Topic: Pin2Hot's 73 CB750

[Pin2Hot]

Making slow progress but progress nonetheless.  My main goal is to get the headlight bracket made up because basically all of the wiring depends on its location.  Mocking it up has been a challenge to the weight of the headlights so I'm starting to make a first pass at it with sheet metal instead of cardboard.  I'll document that process when these little magnets I've been waiting for show up but in the meantime I've been working on cosmetic items as well as shortening up some cables.

The clutch cable was about 4 inches too long so I ended up shortening it up.  I was pretty nervous to tackle this because I wasn't certain I'd be able to effectively solder on a new barrel but it ended up being pretty straight forward.  I got some new barrels off of eBay and started chopping.

Some solder flowed down onto the cable a bit but I think it'll be alright.


Made the cable wrap much more neatly down through the forks.  Going to tackle the throttle cable later:


I'm going to use this fancy heat shield for the clutch cable and ignition wiring just for funsies.  Not in its final location but will look similar, may shorten a bit:


One of the reasons this project takes fcking forever is because I decide to wrap every wire but in the end it's worth it.  A big challenge in fitting these Deutsch connectors is making sure the wires are the same length so that things look nice in the end.  So I spend a lot of time pre-routing the wires and getting them how I want them before cutting.

Pre-routing/forming the reg/rec wires and chopping them evenly:


Crimping pins onto the wires.  I ended up re-doing the red one as it wasn't that secure.  I refuse to spend $380 on the proper tool to crimp this specific connector so I've been using a different crimping tool which does an OK job.  I then solder (YES, I SOLDER MY CRIMPED JOINTS) the pin only where it's crimped (not shown in this pic) to ensure a good connection.


Then I spent some time working through the last bit of control wiring on the right handlebar that houses the kill switch, start push button and front brake switch.  Honda does this funny thing inside the housing where it basically folds over and glues in the front brake switch to "clean up the wiring.  I'll just run those separately.  I'm also able to remove the normally closed wire from the start push button so that cleaned up some space.

Removed N.C. wire from start PB:


Finished product:


AND finally, I covered the reg/rec wires and made them pretty:


I'll be 3D printing some "cable combs" that will help organize the cables more neatly.  Think of PC modding techniques and cable routing.  OK BYEEEEEEEEEEEEEEEE

[Pin2Hot]

Cal, seems like an old post of yours is helping me out: http://forums.sohc4.net/index.php?topic=155532.msg1785772#msg1785772

I bought a Rick's 14-100 reg/rec to charge my Antigravity battery and noticed something funny in their documentation.  The loose white and green wires are said to go to the field coil but the 6-gang plug already has a red and green wire going to the coil itself.  Your post confirms what I had suspected that the white loose wire needs to be swapped with the red 6-ganged wire.  I find it strange that Rick's included that red wire in the 6-gang plug and does not specifically address it in their documentation. 

All it says is: The one plug (6-gang) on our rec/reg plugs into the wiring harness where the stock rectifier did. The other 3 terminals are color coded to plug into the harness where the stock flat regulator plugs did.

It seems to imply that you should swap these wires but doesn't explicitly say so.  I emailed them to confirm this is required and am currently waiting for a response.

EDIT: response received:

In the 6 place connector the wires are:
3 yellow = Stator
Red = battery "+"
Green = battery "-"

So I'll be pulling out the red wire from the connector and replacing it with the white.  Booooooooooooooooooooo.

[calj737]

It will actually work as shipped. The white, green and black are the Reg functions. I swap them for color matching only. But it will work either way.

[Pin2Hot]

Hello.

Believe it or not I'm still working on this.  Here are some updates.

More or less hit a big wall in terms of how to route my wires beneath the bike.  I've always wanted to display the wiring as a part of the bike instead of hiding it.  But making that look pretty is certainly a challenge with limited real estate.  The idea of making some kind of routing platform came to mind one night and below is the result. 

Basically the mUnit (the older version only works with this idea - mostly because a hundred newer versions of this unit have come out since I first bought the damn thing) fits inside a cradle and "arms" help route the wires to their destinations on the bike.


That was the first design which I 3D printed and fit to the bike:


Back view:


Wires will come from their ports on the mUnit, travel down each arm all nice and pretty, tied down in some as-yet-to-be-determined fashion and head to their final destinations.  As with any design, it went through a million revisions.  Here's the mUnit sitting on v3:


Because of the layout of the inputs/outputs of the mUnit, crossing over cables that need to go to the front and back of the bike needed to be accounted for.  So in v5 below, you can see how some will go above and below others.  The arms heading towards the front of the bike have also been extended to make a nice sloping drop for the wires.


