24” mountain bike project

Greg58

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May 1, 2011
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I’ve been thinking about building a 24” bike for a while, but never got around to starting. After looking through all the parts and pieces it looks like I have everything I need to do it. I have a 24” mountain bike that is over 20 years old that my son got for Christmas when he was probably 12, he dug it out of his garage and brought it to me since he’s well overgrown it. I’m going to use my oldest engine on it , it’s a 2010 48cc grubee, has a lot of porting and piston work that need high rpm, should be able to reach that range with a 44 tooth sprocket on a 24” bike.
 

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Greg58

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After looking through what I have it’s amazing how much you accumulate over the years, everything I’ll use is new, I found a dual brake lever that I bought at one time or another. This will the first time I’ve had a bike that can run without a tensioner, should be a lot less drag on the engine.
 
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allen standley

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Oct 22, 2011
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That looks like a great candidate Greg. I've done a couple 24s I've found 24" wheel and a 44t sprocket to be torqy at the bottom and it'll wind up to top speed quickly. Sketchy handlers tho. I too am scrounging and looking for parts and pieces I know I have around here somwhere. Pretty certain I got all I need without spending any more money (yeah right). Good Luck with it and enjoy the build.
 
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indian22

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Greg the bike looks a good candidate for the the 2 stroke; you and Allen got me thinking about putting a CG that I have on and old hard tail steel frame mountain bike that's been hanging from the rafters for several years, 26" though, and I've parts galore...

24" bikes are real sporty and feel really quick. I've motorized a straight bar Schwinn with 24" tires and another Fito frame with the 3" wide on 24" rims, which pretty much feels like a 26" cause it is...

I like them both.


Rick C.
 

Greg58

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If it were for me I would but its just something to tinker with, I'm 6'1" tall so its a 26" for me. I had planned to build a bike for my wife but it will probably be rode by my daughter in law, my wife has said she would like a trike.
 
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Jimmy Bloodmaker

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i have a 24" build. lotta fun. not as fast as a 26", but winds up way faster. tht 44 and a 24" will climb any hill. if its all muddy or grass you might have to pedal a bit. out of all my bikes i love my 24" the best. rougher ride on the street, but tight maneuvering and good torque gets me anywhere i wanna go. 24" makes a great trail buster.
 
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indian22

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Yes Jimmy I agree the 24" with a 44 t is a nice setup. I also am 6'1" and prefer the 26" plus for long rides but the 24"is a hoot for shorter scoots, even for taller riders!

Rick C.
 
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Greg58

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I haven't had time to do much on the bike, I did pick up a free Donner bike that has a set of handle bars that I like. We skipped spring here in Georgia and went straight to summer, mowing grass and planting the garden, plus pressure washing and cleaning and so fourth. The temperature has been in the mid 80's most days, I'll get back to the bike as soon as I get a little closer to caught up.
 

Jimmy Bloodmaker

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I haven't had time to do much on the bike, I did pick up a free Donner bike that has a set of handle bars that I like. We skipped spring here in Georgia and went straight to summer, mowing grass and planting the garden, plus pressure washing and cleaning and so fourth. The temperature has been in the mid 80's most days, I'll get back to the bike as soon as I get a little closer to caught up.
oh man, the bike always comes first. she's sitting there wondering what she did to lose your attention. you better get back to her before she decides she wants someone elses rear end on the seat. lol ;)
 
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Greg58

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I'm getting closer, if I didn't have two bikes to ride I would probably be working on it now. I kinda got behind last year, had knee surgery late December 17 and it took a while to recoup. Too many moons have past I guess. I got all my pressure washing done( including my shop). Had to repair the pull start on the pressure washer Saturday morning before I could finish.
 
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indian22

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Greg A man gets older and time speeds up as work expands at exponential rate, there may be a theory in all that...

Rick C.
 

indian22

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Wise man Greg. Old guys must appear easy targets for all manner of projects, not all of which are voluntary in nature.

Rick C.
 

Greg58

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I did a little on the bike today, got the bars on and changed the seat, set the engine on to fabricate the front mount. I’m thinking of using the water bottle mounts to connect the mount to the frame. I stuck a tank on to kinda get idea of what it will look like.
 

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Greg58

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I got the bike together today, did a couple of tests to find that the CDI I had is bad. I'll probably stick on the homemade one i built a couple of years ago to see how it runs. I hate it when I dont throw away bad parts.
 
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Jimmy Bloodmaker

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i've
I got the bike together today, did a couple of tests to find that the CDI I had is bad. I'll probably stick on the homemade one i built a couple of years ago to see how it runs. I hate it when I dont throw away bad parts.
been using a bbr stage 1 cdi with a super magneto, bang up combo for reliability. used to get some missing in the top end ( i have a high hat high compression head on my main bike), the combo fixed it. i was also burning through cdi's ( must have been a bad batch i bought, usually they last at least a season). the super magneto coil has i think 36 or 38 hundred wraps instead of 26 to 28 hundred. coupled with the stage 1 cdi i get a purple spark now, means it's really hot. was a tiny blue to white spark. now it's thick and robust, great for high compression at higher rpms. haven't had one problem with my engine since. i think the cdi has a slightly retarded curve compared to stock, at least it acts tht way and runs a bit cooler with it. try one out, i'd like to hear what other people think of them, i can't find any info on here about them at all. so it was a buy and try, working pretty good so far, 800 miles or so on it.
 
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Jimmy Bloodmaker

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I got to do a couple of test runs today, flat out on flat ground I got 28mph, that’s with 24 “ tires and a 44 tooth sprocket. The little 48 was really humming too.
thats about right for a 44 on a 24". i'd keep it around 18-20 if you want the motor to last. really though if you want some lower rpm's at cruise, run a 36 tooth or even a 32 tooth. i am running a 32 tooth on my main bike, it's a 24" mtb.
 
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