My First Motorbike Project

gera229 said:
That freewheel seems good. I think it would also be more reliable than attaching to the spokes right? Does that one fit the 72T sprocket?

Heaven I wish you could have told me earlier. I spent so much money on the actual motorized bicycle sprockets and bicycle attachment sprocket kit for nothing lol.
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Yes, your four-bolt sprocket SHOULD bolt directly onto the freewheel.


LOL, pocket bike parts are cheap and readily available (quality unknown). The freewheel wobbles, and I've had one fall apart on the rear hub. For $10, it's expected. You could always buy a top-quality WHITE INDUSTRIES freewheel for $85. Out of three $10 freewheels, only the rear-hub freewheel failed. The other two are on my chainring sprockets. They've always wobbled, but they haven't failed yet.

I LOVE to gear my bike EXTREMELY low. That way, even 8th gear is usable, and first gear is great for steep ramps and hills.dance1
 
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How much does the gearing thing cost assuming it's just a thing to attach to the rear wheel.. is that all I would need?
I don't get why you mentioned pocket bike parts in that post since I didn't ask anything about them.
I bought motorized bicycle sprockets to trace the holes on my pocket bike sprocket (Which I will attempt to do) and then drill it in the right spots.
 
gera229 said:
How much does the gearing thing cost assuming it's just a thing to attach to the rear wheel.. is that all I would need?
I don't get why you mentioned pocket bike parts in that post since I didn't ask anything about them.
I bought motorized bicycle sprockets to trace the holes on my pocket bike sprocket (Which I will attempt to do) and then drill it in the right spots.
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Read the link on #94. This hub needs to be assembled onto the bicycle wheel by your local bike shop. Do not tell the bike shop about your motorized bicycle idea, until you find out if they're MB-friendly. If they're friendly, they'll be extremely helpful. If they're not, just tell them it's for a environmental science project. Do NOT mention the word "ENGINE"!

Believe it or not, your entire drivetrain comes from a pocket bike. Engine, 3:1 gearbox, 72t sprocket. You'll need to buy 8mm pocket bike chain. The left-hand freewheel on that custom hub is from a pocket bike. You do NOT have to drill your 72t sprocket. It will bolt right on.dance1
 
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I have the chain from pocketbike parts. I got their largest chain they have, it's 44 inches long and T8F and came with a free master link in a separate little bag. And the chain seemed to be of quality and already lubed.

I know I won't have to drill my sprocket, but the thing is I want to put it on the 9 hole wheel spoke adapter like on a motorized bicycle, so in this case I will drill it to make it fit.

The left-hand free wheel? You talking about the one you linked me to on ebay?

My other quesiton is, if I want to add gears, where do I get the 8mm sprockets to fit the chain? The gear set and a little shifting lever is all I would need to have it working right? And everything else I would have such as gear shifting on the handle bars, etc.
 
You don't need to use any 9-hole adaptor. Just bolt your 72t sprocket onto the freewheel, which is included w/the custom hub on ebay.

Methinks you need to ask less questions and do more research. :)
 
Ok, just another thought came up.

If I use that free wheel with hub, will I be able to attach sprockets on the other side so that I would still be able to pedal?
 
Not to 'throw a wrench in your sprockets' or anything, but doing a v-belt drivetrain with one ratio is cheaper...(when money is an object)
...Carry on...
-Lowracer-
 
But I already got all my parts for chain drive.
Also the rear mounting parts is more expensive, and I would have to get a new clutch that accepts V belt. So in that case it would cost more.
And I would have to weld the large pulley on the wheel(Which is something I wouldn't really want to do) or buy one to attach and spend a lot of money.
 
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Hey lowracer, do you know how to check for spark on the spark plug?

If so, can you try turning the fly wheel as fast as you can with your hand and check if it produces spark and let me know? take spark plug out and ground it by placing it on the engine casing, then pull the pull start and it should show sparks. I am asking to turn the fly wheel by hand or pull the pull very start slowly but consistently (of course if this produces spark, then try to turn it by hand and let me know the results because by hand as fast as you can is probably slower than pull start being turned slowly).