I haven't fit this to the bike yet but will soon.  In other work, I've been tackling the items that I've been putting off like finishing up the front brake, fender and other odds an ends.


Here's the bike so far, nice to see some progress.  Happy quarantining!

[SOHC4 Cafe Racer Fan]

Not to be a naysayer, but do you have sufficient clearance between the m-unit and the shock spring when under full compression?  Also are you making any cover to protect the m-unit and wiring from water, dirt, grease, etc.?

[scunny]

That's a neat idea for the wires to the m unit. to hold them in place could you put l><l holders in your design ?

[Pin2Hot]

Not to be a naysayer, but do you have sufficient clearance between the m-unit and the shock spring when under full compression?  Also are you making any cover to protect the m-unit and wiring from water, dirt, grease, etc.?

There's plenty of clearance down there, the photo doesn't show it very well.  The shock will bottom out well before it would interfere with the mUnit.  Yes, there's a cover in the plan too.

[calj737]

Not to be a naysayer, but do you have sufficient clearance between the m-unit and the shock spring when under full compression?  Also are you making any cover to protect the m-unit and wiring from water, dirt, grease, etc.?

There's plenty of clearance down there, the photo doesn't show it very well.  The shock will bottom out well before it would interfere with the mUnit.  Yes, there's a cover in the plan too.

Not to be a nag... but you'd better test that properly. Remove the spring from the shock and compress the suspension fully. Then measure the clearance with the spring diameter included. Under load and dynamic compression, shocks do some funny things. You don't want to learn that the expensive way.

There's also some commercially available, simple wiring looms available. Route your wires out, collect them a bit away from the mUnit, capture them in a loom, screw the loom to the underside of the seat pan. You've probably seen these for spark plug wires. Same principle. Should make what you've done a bit smaller and less complex 

[Pin2Hot]

Should make what you've done a bit smaller and less complex 

Cal, all due respect here . . . but where in the past 11 pages and 12 years has made you think I'm interested in just buying a loom?  I've spent countless hours covering each wire in paracord, designed a PCB, soldered every pin connection and gone out of my to design a system to avoid just screwing the loom to the underside of the seat pan.

Complexity IS the point.     

I had hoped that the detail I provide in my posts speaks to the level of testing I perform for each decision I make but obviously that's not enough.  Sometimes I wonder why I update this thread.

[calj737]

Wow. That’s an awfully petulant reply to some helpful hints. Given how many people have given you really good advice, tricks and followed along with you for years as you built this, I’d say you ought to be flattered.

Accept the idea or reject it, but FFS it was offered as an option to help solve potential issues.

[SOHC4 Cafe Racer Fan]

Not to be a naysayer, but do you have sufficient clearance between the m-unit and the shock spring when under full compression?  Also are you making any cover to protect the m-unit and wiring from water, dirt, grease, etc.?

There's plenty of clearance down there, the photo doesn't show it very well.  The shock will bottom out well before it would interfere with the mUnit.  Yes, there's a cover in the plan too.

I'm really glad to hear that, and your're correct - that photo makes it hard to tell.  More planning and effort up-front is MUCH better than having to correct afterward! Oh, have I learned the hard way on my projects!!  I try to point these things to members giving them the benefit of the doubt when you hope they considered things - especially monoshock conversions which can be tricky.  I'm glad you took my comment the right way.

Unfortunately, so many people just slap in what they think fits but might not allow the rear tire to effectively track bumps and hook up.  One of the worst thing is to see someone spend so much time (and money) and then the build is completed and "POOF" you never hear how it rides or it rides terribly.  This happens a LOT with builds with monoshocks, EFI and superchargers.

I think it would help people aspiring to do a monoshock conversion to share some of your engineering insight, such as mount points on the existing swingarm, angle of brace/shock mount to the swingarm, suspension travel distance, shock length and shock type (including spring rate).  If it works well, it could help others coming after you -- by saving a ton of time and effort re-inventing it or by preventing mistakes.  It might even be a good subject for a sticky thread.

I think that Cal's comment was in the same spirit, too, although he makes FAR fewer mistakes than I do.

[Pin2Hot]

If it works well, it could help others coming after you -- by saving a ton of time and effort re-inventing it or by preventing mistakes.

Totally agree.  I've leeched from the internet enough, this build thread is just one small way of giving back.

