How fast can your 80cc really go?

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At a friend of a friends house the other day showing off the bike yada yada, my mates friend tells me his motor less sting ray can do 60kmh pedalin down the road and his speedo says it to. with a funny look i gave the front wheel a spin sure enough 32kmh! Awesome!
This Speedo came from my mates 26" bike
" you know you have to measure ya wheel yeh? did you do that" No its got a magnet he tells me! and it works it out for ya. So i say show me 60 off he pedals down the slope pedaling madly, would have hit 25km tops. Ok take this for a ride.... comes back big grin man this thing is cool i must have been doin 100!
Nah bro you nearly broke 60 though. would love to get a look at the figures in the speedo im sure it thinks the wheel is 26"
 
stv1jzgte said:
At a friend of a friends house the other day showing off the bike yada yada, my mates friend tells me his motor less sting ray can do 60kmh pedalin down the road and his speedo says it to. with a funny look i gave the front wheel a spin sure enough 32kmh! Awesome!
This Speedo came from my mates 26" bike
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I can't count the number of times guys I built bikes for came in bragging about how fast they go with speedo still set for KPH instead of MPH. Then there's the ones that didn't bother to change wheel diameter.

I suspect this accounts for many of the absolutely comical speed claims on this forum.
 
I went 50 mph once on a bicycle. It was down a 1 mile hill in southern Ohio. I didn't even have an engine kit at the time.

A woman came around a blind corner on the wrong side of the road and I instinctively swerved to the right....right into a guardrail which destroyed my bike and launched me over a 50 foot embankment. Halfway down the "cliff" I hit a tree square in center of my back, fortunately it was a dead tree and gave way. I landed over 100' feet from the road by the time I stopped tumbling. I was virtually uninjured except for the fact that most of my clothes were removed on the trip down while tumbling through the briars.

Why am I telling this story?
I was extremely lucky and I would NEVER again want to crash a bicycle at that speed.

I have crashed twice on motorcycles at speeds around the 60 mph mark, and neither time was anything I would recommend to anyone, no matter how much safety equipment you wear.

These bikes are for puttin' around on, not trying to go as fast as the blue haired gramma in her Volvo, who can go 50 mph with the touch of a toe.

The bottom line is that I don't think anyone really cares "how fast" you go on a motorized bicycle.

Just my humble "O".
 
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I TOTALLY AGREE!!! I've only ever seen 53.8km/h with an engine, but I've ridden bicycles my entire life. I've crashed a lot, been hit by 8 cars, lost tires off of jumps, I've had quite the journey. lol. However, nothing compares to crashing a bicycle with an engine on it. I've crashed three times with the engine. None were forgiving in any way what so ever. I know these things can go pretty fast, I'm sure it depends on a lot of things, and every kit is different. But in reality, taking these things to the limit is one of the most dangerous things you could do on a bike! If you're bearing breaks, and you're running a #41 chain, you're going over those handlebars at whatever insane speed you're doing. If you live in a high traffic area like me, you'd be a dead man should that happen. I hope the best for all you speed demons out there, I'm a cruiser myself, I've learned my lessons the hard way. Good luck to you all.
 
usflgBeing able to go fast is great. As long as you live though it so you can go fast again tomorrow! I have been hit by cars three times in the last five years. A couple of near misses since I motorized. It is true I have spent this entire summer porting, polishing, jetting, experimenting with expansion chambers, gearing and shift kits in the pursuit of that elusive 50mph mark. I got close enough with the Stiletto and rode it on a street with a 45mph speed limit. I must have been nuts to ride beside people driving 45-50 while talking on their cell phone, putting on make-up, messing with the CD player and truely not paying attention. Cars can stop a lot faster than I can even though I have F@R disc brakes..duh.
I hope all of you speed demons are doing your speed tests on a straight level road away from all the idiots that see you as points if they run you off the road. The last thing I want is a cop pulling me over and telling me I have to put plates and insurance on my bike! Or even more wrecking at 30+ mph. Most of these bikes were not designed to go that fast anyway. I know 37 was to fast for the Jag.
Lets try to stay legal and alive..trk
 
I'll admit, I have a serious problem with speed. I just love it!

I was in construction traffic once this summer and had to get in line with all the other traffic because the shoulder was blocked. I was following an asphalt truck and I had 20 some cars behind me. The speed limit was 45 and he was pulling away from me until we hit a hill and I kept up with him, while everyone behind me stayed at their 45 mph. He was doing 54-55 mph before he had to stop and dump his load. I was right there all along behind him and the long line of cars was way behind. I passed him and just tooled past the guy holding the next line waiting to go and I got all kinds of strange looks, like "Is that a bicycle??"

