Hello Everybody!
I recent purchased two old non running cb750's (Craigslist bundle) to start a little side project after being intrigued by some of these custom rides on this site and on the net in general. I current work as a mechanical engineer in an aviation interiors company. As much as i like my job sometimes the aviation thing gets a bit stale(too much red tape on imagination), so as an exercise i wanted to digitally mock-up my project as we do in the aviation business to essentially a bare bones level then add my own features, go through trial and error and eventually be able to make the "blueprint" of my final product and start fabricating once i know what this thing is going to look like. Its a good exercise to keep my CAD skills in check and some portfolio material for perhaps some side work in the future.
So most important to me at this point, is gathering the data from the parts as i am disassembling the frame. Typically what i do is grab the dims using caliper, rulers whatever to the best of my ability, then follow it up with a 3D scan of the part to make sure my dimensions are on point, if not i just readjust the model where it needs to and go on from there. During this timeline in parallel i'm trying to refresh the engine so at least that keeps moving forward as its the "heart" of the bike.
So this is what the first bike looked like when i bought it.
I had decided on using modern front suspension so i scored some 03 GSXR forks in great condition for a great price. First thing i did was take them apart and reverse engineer them since i will need that data to establish the necessary dimensions for fabricating spacers to line up the brake rotors from the original cb750 hub.
I took special care to validate the dims on the lower portion of the fork. So i used a 3d scanner from work, and overlayed the data over my CAD model to make sure everything lines up correctly.
I travel quite a bit to Montreal for work so i had to pretty much eyeball things from when i was over there and then put the correct dimensions in when i got back home. This is an early mockup of the rear of the frame i was using so i could get an idea of what i wanted to do for an under seat oil tank.
Just this weekend i finally had a chance to survey the front hub properly and model that so i could start working on an adapter for both sides of the hub to allow mating with the newer brakes. I'm not quite happy with how i modeled this setup, ideally i want to make a configurable model so i can plug in rim diameters and widths and have all the parts automatically update (so i can easily see how different wheel sizes effect the stance and look of the bike. ) The hub is validated but the spokes and rims are stuck at 19''. I was pretty much learning how to lace a wheel up on the fly.
Also since then i have completed the frame to some extent, the front motor mount holes i still need to measure out. Here's a mockup of all the parts i have going so far.
So that's it for now, the "real" bike is pretty much completely apart at this point. Hoping to have the rear wheel mocked up soon, and make this thing a virtual roller. At the end of the day the goal is to gather information while i'm working on the bike and perhaps make a configurable model to validate design intent and mockup concepts to have a solid plan before cutting anything up. I think i'll take the 2nd post on this tread as well to document the "real" bike build and leave this one as the digital build.
I've been posting up more progress pics on instagram under the handle D_lobos if anyone wants more up to date updates.. Thanks for looking!
David.
I recent purchased two old non running cb750's (Craigslist bundle) to start a little side project after being intrigued by some of these custom rides on this site and on the net in general. I current work as a mechanical engineer in an aviation interiors company. As much as i like my job sometimes the aviation thing gets a bit stale(too much red tape on imagination), so as an exercise i wanted to digitally mock-up my project as we do in the aviation business to essentially a bare bones level then add my own features, go through trial and error and eventually be able to make the "blueprint" of my final product and start fabricating once i know what this thing is going to look like. Its a good exercise to keep my CAD skills in check and some portfolio material for perhaps some side work in the future.
So most important to me at this point, is gathering the data from the parts as i am disassembling the frame. Typically what i do is grab the dims using caliper, rulers whatever to the best of my ability, then follow it up with a 3D scan of the part to make sure my dimensions are on point, if not i just readjust the model where it needs to and go on from there. During this timeline in parallel i'm trying to refresh the engine so at least that keeps moving forward as its the "heart" of the bike.
So this is what the first bike looked like when i bought it.
I had decided on using modern front suspension so i scored some 03 GSXR forks in great condition for a great price. First thing i did was take them apart and reverse engineer them since i will need that data to establish the necessary dimensions for fabricating spacers to line up the brake rotors from the original cb750 hub.
I took special care to validate the dims on the lower portion of the fork. So i used a 3d scanner from work, and overlayed the data over my CAD model to make sure everything lines up correctly.
I travel quite a bit to Montreal for work so i had to pretty much eyeball things from when i was over there and then put the correct dimensions in when i got back home. This is an early mockup of the rear of the frame i was using so i could get an idea of what i wanted to do for an under seat oil tank.
Just this weekend i finally had a chance to survey the front hub properly and model that so i could start working on an adapter for both sides of the hub to allow mating with the newer brakes. I'm not quite happy with how i modeled this setup, ideally i want to make a configurable model so i can plug in rim diameters and widths and have all the parts automatically update (so i can easily see how different wheel sizes effect the stance and look of the bike. ) The hub is validated but the spokes and rims are stuck at 19''. I was pretty much learning how to lace a wheel up on the fly.
Also since then i have completed the frame to some extent, the front motor mount holes i still need to measure out. Here's a mockup of all the parts i have going so far.
So that's it for now, the "real" bike is pretty much completely apart at this point. Hoping to have the rear wheel mocked up soon, and make this thing a virtual roller. At the end of the day the goal is to gather information while i'm working on the bike and perhaps make a configurable model to validate design intent and mockup concepts to have a solid plan before cutting anything up. I think i'll take the 2nd post on this tread as well to document the "real" bike build and leave this one as the digital build.
I've been posting up more progress pics on instagram under the handle D_lobos if anyone wants more up to date updates.. Thanks for looking!
David.
