mountain bike thing

[jak stoll]

so I got the sprocket on the back wheel
I used some bits of 1/8 inch plate which I threaded to put on the inboard side of the spokes
this is a 32 spoke wheel so I drilled a 4 bolt pattern & used 8mm bolts
the sprocket centered perfectly I put tire rubber on the inboard side & inertube between the the sprocket & spokes
I took apart a dirailure ? I actually used a porting burr on the inside of the plastic sprocket so I could get a skateboard bearing in there

it keeps the chain pretty tight but this engine is bump started so Ill need something more robust with a skateboard wheel as a tensioner
when the chain is pulled tight it dosent hit the frame on top by about 1/4 inch

this is about where it stands for now
take care
JAK

[mabman]

Unless you re-heat treated that frame after doing all that fabrication I would be real careful about riding it.

[jak stoll]

Originally Posted by mabman

Unless you re-heat treated that frame after doing all that fabrication I would be real careful about riding it.

thanks man :-)
IM not worried about heat treating as I am stress relieveving
so the welds & tubing next to the weld should be heated & let to cool at its own time


have a great week
JAK

[mabman]

JAK, I certainly recognize your skill as a designer/fabricator/mechanic but my mentor in regards to all things bike frame building is very knowledgeable in the ways of all types of materials, Steel, Alu, Ti and Carbon Fiber for construction of said bike frames and one of the things that he told me awhile back that has stuck with me is the fact that whenever you reweld aluminum like 6061 or 7005 the entire frame needs to be re heat treated in order to really make it stick.

I sent him a picture of your bike and your latest response and his was "You have to be kidding me."

This isn't about disrespect for what you, and others on this site, are doing in order to get to their ultimate goal(s) of having the MAB of their desire as cheaply as possible by using parts at hand and I have warned others of this before here and other places. I don't do it for any other reason than to save someone from experiencing the type of failure that can occur if the material fatigues then fails due to not only the fact that the base bike was never designed to have a motor/extra torque/extra weight in the first place, but cutting it apart and refabbing it just adds to the danger that what can go wrong, eventually will. May be not for you, but for someone it will and already has I'm sure. I have seen a number of frames on these boards that broke in stock form for instance.

Anyway that will be the last I have to say on this matter and do as you will. Have a nice week yourself and a Happy and Safe Holidays.

BP

[jak stoll]

Originally Posted by mabman

JAK, I certainly recognize your skill as a designer/fabricator/mechanic but my mentor in regards to all things bike frame building is very knowledgeable in the ways of all types of materials, Steel, Alu, Ti and Carbon Fiber for construction of said bike frames and one of the things that he told me awhile back that has stuck with me is the fact that whenever you reweld aluminum like 6061 or 7005 the entire frame needs to be re heat treated in order to really make it stick.

I sent him a picture of your bike and your latest response and his was "You have to be kidding me."

This isn't about disrespect for what you, and others on this site, are doing in order to get to their ultimate goal(s) of having the MAB of their desire as cheaply as possible by using parts at hand and I have warned others of this before here and other places. I don't do it for any other reason than to save someone from experiencing the type of failure that can occur if the material fatigues then fails due to not only the fact that the base bike was never designed to have a motor/extra torque/extra weight in the first place, but cutting it apart and refabbing it just adds to the danger that what can go wrong, eventually will. May be not for you, but for someone it will and already has I'm sure. I have seen a number of frames on these boards that broke in stock form for instance.

Anyway that will be the last I have to say on this matter and do as you will. Have a nice week yourself and a Happy and Safe Holidays.

BP

well if it breaks Ill fix it better :-)
hopefully no one will be hurt
take care
JAK

[jak stoll]

Oh by the way
that is not aluminum :-)
its steel
take care
JAK

[mabman]

My bad I guess but I was unaware that Mongoose ever made a steel FS frame and that section that says se looks alot like an oversized aluminum tube to me.

[jak stoll]

yeah this was a real crappy one :-)

the part near the head tube is actually 2 1/4 mandrel bent aluminized steel exhaust tubing I use sometimes here :-)
have a great week & hapy holidays
JAK

[jak stoll]

I rode it today as a bicycle :-)

I got the cranks, rear deraliour ? (I have no idea how to spell that)
& the chain
Im going to run a cheap cable disk setup in front I think so its that & the cables for the start clutch, throttle & brakes

I cant wait to ride it with the engine
take care
JAK

[jasonh]

That thing is just...weird. ...but I like it!