FOUR problems on my new chinese 2-stroke

i just looked at the exploded views of this after having the same problem of my clutch not disengaging. i took off the side with the bucking bar and i swear i can not find the small little round ball that goes in before the bar. could this be a oversight or can it actually be missing? if so how do i get one or get this fixed?

I hate to answer here, might be better to start your own thread vs hijacking a previous post.

Anything that the Chinese can be a oversight. You wouldn't believe the short comings of these Chinese HT's.

First, is the bucking bar protruding about 1/4" from the shaft. If not I'd expect that the ball is missing. A pencil magnet is strong and small enough to insert in the shaft and pull the 5/16" ball out, should it be in there. If you want to make a new bucking bar, a 5/16" drill bit (the flute) makes a good one.
 
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OUCH!


Don't even attempt to use the bike until that part is sorted.
What I do is throw away the china toy bearing and replace it with a real ball bearing, at least.
To go a step further, a bit pendantic, but I use 2 quality bearings and shorten the bucking bar.
To shorten the bucking bar, keep grinding one end bit by bit at a time and fit back on to test till the cover sits flush.
Don't shorten to much or it defeats the purpose. Zero tolerance works ok, it will wear in.
File both ends till smooth then fine wet/dry "polish".

To take it a step further, case harden both ends of the bucking bar using the heat-to-rosy-red-dip-in-fossil oil trick, and case harden the cam where it presses on the bucking bar to.

I'm just shocked that its missing. Where could have gone? It's not like it could have fallen out since it's fully encased. And to think it was put together without it amazes me. Where could i get one of these?
 
I'm just shocked that its missing. Where could have gone? It's not like it could have fallen out since it's fully encased. And to think it was put together without it amazes me. Where could i get one of these?
find a ball bearing the same diameter as the bucking bar. The large ball bearings from a one pieced crank is close.

I appreciate your searching & posting in a similar thread!!
 
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How do you know it's not in there. I mean, how sure are you?

Honestly I'm not 100% sure since I've only taken it apart once. But the bucking bar goes all the way in and is flush inside , if not going in 1/32 more and its still engaged. Almost like there is no ball inside or the bar is to short. I'm to the point I am going to just take it back to the guy who built it and see what it would cost to fix. I've rode it all of maybe 30 minutes so I'm hoping he'd understand and fix this.
 
Okay, sounds like your ball bearing truly is gone. I did want to check first. Replace with an 8mm bearing, grease it and you'll be in business.
 
The very first build, very first kit I bought in 2007 had this ball bearing problem.
What happened was, after a few miles the clutch seemed odd.
Fortunately we were near another builder's place, wheeled the bike there and we had to use compressed air to force the flattened, yes, flattened china toy bearing out. It took some doing with the compressed air nozzle, but it eventually came out.
A magnet would not have had enough oommff to get it out.
It had literally become flat, seized and blued.
It was not proper bearing steal, I think they are round fishing line weights!

So if you have already started you engine, chances are it is still in there, but flattened, or it's fallen out, or never was there in the first place.

Every new kit I buy, I'm on auto-pilot in regards to replacing that particular bearing. Even if the vendor say's they "upgraded" the bearing, I don't give a stuff.
At least I know where the bearing came from and it's not china-toy-steel.

Just measured the stock I have, they are 8mm as mentioned.
I buy them in 20's, enough for 10 kits, 2 bearings per clutch mechanisim method.
One bearing still works, it's just me that I use 2 bearings with a shortened bucking bar.
But don't do anything else till it's sorted or it may cause further damage.
 
Ok. I am going to sound like a complete idiot, but here it goes. I took the bike to the guy that built it and within 2 minutes he found the problem. Seems like I wasn't riding the bike correctly. He told me that when starting the motor I need to peddle, let go of the clutch, and KEEP PEDDLING, until the motor completely takes over. What I have been doing wrong is popping the clutch and just taking off letting the motor take the full torque of my weight and starting off by itself. The result was a bucking bar severely worn out with a HUGE divot on the end where the ball bearing would be. Resulting in a very short bucking bar. So, hard lesson learned, I rode today doing exactly as he told me and it runs like a dream. He also told me to save on wear and tear to do the same with full stops at a stop sign and starting off again. Thanks everyone for your help and hopefully anyone that reads this in the future will not make the same mistake I did.
 
No need to find a 8mm ball bearing as a 5/16" ball bearing is close enough and works fine.

Ace hardware has them for cheap!
 
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