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Post by glennb on Dec 14, 2014 11:13:50 GMT -5
Is it very hard to change out a 50 cc engine, also what do they mean by short and long engines? Thanks for any help
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Post by dmartin95 on Dec 14, 2014 12:30:09 GMT -5
Is it very hard to change out a 50 cc engine, also what do they mean by short and long engines? Thanks for any help Is it hard to swap a 50cc??? That's not a yes/no answer. It depends upon a great number of variables, such as your mechanical skill set, access to tools (and perhaps a shop/garage) and one of the most important factors: How close is the donor to the original..... When it comes to these scooter engines, if you have a 10" wheel, you most likely have a short case, 12~13" most likely a long case... A 16" wheel means you have what is considered an "extra" long case. But this is meant only as a guide because you will always find exceptions to this rule. I will include a pic of the three different engines, but to be sure, get some rough measurements of your crankcase.  Other factors will be things like if the stator/magneto is wired for DC or AC, CDI. My advice is try to find the same motor you have in your existing machine. If your trying to put a GY6 into a Honda spree, you have your work cut out for you.... If it's a chinese scooter and you have a replacement thats very similar to the original, it will be rather simple. What are you working on? What type of Scooter? |
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Post by blue on Dec 14, 2014 20:21:05 GMT -5
I took a long case out og a scoot and put in a short case but I hade to swape the stator and that was all the scoot was a kymco 50 long shaft and I replaced it with a short case wildfir 50.the lasted me about 4 years so I think I did good.
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Post by glennb on Dec 15, 2014 10:33:43 GMT -5
Mine is a chineese scooter qmb139 50cc, it looks like 4-5 mounting bolts fuel lines and electrical plugs and exhaust. I have been a mower mechanic 49 years, this is my first scooter repair
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Post by dmartin95 on Dec 15, 2014 12:50:08 GMT -5
Mine is a chineese scooter qmb139 50cc, it looks like 4-5 mounting bolts fuel lines and electrical plugs and exhaust. I have been a mower mechanic 49 years, this is my first scooter repair What size is your rear tire and do you know if you have AC or DC CDI? I may be able to help you find a good deal on a new engine... |
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Post by geh3333 on Dec 15, 2014 14:38:42 GMT -5
Even with little mechanical skill its pretty easy to swap one out . there is not much to these engines . its really just plug and play as long as your swapping it out with a complete engine . they usually come ready to be bolted on and the electrical parts plugged in and its ready to go . other than an oil change.
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Post by dmartin95 on Dec 16, 2014 0:27:25 GMT -5
Even with little mechanical skill its pretty easy to swap one out . there is not much to these engines . its really just plug and play as long as your swapping it out with a complete engine . they usually come ready to be bolted on and the electrical parts plugged in and its ready to go . other than an oil change. Even though it's plug and play, there's vacuum & fuel lines, wires to keep track of etc etc.... One of the most important things to keep in mind when working on the gy6 engines is that there isn't much meat on these little aluminum blocks and they strip very easy.... Seeing as how torque specs are almost non-existent, you kind of have to learn the feel with how tight you can go..... |
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Post by geh3333 on Dec 16, 2014 4:39:14 GMT -5
Even with little mechanical skill its pretty easy to swap one out . there is not much to these engines . its really just plug and play as long as your swapping it out with a complete engine . they usually come ready to be bolted on and the electrical parts plugged in and its ready to go . other than an oil change. Even though it's plug and play, there's vacuum & fuel lines, wires to keep track of etc etc.... One of the most important things to keep in mind when working on the gy6 engines is that there isn't much meat on these little aluminum blocks and they strip very easy.... Seeing as how torque specs are almost non-existent, you kind of have to learn the feel with how tight you can go..... I agree . if its your first time you need to make sure you either take a pic of the hoses or draw a diagram before you do the swap . when it comes to the electrical components you can do the same however there is usually only one place to plug each component into the harness. |
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Post by glennb on Dec 18, 2014 10:09:27 GMT -5
Thank you all for the info, I need a short case GY6 QMB139, anyone one know where I can get one, ebay has one for $299.00, I don't know if that's a good price or not?
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Post by glennb on Dec 18, 2014 12:23:01 GMT -5
I have a picture of 3 GY6 QMB139 engines, a 3 have a long axle shaft, on line I see the same engine that has a short shaft does that mean a short case engine, I am going to pull the rear wheel off to make sure I don't order the wrong engine, but I am still confused about the picture with 3 engine and all have the long rear axle even the short case
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Post by geh3333 on Dec 18, 2014 19:10:48 GMT -5
The main difference between a short case and a long case is the length of the CVT " left side of the engine case". A short case will have a shorter distance from the back of the engine to the axle. This mean with a long case engine you would be able use a bigger diameter wheel due to the distance from the rear of the engine to the axle will be greater. When it comes to the axle length you will def want to measure it so you do not get the wrong one. However you could always use your old axle if it is in good shape.
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Post by dmartin95 on Dec 18, 2014 20:12:05 GMT -5
I have a picture of 3 GY6 QMB139 engines, a 3 have a long axle shaft, on line I see the same engine that has a short shaft does that mean a short case engine, I am going to pull the rear wheel off to make sure I don't order the wrong engine, but I am still confused about the picture with 3 engine and all have the long rear axle even the short case Hi, the axle shaft has nothing to do with determining if it's short or long case. What determines if it's a long/short is the size of the left crank-case. I will include some pictures to help you determine which engine you have. LONG CASE:   ---------------------------- Short case:   |
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Post by geh3333 on Dec 19, 2014 17:48:44 GMT -5
The main difference between a short case and a long case is the length of the CVT " left side of the engine case". A short case will have a shorter distance from the back of the engine to the axle. This mean with a long case engine you would be able use a bigger diameter wheel due to the distance from the rear of the engine to the axle will be greater. When it comes to the axle length you will def want to measure it so you do not get the wrong one. However you could always use your old axle if it is in good shape. Hopefully you didn't take my statement about the axle wrong. Its good to measure the axle length so you order a short case with the right axle . if you get a short case with a different length axle then u need u will not be able to use that axle and will need to pull it and order a new one , or use your old axle if it is in good shape. |
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