Mountain Bike Build

GoldenMotor.com

jschatte

New Member
Dec 19, 2010
20
8
3
Saskatchewan
So I was brainstorming with my friend on saturday as what to do with my 50cc horizontal engine I have sitting in my basement. After a while on the computer, I came up with this. What do you guys think?
 

Joaquin Suave

New Member
Dec 9, 2008
75
0
0
Alta & Baja California
Please don't take this the wrong way...

If your are REALLY interested in mechanical design,than you should build it. If for no other reason than to see how it would fail.

I think you need to do a little more research into "cycle" structure design.
 

kevinkrg6

New Member
Jun 3, 2011
170
0
0
ohio
Looks cool to me, of course, I would want a bigger motor......

Yeah, I have no idea how that would perform though.

Looks like there would be way too much leverage on that rear shock.
 

jschatte

New Member
Dec 19, 2010
20
8
3
Saskatchewan
Thanks kevinkrg for the input... I feel good about the rear shock. like you said its not the best setup, but I modeled it similar to those smaller honda pit bikes, so I will assume it would be fine.

Joaquin Suave... I did kind of take it the wrong way. I was looking for input but all you said was build it and see it fail. thanks.Instead of maybe saying what you think the reason for failure would be.
 

NunyaBidness

Active Member
Jun 29, 2008
1,062
2
38
memphis tn
I'm just guessing here, I think he is referring to the single top tube. I bet it would have catastrophic frame failure somewhere along the top tube. The traditional diamond style frame has been around so long for a reason.
 

jschatte

New Member
Dec 19, 2010
20
8
3
Saskatchewan
ok... that makes sense. I made it similar to the motorbike fram i took the engine off of, as it did not have a lower tube. But yeah it would definately benifit from the extra support, this horizontal engine just makes it hard to fit that tube in there.
 

NunyaBidness

Active Member
Jun 29, 2008
1,062
2
38
memphis tn
That does look a lot better. There are sites that discuss, in great detail, how to build a good frame. The next weak spot looks like your rear swingarm. My old full suspension TREK that I used to have used a triangle for more strength and rigidity.

Please don't take these suggestions as slights on your design. We all only want to see you build a frame worthy of a motor. Something that you will be able to enjoy riding without having to worry about your frame failing on you. I'm following this thread because I want to watch you succeed at this build and this is the kind of motor bike that I'd like to build myself.
 

KDB

New Member
Jun 19, 2011
47
0
0
Maryland
I bit my lip when I saw that single top tube and though about all the stress that would be on it but I was going to suggest making it a lot thicker and using it as an integral gas tank.
 

NunyaBidness

Active Member
Jun 29, 2008
1,062
2
38
memphis tn
I bit my lip when I saw that single top tube and though about all the stress that would be on it but I was going to suggest making it a lot thicker and using it as an integral gas tank.
That's what I've been thinking for the frame I would like to build for a motor. I would put some curve to it instead of a straight design.

I am very interested in what the OP comes up with and rather anxious to see the end result. I haven't posted much in the few years I've been a member here only when I feel a keen interest in the tread. I love to see what other members here come up with to build. Maybe one day I will be able to incorporate all of the ideas I have gained here into a build of my own.
 

Joaquin Suave

New Member
Dec 9, 2008
75
0
0
Alta & Baja California
Joaquin Suave... I did kind of take it the wrong way. I was looking for input but all you said was build it and see it fail. thanks.Instead of maybe saying what you think the reason for failure would be.
Sorry you didn't like my input! When I first started learning to design and build frames, I built and broke close to a dozen of them until i got the structure and geometry correct. There was no internet back then and only 2 or 3 other people building "those strange bikes for riding on dirt trails" (mountain bikes). There was no one ask...So I tried my best and make a frame, then went out and broke it...then went back to the "drawing board".

That is why i suggested what I did!

Not that you are doing this...But it kinda irks me when somebody (usually a kid) makes some rudamentry drawing of a gizmo than asks for input rather than first doing some research about how others have have designed the same gizmo before them. To me it is like saying...Hey will somebody design this for me but I going to the credit for my fantastic design.