1981 gs750 (gs750e) Retro Racer project

[LarsKroghStea]

When researching how to route the wires, I also came upon a diagram showing how to route the cables:

Wire routing_3 by Lars Krogh-Stea, on Flickr


The same problem arises here, as the handles are so low, that the cables must be routet differently. I will have to do some googling to se how others have solved that problem, as I'm not comfortable with the cables going in big loops from the handlebar to the frame. In the picture, the "flat handle model" shows some degree of loop, and I think that's manageable.

[LarsKroghStea]

One final point for today: I read through my discussions with posplayr about correctly grounding the R/R etc (https://www.thegsresources.com/_foru...the-1982-gs750). I learned a lot from it, and I think he and I were essentially aggreeing in the end. One thing I will stand corrected on not beeing to clear on, is that the SPG (in my drawings) he was going on about, is in reality through a bolt to the frame. That means the R/R is grounded to; the frame, the loom and the battery, as he recommended There's also a common ground at the front of the frame (for handlebars, lights etc), and that groundpoint has it's own wire to the SPG. The ground for the ignitor and horn is through the front ground point, but I'm not changing my drawings as I would rather spend time on the actual wiring

The rear lights also has their grounding through SPG.

Feel free to ask or comment, I'm still figuring this out

In the app for the Mo-unit blue (as it is now called, I still have the same unit) I can turn on and off the different inputs and outputs, so it is easy to check for faults. There's also a readout for electrical current on all outputs, so I can check if I have an issue with unwanted grounding/unwanted draining of the battery.

[Suzukian]

I wasn't here when this thread started, having run through it very quickly, awesome CAD skills, I use Rhino3D. I used to program 3,5 and 8 axis CNC machines. Seeing what you are doing at home is very inspiring. You are a 1%'er!!

[LarsKroghStea]

I wasn't here when this thread started, having run through it very quickly, awesome CAD skills, I use Rhino3D. I used to program 3,5 and 8 axis CNC machines. Seeing what you are doing at home is very inspiring. You are a 1%'er!!

Thanks! I don't have anyone to compare myself to, as the guy who owns the CNC only uses it for wooden cabin signs I use Fusion360 (non commercial license) for modelling 3D printed parts. They arre printed via Ultimaker Cura. For CNC, I used the software my friend already had, Vectric Aspire for modelling and setting toolpath etc., and NC Studio for controlling the CNC router. About 25 years ago, I got hold of a copy of 3D Studio max and did some 3D modelling (waiting 30 hours for a picture to render..), and adapting basic understanding of 3D modelling to CNC/3D printing wasn't too much work.
I really like working with these machines, and my wife always say I would be happier if I was an engineer. Maybe she's right, but I'm turning 50 next year, so I think I'll just stick to what I do and try to set aside some time for hobbies.
It's nice to know that we have a CNC expert on the board, and I'll probably message you when I get my own CNC up and going. Milling the parts I have now was a lot of work, as neither of us had any experience with rpms and toolspeed for effective machining of aluminum (Also; had to google 8 axis CNC.. looks awesome )

[Suzukian]

You are an engineer. You just don't have a piece of paper saying so.

If you have any children, or grandchild, or related child, in school, you can get a full working version of Rhino 3D NURBS Modeling for 3 computers for only $200 bucks. It is the same as the commercial version, and you can use it for profit. You can give it to a minor as a gift, you just need their student I.D. to buy it. It allows you to mount it on 3 different computers. It was used to make the Space Shuttle Tiles, many sets for movies, Nike Sneakers, the list goes on. It's N.U.R.B.S. modeling capabilities are unmatched. 1000's of videos using Rhino on YouTube.

https://www.rhino3d.com/

N.U.R.B.S.(Non-Uniform Rational B-Splines) in a nutshell:

NURBS in 3D modeling are used to create curves and curved surfaces. Whenever you need to create a unique or unusual curved shape quickly, without worrying about painstakingly carving it out by way of pure polygonal geometry alone, NURBS curves make following any example easy.

[LarsKroghStea]

If you have any children, or grandchild, or related child, in school, you can get a full working version of Rhino 3D NURBS Modeling for 3 computers for only $200 bucks.

Will definitely test that out. I remember NURBS becoming a thing, but Youtube wasn't a thing when I dabbled in 3D modelling, so the learning curve was too steep. I've looked for a way to model more organic shapes, so Rhino looks interesting.

One thing i did try, was "generative design". For those of you not familiar, you specify mounting points, maximum dimensions and interfernce points, materials and load requirements etc. Fusion360 then calculates an organic shape meeting your requirements, and at the same time optimizing for weight/material use. I made brackets for my headlight, but they looked too futuristic for my style.

