just found a new engine- Pocket Bike rack mount?

P.S. since i've finally decided on a rack mount, someone who can should probably move this thread to that forum. was hoping for a frame, but with the physical size of the engine, rack is better. plus, i won't get exhaust smell on me while riding.
 
You've got skills!:D

Actually, that "transmission" is an enclosed jackshaft. I had one on my ebay pb engine, but I removed it since I didn't need it. The gear reduction I believe is 1.8:1, so ya might need another 14:1 gear down to utilize the pb's power range.

5-7
 
counting teeth

well here it goes. according to 5-7HEAVEN the trans mission is 1.8:1. on this i trust him cuz he's been doing this a while. not sure what the 1.8:1 means, but at this point i'm gonna go with it. the drive sprocket coming off of this is 16 teeth. at least, i plan on 16 teeth. the little green wheel is planned 16 teeth. the green and blue wheel is the mystery. the wheel gear is yellow blue and orange withe teeth of 48 38 28. yes three choices i'll use which ever one works. so what, if anything should go for the jackshaft (green and blue) in the green (number of teeth)and blue (number of teeth) or can i just eliminate the green blue wheel? is this clear as mud???
signed
perplexed :confused:
 

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http://jimsitton.net/ratiocalc/ here is a link to a gear ratio calculator provided by member jpilot. Here you can go nuts running numbers for your drivetrain. The target reduction you are looking for is approx. 18.75:1

So if your gear box is assumed to be 1.8:1 input 10 in the first field and 18 into the second field Since the output from you gearbox is going to be 16 input 16 into the third field now if you go straight to the rear wheel from the 16 you will need a 167t rear sprocket to get 18.79:1 input 167 into the forth field to see final reduction of 18.79:1 at the bottom. I doubt that a 167t sprocket is readily available. So yes probably you are going to have to add an additional jackshaft to get the reduction you need.

ocscully
 
The blue-green wheel is 35-tooth/10-tooth. Using the 48-tooth drive sprocket computes to 18.9:1, which is very close to Staton's 18.75:1 gear chain box.

So it's 16t to 35t, then 10t to 48t. Count the teeth in your "transmission" to verify 1.8:1 ratio.

So 1.8 times 2.1875 times 4.8 equals 18.9:1.

5-7
 
ok thanks ocscully. the numbers come out this way first box set 10 18 second box set 14 48 third set 16 48. drive ratio is 18.51:1 that works but obviously i have some numbers to play with. this gearatio.exe is gonna help alot. now i got some thinking to do. thanks again.
 
thanks to 5-7heaven and scully. it's obvious now i'm gonna need a jackshaft. well that does not mess up much. i'm designing this with the word "flexible" in mind. sort of change the process as i go. once again, you can see why "i'm pacing myself" the goal is the final product, and getting there takes patience. thanks much. i'll be back.
 
Actually, the gear ratio may need to be stiffer, depending on the optimum hp/torque range at a particular rpm. You'll need to either do your research and find out your engine optimum range, or start at 18.9:1 and experiment progressively higher numerically gear ratios..

Ya might end up at 25:1 gear ratio, which means that drive sprocket is gonna be much bigger than 48 teeth.

5-7
 
The blue-green wheel is 35-tooth/10-tooth. Using the 48-tooth drive sprocket computes to 18.9:1, which is very close to Staton's 18.75:1 gear chain box.

So it's 16t to 35t, then 10t to 48t. Count the teeth in your "transmission" to verify 1.8:1 ratio.

So 1.8 times 2.1875 times 4.8 equals 18.9:1.

5-7

Counted the teeth in the trans. 9 on the little one. 27 on the big one. tiny teeth though. will that make a difference?
 
Counted the teeth in the trans. 9 on the little one. 27 on the big one. tiny teeth though. will that make a difference?

Yes it makes a difference. The Gear box is a 3:1 reduction ratio rather than the previously assumed 1:8:1. Run the numbers thru the ratio calulator and make adjustments to the other sprockets accordingly.

ocscully
 
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