Mini bike help

[winchman]

Bought a Mini Bike
Bought a Honda GX160 clone the shaft is 20mm Dia

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Needed a chain a Chain kit with clutch is £15 chain on its own is about the same, problem is the clutch is 3/4 not 20mm

Go Kart Centrifugal Clutch&Chain #35 Mini Bike 3/4" Bore 12Tooth Screw Set 6.5HP | eBay

Find many great new & used options and get the best deals for Go Kart Centrifugal Clutch&Chain #35 Mini Bike 3/4" Bore 12Tooth Screw Set 6.5HP at the best online prices at eBay! Free delivery for many products!

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So I am struggling to make it fit as if I bore it out it would only be left with a 1mm wall where the circle fits.
Am I missing something?
The Original bike clutch is 16mm
A 20mm Bore clutch isnt cheap!
So I need to fix this and not spend anything

 

[James1979]

I think you’ve more chance of a positive result if you take the shaft out of the engine and turn it down to suit the cheap clutch.

 

[roofman]

I had a similar problem once trying to fit a motor to a washer pump...solution was to bolt the motor down to a slotted table and run the motor,then get the files out, followed by emery papersurprisingly worked a treat.

 

[a111r]

Ah yes, the thing you're missing is that both will be absolute junk that lasts 5 minutes.
I learned that with GY6 engines.

 

[Kram]

The clutch inner looks like it has plenty to be bored out..?

 

[Parm]

After you and the winch clan amassing years Of stuff for thone round tuit projects and you don’t have a solution?

disgracefull post I’d say

 

[merryman]

I nearly posted, warning about this in your monkey bike thread. No idea why, but a lot of the Chinese knock off engines have 20mm cranks and don't fit anything as standard size for small engines is 19mm/3/4" One odd thing is the clutch you show doesn't seem to be keyed so what stops it turning on the shaft? You may get away with boring it out by 1mm. I had a go at machining Buyang variators to fit 3/4" B & S engine shafts, not much meat left (original shaft was 16mm spline) but they worked.

 

[Gwil]

I had a similar problem once trying to fit a motor to a washer pump...solution was to bolt the motor down to a slotted table and run the motor,then get the files out, followed by emery papersurprisingly worked a treat.

Now that is shade tree engineering!

I once watched my pal Pete stick a large steel billet on the PTO of his tractor, and sculpt it into a conical screw for a log splitter with a 9" grinder. Respect.

The thing was lethal, he used to throw logs at it from a distance while standing behind a 500 gallon diesel drum......

 

[winchman]

After you and the winch clan amassing years Of stuff for thone round tuit projects and you don’t have a solution?

disgracefull post I’d say

Some times my brain farts and just needs a bit of inspiration, looks like it worked as I now have a few ideas

 

[winchman]

The clutch inner looks like it has plenty to be bored out..?

Its the side with the circlip thats the problem, I dont think there is enough room to skim it and fit a clip

 

[winchman]

I nearly posted, warning about this in your monkey bike thread. No idea why, but a lot of the Chinese knock off engines have 20mm cranks and don't fit anything as standard size for small engines is 19mm/3/4" One odd thing is the clutch you show doesn't seem to be keyed so what stops it turning on the shaft? You may get away with boring it out by 1mm. I had a go at machining Buyang variators to fit 3/4" B & S engine shafts, not much meat left (original shaft was 16mm spline) but they worked.

It does have a key way inside

 

[winchman]

I will investigate further over the weekend, just wondering how to hold the tank in the lathe, will root through my boxes of bits

 

[merryman]

It does have a key way inside

That makes things complicated as, apart from reamers, tools tend to jump when they hit the keyway, when boring out, making for a slightly offset bore. Same goes for shafts with keyways.

 

[James1979]

That makes things complicated as, apart from reamers, tools tend to jump when they hit the keyway, when boring out, making for a slightly offset bore. Same goes for shafts with keyways.

It’s easier on a shaft as you can fit a sacrificial key but it is a consideration

 

[winchman]

Thanks for all your input, its got me thinking again
A 19mm (3/4"0 Bore clutch is buttons but as already mentioned a 20mm one is a fortune but all the cheap GX160 clones are 20mm?

 

[merryman]

but all the cheap GX160 clones are 20mm?

No, but the ones you see on eBay etc, always seem to be. Perhaps someone imported a vast number of them without knowing the size everyone uses is 19mm and they are now trying to get rid, note "20mm shaft" is often fairly small print in the ads. Honda do make 20mm shaft models themselves, I think it is an electric motor shaft size, so probably for use where electric or petrol powered versions of a machine, are options.

 

[CompoSimmonite]

Might be worth asking on a Kart forum as I suspect they will have come across the problem many times

 

[Tinbasherdan]

Ive got two Honda 5.5hp engines sat under my bench collecting dust

 

[winchman]

Ive got two Honda 5.5hp engines sat under my bench collecting dust

All depends on which ones and price, what size output shaft?

 

[Tinbasherdan]

I’ll have a look