Honda gx series

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Steve

Active member
Has anyone changed the crank on a Honda GX engine? I have just bought a GX 390 with a taper shaft as fitted to generators and pressure washers & I want to change it to straight 25mm keyed shaft. Is this a straight swap are all the other internals the same?
 
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Russell

Active member
I tried that but the bigend bearing niped up too tight when the cap was bolted on so that may be something to think about . I ended up getting a local engineer to cut a key way in the original crank but he did moan about it.
The engine now powers a pressure washer
 
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Smiffy

Well-known member
Depending on if it is going in a home brew contraption or something else I think there are off the shelf adapters available and if not should be simple enough for an engineer to fabricate it will just move everything out a bit
 
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Steve

Active member
I tried that but the bigend bearing niped up too tight when the cap was bolted on so that may be something to think about . I ended up getting a local engineer to cut a key way in the original crank but he did moan about it.
The engine now powers a pressure washer
Thanks, so presumably there is a slight difference internally.
 
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Steve

Active member
Depending on if it is going in a home brew contraption or something else I think there are off the shelf adapters available and if not should be simple enough for an engineer to fabricate it will just move everything out a bit
Thanks I will have to look into adapters moving the engine back slightly shouldn't cause any problems.
 
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Russell

Active member
The engine was from a step hill generator so I would have thought genuine. Maybe the crank I bought was non genuine , I don't know really
 
Gunners

Gunners

Well-known member
Having just rebuilt a GX120 engine (which was a success too!) I would say its possible but you will need to do a lot of homework as there are all manor of types of the same engine and (in my case) 3 types of piston for example, depending on what application it is for. Once you've mastered part numbers, they are a simple unit to rebuild though and not expensive.
 
GazCro

GazCro

Well-known member
Having just rebuilt a GX120 engine (which was a success too!) I would say its possible but you will need to do a lot of homework as there are all manor of types of the same engine and (in my case) 3 types of piston for example, depending on what application it is for. Once you've mastered part numbers, they are a simple unit to rebuild though and not expensive.
They cover a vast age range as well and some parts are interchangeable between years but some aren't.
 
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