Gx160 from a water pump, no key way and male threads.

#1
I have a gx160 that came of a 2” trash water pump.
It has a straight shaft but it has male threads at the end and I need to measure the length of it.
Also no key way cut into the shaft.
So what are my options with this engine?
Any way to make a key way notch and tap the shaft?
Or do I have to replace the crank only?
 
#4
Any way to make a key way notch and tap the shaft?
Or do I have to replace the crank only?
If the shaft is 3/4" and has enough length, then it could be machined. Doing that would be just as much work and probably more expense that just installing another crank. It already has to come out for modification, right?
 
#6
If the shaft is 3/4" and has enough length, then it could be machined. Doing that would be just as much work and probably more expense that just installing another crank. It already has to come out for modification, right?
Shelbyclone... I was thinking about that also. I’ve seen prices all over the place for a crank shaft.

It looks like it’s 3/4” per a quick look with a ruler. I didn’t put a mic on it to be sure.
It’s only 2.25” long before it steps down and the threads begin. So it has 2.25” of straight shaft.
No key way cut into it also.
Is 2.25” too short of a shaft?
 
#7
I bought a brigg 8hp (cheap, but ran good) and it was used on a cement mixer, changing the crankshaft was the easiest fix to make it a 1" PTO that I needed. Hardest part for me was to find the right crankshaft.
 
#8
Assuming your intent is to power a bike or kart: Toss the thing in the trash and get a Harbor Freight 212 for a hundred bucks. A decent and correct action would be to freshen an engine as long as the crank is pulled. At that point, you will spend as much or more than you would have spent to get a Harbor Freight engine and modify it to put out twice the power. Honda quality and longevity tipping point is rendered moot given the age of your machine.
 
#10
Well I don’t want to throw any small engine in the trash unless it was under sea water or has a rod through the block.
I understand the point of buying a new 212 vs fixing this one correctly, the 212 is the better deal as in mount it and go.
On this one bike I am not looking for balls to the wall power, just more power than the 79cc engine it already has, but we know how that goes.
What’s the shortest of a shaft you need for clutch to work?
 
#11
Well I don’t want to throw any small engine in the trash unless it was under sea water or has a rod through the block.
I understand the point of buying a new 212 vs fixing this one correctly, the 212 is the better deal as in mount it and go.
On this one bike I am not looking for balls to the wall power, just more power than the 79cc engine it already has, but we know how that goes.
What’s the shortest of a shaft you need for clutch to work?
It's your money. I've rebuilt some pretty far gone engines, including engines (outboard and diesel) that have been submersed in salt water, and small gas engines that were way out of spec. So I am not some kid here who loves Predators. I have never bought a Predator, or any other OHV engine in my life. I restore vintage bikes, and in all cases, rebuild the engines myself.

To do a proper rebuild on this engine, after spending it's life as a trash water pump, you're going to have to go through it. Can you bore it and lap the valves, install new rings, set the valves, and are you willing to pay for those new parts? I know what it costs, and what these guys are spending on Harbor Freight engines. Anything can be rebuilt. That isn't the question.

And yes, I said toss a "Genuine" Honda in the trash. As if there are non-genuine Hondas. LOL.

By the way, if you're using a centrifugal clutch you need 2 1/2" however you can use an insert partially in to the clutch bore and thread it into the 5/16-24 PTO threads and "cheat" a little bit. I wouldn't do it with a lot of power or weight though.
 
#12
Dave, i think I’ll judt put it to the side for now and worry about it later.
The only reason I was thinking this engine as I don’t have a lot of money into it &
If it makes a little less power than a 212, that may be better for the kids when they ride it but enough power to move me on it.
The 79cc is crap.
Probably better to just put a 212 and keep the throttle stop or make one
 
#14
Dave, i think I’ll judt put it to the side for now and worry about it later.
The only reason I was thinking this engine as I don’t have a lot of money into it &
If it makes a little less power than a 212, that may be better for the kids when they ride it but enough power to move me on it.
The 79cc is crap.
Probably better to just put a 212 and keep the throttle stop or make one
Yep. The thing with old engines, is that you get saddled with a case of the "might as wells." Might as well check the ring end gap. Might as well get some new bearings. And all of those things are things you should do when you have an old engine apart.

Sure, you could probably bust it open and replace the crank, and have a running engine. Also, it makes a LOT LESS power than the 212 does, according to the guys who run these. In a recent post, a guy had modified his 160, and it still didn't perform with a 212.

Anyone who knows me, (I've been on this site since 2012) would laugh their butts off to see me championing the use of one of these Chinese engines. I've never owned one, and don't plan to. I do spend a lot more money on flatheads though, so I can go slower.

Just seems obvious to me, taking all things into consideration, and not just money, but longevity, enjoyment of the machine, and future building of the engine.
 
#15
Another way to look at it, it doesn't cost anything to tear apart the Honda and price out the costs of parts besides the crankshaft that needs to be repaired. If nothing else, its a good learning opportunity.
 
#16
Chriser that is true. But that’s for another time to take it apart and see about a crank swap...
Too many other projects going on. I don’t want to take it apart and don’t have time to finish it as it’s not a priority.
 

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