For reference, this is how a swingarm looks when it's generated only for purpose, not for looks:


You can read more about it here: https://www.autodesk.com/campaigns/g...ng-motorcycles


And here's a complete elektric bike. The weight savings for theese designs are typically between 30% to 50%, while retaining torsional rigidity optimized for your application:



More pictures here: https://www.carbodydesign.com/2016/0...bionic-design/


Well, I digress.. But I am thankful for the NURBS-info. I'm making a small housing for the Motoscope Mini, as I want to move it from the headlight to the top triple. Rhino/NURBS might be perfect

[Suzukian]

I cannot make a swing arm like that. I can make you a bulk head for a Blackhawk helicopter, or CH53 series, but I know my limitations. The NURBS modeling is Rhino is so fluid, once you start working with it, and with it's smash, squish, and unfolding a developable surface functions, you'll find it's a hard program to beat. It exports into over 60 different formats, so you can make a model on Rhino that 3DS Max, or Cinema Las Vegas Pro can read. It's very compatible.

One of my Paper models.

Stealstar.jpg

[LarsKroghStea]

I cannot make a swing arm like that. I can make you a bulk head for a Blackhawk helicopter, or CH53 series, but I know my limitations. The NURBS modeling is Rhino is so fluid, once you start working with it, and with it's smash, squish, and unfolding a developable surface functions, you'll find it's a hard program to beat. It exports into over 60 different formats, so you can make a model on Rhino that 3DS Max, or Cinema Las Vegas Pro can read. It's very compatible.

One of my Paper models.

Stealstar.jpg

That's awesome

[Suzukian]

Thank You! The model unfolds flat. I may release it, not sure yet. It would be a complicated built, but more intricate, than complicated. This was all done with Rhino 3D.

[LarsKroghStea]

Haven't ordered anything for the bike in a couple of years, so I decided to fix a problem I've postponed for a while. I've bought some really cheap turn signals from ebay earlier, and they've all turned out to be crap. In sunlight it's almost impossible to notice when they're blinking. Two of the sets have decent light output, but they either look really cheap or they're too big. So, as a "back on the horse"-gift for my self, I ordered the Mo.blaze tens 1 for the front turn signals. Maybe not worth the money, but they are exactly what I was looking for A step up in safety too.



Image from the web:


I 3D-printed these headlight-brackets to test headlight placement, and I'll make new ones in aluminum with an M8 threaded hole for the Mo.blaze tens'.

[LarsKroghStea]

I want the bike to be easy to move around, so I'll start with throttle, clutch and brakes. I've ordered Domino XM2 Throttle with universal cable kit. It's a push/pull setup, but I will only be using one cable and block the other holde. Then I have on in reserve. The sleeves are teflon-lined for low friction, and the kit includes two small teflon tubes for the adjustable carburettor end. They will be cut to fit the adjuster of choice. The kit also include two small "lock-barrels" with set screws. I also ordered ODI grips.

The kit looks like this (the old throttle-cable is in the picture for comparison):

[LarsKroghStea]

The finish is great:


It seems like the barrel clamps down really well. When all is good, I'll fix it with locktite and keep a spare with me. I had to cut a couple of strands from the old cable, as the Domino cable is thinner.



Here's a test with some old gsx750 carbs:

The original cable had a bend in it, near the carbs, so I think I'll go with the prebent adjusters. Any advice (apart from cleaning the engine..)?

[LarsKroghStea]

Fitted the throttle today, and the wire is extremely smooth. The kit came with three different cams; green, white and red. The red cam gives fast resonse from the start, then tapers off. The white has a greater circumference all the way around, and requires less twist to full throttle. The green one is the mildest, and the one I'm choosing as I think it will be easier around town. The other two are mainly for racing.






The bends have separate teflon tubes:




The sleeve was about 22cm too long:




The bend at the carb end made for a pretty smooth installation, and a nice slope towards the frame:




This is with the handlebars pointing straight forwards:




And this is with the handlebars all the way to the left (more than all the way, as I haven't installed the stoppers yet):

[93Bandit]

Holy smokes the corrosion on the carbs in that image!

[LarsKroghStea]

Holy smokes the corrosion on the carbs in that image!

I know.. It breaks my heart
Luckily, I took off some of the parts before I put the bike away. The old shed where I kept the bike was more damp than I knew. I cleaned and refurbished the carbs and painted the engine the year before, and now it looks like crap. The aluminum surface of the engine has also corroded, and the paint is flaking off. I'm not sure how I can fix this, so I'll fockus on finishing the build first, then I'll have a go at the paint. I'm considereing buying a set of engine sidecovers and a valve cover to make the job easier. The carbs will be pretty easy to clean, but I'll probably wait until winter before I take them completely apart.