50 mph ?? (Down hill doesn't count)

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shiloh0

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Jun 28, 2008
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im wondering if anyone here has achieved 50 mph or more on a motorized bike. my top speed with a 26in mountain bike is 42 with a 27t sprocket. i want it to go 50. i might even buy a helmet if i can get it there. i m looking at that tuned pipe thinking it might help.
 

Jemma Hawtrey

New Member
Dec 29, 2007
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BUY A HELMET ANYWAY!

flat out speed of 42mph is more than enough to kill you if you came off head first, that or reduce you to a dribbling wreck... either of which arent good.

As to top speed - you could probably eke out another 10% on top speed or maybe more with a pipe - depending on how the pipe is tuned (some are tuned for all top end and others for a mixture). More to the point the frame and wheels arent really designed to take that sort of stress and you may get serious breakages leading to the scenarios indicated above.

another point is that most police forces would have 50 fits if they are sitting in their panda car and someone sails past on a pushbike at 50mph and throw the book at you bigtime..

Jemma xx
 

shiloh0

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Jun 28, 2008
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ya, a helmet is a safe idea. but kinda looks odd to wear on a bicycle going 15 mph while the motorcycle guys go by with no helmets. but this is not the safety section of the forum, it's the "high performance" section. and as far as the "going 42mph gonna kill me"
ya, but life is killing us all anyway but we still keep living it. it's my sincere belief that going faster (to an extent) is safer. this due to speed difference in CARS and bicycles.
a car going 60 not paying attn...and smashing into a 20 mph bike would kill quicker than
going 42 on the bike. my bikes are tuned, the wheels are true, the chains are properly tensioned and they feel solid.
i did see a cool looking helmet that i might get, but its not one of those court jester looking bicycle helmets. i would never wear one of those getups. i like the motorcyle half helmets and the race car helmets. prolly more protection too.
 

comfortableshoes

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Jul 22, 2008
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shiloh0 when you suddenly stop posting we will know why ;)

I wear a real motorcycle half shell DOT approved helmet. I felt silly at first BUT when a motorcycle was cruising down a nearby street slowly was hit and rider very hurt I decided it was less silly than NOT wearing helmet. In MA where I am, I have to wear the helmet but I feel better with a lid on my head...

anyway. 50MPH on a soild bike should be doable in short bursts. I hit 33mph on a rough patch of road and it sucked more than i can tell you, hit the same speed on a smooth stretch and it was an exhilarating feeling... I don't maintain those speeds on my friction drives but can't wait to see what my HT will do.
 

Easy Rider

Santa Cruz Scooter Works
Jan 15, 2008
2,144
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My bike could probably hit 50 if I threw a 44 or 36 tooth sprocket on it but I'm into more low and mid range power.
As for wearing a helmet, I wear one everytime I ride even if its a short test ride up and down the street. I've seen too many head injuries in my life to know how easy it is to crack your head open like a melon and that scares me. Plus, I still have young kids I want to see grow up.
 

Motormac

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Sep 23, 2008
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Don,t be STUPID shilohO, wear a helmet. you may not get lucky and get your deathwish but you may end up a drolling babbling vegetable.. Take a minute and think about it.
 

Saddletramp1200

Custom MB Buiilder
May 7, 2008
1,446
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Houston, Texas
Five years or so back I was going to a friends house. I was riding a Honda Goldwing. Very powerful very heavy motorcycle. The idiots with the hiway dept. desided to dig a hole in the asphalt during the day and then cover it with dirt. No warning at way over the speed limit, in excess of a hundred I hit the 45 yard long hole. If not for my speed I would have died. I was wearing my cop like half helmet. Almost dumped it. The weight of the bike and momentum is all that saved me. Hiways in Texas are bad at best. 4 H4 halogen road lights and an H6 head light was not enough to see it in time. No construction sighs at all. I have never wanted to sue anyone, but I would sue Live Oak county for being Morons. The hiway was fine the day before.
 

Andyinchville1

Manufacturer/Dealer
Dec 26, 2007
502
1
18
Scottsville, VA
Hmmmm....safety issues aside (BUT Please do be safe and dress appropriately), I think you will need a smaller sprocket unless you are running an engine other than a HT capable of high RPM's....

A properly designed tuned pipe would no doubt help....probably a fair amount of power will be needed to overcome aero drag at those high speeds..

If you are hitting a true 42 MPH with the 27T (are you RPM limited or power limited at that point?.....I would guess RPM limited?)....A 19T or maybe 18T
would get you to 50 MPH IF you can get to those same RPM's on the engine
(A slight down hill would also help! A sprocket that small would require use of the disc hub mounting method....a 9 hole mount will not work (bolt circle is too large).

