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So I have a little dirt bike, 49cc I'm assuming, the pull start keeps breaking and somehow damaged the fly wheel. So I ordered replacement parts for those. And now the bolt in the center of the flywheel, the one you would turn to start it I assume, the head of it is broken off. I know some basics 2 stroke stuff but not much so questions I have:
1. What is that bolt called? And where might I find a replacement?
2. I don't have any special tools, but I might be able to find them.
what is the easiest way to remove the bolt? And what about the most basic way to remove it without any fancy tools?
3. Any suggestions for finding parts? Everything seems so generic and similar.

this is what the bike says it is YongKang Jiayue industry& trading co. Dirt Bike Mode:A02
And this a picture before everything else was broken
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Hello and welcome. In the picture the flywheel bolt is not broken but I don't know if that was before. That has a nice flywheel with a different pull start, surprised it broke especially on a stock engine.
Unfortunately without special tools that bolt is really broken off, you will need to replace the prank. Otherwise you need a tap and die set and it's not easy if you haven't done it before to remove the broken bolt. If it's not broken screwdriver to hold the flywheel in place in a nice long breaker bar or ratchet. Do you have to be careful prying on the fins cuz you could break them.

Parts are easier to find on eBay or Amazonmo, look up 47 cc dirt bike or 49cc dirt bike. If you need tools Harbor Freight if there's one near you or local hardware store.
And the bolt in the center of the flywheel is called the flywheel bolts and your local hardware store should have a replacement but again if it's broke off I would just get a new crank or in your case probably just get an engine off eBay and swap over. That's the simplest thing. The motors are about 50 to $55.
 

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On all the new engines that I have seen they are now gluing that bolt in to prevent people from taking the engines apart and modifying them I have been really lucky lately heating the bolt up with a plumbing torch and removing it while it's still hot.

The flywheel is also probably glued on as well I also heat the flywheel up with a plumbing torch until it starts to smoke the glue then I get a flat bar behind it and put pressure on the flat bar and thread in a long bolt that I get from the hardware store and give it a whack with the hammer and I have been lucky and they have popped off.

Make sure you replace the crankcase seal after using the plumbing torch method!!!

Your flywheel does look okay and one broken fin is not going to make a big difference at all but you need the easy pull pull starter and not the regular one.
 

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She does not have a 'regular ' pullstart. It is the easier one for high compression engines. Same as the air cooled Blata engines. No CAG comes stock with that setup EXCEPT the newer dirtbikes.
 

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Like I said this bike needs the easy pull starter and not the regular one 😅
 

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If the flywheel mount bolt is broken, who cares, that flywheel is not coming off. Its on a tapered shaft and once you mount it with a bolt and with glue and rust. I have taken many flywheels off, and they don't just come off. The clutch is on the other side. On a piston port engine the clutch mounts to the flywheel, a different story. Many bike factories in China making the same bike. That's a QC 50cc dirt bike. You have the new style starter, I have them on my hot rod engines, much easier to start than the old ones. crank threads are 6mm x 1.0 pitch and 5mm x .08 pitch, going to see a loyt of them on that bike.
If you rope breaks, you go buy 4ft of chainsaw cord and re-wrap the starter pulley, no need to take it apart.
 
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