loud noise over 35 mph...

my bike is well into the 40 mph club and doesn't feel particularly sketchy up there. so long as your wheels are true, your tire pressure isn't too low, and your frame is of reasonable quality there's no reason your bike can't be a speed demon and still reasonably safe.

not that I regularly do 40+, but it's there if I need it. sort of like how your car does 120 but you haven't taken it past 80 but once or twice
 
why do we have all of this stuff to modify our engines and forums to help us go faster if the engines already go a speed that is too fast to be considered safe?

Because some people are born with a penchant for putting their life on the line, and sometimes over it.
Fortunately the human mind has enough intelligence to value the concept of self preservation, even though a small percentage of people have abdicated themselves from it.
 
There was an article in a mid-west newspaper that reported a great bike that could reach the speeds being discussed here. Shortly after that the Secretary of State wrote that person featured in the article to let them know at those speeds the bike was considered a motor cycle, not a motorized bike which meant is should be inspected and tagged and that the driver should immediately get a new drivers license with a motorcycle designation. I am sure you can make your machines safe at the speeds discussed, but the states have the ultimate word in this argument.
 
I am sure you can make your machines safe at the speeds discussed, but the states have the ultimate word in this argument.

Where i live, the state lists a motorised bicycle as a motorbike if engine power is greater than 0.27 horsepower and if engine power allows it to travel faster than 12.54 MPH.

These figures are absurdly low, and don't take into account riders who might be on the heavier side, nor does it take into account riders who tow a loaded bicycle trailer, or riders who live in a location with very steep hills.
Unfortunately the police don't give a damn about your situation or your reasons for breaching the regulations, and will happily nail your arse to the wall, if they know what they are looking at, which in my location (legislation) is a heck of a lot of nails through your arse.
 
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I go slo

Hi ya'll, I'm new here.
I am putting a 49cc on an Onyx 29" WWorld bike. They're actually getting scarce. I bought it from Dax, and told him I don't really care to go fast. I intend to use it under 20mph around here. It's illegal but the cops in this town put up with a lot if you're not trying to act like a racer/motorcyclist.

I started riding motorcycles in 1971 and sold my Roadstar a few weeks ago.
I've crashed a few times over the years but never got hospitalized (knock on wood), but the worst case of road rash and bruises I ever got was when I was a kid and crashed all tangled up in a 20" bike. Weak brakes, short wheelbase, high CG, no suspension, bicycles are spooky above 30, for me.

I ordered a 48" sprocket to fix the tall overall gearing the 29" rims would have had, and to help it pull my heavy butt up the railroad overpass between me and my convenient store. I'm just going to be a bicyclist that pedals very little. I bought a bell bike helmet (cops love that) even though I rode m/c's bare headed all those years.
Drug dazed, texting drivers are the threat, the helmet seems like a good idea on a bicycle that moves a little quicker than they expect.
I just wish I could figure out a way to quiet down the engine. Engine noise draws the cop's eye. I called the desk sergeant, he told me to go by bicycle rules and keep off the sidewalks and there shouldn't be a problem.
We'll see.
 
Spencercan

I once rode my 20" 10 speed at 72mph. A friend and I tried to ride from the Bronx to Bear Mtn State Park. Hit a nice long down hill about 5 miles north of the George Washington bridge on Rt 9W north.
I reference that ride because the day before, I toer my bike down to clean and grease the bearings. Crank, head and axels. The preload on the bearings is critical!
I now have a 26" beach criuser that I've swapped the rear wheel for one with a 7 speed hub. That combined with my 49cc 2 stroke and a jackshaft kit maxes me out @28mph on flat ground. If I find a nice downhill, when I hit 32mph I hear and feel the same vibration you spoke of.
My rear axcel was too tight.
$469 to have the wheel built and they just about crushed the bearings =-O :O
I've since cleaned the bearing cups, replaced the bearings and properly snugged the axcel (not crushed the bearings).
No more vibration @54mph ;-)

You'll want to at the least, pull the wheel you're getting the vibration from and check that your axcel is properly torqued.
Too loose and you can feel it wiggle in the hub. Too tight and the friction on the bearings (no matter how much or what type of grease you use) can make a wheel feel like its going to explode at speed.

