Would like to go really fast!

R

rider

New Member
Hey, i have a regular road bicycle. i think it is 700x25mm. i can cruise at around 20mph on a smooth, flat road. i do not use the top gear. on downhills the most ive ever got was about 45mph and it was dangerous because downhills are always curvy... i didnt have the bike in the top gear so i dont know if i did if i would even be able to pedal it if i wanted to(or the wheel just goes too fast). i feel that on a smooth flat road it would be nice to go 45mph if you're travelling cross country. so i wonder if there are engines that can perform like this??
ive found this site by using google. and so far there seems to be info that >30mph is illegal. i dont care about legality. if a cop stops me and gives me a fine, it's my problem.

also i think that if both electric and chemical engines can go this fast, i would prefer electric because oil smells and all that. but of course it might be a problem to charge an electric engine when going on a long trip as i doubt i can just stop at any restaurant and ask them to charge it?
thanks for any recommendations.
 
Hi Rider,

I like the way you think! HA...As far as bike choice I'm not sure I've seen anybody with a regular road bike yet....mostly Mountain bikes or cruisers....so it's good to see some variety!

As far as getting that speed....depends on how much you want to spend....

Easy Rider has a uses a really nice engine...I think it is a Morini ....

Lots of people here run the center mount Chinese engines....If you go that route and want speed go with the large displacement models (the so callled
80's (really 66/67 or so CC's) and use a small sprocket in the rear or you can go get Pablo's Shifter....depending on terrain, rider weight, altitude etc....you can get to about 40 or so MPH (My Dax 70 with a 36T sprocket can get to 34.4 MPH at 6400 RPM....NOT sustained because the engine RPMs make it sound like it wants to blow....probably can gear higher (smaller sprocket) for more high speed cruise though...

Hope this helps....Please post pics of your creation!

Andrew

PS - Welcome to the forum!
 
45mph is a tall order for the stock 70cc Chinese engines, they just don't have the horsepower.

You may want to consider a scooter. Some of them can go 45 no problem.

Electric is about out of the question for cross country trips because gas stations don't sell battery power.

One option would be to mount a bigger motor like this Lifan 125cc 4-stroke eBay Motors: LIFAN 125CC ENGINE MOTOR HONDA XR50 CRF50 XR 50 1DW/3UP (item 150281871507 end time Aug-18-08 02:25:03 PDT)
on to a homemade pusher cart. It would work by the motor driving the wheel of the cart which would be "towed" by the bike.

Another option is a front mounted engine like this: http://motorbicycling.com/f36/briggs-stratton-bike-2260.html#post21651

As you can see fabrication skills are required most of the higher power options.
 
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45 mph sustained speed on a bicycle is foolish and dangerous. They are not made for that type of use. Buy a motorcycle for that.

The view expressed is the humble "O" of Bikeguy Joe and should not be considered law.

Still, seriously.....
 
Hey thank you guys for the replies! I have built nothing. And I wonder if there is some book i could read to learn some of these technical terms about motors? I wonder if it's possible to keep the original wheel and chain? what's a homemade pusher cart? Are electrical batteries charged by an electric plug from a wall? If i go on a crosscountry trip I would still do much of my own cycling but I would use the motor whenever i needed to get somewhere quickly. Like if i wanted to get to some beach 300miles awya, it would be nice to use battery power for 200miles and then get to the beach before dark. I understand that bicycle wheels dont have as much traction as thicker wheels but it doesnt make it unsafe. World class cyclists go for 2miles at 40mph without any problems. Of course if the road is not perfect you will get flat tires whether you go 20mph or 60mph.
 
i'll put in my 2c,

for the kind of use you describe, buy a for real down hill sport bike. front suspension, rigid rear. many now have hydraulic disk breaks, all have light motorcycle grade forks, rims,hubs and bearings. invest in a sprung seat post.

take your pick of either a frame mount Franco Morini engine (go to the home page and read "EZR's full suspension summer project" for more on that engine )or a Staton rack mount with a GP460 engine.

either of these will give you 45mph sustainable true cruise ability depending on gearing choices.

as you suggest, the consequences are fully yours.

steve
 
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rider said:
And I wonder if there is some book i could read to learn some of these technical terms about motors?

Yes, read all you can right here on motorbicycling.com

I wonder if it's possible to keep the original wheel and chain?
Yes.

what's a homemade pusher cart?
It's a cart with a motor or engine that pushed the bike it hooked to...crazy and not the most stable set up, IMHO.

Are electrical batteries charged by an electric plug from a wall?
Yes, with a battery charger.

Like if i wanted to get to some beach 300miles awya, it would be nice to use battery power for 200miles and then get to the beach before dark.
20 miles? Yes. 200? No way.

I understand that bicycle wheels dont have as much traction as thicker wheels but it doesnt make it unsafe.
You are correct sir!
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.....................................................................................................
 
I would just go with an 80cc Chinese kit from ebay, tuned and with a fair amount of modifications you can probably reach 45mph but not for a sustained time, and besides, your bike probably won't hold up to a sustained speed of 45mph. 30 mph cruising is more than adequate if you ask me. Good luck with build!
 
I'm going to chime in here and agree with BikeGuy Joe. Bicycles are not designed for the kind of use that 'Rider' is wanting. Especially the Chinese in-frame engines and kits. Yes, I know there are people who can build a motorized bicycle that can do 40 or 45mph and that will run all day but you have to listen to what 'Rider said; He freely admits he's not a mechanic or a fabricator. The bike he invisions would take a lot of skill and experience to build. My suggestion: Buy a motorcycle or scooter and be able to afford to pay a professional to maintain it.
Tom
 
Just my 2 cents

After many years of using a happytime engine on a motorized bicycle.

