Mini Bike Chain Adjustment Trouble?
I recently bought a bunch of pocket bikes all in good shape but all had some sort of problem. I took the best parts off of them and made one extremely nice bike. The one problem I am having with it is that the chain likes to come off. There is a bolt connected to the back axle that tights and loosens and slcks or tensions the chain. How do I find the "butter zone" where it isn't too loose to come off, and it is too tight to come off? The two sprockets are lined up really well, but they are a little off. Would it be possible that that was the problem? When I say a little I mean like so small its less then 2-3 mm from drive sprocket to driven sprocket.
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Align the sprockets.
If the sprockets are getting worn out the chain will have a tendency to come off also.
Thanks for all the help!
So as for how I liked them, if you can ride the street bikes comfortably, then 5/5 if you race them at a local track, and 4/5 if you cruise around the neighborhood on them, if you don't find them comfortable, 1 or 2/5. The dirt bike ones, 5/5 for everyone, no matter where you ride them. They are fun little toys though as they can be found on bargain finder type sites for $50 - $100 each.
Also, that bike of yours sounds interesting. If I had an electric one, I would have converted it to gas as well! Haha!
So to sum up, you would have to make a pipe that connects the 2 intake manifolds and in its center, as to not favor one engine over another, mount a larger carb. Next you would have to weld on/bolt on a gear on each shaft of the same size and link the two engines with a chain. Time both of them 1 stroke apart. Mount a second ignition coil, exactly 180 degrees from the ignition coil on one of the engines, use the coil from the slave engine. If done very accurately this will fire both engines 180 degrees apart and keep everything synced. Lastly, off of one of the shaft mount the clutch, independent of the chain drive linking the engines, and this will what drives the wheel.
Does this make sense? The way it is set up in that picture, you are trying to sync 2 carbs to give engines the amount of gas they need to run at the same speed, impossible (Almost) to do. Because they both have clutches then linked together, when engaged they could engage firing at the same time, which would make the whole bike shake. Also, without having a feedback system of sorts that can adjust each engine with the other, once both engage, the faster of the 2 engines is driving the wheel and driving the other engine faster and therefore will get less power then a single engine. Its surprising, but if one engine but in the setup in the picture, if one engine runs slower, it will actually cause resistance to the other engine, reducing power.
When doing the spark, you might be able to use the magneto from each engine for them selves, rather then use one to drive both spark plugs. And when you link the 2 engines with the chain, make sure one has its piston as high as it will go, and the other has the piston as low as it will go. This will greatly reduce vibrations.
Good Luck! I want to see it when its done! :D
Make sure the rear wheel is aligned correctly
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Adjust the rear wheel to take out all the slack in the chain across the top of the sprockets. Remove the front sprocket cover so you have access to it.
Using a straight edge, (a 2 foot level should do it on a pocket rocket) hold it against the face of the chain on the top of the sprockets, down the full length of the chain, from the back of the rear sprocket to the front of the front sprocket. The chain should touch the straight edge for its its full length. If it doesn't, the sprockets aren't properly aligned.
I don't know on your particular bike if it uses shims or an adjuster nut to correct alignment but whichever it is, correct the alignment so the chain is straight, re-tension it and you should have the problem fixed.