I hope this helps...
 
Spencercan

I once rode my 20" 10 speed at 72mph. A friend and I tried to ride from the Bronx to Bear Mtn State Park. Hit a nice long down hill about 5 miles north of the George Washington bridge on Rt 9W north.
I reference that ride because the day before, I toer my bike down to clean and grease the bearings. Crank, head and axels. The preload on the bearings is critical!
I now have a 26" beach criuser that I've swapped the rear wheel for one with a 7 speed hub. That combined with my 49cc 2 stroke and a jackshaft kit maxes me out @28mph on flat ground. If I find a nice downhill, when I hit 32mph I hear and feel the same vibration you spoke of.
My rear axcel was too tight.
$469 to have the wheel built and they just about crushed the bearings =-O :O
I've since cleaned the bearing cups, replaced the bearings and properly snugged the axcel (not crushed the bearings).
No more vibration @54mph ;-)

You'll want to at the least, pull the wheel you're getting the vibration from and check that your axcel is properly torqued.
Too loose and you can feel it wiggle in the hub. Too tight and the friction on the bearings (no matter how much or what type of grease you use) can make a wheel feel like its going to explode at speed.

I hope this helps...

P.S.

After getting some sleep I thought of a few more safety tips: some are pretty basic but a refresher course never hurts ;-)

I'm on my second motorized bicycle and I've noticed some differences between the two buils...
1: I'm never building on another inexpensive 'Aluminum' frame or a frame design that requires an over sized spindle. Aluminum has more flex than steel and the oversized spindle created a monkey wrench effect. The torque output of the motor actually twisted the bttombracket housing every time I hit the gas.
I had to sacrifice/reduce my chain ring sizes from 48/44 to 36/24 so the chain from the jackshaft output would clear the clutch cover.I still top out at about 26mph and my hill climbing ability has almost tripled.
2: Please wear a helmet. Many of the people near me that have motorized their bicycles complain about being stopped by the police. I never have. The one difference between me and them is I wear a helmet.

I know this a little off topic but ultimately the topic is safety.
Know your equipment and its limitations. Make sure every thing is properly adjusted. We are trusting our lives to bearings and brakes that are abut the size of your pinky.
 

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It's always a beautiful day in the neighborhood,..I ride a lite bike with a 66cc engine..i do 25-38 mph all the time.
My mom may have dated a Mr. Rogers but she didn't marry one.
 
It's always a beautiful day in the neighborhood,..I ride a lite bike with a 66cc engine..i do 25-38 mph all the time.
My mom may have dated a Mr. Rogers but she didn't marry one.
Beautifully put ;-}

I am no stranger to Mr. Rogers Neighborhood and it's kinda fun when youngsters scratch their head about our old time references ;-}

For the short running around I do I like 35-38MPH, but what I like more is getting up to 25MPH in the blink of an eye so I don't get rear-ended in traffic, after that it is all about being seen buy people in front of you liable to cut you off.

A daylight front strobe is my first defense, but great brakes make the difference between a scary panic stop and the hospital.
 
thanks for your post piecepatrol...i will be sure to take the rear wheel off and check everything out. im sure that must be the problem. if it is...is it dangerous to leave it as is for now? in other words...is it just a harmless noise or is it the symptom of an impending disaster?
i dont like wearing a helmet, but i do use one because i have a rear view mirror attached to it (hate having to turn around).
theoretically id like to put disk brakes on the rear and since the v brakes work so well in the front, leave them as is. usually i see the opposite though...why? is it difficult or expensive to put disk brakes on the rear as opposed to the front? my front brakes already make me stop abruptly enough to seemingly send me flying over the handlebars. i cant see needing more stopping power than that.
this is definitely off topic, but id also like to change gas tanks, as the stock one just looks so silly on my bike. i saw some cylindrical looking stainless ones that mount in the rear that looked cool. any ideas? any recommendations on where to buy performance parts online (or in store)?
 
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