I love hills!

I always wear a helmet too..................makes me feel safer to fly!

.fly
 
hiker472 said:
I'll admit, I have a serious problem with speed. I just love it!

I was in construction traffic once this summer and had to get in line with all the other traffic because the shoulder was blocked. I was following an asphalt truck and I had 20 some cars behind me. The speed limit was 45 and he was pulling away from me until we hit a hill and I kept up with him, while everyone behind me stayed at their 45 mph. He was doing 54-55 mph before he had to stop and dump his load. I was right there all along behind him and the long line of cars was way behind. I passed him and just tooled past the guy holding the next line waiting to go and I got all kinds of strange looks, like "Is that a bicycle??"

I love hills!

I always wear a helmet too..................makes me feel safer to fly!

.fly
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55mph! could you tell me what size rear sprocket you have or if jack shaft how many teeth on the rear sprocket? thanks!
 
Hiker, Welcome Back. We Have Been Enjoying All The Great Emoticons You Built For Us. Are You Going To Be Around For Awhile Now?? You Should Be Having Frost Warnings Soon!! Ron .cvlt1 . I May Need My Engine Changed To A Titan 4 Stroke !! Lol
 
stv1jzgte said:
55mph! could you tell me what size rear sprocket you have or if jack shaft how many teeth on the rear sprocket? thanks!
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For one thing, I was going down a long hill. Hills are the ONLY way I can get higher speeds.

I have a 34 tooth sprocket on it.

Also worth noting, for being able to achieve higher speeds, is the simple fact that I am lighter than the average (120 lbs soaking wet).

Also, my speedo IS accurate, unless the people who've clocked me in the past have lied.

All I can get out of it is 43 mph MAX on a flat..................but, the bigger the hill, the faster I can go!

Oh, no jack shaft. Just a standard single speed bike with a coaster brake.

EDIT: Speed is easy as long as you have good hills. It doesn't matter if all you can get is 30 mph out of your machine due to whatever, but if you are willing to keep it at full throttle all the way down.......well then, anybody can fly on these things!
 
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xlite said:
One time in band camp... :) :) :) :)

FWIW he didn't actually say it was a Happy Time engine. Coulda been a Ninja powerplant on a Walmart special.
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It's an "80cc" Happy Time on a Greenline cruiser ($149 delivered off EBay).................................the only thing I ever buy from Walmart is oil.

The only upgrades are a high perf. plug wire, an NKG spark plug, new fuel line, and fuel filter.

Hills are the best and only way to get higher speeds!
 
hiker472 said:
It's an "80cc" Happy Time on a Greenline cruiser ($149 delivered off EBay).................................the only thing I ever buy from Walmart is oil.

The only upgrades are a high perf. plug wire, an NKG spark plug, new fuel line, and fuel filter.

Hills are the best and only way to get higher speeds!
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So stock motor 55mph on a 34 tooth sprocket? your spining your happy time to 10,000 rpm i just dont see it.
43mph 8000rpm
 
stv1jzgte said:
So stock motor 55mph on a 34 tooth sprocket? your spining your happy time to 10,000 rpm i just dont see it.
43mph 8000rpm
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The engine doesn't scream any louder, and I'm betting that by going down hill, with the wheels continuing to spin faster, it may just allow the engine more room for power.

I really couldn't tell you the "why" of it, but I can tell you I keep blowing exhaust gaskets, but don't know if that's related or not.

Find a nice hill close to you, get to the top of it, and scream down it........................you'll have your answers!
 
hiker472 said:
The engine doesn't scream any louder, and I'm betting that by going down hill, with the wheels continuing to spin faster, it may just allow the engine more room for power.

I really couldn't tell you the "why" of it, but I can tell you I keep blowing exhaust gaskets, but don't know if that's related or not.

Find a nice hill close to you, get to the top of it, and scream down it........................you'll have your answers!
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Yeh sorry but i still cannot see it, i can go down the steepest hill in the world and will still see the same speed at top rpm goin down hill or not, to get that speed your spinning the motor to 10,000rpm
Regardless you have answered my question that no you cannot do 55mph in gear on flat ground.
Saying you can do 55mph even down hill has nothing to do with the motor after 6or 7 thousand rpm.
 
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