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Old 11-26-2017, 08:05 AM
zogthegreat zogthegreat is offline
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Default Can this motor be saved?

Hi everyone!

OK, so I scored a couple of motors on www.offerup.com.



The guy selling them wanted $30.00, but took $20.00 for the pair! Nice, I think to myself. One is a Honda GX160, the other is a 6.5 clone.

However.....

(Sigh), Neither motor would start, I check the spark, good, I swap carburetors with a spare that I have for my geny, they still don't start. I run to AutoZone, get a compression gauge and get a reading of 30 psi for the Honda and 55 - 60 psi for the clone. Now, I couldn't find the specs for the stock head compression online, (lot's of info for increasing the the head pressure, nothing on stock), but I felt confidant that these numbers were somewhat low!

I stripped the Honda down and pulled the head and found this:



Now, this is the first time I've played with a small motor, but on a car motor, this would be kinda bad!

The surface rust came right off with a brass brush, and I don't see any pitting on the cylinder, so would honing the cylinder work? If so, should I just replace the rings with stock, or do I need something special?

The head looks like it needs some reworking also:





There is minor pitting on the valves and the intake/exhaust ports, nothing serious, (I've seen much worse on car heads).

On the 6.5 clone, I'm not sure whats going on there. I pulled the head and I found some varnishing on the cylinder wall, but nothing else:





The valves look pretty good and when I used a straight edge, both the head and cylinder are straight:



Maybe a bad head gasket? Although I don't think so, because the varnish doesn't go beyond the head gasket.

LOL, while I was playing with the motor's on my picnic table outside, one of my neighbors walked by and said. "I got a motor like that if you want it".

Turns out that he has a Honda GC160A that used to be part of a power washer! He gave the pump to someone and gives me the motor for free!





This one started right up! zoggy is wearing his happy face!
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Old 11-26-2017, 08:55 AM
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If you use the Honda GC160A on a kart, you'll have to adapt the exhaust. It blows directly on the seat of a kart. Not too hard to do. Also, make sure the crank is long enough for a clutch.
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Old 11-26-2017, 09:36 AM
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To your first question, just hone it and use standard rings. Installed properly, blowby will be minimal. The next issue is piston rock, which doesn't seem to be a big deal with just a few thousandths.
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Old 11-26-2017, 10:03 AM
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Thanks Nosandwich!

BTW, another question. Since I'm going to be cracking open the cases, it would be a good time to remove the low oil switch and the governor. I know that the low oil switch is no problem, but I have read that you should replace the flywheel due to the danger of it essentially disintegrating and sending shrapnel everywhere. Based on my training in the military, "shrapnel everywhere" is bad! Since I'm not currently planning to use the motor for racing, could I remove the governor and just make sure I don't high rev the motor until I have the extra money for a higher quality flywheel or should I leave it in and reopen the case when I upgrade the flywheel?

---------- Post added at 11:03 AM ---------- Previous post was at 10:59 AM ----------

Quote:
Originally Posted by qtband View Post
If you use the Honda GC160A on a kart, you'll have to adapt the exhaust. It blows directly on the seat of a kart. Not too hard to do. Also, make sure the crank is long enough for a clutch.
LOL, I'm currently trying to convince my landlord to let me use it on my mini chopper build. I think the straight up engine would look good on it, (although not as good as a Predator V-Twin!), A lot of the people around here use gas golf carts, and if I can convince him that I can get it to be as quite as a gas golf cart, if not quieter, then a custom exhaust is in the works.
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Old 11-26-2017, 11:04 AM
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No.... if you feel you need to then go ahead....But there has been a fare amount of misinformation on this subject....
Here a number have done torture testing to the effect that if you remove the gov, leave the stock valve springs installed. They will float around 5k limiting your speed and essentially being a gov.
However if you remove the stock spring and go for heavier ones, then the con rod will let go thereabout of 5-6K......Still the danger is the con rod not the flywheel for the lower end speed of rapid inadvertent disassembly....
Of course if your wanting to go faster than 5.5-6K then ya get the billet parts... youll need them... as youll be in the performance territory...
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Old 11-26-2017, 11:59 AM
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Thanks mckutzy!

Another question. When I hone the piston cylinder, should I go coarse and fine hones like when doing a car engine, or just coarse to preserve as much of the cylinder wall as possible?
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Old 11-26-2017, 01:10 PM
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Doesn't really matter, but you're not looking for that smooth a finish , TBH.
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Old 11-26-2017, 01:19 PM
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Thanks Nosandwich!
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Old 11-26-2017, 06:30 PM
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No one has mentioned the compression release built into these engines; to get a more accurate compression reading, you need to turn the engine backwards...
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Old 11-26-2017, 06:41 PM
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Quote:
Originally Posted by OzFab View Post
No one has mentioned the compression release built into these engines; to get a more accurate compression reading, you need to turn the engine backwards...
I was thinking that as I read through.

Beat me to it.

