What is top RPM of Hua Sheng?

[Deleted member 8310]

Only have about 5 hours on my HS motor but had to try for top speed
just out of curiosity and it topped out at 34.

My gearbox is 3.2:1
Output gear 12
Rear sprocket 56

According to the ratio calculator 14.93:1 is the final ratio and top
speed anticipated @8000 rpm is 41mph.

But, topping out at 34 caps my rpms at 6600. Really need a tac to
see what is actually happening but had to ask.

 

[Deleted member 8310]

yea it was a stupid question

Even though I asked a stupid question it took me a couple days to find it
on my own (in spare time, didn't slave it for 48 hrs ya know).

The little book that comes with the motor states 8500rpm and Googleing
got me a couple posts stateing over 7000. The site search got me nothing.

Anyway have a tac on the way to see what's really going on.

 

[clay]

i have never seen a stock bike do 34mph. maybe 24mph.

 

[Deleted member 8310]

what's a stock bike

Clay

Please define for me what a stock bike is.

 

[jared8783]

my gxh50 with firebelly's combo does about 35-40 on flat land

with no engine mods and a 44 tooth rear

And I do beleive that the hs is 7000
And the gxh50 is 7800

 

[Mountainman]

way to break that baby in
will be interesting to see how well it holds up for you
thinking that the rings may have already lost a little of slide to the sleve ??

ride the heck out of that THING

 

[Old Bob]

One thing you need to consider when doing these calculations is to use the rolling radius of the loaded tire not the diameter of it, if the load compresses the tire by 1/2" your calculations could be off almost 500 engine revolutions per mile.

Although these engines rev to a certain point, look at the torque curve, its well below peak at these rated top rpm levels. To run the engine at this rpm, you need to reduce the load on the engine,which usually involves gearing down and reduces your ground speed while increasing the engine speed.
If you have a graph with a torque curve for the engine, the rpm you are pulling now on flat level ground will give you an idea of the torque required to maintain that speed. X lbs. ft @ 6600 rpm for example. To use higher rpm with out gearing down you will have to increase the engine torque to at least the level at 6600 rpm. Or reduce rolling resistance, aero drag and mechanical losses.

 

[Irish John]

Only have about 5 hours on my HS motor but had to try for top speed
just out of curiosity and it topped out at 34.

My gearbox is 3.2:1
Output gear 12
Rear sprocket 56

According to the ratio calculator 14.93:1 is the final ratio and top
speed anticipated @8000 rpm is 41mph.

But, topping out at 34 caps my rpms at 6600. Really need a tac to
see what is actually happening but had to ask.

The only way you can get this speed from a HuaSheng is to use a very small rear sprocket. With a 44T I hit 40 mph on the flat but it couldn't climb any hill and a headwind would stop you in your tracks. It isn't possible to get 41 mph from a HS unless you don't mind pushing the bike up hills. Ipso facto.

 

[Irish John]

my gxh50 with firebelly's combo does about 35-40 on flat land

with no engine mods and a 44 tooth rear

And I do beleive that the hs is 7000
And the gxh50 is 7800

The Honda has more power than the HS that's for sure. I doubt a 44T would suit it though unless you live on fairly flat country. It likes the 48T though and sings along nicely at 33 mph and a bit more on a cold night cos it likes the dense air in the carby. Crouched over the tank I was once able to reach 40 mph but the motor wouldn't take that abuse for too long. It's worth balancing the wheels and having the hub bearings really nicely greased and getting the chain & motor position set up perfectly to get the best cruising speed possible. Losing 20 kilos helps as well!

 

[Deleted member 8310]

MountainMan

Ride it like you stole it!


Where I live your either going uphill or downhill. The spot where speed test
done is flat though.

I did climb a short hill perhaps 600' long at 20mph and pedalling all they way.
Very impressive considering that I hit the bottom at about 16mph.

So if wondering why the need for speed there are a couple streets that
require 30mph if you don't want to end up under the tires of a cager. Was
just hoping there was more top end so that when going 30 it wasn't winding
out. Tach arrives on Tues.