Repair Slipping Drive Gear on 49cc, 66cc or 80cc Bicycle Motor
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- Опубліковано 6 жов 2024
- My friend's motor stopped getting compression and we noticed that the drive gear was slipping on the crank shaft. Since nobody else has made a video of how to resolve this, we decided to make a video of ourselves learning how to fix the problem.
We bought a replacement Woodruff key from a local big box auto parts store, but I strongly recommend buying the correct key for a few bucks from eBay by searching for "49cc woodruff key". Additionally, the gear puller can be had for just a few bucks from eBay by searching for "49cc clutch puller".
This looks like a complicated and difficult process, but it isn't. It does, however, require a lot of patience.
Hey man. It’s all a learning experience. You won’t know everything til you’ve made a few mistakes. You can’t learn anything without a couple of mistakes being made. Keep up the good work
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.
Job done with hand tools ,well done , as stated in a comment above ,easier removing clutch
Just had this same problem and today and this video has made my whole week thanks guys🙏🏾🙏🏾
Had all those same problems you guys were having
That engine must be rather old, the clutch looks very well used
Also sometimes it's just loose make sure to check around the clutch
Be sure u use a metric key
If not you can mess up.the crank
Put blue locktite on the screw
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.
This is my exact problem thank you so much
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
Thank you for the help.
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.
It's amazing how such a tiny piece of metal smaller then your pinkie fingernail (and/or a lack of piece) can render an entire complex construct non-functional.
You would love a can of Sta-Bil starter fluid!! Great video...thanks!
"It's just rusted away", 😖😖, think about what your saying, and what that might look-like before you say it aloud, I can't help but wonder where the old one went, lol, thanks for sharing.
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.
The proper key is 2.5x3mm key
Fomt try to use an American
Key it will damage the 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.
@@SAPLSMW
I order parts from
Gassbike.net
Has every part for 2 stroke.and 4 stroke motors
Pluss a full line of acc.
You should have used the gear puller to put the gear back in rather than hammering it.
How so?
Was the original key made of steel or aluminum? Because steel can break shafts if it gets bound up for some reason. Briggs and station uses aluminum keys that will sheer instead of permanently destroying the crankshaft
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
I got the gear puller with my engine but threw it after not needing it many years.
I just got mine today and didn't kno what it was for. Spend 10 min looking where it might go
What is the part called that the round bolt goes into ? Mine is stripped out for some reason and i need a replacement. I'm not sure what to look up.
I reckon that's called the drive shaft. It's connected to the solitary piston in the engine.
Those woodruff keys sure are a pain to install aren't they?
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.
I forgot to mention that you can purchase a whole case of woodruff key for under $6 or $7 at your local Harbor Freight store.
Be sure they are.metric
Yeah but none of them fit that
i got that problem... brand new motor
I sure hope this video helped and that you saved time by not buying a replacement woodruff key from the local auto parts store.
What happened if I don't use Round Column Bolt for the small bevel gear you think my clutch start slipping
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.
Next time use a block of wood to help tap that gear into place
The key u ate using is American standard the key u need should be metric
The key u ate trying to use is smaller than the groove it will cause ytje key way to woller out damaging the crank
Get the proper key!
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.
My drive gear is engadging but its skipping idk what to do its turning but then it isnt idk what to do
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 UA-cam for the 'net to see. It'll be easier to diagnose the problem then.
Do you know if you would clean those parts up before reassembly you would find things would go a lot smoother. What’s wrong with you?
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
What’s the name of the screw mine stripped and fell out ??
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
What 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.
I wonder if this is the problem on my buddies bike
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
you put the gear on backwards it has to be flush with the other one good luck getting off now the threads or on the back side now you should let someone do it that knows what there doing because you dont
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.
So what do u do if its locked up
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.
I need some help! On my 66cc bike when I pedal I hear this screechy noise and when I start the motor or just roll the bike without the motor on the pedals spin by it self. If I let them spin when the bike is on and stop them with my feet the motor turns up and the rear wheel locks up. How do I fix this? This has never happened before?
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.
So if my clutch don't engage does it need a new woodruff thingy?
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
👍👌
The drive gear won't jam
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.
All you can see is your damn hand you can't even see what you're working on dude
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.
My drive géar is like yours. It keeps turning when you want to pull the sctew out but I dont know how to get it out
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
Is there meant to be a seal on that gear shaft?
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 will tell you how I fix it... where's the trash can?????
The obvious solution isn't nearly as much fun as fixing it.
like your vido
exactly what NOT to do to your bike this whole video was cringe
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.
Crank turns the piston .....not camshaft 2 strokes don't have cams😊
These engines are made so cheap
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.
Hit it with your purse. Your taping on it like a girl .
All I see is your hand, dah.. Terrible video.
My soldering videos are even worse.