How fast can your 80cc really go?
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I've been tuning on the Stiletto today and decided to try a stock muffler rather than the expansion pipe to see if my low to mid-range chug was coming from the wrong header length. Yep. Bike runs awesome! My Buddy was on my bike with the 44t sprocket and was WOT doing 33mph. I was in 2nd gear and passed him like he was standing still! I wonder what it will do in 7th? I was taking it easy because this is a new motor. Time for a speedo. I think this thing is capable of going way to fast. But I should be able to run with traffic around town at low rpm and get unbelievable gas mileage. Want to go fast? Tune your bike for good low and mid-range torque and get a shift kit!
About 40.
Just because you gear up, does not mean you will see an increase in speed. You need horsepower for speed.
This I have proven on the flat road and calculated by a gear ratio calculator. 2nd gear, 4100rpm, 33mph. Accelerated from there like it was on fire. 5th gear, 2250rpm and 24mph. Still accelerated nicely. Have yet to try 7th but I think I have enough horsepower to run in 7th as long as I am not going up to much of an incline. I am not kidding, This thing runs awesome! A little to good to be legal! And way to good for just having a rear disc brake and no front brake. I will be getting a speedo for my little red ride asap. Front disc brakes may require some machine shop work as I cannot seem to locate a 48 spoke disc brake front hub with a 14mm axle to match my 20 x 3.0 front tire. Nothing over 45mph until I have both brakes. And I don't want to be stopped by the law and told I have to get plates and registration because It goes to fast!
I ran into a guy with a motorbicycle at the Long Beach M/C swapmeet last weekend, He had a stock chinese engine with a 44t sprocket. He told me his bike goes 43MPH... I LAUGHED AT HIM! 
If he has a 26" tire he would be winding that motor over 7300 rpm. Possible but not probable in my opinion. It may go that fast but I wonder how long it will last. From the way my motor sounds I think 35 mph is plenty fast for a 44t sprocket.
did you ask him if his speedometer was calibrated correctly? no reason to laugh maybe he got it up to 43mph once before it would not suprise me.I ran into a guy with a motorbicycle at the Long Beach M/C swapmeet last weekend, He had a stock chinese engine with a 44t sprocket. He told me his bike goes 43MPH... I LAUGHED AT HIM!
I've been building these for a few years now & I'm pretty good at tuning them... The only bikes I ever built that could come close to that kinda speed had a sprocket!
also... down hill DOESN'T COUNT!
also... down hill DOESN'T COUNT!
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Agreed. you see, gears are for achieving max torque/power at a specific RPM as combustion engines don't produce a 'flatline' torque. and gears are a way of accellerating and keeping speed/velocity without producing excessive rpm on an engine.
must apologize this post taken so long to type im still drunk
As a former USCF racer, and the owner of a now-36 tooth rear sprocket, I have to take exception to the statement that only horsepower makers a difference, not gears.
Gears really do make quite a difference given the same power moving them, but also the weight of the bike and the rider, and the rolling resistence of the tires, too.
When I switched this summer from the 44 to the 36, I was pleasantly surprised that the accelleration hadn't fallen off that much pushing the bigger gear (smaller rear sprocket)-
I'm close to 200 and the bike is a cruiser, so pretty typical here- now if I start from completely stopped, it helps to give just a small pedal assist at the very first, but the motor takes over quickly, even with the 36- Acceleration from just a few mph up is still quite good.
On the other hand, the top end, and especially the functional cruising speed are much improved, with the motor running the same otherwise- I haven't clocked it and I don;t have a speedo, but I'm guessing I'm topping out at around 40 wide open and maybe a good steady of close to 30 or more- and mostly judging from 14 seasons of road racing.
It's pretty much as fast as I really want to go, especially at 55 years of age (and I'm the real dude at 60 mph behind the truck in "Breaking Away"- please don't try this at home!)
A lot of difference was noticible when I switched from 2.25 cruiser tires (VERY heavy, and knobby) to smoother 1.75 tires- They rolled so much better I started thinking maybe I should just put 700 C wheels and 1 inch wide tires on the cruiser- 700C would fit, but I'd have to get road brakes too- 27" is too large.
Alas, since I've also been building up a Schwinn World Traveler 12 speed with a light frame and 27" wheels, and BMX bars. I'll probably just stay with the cruiser wheels on my hauler- like I said it's about as fast as I want to go otherwise-
The schwinn will probably get flip/flop track wheels, and I can bolt a sprocket right to high flanges and eliminate all kinds of weight-
and a 49cc slant head, also for weight reduction- I might get even a 32 sprocket, or I have a really light 34 if i can get it machined and drilled a bit
Anyway, I'm hoping to keep the whole thing as light as possible- 35-40 lbs tops-
and with narrow 700 C wheels I think it'll roll fast without straining the motor.
