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Post by jaranda on May 7, 2012 0:13:14 GMT -5
I was starting to take apart a erurostyle rx125 so I could inspect and get it running when I made a not so good mistake. First a little about the scooter. I bought this from the original owner with 4k miles on it. He told me that it has spark and that the only thing wrong with it is that I would need to get all the fuel lines and hook everything back together again. I noticed that the plastic engine cover was melted as well as the fan (some of the fins are melted) and asked what happened. He said that as he was attempting to get it running again from being in storage for a while he somehow spilled gas on top of it while the carburetor was off and the gas ignited. After removing the plastic I checked to see if there were other things that were damaged. Things look okay. Now comes the bonehead move. As I was checking things out I decided to check the internal parts so I unbolted the cylinder head to check the cams and then took the camshaft holder. At this point I remembered something about making sure that the piston is in the top dead center position but it was too late. I am not clear as to the markings on the fan but I do remember that you line up the big and small holes on the cam's gear which is attached to the chain. when I tried to move the fan the chain started to come off the cam. I went backwards to keep it where it was but I lost my place. Is there a way for me to fix this without needing a timing light? I should have known better to work on it this late (1am). Hope this is not a hard fix. Thanks. BTW as far as I know this engine is a QJ153QMI-3 and is found on other scooter makes like Keeway :F-act 125,RY8 125,Matrix 125, ARN 125
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Post by warmpudgy on May 7, 2012 0:22:10 GMT -5
youre in luck, its not a hard fix
im not an expert, but i do know that the timing for these scooters is much, much easier than a car
lets do some searching and see if we can give you step by step instructions to set the timing back
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Post by warmpudgy on May 7, 2012 0:23:55 GMT -5
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Post by h3nry on May 7, 2012 0:24:51 GMT -5
I don't know how to explain it fully but basically make sure you don't let the chain come off at the lower end,put the piston tdc and check the mark on the flywheel and if its right then go ahead and line the can sprocket up with the head like its supposed to and it should be set good.
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Post by wile on May 7, 2012 0:44:29 GMT -5
Camshaft Timing & Valve Adjustment FIRST GET THE PISTON TOP DEAD CENTER: 1. To set TDC, remove the spark plug, remove the small rubber plug on top of the flywheel cover, so that you can look down the hole at the fly wheel. 2. Using a 14mm socket turn the fly wheel until you see the letter T on the fly wheel line up with a line that has been cast in the case. 3. Now the piston should be at TDC. SECOND INSTALL THE CAM: 4. The camshaft will have one large hole at 12 o' clock and a small hole or line at 3 o' clock and 9 o' clock. 5. Set the cam in the cradle with the large hole facing outward, and line the two small holes or line with the top of the cylinder head. (see fig 1.) 6. Now tilt the camshaft and slide the cam chain over the gear, remember the engine must be at top dead center (TDC), that means the piston is all the way at the top of the cylinder. 7. Unlock the lock nut on the tappet and using a feeler gauge adjust the valves to .004 Inchs. Lock the lock nut into place, and now you should be good to go. Wile
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Post by maveroketa on May 7, 2012 16:23:14 GMT -5
Hey, just thought I would chime in. I just rebuilt my motor and I turned it over and back several times before putting it back together. Follow the guides they mention here and your scoot will be good to go. Mine is running great. I just put it back at TDC before final assembly.
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Post by jaranda on May 7, 2012 22:11:29 GMT -5
Thanks for all the info. I was thinking that I was going to be stuck here. I have reattached the camshaft and made sure that the big hole is on the top and the small holes are aligned. I will follow the steps. I can't wait to see this thing run. I hope parts are available in case it needs new valves and a piston. Thanks again.
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Post by dyoung1167 on May 8, 2012 12:28:14 GMT -5
you cannot use the timing mark on the flywheel for tdc. that is for spark and fires just prior to tdc. also, the plug fires every revolution, not just the compression stroke. the cams determine the compression stroke. this is good because as long as you are at tdc when you istall them they will be correct. now, the easiest way i have found to insure i was at exactly tdc is to use a chop stick or something similar the won't scratch anything or marr the plug threads. stick it in the hole and apply a little upward pressure (toward the valves)using the plug hole as a pivot to put pressure on the piston. while doing this you rotate the engine very slowly and you will be able to feel the piston going either up or down. if you are pretty close to tdc you can go back and forth until you are exactly between the directional change of the chop stick. you are now at TDC. install cams with holes lined up as said and enjoy.
