CVT Honda GXH50 + CVT Some questions

[loquin]

I would wait before making major changes.

The belt on the CVT needs to wear some. After 300 km or so, the belt will be more flexible, and you will have a better 'feel' for the bike. You should also make sure that the throttle cable and 'throttle valve' work smoothly, and are not binding. Lubricate the cable. Make sure that it is not being compressed, or led around too acute of an angle.

 

[loquin]

Also, I think you will need to have the system under load, actually pushing you along, (or, on a dynometer,) to be able to determine the speed at which the shift points occur.

 

[alekor]

I think through some hundreds kilometres all system will be earned extra and awakes to go better.

Under loading it is possible to measure basically - to attach a videocamera to a variator and to establish a speedometer on a kind at the chamber. Further to measure during driving key points of work CVT. The truth I can make such measurements not earlier than spring when snow will thaw.

 

[alekor]

I have understood why the motor-bicycle badly went after 15 km/h - at mine Honda GXH50 the automatic system of maintenance of turns (in a photo the lever of this system is led round red) and when I open an aperture of the carburettor a gasoline and air mix turns out too rich - therefore the motor-bicycle badly went.


When I have disconnected this system the engine have developed 7000 rpm on 1/4 open carburettors (it was necessary to open on 80 % earlier).

After alteration of management of the carburettor I wish to test a motor-bicycle. Then I will write about results.

 

[TREEWK]

Alekor, Good! Now You Can Get Some Speeding Tickets! Lol. Do You Have To Wait Until Spring To Ride It On The Roads. Have You Been Able To Ride It On The Road?? That Is Called A "governor", That You Unhooked. They Are Used On All Garden Tools Etc, It Makes The Motor Last Much Longer. Ron

 

[alekor]

Thanks!
I did not go for a drive yet on roads - it is necessary to make a direct adjuster of the carburettor. Tests I will spend in the winter but on sidewalks and small local roads. On highway I will go for a drive only in the spring. As I will test - I will write results.

 

[loquin]

BTW - There is at least one thread in the 4-stroke engines forum about modifying the Honda GXH50 throttle/governer

 

[NoPed]

Alekor,

i love the idea of a cvt on a motorized bike; the price is so much better than the g4 tbelt and the q matic. I will use the honda ghx 50cc as well but have 0 math skills. I can see that with a jackshaft you could do many variations as per your above post but now the cost just went up. i was hoping to go straight from the cvt output straight to my rear but your saying this won't do, correct? I will need hill climbing power and get as much top end speed as possible; too bad we can't have the best of both those worlds.
PLease....is there amazing benefits to using a cvt over the trannys that are out there? what's the advantage and application it's best suited for?

you guys rock
thank you

 

[loquin]

The issue is that the GXH50 engine can wind out to 7800 RPM. The CVT has a 3:1 gearbox (on some older models, there's a 4:1 gearbox) on the output. If you use a 12 tooth sprocket on the 3:1 output, and no freewheel, 'standard' (18:1 total) gear reduction would mean a 72 tooth rear sprocket on the axle, (which is a foot in diameter. ) This would push you along at about 33 MPH top end, with apx. 11 MPH maximum torque speed (5500 RPM with CVT at maximum reduction.)

So, it is just doable.

If you get a staton rear hub and one of his 65 tooth thread-on freewheels (used with his new rear axle mount systems) with the above configuration otherwise, you would have a total reduction of 16.25:1, which would give you a top end of approximately 37 MPH. The max-torque speed would then be about 12 MPH at 5500 RPM, with the CVT at it's maximum reduction.

Of course, Staton's hubs (inc. lacing them to a wheel) add quite a bit more cost than adding a jackshaft, but, they would also allow transferring (a few percent) more power to the rear wheel than inserting a jackshaft, and they are really, really rugged.

I would suggest that you download the power calculator, to see how much power would be needed at the motor, for your weight, on a hill slope that approximates the steepest slope in your area. For a direct drive out from the gearbox, assume 90% efficiency best case, drop that to about 88% if a jackshaft turns out to be needed. As the belt wears, efficiency would drop some, so, you would probably want to actually use about 3-4% less than this.

Once you have an idea as to the maximum speed which you can attain with 2.5HP on "your" hills, you can then multiply that number by 3.5 (calculated from 2.25 CVT belt ratio change, multiplied by the top end RPM/max torque RPM) to get an idea as to your top-end speed, on the flat, with no wind.

Remember - a CVT is NOT a 'magic bullet' - you don't (can't) get ANYTHING for free! It will give you better acceleration/better hill climbing ability, but, to do so, it adds some efficiency losses into the system, and as a result, it lowers the top end-speed that would otherwise be there (at the same gear ratio.)

 

[locutus_1]

will the cvt this guys talking about bolt up to the hueasang motor?