If I were buying a new bike to put a motor on, I think I'd start with a track bike with flip/flop wheels and brakes- they are selling for about $230 on e-bay- A really light and minimal frame, and flip/flop wheelsets are over 100 bucks anyway. But this Schwinn only cost me $5, before the custom parts.
Gears make a lot of difference though- miss a shift at the wrong time racing and you can be off the back or out of the sprint.
Gears really do make quite a difference given the same power moving them, but also the weight of the bike and the rider, and the rolling resistence of the tires, too.
When I switched this summer from the 44 to the 36, I was pleasantly surprised that the accelleration hadn't fallen off that much pushing the bigger gear (smaller rear sprocket)-
I'm close to 200 and the bike is a cruiser, so pretty typical here- now if I start from completely stopped, it helps to give just a small pedal assist at the very first, but the motor takes over quickly, even with the 36- Acceleration from just a few mph up is still quite good.
On the other hand, the top end, and especially the functional cruising speed are much improved, with the motor running the same otherwise- I haven't clocked it and I don;t have a speedo, but I'm guessing I'm topping out at around 40 wide open and maybe a good steady of close to 30 or more- and mostly judging from 14 seasons of road racing.
It's pretty much as fast as I really want to go, especially at 55 years of age (and I'm the real dude at 60 mph behind the truck in "Breaking Away"- please don't try this at home!)
A lot of difference was noticible when I switched from 2.25 cruiser tires (VERY heavy, and knobby) to smoother 1.75 tires- They rolled so much better I started thinking maybe I should just put 700 C wheels and 1 inch wide tires on the cruiser- 700C would fit, but I'd have to get road brakes too- 27" is too large.
Alas, since I've also been building up a Schwinn World Traveler 12 speed with a light frame and 27" wheels, and BMX bars. I'll probably just stay with the cruiser wheels on my hauler- like I said it's about as fast as I want to go otherwise-
The schwinn will probably get flip/flop track wheels, and I can bolt a sprocket right to high flanges and eliminate all kinds of weight-
and a 49cc slant head, also for weight reduction- I might get even a 32 sprocket, or I have a really light 34 if i can get it machined and drilled a bit
Anyway, I'm hoping to keep the whole thing as light as possible- 35-40 lbs tops-
and with narrow 700 C wheels I think it'll roll fast without straining the motor.
If I were buying a new bike to put a motor on, I think I'd start with a track bike with flip/flop wheels and brakes- they are selling for about $230 on e-bay- A really light and minimal frame, and flip/flop wheelsets are over 100 bucks anyway. But this Schwinn only cost me $5, before the custom parts.
Gears make a lot of difference though- miss a shift at the wrong time racing and you can be off the back or out of the sprint.
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Here's the cruiser, with the newer tires and new suspension fork- dual brake lever added since-
I also just added pipe insulation foam style in the motor mounts to cut vibration, and between that, the new tires and the bigger gear for less rev, vibration is no longer much of a problem
and here's the Schwinn I finished building and have the derailleurs back on and have been riding
I also just added pipe insulation foam style in the motor mounts to cut vibration, and between that, the new tires and the bigger gear for less rev, vibration is no longer much of a problem
and here's the Schwinn I finished building and have the derailleurs back on and have been riding
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Kat... I think what Joe was saying is, the smaller sprokets DO WORK up to a certain point... 36T is a really good sprocket for these bikes! but there are some people who've tried 27T & found that the engine just didn't have the grunt to push the bike up to 50 MPH with that gear...
Also... KEWL BIKES!! I like the BMX parts on them! Can't wait to see the Schwinn finished.
Also... KEWL BIKES!! I like the BMX parts on them! Can't wait to see the Schwinn finished.
its simple change the sprocket and remove a few links from the chain. i have a 36t on one of my bikes i gotta say its a bit smoother and faster top end but i lost alot of bottom end if i stop on a incline and try to take off its like plaaaoouughhh cough lol
im goin back to a 44t i miss the little grunt that it had before.
I just installed a SD Stinger on a 26" Mountain Bike. With my GPS Cell Phone and using TrackR (trackr! - The GPS track location based system for social networking on your mobile phone) after the break-in period, I clocked 31 MPH on level ground with a 35 MPH Max . I weigh in at over 275. That's a lot for such a small engine to push around. The 35 MPH was with peddle assist in high gear.
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