Quick update, got the new harness/loom thing put on the bike and fits really well.  I've realized that the ferrule ends I had planned to use to connect to the mUnit likely won't work, at least for the ins/outs where a sharp turn is required and the shrink tube holding the paracord in place likely won't last long bent a sharp angles.  But I believe whichever solution I find to help tie the wires to the arms will also solve the shrink tube problem too. 

You can see a zip tie in place below which is holding the paracord in place for now.  I think this photo shows best how the harness will work.


Placed under the seat, you can see the fused mUnit power dangling ready to be finally cut to length:


And in unrelated electrical news, I cut my fender down.  I used a neat service called Fiverr to have a guy named Ben Photoshop some options for me.  Ben took some photos I sent him, asked for some direction and he sent back a handful of options within a day or two.  I'd recommend Ben to anyone here struggling to make a design decision.  He mentioned that he'd give anyone mentioning my post a discount if you use him for your project.  Here are some of the options he sent me:

I asked him to lower the stock fender:


Chopped and lowered:


Chopped, lowered and glossy black:


Since my Photoshop attempt at doing this work myself was described as though my front wheel were "wearing a toupee", spending the money to have someone with some skill was WAY worth it.  In all I spent $45 dollars which includes a tip because of the quality of work I received.  A straight up deal if you ask me.  These options helped me decide to chop, lower and paint the fender glossy black.

Here's the REAL chopped fender, waiting to be lowered and painted.


I've got some more hardware showing up today, hoping to have a lot more progress coming soon.

[Pin2Hot]

I've made some great progress wiring the back end of the bike.  I was able to use the mLock to turn on the bike for the first time a few nights ago so that was fun.  Basically everything on the back end is complete as well as battery box, reg/rec and starter solenoid wiring.  Everything is being routed up to the mUnit under the seat.

Battery box and wires.  Zip ties will disappear and routing will get more streamlined.


Motogadget mLock activated in the rear hoop.


Wire loom getting filled out.  The wires will be tied to the "arms" later to make them more straight and neat.


One big obstacle I still face is the wiring behind the headlight.  I previously made a PCB that would handle all of that but have come to the conclusion that it's too big and clunky.  I'll be splitting the board into 2, possibly 3 smaller boards and utilize much smaller connectors.  I had used the Deutsch family of water-tight connectors which are great but entirely too large for my application, at least up front.  I'll continue to use them for the charging system as they're much closer to road grime.

The dashboard up front is where I've been focusing my time lately and have designed a new PCB to hold the LEDs for the idiot lamps on the triple tree.  This PCB will also hold 2 connectors.  The first 6 pin connector terminates the Motogadget motoscope mini, providing power, ground and breaks out the required signals (tach, config, speed).  A 12 pin connector will take the broken out signals needed by the mini, as well as the idiot lamps, to the new to-be-designed boards.  A small button on this dashboard PCB will provide a way to configure the motoscope mini easily. 

Position of the board when it is installed.  Will be flush against the lamp guides with the LEDs sticking into the black tubes.  Yes there's plenty of clearance, Clarence.


Top of the board.


Bottom.  R1 is an optional resistor if I choose to illuminate the button that I've selected. 


More to come.

[Pin2Hot]

Good news everyone.  The new board came in.  BAD NEWS everyone, I can't use it.

One of the big challenges of making boards like this is trying to keep what's on top and what's on bottom straight.  A lot of times it's easy to see because the bottom components are mirrored and look backwards.  However, there are a ton of drill holes for components, vias and other things that get really hard to keep track of especially when you're cramming as much as possible on a board. 

Test fitting back side of the board:


Front side with LED test fit:


I lost track of the through-hole LED positions and placed a connector body directly over 1 and a half of them on the back side.  After soldering in the LEDs, their nubs on the back side of the board wouldn't have allowed the connector to sit flush. 

Offending connector with one hole of the HI beam LED visible, the other is beneath the connector body which would have prevented the connector body from sitting flush:


I probably could have made it work but because the board was so cheap to make ($13 total), I've started a new design to fix existing problems as well as improve on the design.  So V2 is ready to go but I wont' send it off until I'm done with the other two boards I'm still working on.

New design using surface mount components which will be a challenge to solder but the package size is still manageable with a soldering iron, no need for solder paste or a fancy reflow oven.  Some other improvements of this design moves the resistors and diodes needed that were previously on the old board from 2017 onto this one, as well as a small 1A fuse for the motoscope mini.


