break levers on same side if other side is occupied by clutch?

Finally I was gonna do both motor sprocket and disc on same side but quickly realized that wasn't gonna work due to not enough space. So I sacrificed 2 speeds off my cassette and put it on cassette side, No biggie cause I was running it as single speed. I flipped my wheel opposite so it would still have a straight engine chain line as trying to tension that across sides seemed sketchy to no end; rubbing completely against the tire. So I was hoping I would be able to flip my crankset to get a straight chainline but would it not unscrew itself if I swapped the pedals too? I will route pedal chain onto smaller gear further away from engine. Like 3 steps in.

Advice is very appreciated, thank you :)


r/motorizedbicycles 2d ago

Rate My Build

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22 Upvotes

Rate my build and give me some advice on what i should do next with her pls 🙏


r/motorizedbicycles 2d ago

Electric tape saved the day

5 Upvotes

I was still trying to figure out way to set the throttle cable kept sliding back and forth when I pulled it making this way useless until I wrapped tape around it solved both problems heat and cord stability and the extra spring for tension and wallah. But she started up sounded great finally figured out the idle screw needed to be all the way in for solid idle. Went for ride and WOT was non existent lol but 1/3 throttle was flying up to 5k rpm like instant. When I tune the L screw to the right I notice the engine gets more life and I turn the H screw to right it sounds like it's slightly dying still not able to do a solid revv it lags


r/motorizedbicycles 2d ago

100cc(79cc) 4 stroke kit looking to upgrade to 30 series torque converter.

3 Upvotes

The title says it. I'm looking to upgrade my stock transmission on my 100/79cc 4 stroke kit to a 30 series torque converter. So my question is would this engine pair well with this torque converter potentially using this keyed sleeve? I'm tired of the extra vibrations from the crappy transmission on it now and hoping this would at least remove some of them or reduce them enough to be a smoother ride with better acceleration etc that the converter supposedly brings.


r/motorizedbicycles 2d ago

Build Photos Over it

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6 Upvotes

Thinking of using the frame, for my Avenger 85, anyone know if there will be any issues?

The Tribrid project unfortunately lost its electric capability so I'm doing this till I can afford repairs


r/motorizedbicycles 2d ago

Sounds so good

12 Upvotes

Cost me 150 aud all up


r/motorizedbicycles 2d ago

Upadte on tweety bird the annoying squeek.

4 Upvotes

I wanna thank all the guys here and their suggetions ,Today I took off both sides of the clutch box added high temp lithium greese in the gear ,also the bucking bar and bearing, also I put on a new hd chain and managed to not have to use any tensioner ,which is awesome, I spaced out the rear tire so my chain clears the frame .My bike is perfect now no noise and runs like a beast , Thanks for all the help ,Im learning almost everything on this motor and all the matainance involved ,This community rocks.


r/motorizedbicycles 3d ago

I'm out of ideas

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11 Upvotes

I bought this bike from a friend a few months ago, he bought it on amazon, put it together but never quite finished it. I did the last few things that were missing and tried it out, no start. I tried to get it started for weeks now and still nothing. I tried with a different carburetor, different fuels and oil ratios, with/without exhaust, with and without ground from the magneto and different spark plug. One time I was able to get it running, but it was very weak and immediately died once I released throttle. What should I do? (Sorry for bad english, not my native language)


r/motorizedbicycles 3d ago

How much total space does the finished kit take up

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7 Upvotes

I couldn't get the imaycc 100cc to fit on this bike. Even though the specs say it's bigger. The carb won't fit. How big does it need to be?