Frankenbike function over form

[mickal1025]

I loved the idea of riding my motored bike to work but hated the heavy vibration and constantly streaching chain so I built a alternative motor mount and tested it a little while ago. it worked just the way I had hoped it would so I'll start with a discripion and post pics after Tammy shows with her spare camera (mine craped out after 3 pics).

I started with a 1 1/8 OD pipe and cut and welded it in a V shape to match my bike frame. then I welded a 1 in long by 1 in OD by 3/4 ID bushing to the V tube. next I cut and drilled 2 mounting plates, each mounting plate has bolt holes for mounting and a 3/4 in hole centered in the plate. I then assembled all this on the bike using a large washer on either side of the bushing with a 3/4 in bolt going through the plates, washers and bushing. then I bolted it to my bike frame. when I was confident it would work I gambled and tack welded the plates to the frame then put a longer chain back on my bike. I next put 2 utility springs between the frame and new mount. these proved to be too weak so I added a car brake spring to each side. this worked out just right. the mount lets the motor move forward and back while the springs keep tention on the chain. the 3\4 in bolt is tight enough that it works like a brake so it dampens vibrations. if it continues to work and proves dependable I'll look forward to my daily commutes. now for the pics

 

[mickal1025]

I was having trouble uploading pics.

I'll try again.

I also had to lengthen all my wires. when I did this I twisted about 6 in of wire tightly around a small screwdriver shank so my splices will stretch without breaking.

 

[azbill]

does it give any chain tension probs?
that is the only thing that I would worry about

 

[just for kicks]

Wouldnt a spring loaded chain tensioner do the same thing?

I wonder what the constant added stress on the chain will do to the drive sprocket bearings.

Do you have a stop anywhere to stop the motor from rocking backward (for whatever reason) and slacking up the chain and maybe cause it to bind up in the engine case.

 

[mickal1025]

I dont know about a spring loaded chain tensioner. I've never used one. but this cut down on the vibration alot and I can still push the center of the chain down 1/2 in or so with firm finger pressure. I havent had any problems with the mount hitting the frame and right now there is only about 1/2 in of clearace between the mount and the frame. time will tell. I just got it all together this morning and went for 1 short ride so I dont know if its going to be durable. I'll know alot more tomarrow after I ride it to work, the 18 mile round trip should tell me alot.

 

[just for kicks]

I cant hardly wait to read the ride report.

It is a very interesting mod.

 

[srdavo]

cool idea.....I've seen a couple old, OLD, homebuilt scooters, with spring loaded engine mounting plates, to keep tension on the belt-drive.
I really hope this works out for you. (for us too )

Now I must say...... if you can no longer feel all the vibration, good. But it did not go away. It is just concentrated somewhere else.
keep an eye on all your add-ons. and all the nuts & bolts on your engine/bike. (I've had bolts vibrate out of the clutch cover :???: )

just be safe & keep us posted. 8)

 

[custom_tecumseh]

Ingenious mod you got there, can't wait to see how it performs for you.

 

[Large Filipino]

Wow. That's what I call thinking out of the box.
That's seriously brilliant. BRAVO!

 

[mickal1025]

thanks. I think the vibration is being mostly absorbed where the bushing contacts the big washers at the pivot point. I dont know, i'm just guessing.
I'll get some miles on it andpost an up date. thanks again for all the great comments.