governor removal and "little pin" pred 212

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breath_easy13

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Should be, I have the 212cc on a garden tiller and run it wide open for probably a hour at a time.
does this sound accurate

Drive Wheel Diameter In Inches 26
Rated Engine RPM 3600
Teeth On Axle 44
Teeth On Clutch 12

Calculated Results
Drive Wheel Circumference In Inches 81
Gear Ratio 3.667
Maximum Speed In MPH 75
 
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Tony01

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You can safely run 18lb springs it’ll take your motor up to about 6000 depending on gearing. The fun with this motor as stock is in the 3400-5500 range. A good ratio is 8:1 plus minus a point on a 26” wheel (at 7.7:1 on 26” the speed is 1mph per 100rpm so 6000rpm is 60mph). With stock springs your motor might see about 5300rpm.
 
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breath_easy13

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You can safely run 18lb springs it’ll take your motor up to about 6000 depending on gearing. The fun with this motor as stock is in the 3400-5500 range. A good ratio is 8:1 plus minus a point on a 26” wheel (at 7.7:1 on 26” the speed is 1mph per 100rpm so 6000rpm is 60mph). With stock springs your motor might see about 5300rpm.
hmm, well, being thats its a bicycle frame, i dont see myself wanting to go over 50, let alone 60. To know i can hit 60-70 is cool enough but i doubt ill ever need to hit that, unless im running from the cops, and i feel like "livin"
 
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Greg58

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I don’t know how fast you’ve been on a bicycle but 40mph feels like 65 mph on a motorcycle, I’m sure Tony will back that up. A hard tail frame transfers a lot of the road to you.
 
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Tony01

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3.5:1 is way too tall not to mention a mostly stock 212 no matter what gear ratio will not go faster than about 55-60. If you run a ratio taller than about 6:1 you will run into issues like smoking clutches or belts if you run cvt which is crap compared to a clutch anyway. Gear it 8:1 to start and go from there. That’s 50 at 5200rpm or high 30s at about 4K, perfect.

Yeap you do feel everything but you also get used to it, I did 55+ as often as I could even got a speeding ticket for it in a 35 zone. If you do everything right going fast can be safe on bicycle tires, I have seen people do over 80mph on hookworms, myself have gone thru many sets of tires while running up to 65. Now I don’t speed any more...
 
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breath_easy13

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can you
3.5:1 is way too tall not to mention a mostly stock 212 no matter what gear ratio will not go faster than about 55-60. If you run a ratio taller than about 6:1 you will run into issues like smoking clutches or belts if you run cvt which is crap compared to a clutch anyway. Gear it 8:1 to start and go from there. That’s 50 at 5200rpm or high 30s at about 4K, perfect.

Yeap you do feel everything but you also get used to it, I did 55+ as often as I could even got a speeding ticket for it in a 35 zone. If you do everything right going fast can be safe on bicycle tires, I have seen people do over 80mph on hookworms, myself have gone thru many sets of tires while running up to 65. Now I don’t speed any more...
Can you explain the ratio 8:1 ? I dont quite understand. according to the calc outta 3600rpm, the the rear wheel dia, axe, clutch ill push 75, lord knows how long it will take to get there, but under the circumstances should i be able to hit 60 if i want ? And with ease ?
 

Tony01

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can you


Can you explain the ratio 8:1 ? I dont quite understand. according to the calc outta 3600rpm, the the rear wheel dia, axe, clutch ill push 75, lord knows how long it will take to get there, but under the circumstances should i be able to hit 60 if i want ? And with ease ?
Well you need to do some research on gear ratios, jackshafts, etc. you can’t just put a sprocket here and a sprocket there and say “yea I’ll be doing 75 at 3600rpm” this isn’t how it works. With that setup you’ll take 2 minutes to get up to 40mph while lugging the motor and smoking the clutch at 2000rpm. A stock 212 does not have the power to push a bike to 75 no matter how you gear it. Do the research then read my posts again.
 
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breath_easy13

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Well you need to do some research on gear ratios, jackshafts, etc. you can’t just put a sprocket here and a sprocket there and say “yea I’ll be doing 75 at 3600rpm” this isn’t how it works. With that setup you’ll take 2 minutes to get up to 40mph while lugging the motor and smoking the clutch at 2000rpm. A stock 212 does not have the power to push a bike to 75 no matter how you gear it. Do the research then read my posts again.
well tony, no one said i would be doing 75 at 3600rpm, i was stating hypothetically, and according to the calculator i found online, that is max speed, according the numbers and calculations, that the bike would be able to reach. Im not tryin swing my big dong around saying ill hit 75 miles an hour with minimal research lol. im still reading dude, learning more about building bikes in the last month then i have my entire life. so, ill do some more reading then ill better understand your post.
 
