Has anyone used a bigger engine?

john_the_great

john_the_great

New Member
Has anyone done a build with one of these Honda gx100's or some of the bigger displacement four strokes? It looks plausible given this Honda 100 only weighs 23 pounds.

GX100.jpg
 
Hi John, well that engine is oversize, overweight, and low revving.......not to mention not legal as Moped, nor Motorized bicycle anywhere in the country that I am aware of.

So, let me just ask, what would be the advantage of using the GX100? I have not heard that they are sold cheaply either?

It certainly does not look narrow, and if you look at gx50 specs you'll see only .5 hp gain in the larger engine.

Wouldn't this lead us to believe that the gx50 is a "high performance" engine when its own brother is 2X displacement and only .5 hp increase? To be equivelent, the gx100 would need to make 4.2-5.0 hp!

What does everyone else think in this regard?

Mike
 
well, thats true honda's are 'spensive and I found it odd that it only put out 3 hp. It would probably have torque coming out of its ears though.
 
john_the_great said:
well, thats true honda's are 'spensive and I found it odd that it only put out 3 hp. It would probably have torque coming out of its ears though.
Click to expand...

You're right. I have a bike that uses the GX 100 clone. My Titan will out run it, but the Honda clone is great for pulling a trailer up hills. The biggest problem is running out of revs for top speed with reasonable gearing for take off. I can't complain though.....very dependable, and does a good job for me. Also, side by side, it doesn't look mych larger than the 50. I even had a couple of bike cops try it out. They weren't looking for speed, more quiet and tractability. They liked it.
 
Sweet conversion on the b&s from vert to horizontal!

GXH50

GX100

Looks to be a 33% increase from 2.1 HP (GXH 50) to 2.8 HP (GX 100) and continues to climb past 4000 rpms to around 3.2 Hp for a 50% gain and over twice the torque at nearly 4.5 ft-lbs compared to 2 ft-lbs w/ the 50.

Lower rpms give you more drive options too, especially if you are building your own!

The longevity on all of these motors is really good but I would think that the 100 would be less stressed from the loads and be incredibly long lasting.

I say go for it if your up to the challenge! Let me know if I can help and keep us posted if you do build one.
 
5hp from my flat head 148cc not supprised

ive opened up the intake tract

ive shaved off the decompressor on the camshaft

ive removed the governor

ive used a larger carby

stock standard they put out 3 1/2 hp at 3800 rpm and mine rev's much harder than this

thanks love that calculator

Armand.shft.
 
that is the engine i wanted to use on my bike ( project nuchenfuttz ) but they wanted a cool $500 bucks for it , i ended up using a 97cc 4 stroke from a baja dirtbug mini bike .

as for the hp difference between the gx100qa and the gxh50qa the 100 revs to 4000 rpm the 50 revs to 7000 rpm thats were the hp difference comes from .

what i like about the honda gx100qa is the engine dimensions and the fact that the intake and exhaust are on the front and back , and not at some weird angle .

i,m thinking of using the gxh50qa on my next project with belt drive and a torqueaverter .

i,m a 4 stroke diehard , when i do get a new engine i plan to experiment and try to convert my 97cc baja 4 stroke gasoline engine into a 95cc 4stroke diesel engine .

i imagine i will need to use larger head bolts to deal with the 20-1 compression ratio , but thats all part of the fun

my vid of my bike gives a good idea of the sound of a 4 stroke
YouTube - motorized west coast choppers bicycle
 
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Let me know how I can help. I'm running a HF 79cc motor right now and it's awesome. Geared properly you'll get plenty of useable powerband out of it and it has more torque at top end than the Honda/HS so it'll pull faster speeds if you want. Mine is pulling from about 5mph-40mph w/ current gearing. It pulls 40 easilly too, so taller gearing will make it even faster!
 
ShellyBelly WhisperDrive "prototype". Dan and I are developing a kit based around the HF and other Lifan motors. Will also work w/ gx100. Also have another couple of drives in development.

YouTube - ShellyBelly WhisperDrive

xct2
 

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It's very encouraging that you can get 5mph to 40mph. How well does it climb hills with that gearing? I was thinking towards a CVT because of the relatively narrow rpm range of the HF engine. But if it can get by without, that simplifies things.
 
Cool Guys!

Kallsop,

It is by no means a hill climber at this gearing but it is o/a a well rounded set up i.e. pedal a bit to start, and pedal to maintain speed up hills and it's pretty effortless. Ahh, the sound though, is to die for. and it is sooo much smoother a ride.

J the G and everyone,

The truth is, it is an awesome set up as a single speed standard motorbicycle. It is also true that it will be an upgrade if offered w/ CVT. It's in the "visible" future. My personal feeling is that it would be nice too if the "faster" (Honda/HuaSheng) motors had a ShellyBelly all their own! But thats not gonna happen, because it will also serve well as a ShiftyBike/JackShaft transmission for the "slower" motors. And the saga continues! Not a "one size fits all" approach but more a "something for everyone" game plan! We're starting at the most basic and building from there!

We believe that you shouldn't have to pay for what you don't need. So we'll offer many options for you to decide what your requirements and budget are.

Thanks so much everyone for all the positive feedback and the criticism too. It's all very helpful and constructive. Your input goes to great use. Be Well, Evan
 
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