Problems to solutions 1 braking your woodruff key Solution: loctite it in with removable loctite Problem 2: getting the key in place Solution: use a magnet and the right key,or take the clutch off which isn’t hard. Your doing really well just need to learn some technique.

Thanks, man. Whenever I encounter a problem with no solution on the internet, I figure it out for myself and then write and article or create a video. When somebody comes along behind me, he can find the solution on the internet.

Had all those same problems you guys were having

I looked for a video on how to repair this exact problem and, after finding none, decided to record myself solving the problem. That's how most of my videos start.

My drive ,gear keeps locking up and just replaced the woodruff key

1

I reckon that's called the drive shaft. It's connected to the solitary piston in the engine.

You're very welcome. When I see that nobody has posted a video or a how-to article, I just record myself figuring it out and share it here.

Repeatedly in the video, I mention my mistake in not ordering the correct part. There's only so much self-flagellation I can do before I become my own dead horse.

You can adjust the clutch by removing the small screw holding the clutch screw in place and then turning the clutch screw with a screwdriver or pliers. It turns more easily if you hold the clutch open at the handlebar. Do the usual things while you have it open like checking to ensure that there's no oil on the clutch pads and that the pads aren't too thin. I don't imagine that there's any problem what screw you use on the drive gear so long as the Woodruff key locks the gear's rotation to the drive shaft's' techchnically, you could just weld the drive gear to the drive shaft if you don't melt the o-ring between the drive shaft and the engine body.

It sounds like you need to adjust the clutch. At 19:00 in this video, I show how to adjust the clutch; you'll need to loosen or tighten the clutch based on the problem you're experiencing.

@@SAPLSMW I figured it out. It was a problem with the bearings in the rear wheel.

It might have been aluminum which would explain how it was shredded. I'm not a mechanical engineer, so I don't know what metal works best. Steel seems like it would have a harder sheer strength than aluminum and we used steel here and it seems to still work fine.

Steel is the way to go in most cases aluminum will share very easily which sometimes is desirable to save something else

If the teeth are worn out then this this sort of thing can occur. If the symptoms are the same as the beginning of this video then replacing the Woodruff key might be a good solution. Consider taking a 30-second video and posting it on KZfaq for the 'net to see. It'll be easier to diagnose the problem then.

There are three screws in the video. One is the drive shaft screw or "Bevel Gear Bolt". The second one in the middle of the clutch plate would probably be called the Adjustment Screw. The final is the tiny Phillips screw that keeps the Adjustment Screw from turning and that's likely just an M3 or M4 screw. I good place to start is with a simple google search for the engine diagram. www.google.com/search?q=49cc+bike+motor+parts+diagram

Be sure they are.metric

Yeah but none of them fit that

I just got mine today and didn't kno what it was for. Spend 10 min looking where it might go

At the six-minute mark, you can see the powdered Woodruff key collected in a small pile under the drive shaft. I draw an arrow to it at 6:15.

Snatch the side cover off of the motor and examine the tiny drive gear when pushing the bike. If it spins freely when the screw head is stationary then the woodruff key is the likely culprit. If the clutch plate spins freely in the larger gear then the likely culprit is the clutch. There's a great chance that tightening the clutch by backing out the Phillip's screw and advancing the honeycomb-shaped screw in the middle of the clutch one or two positions will resolve the problem. Be sure to test thoroughly by engaging and disengaging the clutch while pushing the bike and to return the Phillip's screw when done. I demonstrate how to adjust the clutch at 19:00. If the problem is a loose clutch then fast-forward to 19:00 and see how the clutch is adjusted.

​@@SAPLSMWwhat size is the gear puller

I don't know the diameter or thread pitch. If you search for "49cc gear puller" then you'll find it right away.

Consider wadding some rope into the cylinder; it can be shoved in through the spark plug hole (easiest) or though the input or exhaust port. This will cause the crank shaft to seize allowing the screw to be removed and replaced after the work is complete. Once the work is complete, just pull the rope out.

Thanks for that but the sctew is very very tight and I cant get it out. Any ideas?

Apply heat

Use a heat gun heat the screw up then it should break free they use thread lock 🔒 on those screws

It hadn't occurred to me to think of that before now. If the piston is seized inside of the cylinder then I would start by squirting a generous amount of lubricant inside the cylinder and then try to rotate the crank shaft. If that didn't work then I'd tease the motor apart to see why the piston is seized. If the cylinder is scored too badly to get compression (around 100 PSI) then I would replace the cylinder and piston rings, but by that point, you might be better off buying a new motor.

Indeed, there is a seal and it's likely very fragile. At 12:30 you can see the Woodruff key rub on the rubber seal.

The crank has a seal in the case

I know I know I know. I preached all through the video about this and advised anybody watching to buy the proper key from Ebay.

@@SAPLSMW I order parts from Gassbike.net Has every part for 2 stroke.and 4 stroke motors Pluss a full line of acc.

How so?

I imagine that they're not so bad if they're the right size. Having a grinder and locking pliers handy made this work a lot easier.

Pop the cover off and roll it to see if that standard screw turns.

@@SAPLSMW I wish I could but dude haven't let me come over to fix it for him yet

I sure hope this video helped and that you saved time by not buying a replacement woodruff key from the local auto parts store.

Try wadding some rope into the cylinder when it's rotated to the bottom from either the intake or exhaust port. When you're finished with the job, rotate the cylinder back to the bottom and tease the rope out of the engine.

I'm a computer programmer and not a small engine mechanic. This was my first time trying this.

@@SAPLSMW it shows

@@catsbyondrepair we all have to start somewhere bud

@@SAPLSMW "stay in your lane!" - lol what a crank

I know I know I know. I preached all through the video about this and advised anybody watching to buy the proper key from Ebay. If there is play in the key and it does damage the crank then I'll be making a video on how to replace the crank. These are so cheap that it might be easier just to remove the screw, weld the planetary gear onto the crank and declare victory.

That's very fair; I was actually learning how to do this while I made the video. Nobody had produced a video explaining how to do this, so I filled the vacuum with my incompetence.

@@SAPLSMW dude everyone thinks they know everything. you did a very good thing with this video. we all learn as we go and im greatful for your willingness to try. my brother went to school for buisness for 4 years to sell clothes and live at home broke. i went to work out of high school and continue to work and learn. we need more people like you on youtube.

I am very sorry for that. My hands are enormous, but that's no excuse. I look for solutions on the 'net when I encounter issues like this and, when I find that nobody else has shared a solution, I record myself solving the problem and share it. I hope this video at least helps with fixing a missing Woodruff key.

The obvious solution isn't nearly as much fun as fixing it.

Thanks much for the criticism; it's sincerely appreciated. It's been working now for two years and still runs just fine, but I recognize I could have done much better and admit as much in the video. Many of these videos I create because nobody has created a video on the topic from which I might learn. I just record myself figuring out how to do something and then share that with the world. Again, the criticism is appreciated. If you make a video showing how to do this the right way then feel free to use content from my video to show your audience how not to do this job.

Yeah, that's so true. Ten years ago, a man could buy these on eBay for under $100 all day long. I remember folks in California selling kits with a few extra bells and whistles, but they were the same too-cheap engine. Honestly, I'd be willing to pay double for double the quality. My next buy will be a 4-cycle engine; I've been meaning to buy one for years, but life gets in the way.

My soldering videos are even worse.