jag767
Over 1,000 Posts
The back story to this new project is about a year ago I picked up an old school looking cruiser bicycle to give away as a promotion for my boxing gym. The promotion didn't really go over well, and this thing has been sitting in the place ever since. So for a year now I've been looking at it thinking how much the overall shape would make an awesome looking motorcycle frame. Hell, the tubing is plenty thick, large enough diameter, and has beautiful mandrel bends in it. Why not just cut it up and use the tubing?
Here's the plan. I've had a cb100 motor kicking around for some time now, and the only part that's up in the air is I which motor to use, my 175 or the 100. If I use the 175 I will be riding this a lot, as I will the take the wheels, front end, etc off the bike for this project. If I go with the 100 I will have to buy everything else for it. Certainly not in the finances at the moment, so will take longer to build. Also, it would be ridden a lot less if I go with the 100.
Here's my plan for the frame. Single 1.5 inch OD downtube running down and under the motor, single 1.25 inch OD backbone, will fab up proper mounts depending on motor. Rigid rear, and still unsure if I want to weld a seat to the frame or run a monoshock under it. 1 inch tube for the rear of the frame, will bend it up to house cb175 rear wheel correctly. Thinking a 2 to 4 inch stretch in the rear section over a stock cb175 frame.
Here's the list of questions I'm in need of input on.
Which motor should I use and why?
Would the 175 be too much stress for that backbone/downtube combination?
Head tube angle?
Anyone machine head tubes and can give a little input?
I can do it no problem on my lathe, just curious what material and how to cut for bearing cups. I read 2 1/4 inch OD with 3/8 wall is what I'm looking for, would like to confirm.
How much would you stretch the rear? 2, 3, or 4 inches?
Any other advice?
Frame will be getting chopped up today, will post some pics as I go!
Here's the plan. I've had a cb100 motor kicking around for some time now, and the only part that's up in the air is I which motor to use, my 175 or the 100. If I use the 175 I will be riding this a lot, as I will the take the wheels, front end, etc off the bike for this project. If I go with the 100 I will have to buy everything else for it. Certainly not in the finances at the moment, so will take longer to build. Also, it would be ridden a lot less if I go with the 100.
Here's my plan for the frame. Single 1.5 inch OD downtube running down and under the motor, single 1.25 inch OD backbone, will fab up proper mounts depending on motor. Rigid rear, and still unsure if I want to weld a seat to the frame or run a monoshock under it. 1 inch tube for the rear of the frame, will bend it up to house cb175 rear wheel correctly. Thinking a 2 to 4 inch stretch in the rear section over a stock cb175 frame.
Here's the list of questions I'm in need of input on.
Which motor should I use and why?
Would the 175 be too much stress for that backbone/downtube combination?
Head tube angle?
Anyone machine head tubes and can give a little input?
I can do it no problem on my lathe, just curious what material and how to cut for bearing cups. I read 2 1/4 inch OD with 3/8 wall is what I'm looking for, would like to confirm.
How much would you stretch the rear? 2, 3, or 4 inches?
Any other advice?
Frame will be getting chopped up today, will post some pics as I go!