Gearbox Ratio

[Deleted Member 4613]

I'm about 75% sold on the Chinese 4 -stroke belt drive, but a I have
one more idea that I think may be better. I may order a friction drive
unit from Staton with a 1.5 inch diameter roller. It will give about the
same top end of 31mph as the Chinese belt drive with a 36 tooth
rear sprocket, but the friction drive doesn't suffer losses caused
by transmissons and vibrating chains. I forgot to mention I have
the Honda GX50, which I consider a muscle machne.

 

[Will'smotobikes19]

Tell that to my ungoverned 53cc that hits 47mph @9000 rpm and takes off like a bat out of hell in first gear. Used to go faster, but a lil too sluggish for me. Think I found the sweet spot.

What shift kit did you have the grubee or is there a sbp version? I'm wondering what it would take to machine a solid steel high lift cam for the huasheng engines.

 

[Chainlube]

What shift kit did you have the grubee or is there a sbp version? I'm wondering what it would take to machine a solid steel high lift cam for the huasheng engines.

First you have to determine how much lift you can use/get. Then pull your cam and have it machined. Re-manufactured cams with high lifts for cars are around a $100 exspect to pay that for the little cam too.

 

[Will'smotobikes19]

Can you weld sintered iron? the rest of it is plastic too so probably have to make one from scratch out of a solid piece of roundstock. Or find a gear with the same tooth pitch and diameter and machine the cam lobe on one side.

 

[CrazyDan]

What shift kit did you have the grubee or is there a sbp version? I'm wondering what it would take to machine a solid steel high lift cam for the huasheng engines.

I got the sick bike parts version, but with custom gearing to be able to pedal to near my top rpms. I have roughly 52:1 gear ratio at my pedals.

 

[Will'smotobikes19]

I just tore my 49cc ebay motor apart hoping to do a tapered crank swap I figured it would still be cheaper to swap the crank and buy a honda fly than buy a new kit and start over. Plus there was only a few hundred miles on the straight shaft motor.

 

[Deleted Member 4613]

So your idea is to go to a tapered shaft and use Grubee's
4G belt drive and clutch. Right? Seems like a lot of work.

 

[Will'smotobikes19]

Still cheaper than buying a new kit like i said have the crankcase split apart and no need to remove the piston. Just bolt the rod onto the new crank. Hardest part is stripping the old gasket maker. I'm also putting a delorto clone on it with a cnc intake. Some other mods in mind too. I'm still debating ball bearing belt drive or double chain gearbox since it's cheaper.

 

[Will'smotobikes19]

My engine is weird though it has a steel rod with a needle bearing on the journal and a metal-lobed cam and it was an ebay motor.

 

[Deleted Member 4613]

You're beyond me. I wonder if the double chain gear box would be too
wide and would need wider cranks. Also, I believe these chain drives
might be 3:1, not sure.