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Motorized Bicycle General Discussion All topics regarding bicycles with engines.

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  #661  
Old 11-23-2012, 02:42 PM
KCvale KCvale is offline
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Default Re: Motorized Bicycle Take a Tip...Leave a Tip

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Originally Posted by bikeman8 View Post
i fixed the problem of the tensioner moving by attatching it to the top wheel brace/mount instead of the bottom, that way it pulls it tight and cant move, it does move very little tho, i fixed that problem by attatching a bolt in the idler wheel slide and attatching a guitar spring to it and the lower frame, ill try and get pics in a bit.
This is a tip you might want to avoid. A chain tensioner is just an easy way to make up for chain and sprocket wear on the slack side and never something you want to put on the power side of a drive train.

If your drive chain gets tight and then loose your sprocket is not true and no tensioner in the world is going to fix THE crucial part of an motorized bicycle drive train, that being the rear sprocket being true on all 3 planes and if you are lucky you never need some POS tensioner at all to keep your drive chain true and tight.
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  #662  
Old 11-23-2012, 03:41 PM
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rustycase rustycase is offline
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Default Re: Motorized Bicycle Take a Tip...Leave a Tip

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Originally Posted by KCvale View Post
To get a lower gear ratio for pedal starting and better coaster brake performance swap out the common 18T rear sprocket with a 19T for $5, easy to do and a game changer on single speed coaster brake bikes.
I really need to do that, KC!
Got one bike that is just difficult...
$5 is a cheap fix!
rc
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  #663  
Old 11-26-2012, 12:17 AM
vincent713 vincent713 is offline
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Originally Posted by BikeBerryKelci View Post
Great pictures! Great tip! Im going to have to borrow that from you!
I've tried this method using card board paper from a card board box and indeed it does reduce engine noise however; when riding for a while and the engine gets really hot it starts smoking and burns the card board paper. I'm assuming using this rubber piece will do the same. Any restriction on the engine fins will cause faster heat and will result smokey hot engine!
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  #664  
Old 11-26-2012, 05:46 AM
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Ludwig II Ludwig II is offline
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Default Re: Motorized Bicycle Take a Tip...Leave a Tip

Rubber doesn't burn like cardboard so you'll be safe.

I've been next to a noise meter when a racing "big fin" Minarelli 50 went past, the exhaust noise was the same as all the other bikes round it, but the fin ringing showed up on the meter as being around twice as loud.
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  #665  
Old 12-04-2012, 04:28 AM
MEASURE TWICE MEASURE TWICE is offline
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Originally Posted by MEASURE TWICE View Post
I found this web page:

http://www.dansmc.com/throttles.htm

I hear just shimming with electrical tape or glue had been done. I'll try putting the tape on, but first I'll have to see how easily the hand grip comes off. Maybe need to lube it? It already is somewhat loose but only I know spinning around. To take it off axlily I don't know how much friction there is in that plane.

I will check with the shop I bought it from later today and see if they have ideas too.

MT
Just to catch up and let you know the cheapest hair spray in a dollar store is what I used to glue the twist grip throttle replaceable grip. It does not slip now. I will also put some on the other hand grip as it is probably OK, but could not hurt. The bike shops use this approach I saw in a TV documentary on building BMX bikes. The twist grip replaceable portion is far away from any of the cable parts so there is no danger of having it stick the throttle. I also just sprayed the inside of the grip and pushed it on. I wiped any excess that leaked when I put the hand grip back on. Let it dry inside at room temperature for 3 days.

Good tip I got from a kids show!
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  #666  
Old 12-08-2012, 10:47 AM
OblivionsKey OblivionsKey is offline
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Default Re: Motorized Bicycle Take a Tip...Leave a Tip

Heres a tip, get a bike with good brakes lol. Also narrow tires seem to make turning radius bigger.
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  #667  
Old 12-08-2012, 11:03 AM
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rustycase rustycase is offline
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Originally Posted by OblivionsKey View Post
Heres a tip, get a bike with good brakes lol. Also narrow tires seem to make turning radius bigger.
+1

If you can't swing disk brakes, or the even more expensive drum brakes, the inline style, or V brakes, are almost a necessity for safety, when you get out in traffic. There is really no way to predict what Others will do!

Narrow tires might be a good option for an outright speed run in a straight line, on a very good surface. Way back when, Auggie said he was very happy he had selected a medium width tire when he ran at Bonneville. He said the cracks in the salt would have swallowed a narrower tire! NOT gud!

Yes, turning radius may be larger, because there will be less gripping surface and the tire will scrub more.

The larger tires also offer some degree of suspension... quite valuable on city streets, driveway aprons, and such. They protect the rim!

Best
rc
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  #668  
Old 12-09-2012, 01:12 AM
MEASURE TWICE MEASURE TWICE is offline
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To stop quickly, just don’t go so fast.

V-Brakes old original have put on my frame after removing the pedals that had the coaster brakes, of which now are both gone, but have fold up foot pegs in their place!

Also for quicker stops, I have a 40:1 ratio so that the bike can't go too fast anyway. Climb hills good for OHV dirt biking and for parade speed under 5mph have no need to keep pulsing the throttle as the ratio fixes that.

There is also a screw I have to adjust max speed on the throttle as well as idle. This is for parade speed to be sure it us under 5mph.

Next mount an Ice Cream Machine in between the sort of ape hanger handle bars, except the ends don’t down point down.

I should hook up one of then output shafts of one of twin jack shafts turning, for what would be a good speed for an automobile alternator. Or it could easily be something smaller. The charging of a battery set up to then goes through an inverter to power ice-cream machine underway and when engine is off still churning.

This should be, as well as an art cover looking like a California Sheeps Head Fish and a bell to ring in the 8000ft elevation of Black Rock City, NV so to help with the heat.

Oh yea training wheels maybe also both front and back using 4ea. 12" tires, no way to fall over...sort of.



MT


Last edited by MEASURE TWICE; 12-09-2012 at 01:16 AM. Reason: typos grammar
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  #669  
Old 12-09-2012, 05:02 PM
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ahdunno ahdunno is offline
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Default Kill Switch Mod

Reverse the wiring on the stock kill switch so you don't have to short the magneto. Details and pics at link below. Post #2.

http://motorbicycling.com/showthread.php?t=44070
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  #670  
Old 01-21-2013, 09:20 AM
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Russ McClay Russ McClay is offline
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Default Re: Motorized Bicycle Take a Tip...Leave a Tip

Here's my tips about the first time starting the motor which I learned after
just successfully building my first 66cc motorized bicycle and having many
(8) unsuccessful attempts to start it:

First make sure the chain is adjusted, aligned. Walk the bike around, a lot,
and watch the chain, from the top and from the back.

If you feel good about it, open the gas line valve, push the float bowl button
to pre-fill it (if your carb has one) a second or two.

Move the choke lever up to choke it.

Then get pedaling at a good speed, pop the clutch and at the same twist the
throttle to give it gas.

What a thrill it was to hear that motor start firing!

The bike starts every time using this method.

Also, after it starts give it some twists of the throttle and then start lowering
the choke lever to open it up.

Last thing, as it warms up you can start adjusting the idle screw while
releasing the throttle.

Might as well show off my bike. =) The used bicycle cost me $20.
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