Help me pick a trany for my 142F

[JerryAssburger]

Unless you're talking specifically about the Grubee 53cc unlimited for $220, I
believe all these 4 strokes are rpm limited. I don't believe the 53cc
is going to perform much better than a 49cc without modding.

Supposedly the 144F was not RPM limited, Grubee or not. Strange Little Beast, we have.

 

[michael whiteman]

Limited or not, I've heard the peak torque is a little over 5000 RPM. Reving it higher will increase your speed, but the better idea would be choose another gear ratio for a top speed at a lower RPM. You wouldn't drive your car at near wide open throttle all day, so why your bike?

 

[Deleted Member 4613]

Right.

 

[JerryAssburger]

Limited or not, I've heard the peak torque is a little over 5000 RPM. Reving it higher will increase your speed, but the better idea would be choose another gear ratio for a top speed at a lower RPM. You wouldn't drive your car at near wide open throttle all day, so why your bike?

In our case(s), there's a few key differences between our bicycles and our daily-driver cars. Our bikes (most of them) lack a transmission that is variable for the prevailing speed or load, so ugly compromises must be made. Usually, a person sets up their bike, cart, etc to hit top speed on level ground at or close to the HP peak rpm. In our case, I believe the little HS engines make peak hp around 6600-6800 rpm. Most user-verified top speeds for a stock HS equipped bike hover around 33 mph-ish... so for best "top-end" we aim for 6700rpm-ish at 33mph-ish. The problem lies on the bottom end... if geared for a decent top-end, the initial acceleration suffers (like being stuck in 3rd gear in your car in downtown traffic.)
Our cars, on the other hand, have the luxury of variable ratios. Low for starting from a stop, intermediate for reaching top speed in a hurry if need be, and a cruising gear, which enables us to maintain a reasonable speed at an economical rpm for the engine.

I'm not sure if the original Honda (GSX50, I think?) motor has any sort of rev-limiter, but the Huashengs of late DO have a rev limiter that pretty much limits them to a top "cruise" rpm of 6800. I'm guessing they did that because their older engines weren't limited and suffered failures from being held wide open at high rpm. I think we're safe, (at least with the HS142F and 144F) if we don't exceed the rpm cut-off. It's probably still possible if someone descends a long hill with the throttle pinned. I don't have the $$$ to find out, though.

 

[Sidewinder Jerry]

In our case(s), there's a few key differences between our bicycles and our daily-driver cars. Our bikes (most of them) lack a transmission that is variable for the prevailing speed or load, so ugly compromises must be made. Usually, a person sets up their bike, cart, etc to hit top speed on level ground at or close to the HP peak rpm. In our case, I believe the little HS engines make peak hp around 6600-6800 rpm. Most user-verified top speeds for a stock HS equipped bike hover around 33 mph-ish... so for best "top-end" we aim for 6700rpm-ish at 33mph-ish. The problem lies on the bottom end... if geared for a decent top-end, the initial acceleration suffers (like being stuck in 3rd gear in your car in downtown traffic.)
Our cars, on the other hand, have the luxury of variable ratios. Low for starting from a stop, intermediate for reaching top speed in a hurry if need be, and a cruising gear, which enables us to maintain a reasonable speed at an economical rpm for the engine.

I'm not sure if the original Honda (GSX50, I think?) motor has any sort of rev-limiter, but the Huashengs of late DO have a rev limiter that pretty much limits them to a top "cruise" rpm of 6800. I'm guessing they did that because their older engines weren't limited and suffered failures from being held wide open at high rpm. I think we're safe, (at least with the HS142F and 144F) if we don't exceed the rpm cut-off. It's probably still possible if someone descends a long hill with the throttle pinned. I don't have the $$$ to find out, though.

This where shift kits come into play. Take me for example: I weigh 230 lbs, my bike weighs 100 lbs, I some times pull a 100 lbs in my trailer my engine only has 1.6 hp. I live in the mountains up to 30% grade hills are a frequent encounter.

There would be no single suitable ratio in my situation. A single ratio would mean hill climbing and level ground speed would be around 8 mph; I could just coast down hills. The only other viable option would be having an engine much larger than the 50cc limit Tennessee has; thus more horse power.

So for me gears are necessary, my reduction range is 66.79:1 to 16.25:1. I may very well have the widest reduction range ever on both forums.

With a shift kit or a single ratio drive I highly recommend a techometer. Engine strain can be just as bad on an engine as over revving.

 

[michael whiteman]

Sounds like Sidewinder Jerry has a pretty unbelievable machine. Necessity is the mother of invention in his case for sure.

 

[Sidewinder Jerry]

Sounds like Sidewinder Jerry has a pretty unbelievable machine. Necessity is the mother of invention in his case for sure.

Before the Sidewinder I had a LandRider that shifted 7 gears automatically.

 

[darwin]

This where shift kits come into play. Take me for example: I weigh 230 lbs, my bike weighs 100 lbs, I some times pull a 100 lbs in my trailer my engine only has 1.6 hp. I live in the mountains up to 30% grade hills are a frequent encounter.

There would be no single suitable ratio in my situation. A single ratio would mean hill climbing and level ground speed would be around 8 mph; I could just coast down hills. The only other viable option would be having an engine much larger than the 50cc limit Tennessee has; thus more horse power.

So for me gears are necessary, my reduction range is 66.79:1 to 16.25:1. I may very well have the widest reduction range ever on both forums.

With a shift kit or a single ratio drive I highly recommend a techometer. Engine strain can be just as bad on an engine as over revving.

More like 66.79000005:1 to 16.259874319:1 You need to be more accurate to make folks believe you, nuff said!

 

[Sidewinder Jerry]

18.75:1 gearbox; 15:44 drive chain; 44:13 large chainring to smallest cog 16.25:1 exactly.

18.75:1 gearbox; 15:44 drive chain; 28:34 smallest chainring to largest rear cog rounded off to nearest 1/100 is 66.79:1

Chainrings 28, 36, 44

Custom built 7 speed freewheel
(34,28,24,21,18,15,13)

Shift pattern

Steep hill climbing and load pulling
1(1-3)
RR 66.79:1 to 47.14:1

Around town general use
2(3-5)
RR 36.67:1 to 27.5:1

Open road use
3(5-7)
RR 22.5:1 to 16.25:1

 

[JerryAssburger]

My Wishlist is a bolt-on CVT for the 4-strokes, based on internals from the 50cc GY6 scooter platform. We can dream, right?