1980 CB750 “Beavertail” Cafe Build

I bought my CB550 as a basket case and the guy gave me the motor stand with it. It made everything easy and you can spin the motor upside down which was great because I dropped a screw into the bottom end.
That looks awesome (engine + stand). I've seen a few cb750 guys make those but I don't have the engine stand and most people weld some steel together to make the brackets and I can't weld...yet lol. If I do this again I'll definitely figure out a better stand to be able to work around.
 
Week 8 & 9 Case Split - Body work - Wiring Begins!

Projects for the week

Split Case
Sending out locally for Black Cerakote
Prime
Sand bondo sand bondo sand bondo…
Prime - just about ready for paint
Wiring Diagram started

Sorry for the inconsistency in updates lately. I found that it’s difficult to learn/document/do the actual work/report findings all in an organized way. Hopefully everyone is still interested - this is a ton of work!

The case split somewhat easily and it looked great inside. Not much to report on that front - I did not get too many photos of the process and I was extremely overwhelmed.

CB750 - Week 8-1.jpg


CB750 - Week 8-2.jpg



Now that the full engine has been sent out to get gloss black cerakote I can work on a few other projects with the freed up workshop space. Bondo/primer on the tank is the main focus and I will be trying my hand at building a wiring diagram as well for the M-unit.

Here are some pics of the tank as it stands currently. Not much to report here aside from bondo/sand/prime repeat. I think I applied my bondo too thick a few times because it cracked when it dried, which was extremely frustrating. Nothing better than bondoing your cracked bondo! If anyone has seen this cracking before I’d like to hear more.

CB750 - Week 8-2.jpg


CB750 - Week 8-3.jpg


CB750 - Week 8-4.jpg


CB750 - Week 8-5.jpg


CB750 - Week 8-7.jpg



And on to the wiring diagram…somehow my most dreaded part of this project is turning out to be the most fun and interesting to me. Wiring diagrams always used to be confusing to me until I took some time to learn about all the components and then tried my hand at building one. I am using the white board to test my skills at wiring the bike without needing to cut any wires just yet (it’s also too early for any actual wiring but I want to stay prepared). This is not the final version of my wiring diagram - so if things look out of place dont worry.

CB750 - Week 8-1.jpg


CB750 - Week 8-6.jpg



Fieldnotes:
Probably missed so many tips and tricks in the last two weeks but I can’t remember any upon writing this

Upcoming:
Engine back from painter
Case Closed and most components back in
New piston rings
Electronics tray welded in
Tank mount welded in
Rear seat pin/mount welded in
Rear seat hoop welded to fit better
Back to powdercoater
 
Still interested.

Nice project and excellent organized reporting. Great job.
 
Week 8 & 9 Case Split - Body work - Wiring Begins!

Projects for the week

Split Case
Sending out locally for Black Cerakote
Prime
Sand bondo sand bondo sand bondo…
Prime - just about ready for paint
Wiring Diagram started

Sorry for the inconsistency in updates lately. I found that it’s difficult to learn/document/do the actual work/report findings all in an organized way. Hopefully everyone is still interested - this is a ton of work!

The case split somewhat easily and it looked great inside. Not much to report on that front - I did not get too many photos of the process and I was extremely overwhelmed.

CB750 - Week 8-1.jpg


CB750 - Week 8-2.jpg



Now that the full engine has been sent out to get gloss black cerakote I can work on a few other projects with the freed up workshop space. Bondo/primer on the tank is the main focus and I will be trying my hand at building a wiring diagram as well for the M-unit.

Here are some pics of the tank as it stands currently. Not much to report here aside from bondo/sand/prime repeat. I think I applied my bondo too thick a few times because it cracked when it dried, which was extremely frustrating. Nothing better than bondoing your cracked bondo! If anyone has seen this cracking before I’d like to hear more.

CB750 - Week 8-2.jpg


CB750 - Week 8-3.jpg


CB750 - Week 8-4.jpg


CB750 - Week 8-5.jpg


CB750 - Week 8-7.jpg



And on to the wiring diagram…somehow my most dreaded part of this project is turning out to be the most fun and interesting to me. Wiring diagrams always used to be confusing to me until I took some time to learn about all the components and then tried my hand at building one. I am using the white board to test my skills at wiring the bike without needing to cut any wires just yet (it’s also too early for any actual wiring but I want to stay prepared). This is not the final version of my wiring diagram - so if things look out of place dont worry.

CB750 - Week 8-1.jpg


CB750 - Week 8-6.jpg



Fieldnotes:
Probably missed so many tips and tricks in the last two weeks but I can’t remember any upon writing this

Upcoming:
Engine back from painter
Case Closed and most components back in
New piston rings
Electronics tray welded in
Tank mount welded in
Rear seat pin/mount welded in
Rear seat hoop welded to fit better
Back to powdercoater

Week 8 & 9 Case Split - Body work - Wiring Begins!