I agree with DetonatorTuningSolutions!!!!!!!!!!!!!!!!!!!!!

I recently re built my happytime Talk about go slow.
My 26 inch happytime goes as well as It can manage.
1/4 the speed of my 24 inch full suspension test bed bicycle.
I tried a maroni air cooled engine .
Nice speed too expensive to repair 4 me .

A gp 460 is nice and CHEAP .
I AM A FAN OF DETONATOR's SOLUTIONS.
 
I had great success with a pusher trailer that went 35 mph easily with a 3.5 hp Briggs & Stratton. 45 would be easily attained with 4-5 hp and I wouldn't hesitate a bit to go that speed on smooth pavement. A correctly designed pusher would work great on a fully suspended bike with substantial road tires.
 
i just rode to my mother in laws house about 7 miles away at 37-40 mph both ways, with a 36t sprocket. ht engines are as good as you build them
 
foureasy said:
i just rode to my mother in laws house about 7 miles away at 37-40 mph both ways, with a 36t sprocket. ht engines are as good as you build them
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It'd be nice to know what building secrets you use to go that fast. Your engine is spinning at7150rpm-7700rpm!
 
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2door said:
Yes, I know there are people who can build a motorized bicycle that can do 40 or 45mph and that will run all day but you have to listen to what 'Rider said; He freely admits he's not a mechanic or a fabricator. The bike he invisions would take a lot of skill and experience to build. My suggestion: Buy a motorcycle or scooter and be able to afford to pay a professional to maintain it.
Tom
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I agree with all of this.

My twin Mitsubishi engines could run 35mph at wide open throttle for 10 miles on the flats.drn2

My GP460 engine has seen 43mph with leftover throttle on flat ground with no wind.xct2
 
Were talking about what i call a "racer" like whats use to race in like tour de france?
These dudes get up to 110kmh or 68mph down hill and up to 80kmh or 49mph in a sprint to the line.
So 45mph is really not that fast
Im sure the bike in question is not of that quality but the bikes are very light, like pickem up with ya pinky, and run skinny as tyres. Rolling resistance is light and day compared to a mountain bike or cruser so gearing would be alot taller being light would also help.
If we all think were goin up to 40+ mil an hour, im sure 1 of these could maintain it.
 
You must be young as it is the young who imagine invulnerability. Until something serious happens to dissuade you from that notion, somehow bad injuries only happen to other people someplace else. Unless you have a death wish listen to these seasoned riders who tell you this is nonsense wanting to push a bicycle way beyond reason. Sure, it is a thrill to get a China Girl going to 35 briefly and then cruise at a sensible 25 or so, but to think you're going to ride along the highways with traffic for 200 miles on an illegal bicycle at speeds of 45mphand higher is nuts and there's no two ways about it. If you want to die that's your business, but don't put others at risk on the highway as you do it. This may sound harsh, but I'd like to think you'll live a long time with many happy years riding and not to have some friend of yours send in a post telling how you died or ended up paralyzed from crashing your bike. Reconsider. "Pity poor flesh" (ee cummings)

Silverbear (who has both a traumatic brain injury and partial paralysis and knows of what he speaks
 
silverbear said:
You must be young as it is the young who imagine invulnerability. Until something serious happens to dissuade you from that notion, somehow bad injuries only happen to other people someplace else. Unless you have a death wish listen to these seasoned riders who tell you this is nonsense wanting to push a bicycle way beyond reason. Sure, it is a thrill to get a China Girl going to 35 briefly and then cruise at a sensible 25 or so, but to think you're going to ride along the highways with traffic for 200 miles on an illegal bicycle at speeds of 45mphand higher is nuts and there's no two ways about it. If you want to die that's your business, but don't put others at risk on the highway as you do it. This may sound harsh, but I'd like to think you'll live a long time with many happy years riding and not to have some friend of yours send in a post telling how you died or ended up paralyzed from crashing your bike. Reconsider. "Pity poor flesh" (ee cummings)

Silverbear (who has both a traumatic brain injury and partial paralysis and knows of what he speaks
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yes!
i will only get the bike to 40 when the road is smooth, and i have plenty of room. i don't mind a little road rash, but i don't want to get run over. plus, it wears you out going 35-40 cause you have a death grip on the bars, and your body is so tense from imaginig giant potholes and women on cell phones.
but, there is nothing better than the look you get flying past someone who is doing 35 and who has just passed you.
 
foureasy said:
yes!
i will only get the bike to 40 when the road is smooth, and i have plenty of room. i don't mind a little road rash, but i don't want to get run over. plus, it wears you out going 35-40 cause you have a death grip on the bars, and your body is so tense from imaginig giant potholes and women on cell phones.
but, there is nothing better than the look you get flying past someone who is doing 35 and who has just passed you.
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To fly past someone doing 35mph you'd be doing 45mph or more.

IFFFFF you could do 40mph you will slowly edge away from someone doing 35mph.

With no SBF shift kit, what are your speed secrets?

Wake up, fella. You're dreaming.
 
In Victoria B.C. in the spring i saw a guy on a pedal bike on a rural road about 1 ft behind an suv with a wind screen he had to be doing 40 + . YOU could try that--of course super dangerous !
 
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