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my biggest problem was the gearing as it was geared to turn a pocket bike tire which is a lit smaller than a 26'' bicycle tire. to gear it correctly ,i would need a back sprocket roughly the size of the tire .

To get around this ,I ran the original pocket bike front sprocket and back sprocket which i connected to the rear tire hub after cutting away the rim. I ran the hub on original back axle and connected a pulley to it aswell which runs a vbelt down to pulley mounted on rear tire. I'll try post a close up of the workings as its kinda hard to see from the pics.

quickly rereading this. i think it might be a little hard to follow . excuse me but i'm trying to get this off quickly as have to go to work . will give a proper layout of system tommorow

~Haggard~

if u look closly at this terrible pic{sorry}, you can see the chain from motor running forward to sprocket connected to pulley running vbelt down to wheel

I am honestly amazed what this 49cc will do over 40mph on straight stretch and takes off from dead stop real well also.

H

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For some reason your pictures have disappeared. I really enjoyed your creations. I am very interested in your gearing. How many teeth on the motor sprocket and how many teeth does the sprocket have that it is connected to? Also, how big (inches) are your two v-belt pulleys (the one on the rear wheel and the one on the jackshaft).

Thanks,

Dr. J.

H

Dr. J

stock gearing on these 49cc' s is 6/68. they also come in other sizes such as 7 tooth ,64 tooth etc.

When i finallystarted getting the gearing close .I coulda kicked myself for missing the obvious.

The problem was i was trying to turn a much larger tire than it was designed for.

Now I am not the sharpest tool in the shop and have no mechanical background of anykind so my formula might sound a little (simplestupid) to some of you fellas.

i realized right away that to turn a tire 4 or 5 times larger , i would need a sprocket 4 or 5 times llarger which meant a sprocket not much smaller than the 26 inch bicycle tire i was mounting it to which is why i had to step it down twice .

after tryiing the hit and miss approach for awhile which consisted of different pulleys, belts to match , trying to work different sprockets into the equation to fine tune the ratio and then 1 day , like a vision bursting across the sky(arlo guthrie line)lol,i realized how simple it was.

Take the circumference of the original tire, the circumference of the new drive tire,calculate the ratio(2.5 to 1, 3 to 1 or whatever it is,and apply that ratio to your pulleys.

i Believe the original tire was 32 inches and the 26 inch bicycle tire was approx 80 inches in circ.

i assumed that if 32 goes into 80 excactly 2.5 times, i should be dead on if i use a 2.5 to 1 ratio if i ran it in conjunction with original gearing.

so if i throw a 5 inch pulley running to a 12 inch pulley which is approx. 2.5 to1 , i should in theory bee getting the same travel distance per engine revolution.

Hope yer following so far?? I'm about as good at explaining things as I am at ratios and Algebra'

T%he reason i mention algebra is because even though a 12inch pulley aoppears to be 2and2/5th's times larger than the 5 inch pulley, the diameters are 15 and 35 respectively which is a 2 and a third to 1 ratio.a 10 inch pulley is 28inches circ.`which would give you just under a 2 to 1 ratio which would gear me a little higher than the pocket bike.

Now heres where your bike is going to go ok or it's gona go like a raped ape because the difference between 2.5 , 2and 2/5th's and 2 and a third will make it or break it

If its geared a touch to low ,you'll be revving to high and running hot which will decrease your power and if its geared a touch too high,it'll start lugging toward the high rpm range and it wont get maximum revs out of it which will cost you speed`

I geared it down about 5% and got an extra 5 mph out of it so the ratio you use is highly dependent on the motor your using,

I am currently using a 5and a half inch pulley running down to a twelve inch with the stock 6 to 68 tooth gears. i used the 5 and a half with a 10 inch sprocket and was ok but this game me a little mire bottom end and didnt cost me neo top speed as i can wind it up a little more .

sorry for rambling and hope this helps more than it confuses.

will gladly try to answer any other questiosns

~Haggard~

OH built a full suspension using basically the same design with same type of motor . got some chrome running boards for free so cut out some full fenders for front and back ,bent and shaped by hand and with a vise. turned out exc. get comments all day long on them. even nicer than the chrome ones on my schwinn cruiser.

`i kept them square cut and flat at the back with an oversized flareout and rounded and arched the fronts. got enough material to make 1 more set which have already been sold for $150 to the same fella that gave me the running boards lol I amaze myself sometimes ??!!!?? lol will post picks if anyone wants to see or try it also they really make the bike as i used the same running boards to make my gas tank supports etc.

D

68T/6T = 11.33

12"/5.5" = 2.18

11.33 x 2.18 = 24.69

24.69:1 overall gearing ratio using two decimal places

http://www.teamdavinci.com/understanding_gear_reduction.htm

If possible, I would love to see some closeup pictures of your jackshaft assembly. What components did you use to make the jackshaft?

Thanks again,

Dr. J.