For me it does not make any spark when I turn it by hand as fast as I can, but maybe it's made to be that way, but I wouldn't know unless you have the same results. If you can check your engine and report the results I will appreciate it.
Does the flywheel have to rotate at a certain speed to produce spark?

Also if you have a multi meter let me know so I can tell you how I checked mines with a multi meter.

I want to make sure I don't have a bad CDI. But I wouldn't know unless you have the same results.
 
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gera229 said:
Hey lowracer, do you know how to check for spark on the spark plug?

If so, can you try turning the fly wheel as fast as you can with your hand and check if it produces spark and let me know? take spark plug out and ground it by placing it on the engine casing, then pull the pull start and it should show sparks. I am asking to turn the fly wheel by hand or pull the pull very start slowly but consistently (of course if this produces spark, then try to turn it by hand and let me know the results because by hand as fast as you can is probably slower than pull start being turned slowly).

For me it does not make any spark when I turn it by hand as fast as I can, but maybe it's made to be that way, but I wouldn't know unless you have the same results. If you can check your engine and report the results I will appreciate it.
Does the flywheel have to rotate at a certain speed to produce spark?

Also if you have a multi meter let me know so I can tell you how I checked mines with a multi meter.

I want to make sure I don't have a bad CDI. But I wouldn't know unless you have the same results.
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I'm not lowracer, but here's an idea. Wait until you mount the engine. Then remove the sparkplug, connect it to the plug wire and pull the starter.

If you can't wait until you mount your engine, then secure/bolt it to something stable and do that same test.

May I ask how old you are?
 
I agree...
Gera, you need to buy a bicycle 1st, then get it all hooked up, instead of worrying about everything in advance. Then once you run into issues getting it together, the forum is there to bounce things off of to help you fine tune your machine.
-Lowracer-
 
I'm just curious.

I did the pull start test and saw sparks yes.

But my father said it should spark while turning the flywheel by hand so I wanted to know if you had the same results as me. Maybe not for these engines should it spark by turning it by hand?

My multi meter readings were in Ohms in 3 different spots and readings were consistent:
0.4
1.6
2.0

And I wanted to make sure I had a good Coil by asking you if you had the same results. That way I can be sure those are the correct readings.
 
Gera,
This is a brand new engine you bought from Big Motor Sport?
Why are you fishing for problems with this engine when you haven't even started the thing or purchased a bike to mount it on?
I gotta give your thread a break until you have it mounted & running on a bike. No disrespect...
-Lowracer-
 
I agree w/lowracer. You're wearing us out on stuff you need to research on.:-||

1. There are no specific mounts for your engine to installed midframe on ANY bike. Concentrate on finding a suitable bike RIGHT NOW.

2. Buy the flat 4-stroke universal engine mount that bolts onto the down tube and seat tube. Don't ask me for the link. You find it. Then buy a steel or aluminum plate that you will bolt onto the bottom of the engine. That plate will then bolt onto the universal mount.

3. Take your engine measurements. Make a cardboard template. Take this w/you when you check out bikes, new and used. Take your engine and the universal engine mount w/you to gently trialfit any used bikes, if seller permits. If the engine fits, buy the bike. Try to find one with suspension fork, preferably an aftermarket one.

4. Your other motor mounting option is to have a welder fab a flat mounting plate, which he would weld onto the bike frame.

5. Once you have that done, then I'll help you.

FWIW, do your research and find your own links.
 
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Got my bike today for a good deal. $60 for the bike.
Steel frame.
Couldn't afford a used suspension bike, maybe I can add suspension forks later if I am not satisfied.

I'm going to make my own mount.
I think I'm learning things the hard way, but I guess I will be ok.

I bought this bike because it has a steel frame unlike most expensive aluminum bikes. Of course aluminum would be good, but steel is durable for a high quality frame.
 

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It's new I know. But on pocketbike planet they say that it is not uncommon to get a BAD CDI, Coil, etc while they are new.
 
Here are my multimeter readings in OHMs in the three different spots you can see in the pictures.
If any of you have a multi meter with upside down "U" setting or OHMs, please test your Coil and let me know your results.
 

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Lowracer when you replaced your paper gasket with the copper gaskets, how did you take the sticky paper gasket off? Did you scrap it off with a screw driver or something?
 
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