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Discussion Starter · #1 · (Edited)
Unexpectedly acquired this chopper. Did a lot of research and found out this was sold by Pep Boys.



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I got it with a bad electric starter, the 43cc engine that came with it is literally brand new. I decided to go ahead and buy a new engine from a scooter, 49cc with pull start and get rid of all the accesories and most of the wiring harness. There is still plenty of wires under the gas tank, but thats for a later time. I broke in the engine with its stock muffler and after a few tanks installed the dual exhaust. I like it much better with the DE, sounds more peppy and seem to have a more consistent power band.



- This is the motor that came with it, there was a broken bolt which was a pain to remove. Will rebuilt this one and use it as a back up.

I had a lot of issues at the beginning with the chain, it would always fall off. I am used to the tension of atvs which has plenty of slack, it looks like on these models it needs to be considerably tight because once I did that no more problems.

Tried to change the oil of the transmission and nothing came out, even poured a ounce and nothing came out of the bottom. I am not sure, but the transmission tends to whine when letting go of the gas, but when I hit the throttle goes away. Its my first two stroke, they tend to run like a light bulb, either full throttle or none.

There was a lot of vibration and if you look at the pictures I placed a plate on the top bolt near the clutch housing, and since then in conjuntion with the exhaust, no more loose bolts. There is a piece of metal with rubber at the end of it, it was done on purpose to keep an eye on loose bolts, every now and then I would take a peak and see if the plate would collapse, so far so good.

Installed a kill switch hidden underneath the saddle, but later will use the starter switch as the kill switch. Only has rear drum brakes, the front caliper collapse, very bad cheap metal. Have to find a way to install a high quality one. It does stop, but not as fast as I would like. For now the only thing that bothers me is the whining noise coming out of the transmission, no grinding, and only happens a little loud right after letting go off the throttle.
Its fun to ride, turns are a challenge and still I pull one leg out just in case, still practicing on how to maintain the momentum out of turns.
There are little things here and there that needs to be addressed, but for now I am stoked, it runs and has a good top end for such a heavy bike and small engine. The mixture is two cycle oil 25:1 w 87 octane, spark plug comes out brownish.
 

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That's like the one CAM2 had, he put 2 engines in it and modded the frame and rear arms & shocks. Must not turn very good with 2 back wheels.
 

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I've also had a problem with one of my gearboxes making a high pitched whining noise because the teeth just didn't mesh together properly. The internal bearings were intact so I guess it was a manufacturing mistake. If you can disassemble the trans box and spin the gears around and hear any grinding noises or feel any resistance, then that's where the whining noise is coming from. All I did was take another 'parts' transmission and swapped out the internal gears. Problem solved. I thought about carefully filing down each tooth of the gears to mesh more evenly, but never got around to it seeing as there's no point in doing so because the spare trans box isn't being used for anything.

 

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Discussion Starter · #4 ·
Nice, I appreciate the pictures

Its a brand new transmission that came w the engine, bought on ebay. Will get a hold of the seller and let him/her know. Still got the old one intact, might as well replace and take a look at the new one. If you happen to know and if its worth it where to get the trans bearings if need be.

The bike is a challenge to turn close radius, but is not bad at all on wide turns. Got to predict the line and simply bank tge bike left or right. It can considerably tilt before it is too close to scrape the floor, just got to be confident. Its on the to do list to swap to a single rear and higher gearing.
 

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Yeah, I'd see about contacting the seller, they might ship you a new one. The people online are all about reputation, they'll do everything they can to get that 5 star feedback rating... If you tell them the problem and sound sincere then they will usually help. I bought an $85 mtb air shock for my dirtbike moped and one of the valve cores wasn't sealing properly.... I told the seller about the problem, then impatiently went to the bike shop for help and they replaced the valve core for free,, then I bought the special $50 air pump for it, lol. I returned home and saw an email from the ebay seller apologizing for the 'defective' part and that there was another shock already on the way. ;):thumbsup:

The gearbox should be filled about halfway with some regular motor oil, I use 10w-40... There's also a chance that your gearbox could have been packed with grease from the factory, I'd take the cover off and find out. Also check the numbers on the bearings once you have it apart, I remember I was able to source all the bearings and seals on these gearboxes but never ordered them or wrote down what the numbers were... :eek: Check out: http://www.vxb.com/
 

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Discussion Starter · #7 ·
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Dear customer,

You don't need to add any oil, since it will suck from the fuel.

