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  #7901  
Old 03-29-2015, 07:19 PM
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mapbike mapbike is offline
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Default Re: what did you do to your motorized bicycle today?

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Originally Posted by Davezilla View Post
Good job on that seat post map... When I did mine up last summer I did it pretty much the same way but used a miter chop saw to cut the post at a 45 and welded it back together with the TIg welder, but I could feel it flexing when I was riding so I took it back off, stripped off the paint and welded in a brace that runs from the seat mount to about an inch down the post which made it feel a lot more rigid. I just made my brace out of 1" angle iron and so far it's held up to any abuse I've thrown it's way.
Thanks Dave, yeah I may need to brace this one also, I cant notice any flex when I sit on it but I may cut out two small triangular shapes and weld them on each side of the bend.

I used my 4 1/2" grinder with a 1/16" Dewalt cut-off disc and just cut through enough so that I could bend short section over until I had the angle I wanted and the I sewed it all up real good with the hanged rod, mine was cut completely in two so Im thinking by doing it the way I did it has retained a good bit of it strength, I really dont think it will ever fail on me, I may add the braces just for insurance factor.....lol

The bsouth end of the north bound mule dropping down on the rear tire at 40mph would be an ugly event that will bring an entirely new definition to a "skid mark"....lol!
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  #7902  
Old 03-29-2015, 07:35 PM
curtisfox curtisfox is offline
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Default Re: what did you do to your motorized bicycle today?

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Originally Posted by mapbike View Post
welds dont have to be pretty to be good and strong, they just need to be done right with good penetration so the parts are fused together well.

Seen many shallow weak welds that looked real nice but failed when they got under pressure.
You got that right, been 50 years sence I got my torch,now mig. The biggest is to clean the metal first, LOL..........Curt
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  #7903  
Old 03-29-2015, 07:58 PM
BOYGOFAST BOYGOFAST is offline
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Default Re: what did you do to your motorized bicycle today?

Took a quick look at the 66 cc again removing a small amount of piston skirt that hangs over the intake port at top dead has been a thought today..
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  #7904  
Old 03-29-2015, 08:23 PM
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Default Re: what did you do to your motorized bicycle today?

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You're very welcome Mark, glad I was able to help in some way, hope it works out great for you.

I been painting primer coat on the trim of my workshop today and then after slinging that paint brush in the 90+ Texas heat today Ive gone into the shop with a couple fans blowing and done a little work on "Taffy" as you suggested I call this bike.....lol!
Im thinking thats gonna be her name, yellow frame, black forks, hrome wheels, red balloon cruiser tires.....

Taffy works for this one....

Seems fair, as I think you named this one.......lol

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  #7905  
Old 03-29-2015, 09:22 PM
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Default Re: what did you do to your motorized bicycle today?

instead of notching the skirt try drilling 4 holes in the skirt two 31mm from bottom ring then two more at 34mm from bottom ring helps keep the integrity of the skirt
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  #7906  
Old 03-29-2015, 10:50 PM
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Default Re: what did you do to your motorized bicycle today?

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instead of notching the skirt try drilling 4 holes in the skirt two 31mm from bottom ring then two more at 34mm from bottom ring helps keep the integrity of the skirt
Have you done this mod?

How is someone gonna drill holes in the very small amount that doesn't clear top of intake port when piston is at TDC when usually only 1/8" - 3/16" is all that needs to be trimmed.

drilling holes above the area that usually needs trimming is gonna be a performance killer since as piston moves downward creating the primary compression that forces the air fuel mix into transfers and ultimately into combustion chamber.

Maybe I've just misunderstood,if so please explain so someone doesn't start drilling holes in the wrong place their piston and ruin the piston.
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  #7907  
Old 03-29-2015, 11:35 PM
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Davezilla Davezilla is offline
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Default Re: what did you do to your motorized bicycle today?

I agree... drilling holes where there needs to be open space will kill performance as well as ruin a piston... what you're describing works with reed valves but not piston port engines and these engines don't come with reeds.... be sure you know what type of engine the guy has before recommending something that can mess up their engine or parts...
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  #7908  
Old 03-30-2015, 01:26 AM
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Default Re: what did you do to your motorized bicycle today?

your right I was referring to a reed valve set up. I just put one on my motor and the performance is amazing !!! my top speed is 47M.P.H. im running a 36 tooth adapter from gasbike.net he has some very good priced.
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  #7909  
Old 03-30-2015, 01:39 AM
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mapbike mapbike is offline
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Default Re: what did you do to your motorized bicycle today?

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your right I was referring to a reed valve set up. I just put one on my motor and the performance is amazing !!! my top speed is 47M.P.H. im running a 36 tooth adapter from gasbike.net he has some very good priced.
ah ha.... now we know.....lol

Yep a reed set up is different, I knew this would get cleared up quickly....

Thanks DRBS
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  #7910  
Old 03-30-2015, 01:58 AM
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Default Re: what did you do to your motorized bicycle today?

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instead of notching the skirt try drilling 4 holes in the skirt two 31mm from bottom ring then two more at 34mm from bottom ring helps keep the integrity of the skirt
Just for curiosity and for info for others who may want to run reeds.

What diameter are the holes you drilled and exactly where didyou drill them in the piston?


This would be good info to share here since other curious about running reeds would have a chance to know what kind of mods would be needed to make the setup work right.
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