Cheap HP pipe?

[motorpsycho]

anyone can make a china 2 stroke do 100 mph with the right gear ratio and tire & wheel size.
it may take FOREVER to get up to 100 mph, but it's not impossible.

 

[bideronit13]

Yea I see your point it probley would with that set up.
I'm going to try it with a stock 4 stroke shift kit and the final drive on the right side of the kit is still 9 tooth and the only gear I was considering to change would be to an 11 tooth. I would probley reach 80 if I did.
I promiss I'll shut it down when I reach 73mph with an 11 tooth.
Other then that I should reach that speed normal which is vary fast of course.

 

[retromike3]

question of wind resistance

the main problem with the debate in question has more to do with wind resistance than any other thing. At about 15 miles an hour over 80% of your drag is just pushing the wind out of the way. Even if you could generate much more horsepower than these little HT units you still wouldn't go that much faster. if you look at the record holders at the Bonneville's salt flats you'll see that some 50cc bike can get going well over a hundred miles an hour. These bikes are fully fared, streamlined recumbents or supine bikes. And unless you're traveling in a place that has no atmosphere (IMHO)you just can't go 75 miles an hour with the 3 hp motor.

My little bike has a 36 tooth rear cog and a SBP tuned pipe I also set my bike up with a more aerodynamic rider position. It's almost the same position I get on my road bike when I'm halfway down the drops. The top speed I was able to get on my little bike was about 39 miles an hour,( okay it was actually 38.5) going on flat ground. I checked this with my iPhone app and I validated that with the speed trap sign that's close to my house.

As I stated before the problem with wind is that it's resistance is logarithmic it doubles and doubles and doubles so to go just a little faster requires an awful lot more energy.

mike

 

[CroMagnum]

flexing the rpm's and that causes more damage then good. So beware.

You need flow master 101 course.
I achieved more as this is my first build as far as adapting racing techniques to this industry.
Its really self explanitory as your achievement of 35mph while I'm at over 70mph.

I ran 50mph stock with no mods. The exhaust pipe was a disaster and as cro magnum was mistaking the pipe was causing my RPM's to flex that could cause a motor disaster.

Heres a little tutorial on performance richirich1113. This is also relavent to the topic.

the smaller the exhaust outlet increases backpressure. This effectively decreases the powerband to create more low-end torque. It also decreases exhaust tone and enriches carburetion.

the larger the increases the exhaust outlet decreases back pressure. This widens the powerband at the top end. It also increases exhaust tone and leans out carburetion.

If you have ever read anything about sick bike parts they which I have choosen. Well they brag of 50mph with little engine stress.
So my simple mods should get me to 70 with just that little stress on the motor.

Yea I see your point it probley would with that set up.
I'm going to try it with a stock 4 stroke shift kit and the final drive on the right side of the kit is still 9 tooth and the only gear I was considering to change would be to an 11 tooth. I would probley reach 80 if I did.
I promiss I'll shut it down when I reach 73mph with an 11 tooth.
Other then that I should reach that speed normal which is vary fast of course.

I'm sorry, but I can't take this any more. Overlooking the horrendous grammar and spelling, the rest of your statements fall into two categories - exaggerations or outright lies, and meaningless nonsensical technobabble.

Statements like flexing the RPMs and your explanation of 2-stroke intake, exhaust, and power band clearly show you have no clue how a 2-cycle engine works. Maybe you learned about all this in your Flow Master 101 class you took in 8th grade. And while every other MBer here is working at getting their stock creations into the 20s, and 30s with mods, you claim you're hitting 50mph stock with no mods, and 80mph with mods?

bideronit13, you are delusional on so many levels. I really hope no one here takes anything you say seriously. I know I don't

 

[keatonx]

Heres a little tutorial on performance richirich1113. This is also relavent to the topic.

the smaller the exhaust outlet increases backpressure. This effectively decreases the powerband to create more low-end torque. It also decreases exhaust tone and enriches carburetion.

the larger the increases the exhaust outlet decreases back pressure. This widens the powerband at the top end. It also increases exhaust tone and leans out carburetion.

You actually want a bit of back pressure... thats what expansion chambers are for.

Anyways, if you tune your ports/exhaust for high rpm, you probably won't have the torque to get above 20, let alone 70.

 

[keatonx]

That's not an issue. I have the gearing fine the way it is. I am only working on mods that will increase top end.
I ran 50mph stock with no mods. The exhaust pipe was a disaster and as cro magnum was mistaking the pipe was causing my RPM's to flex that could cause a motor disaster.
Thats why I am trying to let the OP know about some pipes that people just trust to be OK. When there not even close. You can only prove it by taking it apart.

how do you take apart a pipe?

I don't get your flexing rpm theory. Revolutions per minute can't flex, they can only increase or decrease.

And about the gearing... my 31cc chain deive weed wacker bike hits 60 kmh (37 and a bit in miles). Pretty fast for a weed wacker bike. Gearing...gearing ...gearing... So far it has a 13.5 to 1 ratio on a 16 inch wheel and I'm making it 3 speed so it can get waaay faster. Cuz it has no problem getting to 60.

Continuously modding a motor for speed, but not even touching gearing will soon cause the motor to self desruct... right under your crotch.

 

[richirich1113]

I just put a RedBull can with some holes it on my exhaust and a put a coulple of holes in my air cleaner. WOW! i went from a measily 34mph to 60mph easy! Never flexed my rpm's once. Also ,I promise to slow down if i get to 70 mph. Boy, Fowmaster 101 taught me so much. Everyone should take a lesson from bideronit13..... Oh wait i forgot to laugh.... no I did'nt, LOL LOL

 

[blue 48]

umm yeah my RSE standard 48cc stock carb (basicaly stock)exhaust and 36 tooth rear on 26 inch rims will do 57kmh at full noise.its not much but its good enough for daily riding and our speed limit is only 60kmh , so its enough. take off isnt great but it is smooth and i can comfortably stay on it for hours on end. these things are a good fun CHEAP form of transport. in australia we need to be sensible because theire cracking down HARD on us, sure do what you want but be very careful.one of the members on here has as one of his quotes "never ride faster than your guardian angel can fly" its true!!!!

im finding that making these machines more reliable than excessively fast is a factor that takes up alot of my time well thats my opinion

and after all we are essentialy bolting engines onto BICYCLES

 

[keatonx]

Its really self explanitory as your achievement of 35mph while I'm at over 70mph.

Since you said you didn't touch the gearing, you are basically saying you can make the engine rpms DOUBLE!

Maybe biderondit13 meant 70 KILOMETRES per hour(Such a genious, I am!)

 

[retromike3]

back pressure ?

You actually want a bit of back pressure... thats what expansion chambers are for.

Anyways, if you tune your ports/exhaust for high rpm, you probably won't have the torque to get above 20, let alone 70.

to my limited information its not the "back presser" but the shock wave of the explosion in the combustion chamber that is diverted by the shape of the "tuned pipe" witch first draws more air/fuel into the combustion chamber and then compresses the mixture to almost double the output of a two cycle engine.

mike