Good Luck on your speed run....Keep us posted!

Andrew

PS - Please be careful!
 

ZnsaneRyder

New Member
Nov 21, 2008
163
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FLORIDA
Try a 6.5HP engine on a trailer

With the right gearing, 50mph isn't that hard. My 196cc 6.5HP trailer with lowered gearing, and modified RPM governor does over 49MPH, and I don't drive that speed for long, because it's extremely crazy and scary to be going that fast on a bike. I usually keep it about 35MPH.

I do find it amazing that some folks are getting over 40MPH+ here with less than 80ccs. I'm using a big engine, which is great, but it's really impressive when guys with tiny motors are going nearly as fast as I do.
 

xPosTech

The Old Master Motorized Bicycle Builder
Oct 23, 2008
209
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SETexas
I really don't see how that beer dolly with no suspension keeps the wheels on the ground at anything over 15 or 20 MPH. What do the tar strips do to it at the speeds you're claiming?

And what does all that jostling around do to your engine? I know it's a Honda clone, but still . . . I guess it uses "splash lubrication"! rotfl

If you're getting a high speed miss it's probably the low oil shutdown in intermittent mode.

Ted
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
237
63
up north now
I'm gonna build one of those beer dollies with a front fork added to make it a trike and ride it like a Roman chariot!
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
237
63
up north now
im wondering if anyone here has achieved 50 mph or more on a motorized bike. my top speed with a 26in mountain bike is 42 with a 27t sprocket. i want it to go 50. i might even buy a helmet if i can get it there. i m looking at that tuned pipe thinking it might help.
I'm saying it will do that and more if you ride it off a bridge...rotfl:crash:
 

ibcnya

New Member
Oct 29, 2008
220
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Concord NC
Its law to wear a helmet when riding a bicycle in Australia...thankfully. I was unlucky enough to spend 11 months in hosptital after a motorcycle crash, while in rehab hospital i saw the people in Ward 1 head injured, i suggest if you have doubts abiout wearing a helmet take a visit to your local Rehabilitation Hospital and have a stroll around the head injured ward i have no doubt you will be stopping on the way home to pick up a helmet...if your lucky you will die when you crash, there is worse .... best of luck with the 50mph pursuit, FYI bicycle wheels maybe true but they aint balanced and bicycle tires aren't designed for those speeds...ever had a front wheel collapse on you ? it aint fun...
<<<<<<<Wears his helmet, full faced at that.(^)
 

ZnsaneRyder

New Member
Nov 21, 2008
163
0
0
FLORIDA
I really don't see how that beer dolly with no suspension keeps the wheels on the ground at anything over 15 or 20 MPH. What do the tar strips do to it at the speeds you're claiming?

And what does all that jostling around do to your engine? I know it's a Honda clone, but still . . . I guess it uses "splash lubrication"! rotfl

If you're getting a high speed miss it's probably the low oil shutdown in intermittent mode.

Ted
It Was a Handtruck, but now it's modded up so much, it's a trailer of it's own. It's almost like the rear-end of a small go-kart that attaches to the rear of the bike.

Works fine on bumps. The engine doesn't shut down on me because I always check my oil level, and doesn't have trouble on hard turns either. If I'm on a REALLY bumpy road, like the dirtroad/pothole-asphault road for 1.5 miles exiting my neighborhood, I pedal most of the way on the huge bumps, but still can go faster than the cars on avg, because I dodge potholes @ 25+mph, while the cars are still going 10-15mph. (the road is that bad)

On the main road or highway shoulder, it's smooth, because of the angle of the trailer, giving it throttle pushes the wheels harder into the pavement for more grip, and I ride a full suspension bike, so small bumps are tolerable. I make sure to avoid bumps as much as possible because the trailer doesn't take the bumps as well as the bike, but if I hit any large bumps, I can let off the throttle for a moment to retain control.

It cruises well at 35mph and does over 40mph easily, and as long as I drive it on smooth road, or operate it at the right speed for the terrain, it's a blast to have on the bike. Also having solid-poly Marathon Flat-Free tires on the trailer takes my worries away about tires, and reduced my bounce on bumps significantly over regular air tires.

I just got a new helmet, and car horn, and now I'm setting up the rest of the electrical on the bike. I'll feel very safe riding it, you'd be amazed how well this thing rides. The trailer follows nicely behind the bike.
 
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