Anyone else had this problem

dougsr.874

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Several months ago, as a complete novice, I ordered a so called 80cc engine from a place called BiketoMoped.com...after several days of cussing and wondering if I was gonna go mad, I got the engine installed and got it started...I immediately noticed fuel mixture leaking from between the engine case halves underneath the muffler....this problem became increasely worse and the vendor sent me another engine and I paid the freight...the second engine would not start at all...I eventully found that the crankshaft seal behind the coils was leaking so badly that the engine simply would not run...Since then I have found this forum and I have also SEARCHED IN VAIN for an instruction manual showing how to disassemble these engines...So now I have two worthless pieces of junk...I am somewhat mechanically inclined but I need pictures and guidance.....Any comments would be appreciated....
 
Doug Sr - Wow that is a shame. I hope you keep trying and get one running. If you were close I would give you a hand. This engine is very simple you almost don't need a manual. I will look at this outfit and see what they are selling. I think the one that has the seal pushed out might be the easy one to get running. With your kits did you get a puller in the kit, it is a device that has threads at both ends and a threaded bolt in the middle? It is to take the drive gear off, the sprocket, and the large hub off the secondary shaft. There is a chance that all you will have to do is press the seal back in. You can do this with a deep socket, just tap it in till it is just bellow the surface. The mag rotor will come off easy, just make sure you install it in the same orientation, I mark "outside" before I take it off. Keep us posted. Have fun, Dave

PS: I think there is a photo tear down on the forum somewhere.
 
I'm guessing this is what you meant to say where you bought the kit?

http://biketomopedkit.com/

Bummer, looks like they charge top dollar. And no recourse with them as to help getting one of the two running?

The good news is you won't have to search anywhere else but the archives here to do a teardown and rebuild if you need to, it's all here. And hey, now you got a parts engine.
 
Thanks for the replies...like I said I WAS a novice in this...a friend found an ad in a booklet in Chicago...I should have researched more before I bought....QUESTION...To split the engine halves what has to be removed....I assume the drive toothed sprocket and of course the coils....anything else??????????????The breakdown I found on here shows the engine split apart but NOT how its done.....Doug
 
You can split the cases from any side but you have to get the ends off the shafts to do it. If you get the sprocket off you can use that side. There are screws under the large gear, I need to look and see if you can push the shaft out from the sprocket side, or pull the large gear with the puller. With that off next take the rotor off the left side of the crank and then you can get the halves apart, if there is a problem with the R/H seal you will have to get the little gear off, not to fun. You will need the puller I was asking about. Have fun, Dave
 
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EGOR..Thx for the help...DO you know this....I have the puller...I screwed it into the chain drive sprocket and turned the center of the puller down..I applied liberal pressure but nothing happened ...sprocket did not move....I notice that the center shaft of the sprocket has threads..It does appear that the sprocket cannot come over the threads,,,so, does the spocket screw off ..if so it would have to be left hand threads?????????...or do I just need to apply more pressure to the shaft with the puller...I examined the large gear on the opposite end of said shaft and the same thing happened and it looks the same...PLEASE HELP IF YOU CAN
 
Doug - both of the parts are on a smooth shaft and are located by a woodruff Key. They seem to take a lot of wally to get off. Make sure you get the puller in the gear as far as you can, I also lube the threads in the center of the puller, and the end that scrapes on the shaft you are taking apart. Hope this helps. Have fun, Dave

PS: What do you think about the seal replacement behind the spark rotor? It should be easy, but you might need a new one. I have not purchased one yet so I don't know of a supplier. I was lucky, I dug through a bunch of old boxes and found 3. I have no clue what they were for, its old weed eater stuff.
 
Hey, thanks for the help on this.

I have both the drive sprocket off, and the thing on the other side. So on the clutch I am looking at shafts on both sides, and what looks like seals. That is fine.

But on the CRANKSHAFT part of the motor I still have the magnet on the left (drivers) side, and the small drive gear (on the right side). If I want to split the engine case, don't I have to do something with these things also ?

I am unable to find the "pictorial breakdown", boy that would be useful.

Thanks, if you have the time and inclination

cb
 
You can split the cases with ether of the fittings removed, although you will need to have the one that is in the way of the side that is making the trouble. I will look for the tear down pic's. Have fun, Dave
 
Thanks - I got it ! The last thing is the dang

You can split the cases with ether of the fittings removed, although you will need to have the one that is in the way of the side that is making the trouble. I will look for the tear down pic's. Have fun, Dave

clutch side crank gear (the small one). That isn't threaded on, right ? I have the crankshaft + connecting rod still attached to the clutch side of the crankcase because I am unable to remove this small gear.

I took out the screw that holds the gear on, maybe it is stuck ? It wouldn't be threaded, right ? Is there a woodruff key that maybe is jammed ? I tried a couple (more than a couple) raps with a hammer using a small rod into the hole in the gear, thinking to push the crankshaft out the other side of it.

But it is really in there. If it were threaded, because of the direction of the drive train, it would be right handed, right ?

On my next tear down, I am going to make a photo view - a good one. I am keeping the stuff to do a rebuild.

Thanks

cb
 
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