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Tony01

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well tony, no one said i would be doing 75 at 3600rpm, i was stating hypothetically, and according to the calculator i found online, that is max speed, according the numbers and calculations, that the bike would be able to reach. Im not tryin swing my big dong around saying ill hit 75 miles an hour with minimal research lol. im still reading dude, learning more about building bikes in the last month then i have my entire life. so, ill do some more reading then ill better understand your post.
No prob. Here’s a pretty easy method to calculate speed on a 26” wheel:
speed=RPM*.078/Ratio

You’ll need a jackshaft for two reasons: one is to get the necessary reduction, also you will need it to align your rear sprocket. The 212 is a wide motor. Good luck you got this!
 
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breath_easy13

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No prob. Here’s a pretty easy method to calculate speed on a 26” wheel:
speed=RPM*.078/Ratio

You’ll need a jackshaft for two reasons: one is to get the necessary reduction, also you will need it to align your rear sprocket. The 212 is a wide motor. Good luck you got this!
thanks man. I actually already purchased a torque converter, pretty stoked to get the GOD DAMN GOVERNOR OFF and get the engine mounted and get working on this torque converter
 
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indian22

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Good thread with good questions and answers. B.easy you're off to a good start with your Preddy build. I'm signed on.

Rick C.
 

breath_easy13

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That pin is too long to take out by itself without removing the connecting rod, so cut it with a grinder pretty close to the case then push it out.

The governor gear and oil sensor need to go as well. Plug holes with close fitting screws and aluminum or copper washers, and red loctite all over to seal (red loctite is good to fill gaps up to .015”). Don’t forget to get the little washer stuck to the case under the governor gear.

Also cut off the front gas tank mounts (they will break your case) and use the rear gas tank mount or head bolts for your front/upper mount.

Welcome to the club!
Hey Tony, I've read an article on the web that you dont actually have to remove the oil sensor, you can just unplug it, is that true ? I've read that, it wont shut the engine down either is that true ?
 

indian22

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B.easy that's a great deal on a grinder & the 4-1/2" size is one of the most used tools in a welding or welding shop. You won't believe all the uses you can put it to. That said they are dangerous as well. A few cautions wear safety goggles or better yet a full face shield while operating the cut this tool. I've had both cut off wheels and grind stones explode while using these over the last 50 plus years. Three decades of this in my commercial fabricating shop. Just ordinary use throws a lot of metal cuttings and bits of the cutting tool back at your face. Knotted wire brushes throw wires and I've had clothes and skin that looked like a porcupines hide after running one for several hours. A strong rare earth magnet is useful to pull these out of clothing. Use the side handle & shield while using the grinder. Don't lay the tool down until the blade stops spinning and when you do lay it down do so with the blade facing up. Of course there's more but I see guys on YouTube quite often ignore these three in their "instructional" metal working videos. If they were working in my shop I'd first instruct, correct them once and fire them if they did it again.

Have fun with this and work safe.

Rick C.
 

breath_easy13

Active Member
Aug 27, 2019
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B.easy that's a great deal on a grinder & the 4-1/2" size is one of the most used tools in a welding or welding shop. You won't believe all the uses you can put it to. That said they are dangerous as well. A few cautions wear safety goggles or better yet a full face shield while operating the cut this tool. I've had both cut off wheels and grind stones explode while using these over the last 50 plus years. Three decades of this in my commercial fabricating shop. Just ordinary use throws a lot of metal cuttings and bits of the cutting tool back at your face. Knotted wire brushes throw wires and I've had clothes and skin that looked like a porcupines hide after running one for several hours. A strong rare earth magnet is useful to pull these out of clothing. Use the side handle & shield while using the grinder. Don't lay the tool down until the blade stops spinning and when you do lay it down do so with the blade facing up. Of course there's more but I see guys on YouTube quite often ignore these three in their "instructional" metal working videos. If they were working in my shop I'd first instruct, correct them once and fire them if they did it again.

Have fun with this and work safe.

Rick C.
yeah, i appreciate this post. for real, this is stuff your dad tells you and your let it go through one hear and out the other and then you shoot your eye out. So ill be sure to get goggles and extra precaution next time i need to cutt something.

thanks
 
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