Projects for the week

Split Case
Sending out locally for Black Cerakote
Prime
Sand bondo sand bondo sand bondo…
Prime - just about ready for paint
Wiring Diagram started

Sorry for the inconsistency in updates lately. I found that it’s difficult to learn/document/do the actual work/report findings all in an organized way. Hopefully everyone is still interested - this is a ton of work!

The case split somewhat easily and it looked great inside. Not much to report on that front - I did not get too many photos of the process and I was extremely overwhelmed.

CB750 - Week 8-1.jpg


CB750 - Week 8-2.jpg



Now that the full engine has been sent out to get gloss black cerakote I can work on a few other projects with the freed up workshop space. Bondo/primer on the tank is the main focus and I will be trying my hand at building a wiring diagram as well for the M-unit.

Here are some pics of the tank as it stands currently. Not much to report here aside from bondo/sand/prime repeat. I think I applied my bondo too thick a few times because it cracked when it dried, which was extremely frustrating. Nothing better than bondoing your cracked bondo! If anyone has seen this cracking before I’d like to hear more.

CB750 - Week 8-2.jpg


CB750 - Week 8-3.jpg


CB750 - Week 8-4.jpg


CB750 - Week 8-5.jpg


CB750 - Week 8-7.jpg



And on to the wiring diagram…somehow my most dreaded part of this project is turning out to be the most fun and interesting to me. Wiring diagrams always used to be confusing to me until I took some time to learn about all the components and then tried my hand at building one. I am using the white board to test my skills at wiring the bike without needing to cut any wires just yet (it’s also too early for any actual wiring but I want to stay prepared). This is not the final version of my wiring diagram - so if things look out of place dont worry.

CB750 - Week 8-1.jpg


CB750 - Week 8-6.jpg



Fieldnotes:
Probably missed so many tips and tricks in the last two weeks but I can’t remember any upon writing this

Upcoming:
Engine back from painter
Case Closed and most components back in
New piston rings
Electronics tray welded in
Tank mount welded in
Rear seat pin/mount welded in
Rear seat hoop welded to fit better
Back to powdercoater
I like the idea of the white board. I have a pile of Motogadget stuff but I'm not that far along yet.
 
Are you using the 2 part bondo body filler, or are you using the spot putty that comes in a tube? It looks to me like you're using spot filler for large areas and should be using the 2 part filler. Spot putty is really only good for very thin skim coats and pinholes.

If you are using the 2 part then you're using too much hardener, it should be more pink than red.
 
Are you using the 2 part bondo body filler, or are you using the spot putty that comes in a tube? It looks to me like you're using spot filler for large areas and should be using the 2 part filler. Spot putty is really only good for very thin skim coats and pinholes.

If you are using the 2 part then you're using too much hardener, it should be more pink than red.
Yeah Im using the spot putty and you are right - too big of an application for this type of product. Lesson learned!
 
Week 10 Engine Work + Frame help

Projects for the week:

Engine back from painter
Engine case closed
New piston rings
Electronics tray welded in
Tank mount welded in
Rear seat pin/mount welded in
Rear seat hoop welded to fit better
Frame back to powdercoater


The Cerakote came out great - it was recommended to me because of its increased durability and resistance to fuel/chemicals but also won’t retain too much heat like other coating methods on air cooled engines. Hopefully it will last a long time! Once the engine is all back together I will take better pictures of the coating.

In an earlier post I mentioned that I tested the resistance between the slip rings on the alternator rotor. The resistance was out of spec as it measured open with the ohmmeter. A new one was installed with the work done on the case. Hoping this engine operates like a 0 mile motor once I’m done!

CB750 - Week 10-1.jpg

CB750 - Week 10-2.jpg


I don’t have many photos of closing the engine case - just wanted to power through getting it done. I did have help with the case which was awesome to have more experienced eyes to bounce ideas off of.

Next step is getting the piston rings in order - filing and making sure the gap is within spec. Not really much to report on from that front.

CB750 - Week 10 - 2-3.jpg

CB750 - Week 10 - 2-1.jpg


I’m curious of everyones’ opinion about continuing to run this cam chain tensioner. I’ll likely just get it replaced but I’d like to know how others determine when it’s replaceable or able to still be used.

CB750 - Week 10-3.jpg

CB750 - Week 10-4.jpg

CB750 - Week 10-5.jpg


Also had some help creating the battery box for under the seat. I needed someone with more metal working tools/skills than I had. My highly complex cardboard box from earlier in the thread was used as the template. I also will use quick release push pins for the seat release which is the reason for the tab in the back of the battery box.

CB750 - Week 10-6.jpg
View attachment 18101

Fieldnotes:
-Cerakote is a good option for engine coating - chemical/abrasive resistant while allowing for heat release
-Need a good file for piston rings
-This is an example of the quick release pins for the seat

Upcoming:
Piston rings gapped/aligned
Pistons on
Cylinder Jugs on
Head on
Cams in
Valve adjustment
 
You can check the ring gaps first and you may not need to remove any material. If you do need to I would get a piston ring filer. its critical to get the angle correct and doing it by hand is very difficult to do with accuracy. Also take the time to de-burr after grinding. Lots of videos on the web.
 
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