Any news on a NEW Honda GX50???

[MotorBicycleRacing]

. Looks like they used a longer stroke to achieve the 48cc's from the pics. ?
Staton doesn't list a 1.5in roller but he might be able to custom make one for you,

You cant tell bore and stroke by looking at a pic.
GX 35 39 mm x 30 mm
GX 50 43 mm x 33 mm

Staton used to make a 1.5 roller.
A friend used to run a 1.5" roller with a GXH 50 years ago.

 

[Cavity]

Thanks Cavity for the headsup. How does the Honda 50 do on hills with your 1.34in roller?

I only rode 4.5 miles after mounting the GX50 yesterday. Plus, I'm in Florida, so not many hills to tackle....sorry.
But, I think with a 1", or 1.125", it would be Great on hills.
It was quite clear, the acceleration was substantially better than with my GX35.

 

[CrazyDan]

I'm curious now if someone can take an existing gx35 and find a replacement crank for the gx50 to make a 40cc. It almost looks like most parts would be interchangeable.
Edit: checked the honda site and the gx50 parts are available for sale. If parts match up, it might cost around a little over $100 to convert a gx35 into a gx50.

 

[darwin]

You cant tell bore and stroke by looking at a pic.
GX 35 39 mm x 30 mm
GX 50 43 mm x 33 mm

Staton used to make a 1.5 roller.
A friend used to run a 1.5" roller with a GXH 50 years ago.

In the side by side pics the cylinder bore housing looks taller to me than the 35cc. Might just be an optical illusion in the way they sit or [?].

 

[MotorBicycleRacing]

In the side by side pics the cylinder bore housing looks taller to me than the 35cc. Might just be an optical illusion in the way they sit or [?].

yeah the 50 is 3mm longer stroke than the 35 but also 4mm bigger piston.
Everything will be bigger and different on a 50 as it is completely re-engineered by Honda.
No way is Honda going to stroke a 35 to make a 50.

 

[CrazyDan]

yeah the 50 is 3mm longer stroke than the 35 but also 4mm bigger piston.
Everything will be bigger and different on a 50 as it is completely re-engineered by Honda.
No way is Honda going to stroke a 35 to make a 50.

So you think there is absolutely no way a gx50 crank will fit in the gx35? Guess it was wishful thinking on my part, was hoping I could buy a used gx35 and toss the gx50 parts on it... Maybe @Cavity can tear down both engines and give us measurements? I am pretty sure it has a much wider powerband than the gxh50 and hs144f, although it's shunted up to a higher rpm . It should also have less problems with the conrod, crank, rings etc being more oversquare than the gxh50 and clones. An oversquare engine tends to have less low end torque compared to an undersquare engine, but has a much lower piston speed at the same rpms, so way less stress on reciprocating parts. Normally an oversquare engine can obtain higher rpms than an undersquare engine of the same displacement, ignoring valve float. Look at the high revving, extremely oversquare f1 cars, or that crazy 20k rpm 50cc 3 cylinder suzuki (2 stroke) with a mere 28x26.5mm bore/stroke per cylinder, that required 14 gears for it's 500 rpm usable powerband.

 

[Cavity]

Quick update.
Another 15 mile ride on the GX50 today. Love it! Can cruise at @ 25-30mph all day long. GPS says I got it up to 36mph for a short time.
Would never put the GX35 back on....maybe I'll use it for another friction setup on my 20" folding bike though.

 

[MotorBicycleRacing]

36.3 mph is 9100 rpm.
You are the test case for how much you can rev the GX 50.

 

[CrazyDan]

9100 under load...hmmm.

 

[Cavity]

How do you calculate RPM??
What's the equation?

...When the rain stops here in a day or two, I'll change the oil, tweak the roller tension, adjust tire pressure, and go for broke....lol.