One good practice that I will now perform going forward is making sure that any component footprint I make will clearly mark the "keep out" area of a component which helps you identify that nothing can go in that space.  I didn't intend for this bike build to turn into a printed circuit board manufacturing lesson but for anyone who's willing to tackle this, it's very rewarding and fun.  Just to give anyone interested in an under-the-hood look, here's what I'm calling the Headlight Board looks like as it sits right now, prior to any real board layout or routing.

Schematic - 5 connectors, 2 relays, 2 resistors and 2 LEDs:


Board layout before any routing:


The final layout of this board will greatly depend on the physical size restrictions on the headlight mounting plate which was cut out on Tuesday.  I'm hoping to have the headlights roughly mounted soon which will let me figure out this board orientation.

K bye.

[Pin2Hot]

Some new 3D printing adventures have helped me solve some problems that have been bugging me since forever.  The original plan to use a wooden plate has always been a challenge and getting it done in a reasonable amount of time using the resources at my disposal simply makes this impossible for now.  So I've started on a design that I'll 3D print which will help me move the project along.  I was inspired by this wild project I saw on the internets and became obsessed with the 3D printed "Voronoi" pattern used to generate the case.

Plate design shown in Autodesk Inventor:


The part has to be split into two parts so that I can print it.  Print bed is 250mm x 250mm.  Also added some fillets.


I printed the first half and realized a mistake right away.  Because the headlight faces are perpendicular to the road, it puts them at a 63 degree angle to the plate face due to the 27 degree rake of the bike.  I assumed that I just had to extrude the cut out for the lights at a 63 degree angle and that'd be that.  Turns out, you have to skew the the cut out in one direction by a ratio of the angle of the light and the cut out height.  Who said you don't learn anything in high school trig?

First half printed and fitting to the high beam:


Here, you can see the angle of the light but it's not able to fully rotate to the proper angle because the hole isn't tall enough to allow it:


Another view:


I've drawn up a corrected version of the light hole which I'll print separately to test the fit and then integrate that into the plate design.  That way I'm not wasting time printing a whole plate when I know the headlight may not fit correctly.  Until then, all PCB design is kind of on hold because I want to get this design done so I know where I can mount them.

This 3D printed plate is merely aesthetic and will be mounted to a separate metal bracket.  That'll get designed once this is all done.

[Pin2Hot]

Been a while since an update but I've been working in the background.  The biggest hurdle in making progress has been how to handle the wiring up front.  I believe I've finally solved it but it involved redoing the existing PCB I made back in 2017.  I went through probably 4 different designs before finally settling on the one below.  The final design is simpler, uses far less bulky connectors (although not watertight, I believe dialectic grease will be used to prevent fouling) and organizes the connectors in a much more convenient configuration.  It's got a pretty wild shape which follows the lines of the mounting plate I had water jet cut from aluminum.  This plate will serve as a bracket that holds the headlights, PCB and 3D printed frame that houses the LED strip turn signals and accent halos.

Water jet cut plate, showing mounting tabs.  The upper and lower tabs will be bent inwards to create mounting points to which clamps on the fork tubes will connect.  The inner tabs (which will require modification) will mount the headlights.  On the back of this plate will mount the PCB on brass standoffs.



The plate is a bit thicker than I requested from the water jet dude so I'm forced to bevel the back of each tab to allow it to bend to a 90 properly.  If anyone out there has a better idea or recommend a good way to bend these tabs properly, I'm all ears.



Here's the front of the new PCB, measures 7" by 2 3/4".  Has a bunch of connectors as well as 4 relays.  I got a little creative with the relay situation since I had such a large layout to play with so I was able to add a clutch / neutral circuit that will let me start the bike when the clutch it out if I'm in neutral but forces me to pull the clutch in when it's not.



Back side.  Part of the board will be visible from the front of the bike so I had to add a little flair to it.



Spent some time getting auxiliary power to the front of the bike by making some 3 to 1 connectors:



To make the cabling that's visible on the bike a little more neat, I 3D printed some clips to keep wires organized:

I've since reprinted these in black:


I haven't strapped the wires down yet so they're not super neat yet but this is on the swingarm:



PCBs won't get here for another 2 weeks or so, in the meantime I'll be working to get the plate tabs bent properly and get the lights mounted.  That'll make me feel like I've actually accomplished something this summer.   goodbye

[Pin2Hot]

Two weeks later, they're here!  Spent last night soldering everything together and I couldn't be happier with how they turned out.  It seems I only managed to screw up ONE of the many connector footprints which is a success in my book.  Mocking things up to the bike this morning revealed a slight interference with the fork tube and one of the relays which means I'll likely have to extend the mounting tabs of the plate which is annoying but a solvable problem.