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Post by jaranda on May 8, 2012 13:06:46 GMT -5
Camshaft Timing & Valve Adjustment FIRST GET THE PISTON TOP DEAD CENTER: 1. To set TDC, remove the spark plug, remove the small rubber plug on top of the flywheel cover, so that you can look down the hole at the fly wheel. 2. Using a 14mm socket turn the fly wheel until you see the letter T on the fly wheel line up with a line that has been cast in the case. 3. Now the piston should be at TDC. SECOND INSTALL THE CAM: 4. The camshaft will have one large hole at 12 o' clock and a small hole or line at 3 o' clock and 9 o' clock. 5. Set the cam in the cradle with the large hole facing outward, and line the two small holes or line with the top of the cylinder head. (see fig 1.) 6. Now tilt the camshaft and slide the cam chain over the gear, remember the engine must be at top dead center (TDC), that means the piston is all the way at the top of the cylinder. 7. Unlock the lock nut on the tappet and using a feeler gauge adjust the valves to .004 Inchs. Lock the lock nut into place, and now you should be good to go. Wile Took the cylinder head and body and saw that the piston has pieces broken off on the bottom. I can also see that the valves have some residue on them and look bad. I tried to search online for parts but I can't figure out if gy6 150cc parts are interchangeable with this one since it is a 125cc. The stamp on the engine says qj153qmi but nothing comes up under a search except for chinese pages. Where can I get a new cylinder head and body with piston? Or should i just get a new motor? Thanks.
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Post by wile on May 8, 2012 13:11:15 GMT -5
Just get a new motor a 157QMJ there are parts all over for the motor and its a good motor. Performance parts are all over the place and easy to get. Just make sure you get the right motor for you scoot. Measure the mounting bolts and make sure it is the right length Either a Short Case or the Long Case and the right type of rear brake you have and wheel. Wile
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Post by maveroketa on May 8, 2012 15:14:48 GMT -5
I just rebuilt mine after finding similar damage. Check out the Project Yellow Baron rebuild thread on here for some of my progress or shoot me a message if you are still having trouble. They aren't hard to rebuild if you can find the parts. Parts were easiest for me to find on the sponsored websites here or at ScooterWorks.com.
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Post by jaranda on May 8, 2012 23:33:12 GMT -5
Just get a new motor a 157QMJ I would like to go the least expensive way for now. After some searching on the threads I found one that mentions the 157qmj's compatability with the one I have which after finding the manual It is listed as a 153QMI-3. I am thinking of getting the body head and head cover that fits the 157QMJ and hopefully that will work. Do you think that 4k miles is too much for this motor?
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Post by Blueboy5000 on May 9, 2012 5:32:21 GMT -5
Considering that you had a broken piston, and melted cooling shroud and fan, all signs point to your engine having massively overheated, rather than spilled gas igniting.
This gives you much more potential damages. The smartest and safest thing to do would be a new 157qmj. I personally would replace the engine.
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Post by ericrockstar on May 9, 2012 7:48:37 GMT -5
I have seen top end rebuild kits on eBay for like $100~$200.
From what I've read, you can get a 58mm kit should boost you to 150cc.
Since you've already got it all tore apart it may be just as easy and cheaper to fix rather than new engine. That's a personal choice.
Also from what I've read, the melted plastic shroud is kind of bad. Probably get a new one of them too. Eventually if needs be. Reason is, it helps with cooling by directing air flow.
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Post by justbuggin on May 9, 2012 8:45:54 GMT -5
ou can get a complete motor for 300$ i would go with a new motor
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Post by jaranda on May 9, 2012 17:09:06 GMT -5
I spoke to the guy that sold it to me and asked him a bunch of questions and even told him about the fan and the possibility of the engine overheating. He said again that the fan and the plastic covering had to do with him spilling gas on it when he and a friend were messing with the carb. I checked the fan and the plastic cover and it seems like the melting happened in one spot. most of the fan is fine with just a few fins affected. Also, I didn't mention that the plastic fuel filter was melted along with the gas lines. All of the other plastics around the motor including the bottom half of the covering are in good shape. I will for now end up getting a cylinder head body and cover for a 157QMJ motor and see how it works. My budget is limited so a new motor is not feasible at the moment. I will post an update when the parts come in and I install them. Thanks again for all the comments. Keep em coming.
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Post by jaranda on May 14, 2012 22:00:30 GMT -5
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Post by ericrockstar on May 15, 2012 5:13:43 GMT -5
That's the ticket!
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Post by jaranda on May 18, 2012 10:01:54 GMT -5
Got the parts in today. This kit comes with an oil pump and gear. I'm wondering if I should install that aswell or keep the one already on there. I will start the project today and spend a couple of hours on it then continue on it through the weekend. I will post my progress.
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Post by dyoung1167 on May 18, 2012 10:31:50 GMT -5
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Post by jaranda on May 18, 2012 20:27:01 GMT -5
Installed the kit but it does not line up with the bolt threads on the crankcase. Also, the chain is a bit loose and the valve cover will not close. I tried to start it and it seemed to want to start but I will try to get a different valve cover. This might work yet.
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