36MPH on a 4 Stroke

[Deleted Member 4613]

This is quite good if it's true, but here's a vid of 37mph max
on a 49cc 4 stroke. The explanation has to be in the gearbox ratio,
which is not described by the seller. Any thoughts? There is one
more vid claiming 38mph with this gearbox.

 

[Deleted Member 4613]

I believe this may be the BGF 5:1 gearbox.

 

[Sidewinder Jerry]

Weight, terrain angle, wind direction and possible speed device error. On my 33 cc engine it moved 350 lbs at 50+ mph. Oh did I mention that I live in Tennessee and was going down a mountian.

I've had GPS apps tell me l was going a certain speed while my speedometer/bicycle computer showed l was going 5 mph slower. Most bicycle computers are set for 700c tires. If you have smaller tires and don't recalibrate the computer it'll show a faster speed than what you're actually going.

 

[Deleted Member 4613]

You could be right. I believe this bike was going about 32 tops mph. It's just
an inaccurate measurement.

 

[Will'smotobikes19]

I have seen this vid before it is a mountain bike which could weigh less than a beach cruiser (not all of them) or he is about 160-170lbs. Low 30's seems to be the top speed with a 44 when my crappy speedo was working.

 

[Will'smotobikes19]

I have also heard the 144F can rev higher now but I guess older ones were still rpm limited. Not sure how high the 144F can rev but it has a little more power people say.

 

[Sidewinder Jerry]

I have also heard the 144F can rev higher now but I guess older ones were still rpm limited. Not sure how high the 144F can rev but it has a little more power people say.

You can get a tachometer/hour counter fairly cheap from eBay

 

[mony0_3]

The clutch doesn't last long on the 4 stroke.

 

[Sidewinder Jerry]

The clutch doesn't last long on the 4 stroke.

Mine has held up for 11 years. However I use a shift kit and have a tachometer. Therefore I'm not in ratio that's causing engine strain.

 

[Sidewinder Jerry]

Unless the newer engines are pushing more than 1.6 hp rating of the old ones at 6800 max hp rpm and under 225 lbs 36 mph on 26" wheels would mean a total reduction of 14.6:1. About the lowest one can take only 1.6 hp is 16:1.