Next steps are conformally coating the boards and wiring up connectors.  A lot of crimping is in my future but this opens the door to getting all the forward controls permanently mounted and setting the stage for some real progress.  Looking forward to it.

The top board is where I connect to the mUnit and all sensors/controls across the bike.  It has relays for various purposes (mentioned in previous posts) as well as a connector for the smaller board which controls the dashboard (neutral/oil/turn/hi beam lights) and Motoscope mini.


This shot explains the weird shape, taken before soldering components.  This will be visible from the front of the bike:


Up close with the smaller, dashboard PCB.  Left connector connects to the larger board and the right connector goes to the Motoscope mini.  Tach signal, wheel sensor, power (through the fuse) and ground are provided to the Motoscope.  The button is the config button for the Motoscope.


Back side of small board, feel free to judge my SMD soldering skills.


Here are some shots with the plate mounted on the bike:




Shot showing the depth of the plate that may need to be extended out a bit to solve my clearance issue:


It's nice to have things in hand and instead of all in my head.  Excited to get controls wired up and make this thing run.

[SOHC4 Cafe Racer Fan]

For lack of a better description, are the small and large exclamation points ! going to be covered with LED strips?

[Pin2Hot]

Those are actually tabs that will be bent inwards and outwards which will provide mounting points for the hi and low beams.  I just haven't bent them yet.  The smaller of the two is the low beam and the larger is for the hi beam.

[Pin2Hot]

First light!  Started wiring up the connectors and began with the motoscope mini.  The mini plugs into the dashboard PCB which also houses the LED indicators for oil / turn / hi beam / turn signals.  Another connector, represented by the red/black wires in the photo below, will carry power and all the various signals that the dashboard PCB and mini need to display information.



I'm using Molex Nanofit connectors on the dashboard PCB and Molex Microfit connectors on the main board.  Crimping the nano pins is by far the most tedious but if you're willing to practice a dozen or so times before working on a real part, you can get the hang of it.  One thing I had to be careful of was the orientation of each crimped pin.  I had to crimp each one in the same orientation so that a) all pins slid nicely into the connector 2)the pins only go in one way so having to rotate 5 wires in 5 directions AND fit it into the connector would be impossible and iii) well, I forget why I've listed 3.  Here are the crimped pins before placing the connector:


Some metal shows up tomorrow which I'll use to make the mounting bracket for both the mini and the dashboard PCB.  This will all make more sense once I can show it on the bike itself.  It was nice to finally plug stuff in and have it work instead of taping things together temporarily to prove a concept.  It's a good feeling.  I'll complete the other connectors next, particularly the main signals back to the mUnit and bring forward the outputs for headlights.  bye

[Pin2Hot]

Dash is alive!  Almost everything is terminated up front which has allowed me to test quite a bit of functionality.  It was a good feeling seeing that oil light come on as I applied power.  Remaining wiring: headlights/turn signals/accent lights, main mUnit connection, neutral switch and some grounding.  I tested the ignition circuit last night and forgot to disconnect the sparkplugs.  As I rotated the engine, expecting to see the TDC light flash as I went past top dead center, things went dark.  I purposefully put a 1A fuse in place so that in the event of a wiring mistake, I would hopefully minimize damage.  Nothing fried, just interesting to see the coils pull more than an amp while slowly rotating the crank with the kick starter.  At least I know it works!

Custom painters tape bracket holding the motoscope in place until I can weld the aluminum bracket together:


Looking from the front of the bike, you can see the oil LED beaming through the gap:


Headlights placed in their general position.  Still have to make mounting arms for them from aluminum and weld them to the plate.


Last step for the headlight is getting the 3D printed bracket fitted with the turn signals and accent lights.  That will be mounted to the front of the aluminum plate and will finish up the front end.  After that, it's rear brake, finalizing rearset brackets and fixing the exhaust mounting.

[Pin2Hot]

I made a video walking around the bike to better explain the electronics on the front.  Still have some wires to terminate and a lot of tidying up to do.  Hopefully this explains things a bit better.

[SOHC4 Cafe Racer Fan]

That's quite a wiring job using the circuit board.  Will there be any bodywork between the light/electronics panel and the dash instruments, or are you just going to sheath the wires with loom?

[RAFster122s]

Is any of your electronics water sensitive or are you encapsulating the board components?

[RAFster122s]

How are you handling aiming of your headlight and fog lights?