my 66 managed 46 kph a couple weeks ago,after 1/2 hour ride (still in break in mode)
i had to crack it open on a little downslope past my house,i was cruisin.
this is on gravel,btw.i dont get much pavement driving.
I've built my own Zenoah 30cc lh/rc hybrid with a walbro 257 HP carb/ ada filter and an old crusty ADA s2 pipe and i cruise at 25, 35 is no problem and 40 is possible if i pedal really fast. I run a 14t pinion sprocket and a velocity built HD wheel from gebe.
I like to cruise at 25/26 on either of my bikes, my op with the gt2b grubee 48cc and 44t rear sprocket does 32on flat ground. My crandbrook with the bgf48cc and 41t sprocket does 31, I have ported both and trimmed the piston skirt on the bgf.
I have got 53.7kms per hour on the flat but I have spent a bit of money on the thing:
delorto 16.16 carby
SBP jackshaft kit
SBP Expansion Chamber (Chrome)
Rocksolid reed kit
NGK spark plug
Performance CDI(Not the good one Jaguar makes im waiting on delivery of that)
on a stock 66cc no head mods or barrel mods
I agree, it's not the speed that is the problem as is plainly evident in motorcycle racing, where those guys fall off their bike at 150 mph; sliding to a stop, then pick themselves up and walk back to the pits.
The issue is all about what kind of things you hit along the way. A sharp faced rock sticking 2 inches out of the ground will kill you if falling off your bike at 5 miles an hour and landing on the pointy part with the side of your head.
Having said that, a person tends to wear either no safety gear or next to no safety gear when riding a bicycle, causing shocking levels of skin abrasion when taking a spill, and at 40 miles an hour, it's going to get seriously messy, even at 30 miles an hour it's going to be messy and that's well within the speed capabilities of a non motorized bicycle.
Road conditions limit speed more than anything. Here in New England, roads are often steep, curvy, and full of cracks. Torque is more useful than speed under these conditions. The Cops recently set up a ' Your Speed ' trailer on a straight, smooth road, right near my place too. I made a bunch of runs Highest speed 35 MPH 70cc w. 44 tooth sprocket 25 MPH 50cc Grubee 44 T sprocket.
Given enough straight away, the 50 cc can keep up, but gives up too much torque on hills, compared with the ' big ' motor.
Ive hit a car at 35mph and been hit 6 times by cars at high speeds over 30mph on my racer bike gets mangled but so far im still here, I ride a harley and a drz400 which both go twice s times the speed and ill die if i hit a car on one of them too so is there a difference?
Well guys I found the issue with my motor, why I wasn't getting expected power, the heads on these chinese motors look like they have been milled with an angle grinder! the gasket only seals for about 1-2mm and is not tightened more than finger tight! and leaks like you would not believe. I remedied the problem by hand milling the head (my hand still hurts) and making my own copper gasket, I milled about 1.5mm off the head checked the barrel surface (was fine) then made a copper gasket out of 1.6mm copper sheet (original head gasket is 1.45mm) therefore I have increased compression a little. hard to start first time round but much easier now! I will take it for a speed test soon and tell you if it made a difference.
well got a top speed of 55.5kph which is 1.8kph increase over my first top speed which was 53.7kph which quickly deteriorated to a top speed of 47.6 kph within a week, so I basically got an increase of 7.9 kph by torquing the head properly and machining the head flush, but an actual speed increase of 1.8 kph by upping the compression a little, I know my fuel to air mixture is too much fuel, so a change in size of the main jet to a smaller one will fix that, and then trying to tune the exhaust with out a dyno, not sure how I'm going to do that, and I'm still waiting for Jaguar's CDI to arrive. I'll get to 60 kph somehow haha