I like doing compression testing by attaching a socket with the same OD as the crankshaft to the crankshaft with a piece of vinyl hose and some hose clamps and spinning it with a socket adapter on a (good beefy) drill.
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Old 11-26-2017, 06:58 PM
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I do compression tests by sticking my finger in the spark plug hole & pulling the rope; if my finger is blown out of the hole, it has sufficient compression...
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Old 11-27-2017, 05:28 AM
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Me too! I like to stick my finger in the spark plug hole ( twin cylinders get a bit tricky) and walk 4 times around the engine while screwing my finger in tighter for a more correct reading on my high compression engines. It's gauged by how far my eyes bulge out of my head while pulling the rope with my free hand why looking in a mirror!
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Old 11-27-2017, 07:08 AM
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Quote:
Originally Posted by KingCobra View Post
Me too! I like to stick my finger in the spark plug hole ( twin cylinders get a bit tricky) and walk 4 times around the engine while screwing my finger in tighter for a more correct reading on my high compression engines. It's gauged by how far my eyes bulge out of my head while pulling the rope with my free hand why looking in a mirror!
(sigh), Yeah, definitely a former Marine!

BTW, "CobraKing" = AH-1?
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Old 11-27-2017, 04:35 PM
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So, I'm at an appointment at the VA today and I start chatting with another elderly vet who also served in the USAF. He notices the cuts and scrapes on my hands and asks how I got them. I explain to him that I'm working on a small motor that I might be putting on a mini chopper. and that I'm too stupid to wear gloves.

He tells me that he had built a go kart for his grandson and when it broke down, was left in his back yard with a motor on it and that I'm welcome to come over after my appointment and take them if I want.

When I get there, I see that the term "go kart" was perhaps generous!



He tells me that it's been sitting in his back yard for about the last ten years! However, the motor doesn't look so bad:



No real rust, although this one is also missing it's carb and the ignition coil might be bad:



I got the impression that he just wanted someone to haul it away for him, so I took it.

Now I have 4 engines, a mini bike frame and something that I have to decided if I want to use as a foundation for a go kart build or recycle.
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Old 11-27-2017, 05:17 PM
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Quote:
Originally Posted by zogthegreat View Post
So, I'm at an appointment at the VA today and I start chatting with another elderly vet who also served in the USAF. He notices the cuts and scrapes on my hands and asks how I got them. I explain to him that I'm working on a small motor that I might be putting on a mini chopper. and that I'm too stupid to wear gloves.

He tells me that he had built a go kart for his grandson and when it broke down, was left in his back yard with a motor on it and that I'm welcome to come over after my appointment and take them if I want.



When I get there, I see that the term "go kart" was perhaps generous!



He tells me that it's been sitting in his back yard for about the last ten years! However, the motor doesn't look so bad:



No real rust, although this one is also missing it's carb and the ignition coil might be bad:



I got the impression that he just wanted someone to haul it away for him, so I took it.

Now I have 4 engines, a mini bike frame and something that I have to decided if I want to use as a foundation for a go kart build or recycle.
And...your point is?
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Old 11-27-2017, 05:34 PM
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Quote:
Originally Posted by Nosandwich View Post
And...your point is?
LOL, I'm coming over from electric motors! They are much smaller and are much easier to pack away for travel. I have limited space in my "house".

I've managed to convince my landlord to let me put a motor on my chopper, (I'll have to ask a moderator to either close or move my thread). If I do do a cart build, that still leaves me two extras, (if the GC160 can be saved, that cylinder really does look nasty).

Question, with electric motors, you can run multiple motors on the same controller and chain. Is it possible to run two gas motors on the same axle? I.e. two different sprockets of the same number of teeth? I realize that working out the throttle would be tricky, but would look cool.

(EDIT) BTW, I guess my point is that I'm going to be rebuilding another engine.
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Old 11-27-2017, 05:40 PM
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My dad when he was younger put 2 engines on a kart of his. Each engine drove one wheel. He said it was fast but getting the throttle linked together and keeping them tuned similar was a real PITA.
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Old 11-28-2017, 06:39 PM
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2014 build-off winner was a twin engine kart... just saying...
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Old 11-28-2017, 08:50 PM
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Meh...stick to two women...(easier to control.)
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Old 11-29-2017, 12:09 AM
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Dont take offense, but personally theyd all go in my aluminum pit bonfire and turned to ingots and id be off to harborfreight. At least I wouldnt throw them away like many would. Just depends also what your time is worth and other, if any, priorities. Of course being young and no money is a factor and learning to work on them is cool also. So, just depends where youre at.

---------- Post added at 12:09 AM ---------- Previous post was at 12:05 AM ----------

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Originally Posted by Whitetrashrocker View Post
My dad when he was younger put 2 engines on a kart of his. Each engine drove one wheel. He said it was fast but getting the throttle linked together and keeping them tuned similar was a real PITA.
I will take that a step further and tell you about my twin mac 101 dart on a live axle. Making matters even more fun was it was direct drive. And we didnt have car starters. Either took a really strong guy to pick it up, run and drop it or we pulled it with a rope to my friends dirt bike. There was no mistaking when it took off lol.

Last edited by Kansaskart; 11-29-2017 at 12:11 AM. Reason: Spelling
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