We're not sure what's the whining sounds, and we're not able to see or touch the engine to check, if you think it's a problem, you may bring it to a local bike shop to inspect it.

Thanks
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Thats the response from the Ebay seller in regards to the whining sound in the transmission of a 49cc engine. They are definitely blowing smoke with such answer.

With the compressor blew through the top hole and a paste like grease came out of the bottom crankcase. Poured 30cc of 30w oil with 30cc of automatic transmission oil. Did a quick lap, shut it off, and immediately drained all the oil out. A gunk like mixture of paste and oil like the consistency of toothpaste. Did the same thing again until regular oil came out. The whining is still there, but can tell the engine can pick up much faster and smoother top end.
 

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Oh geez, tell them the product they sold you already does suck. lol. I'd take the cover off that gearbox and wipe out all the grease. Then unload a $3 can of aerosol carb cleaner to remove the rest of the grease from inside the bearings and other small crevices. Once it's clean and dry, try rotating it and see if the noise gets worse with no oil. It could either be a busted radial ball bearing and/or improperly meshing spur gears.
 

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Discussion Starter · #9 · (Edited)

On this video one can compare the two transmissions again, its easy to know which one is bad.


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I think there should be a spacer or a bearing between the clutchbell and casing.


A few more pics.
 

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Sounds like you got a transmission with slag on the internal gears......I had a trans that sounded similar and I disassembled it,,ran a jewelers file between the grooves and softened the teeth a lil on a bench grinder with a fine wire wheel and some metal polish...After that it worked better than ever/.It sux the seller doesnt care.If hes an ebey seller slap him with a negative.......
 

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Discussion Starter · #11 ·
Allright, finally was able to upload more pictures.



The linear ( I guess thats how they are called) gear is from the old engine. The spiral/bevel gear or something like that, the one on the right side, its from the new engine/transmissions. Its all oxidized, the quality of the original engine and transmission is evident. QC on the one I bought from EBAY its cheap.





Left, good, right bad.

 

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The gears are probably worn real bad and don't mesh good, and straight cut gears make a lot of whining noises on race cars.
 

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Rubber sealed bearings and angled cog internals that look like their warped from too much heat...wow;-what a combo................Someone didnt have their propeller cap on that day.......:D

I say youre entitled to a new transmission...............
 

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I've never seen helical gears in one of these gearboxes, nor rubber sealed ball bearings lol. They just don't make em like they used to. :rolleyes: The teeth on helical gears engage gradually as opposed to straight cut spur gears which is actually supposed to produce less noise... I guess this is too much for the Chinese manufacturers to pull off lol. Since you don't have much to loose with that gearbox, I'd take a file and go between each tooth, do like CAM2 said and wire wheel & polish also.
 

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Discussion Starter · #15 ·
I sent the video and pictures to the seller. We closed the deal with a $30.00 partial refund, and I keep the transmission. Will polish it and if anything use it as spare parts.
 

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For bearings I go online to Bearingsandbelts on the www. .com. They have China $1 bearings with 10 ea., to SKF $6 to $8 ea. All you need is the bearing number w/ letters and type it into the search box. My ten Cag China wheel bearings where like $9.
 

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Discussion Starter · #20 ·
You can buy them online, do a search as mini chopper parts.

Honestly, your best bet stay on a lookout on CL on a daily basis. I was amazed how many were circulating around used/ for parts on CL. The other option is to do the one wheel conversion.

Its a chinese quality bike. The ride is rough and the welds are not the best. The front caliper brake cracked on me luckily while dialing and making adjustments. The tires, engine and dual pipe muffler are strong.

Bought recently two Cateyes and am on plans on doing the one tire mod and drum to disc brake conversion. Will let you know and upload pics w results.

You have to put a bracket on how much to spend and if its worth it.
 
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