Topic: 1974 CB750K - Restoration

[calj737]

I bet Nick's talking about the PC questions.

Shhh! Don't tell, dang it!

[onetruepunk87]

I bet Nick's talking about the PC questions.

Ohhhhhhhh... Well that makes sense, haha

[onetruepunk87]

Little bit more work done. Engine case is painted!

I'm on to polishing the side covers.




Rear wheel hub is done too as well as the clutch cover. All that's left on the engine are the stator, cam and breather cover. I think the only aluminum left after that are the forks.

Damn, my fingers are going to hurt.

[SOHC4 Cafe Racer Fan]

I'm on to polishing the side covers.




Rear wheel hub is done too as well as the clutch cover. All that's left on the engine are the stator, cam and breather cover. I think the only aluminum left after that are the forks.

Damn, my fingers are going to hurt.

Yes, but your covers and wheels will look better than the hipster who skipped polishing his hubs before lacing them with new spokes and rims!

[onetruepunk87]

Finally finished polishing everything up and cleared it all with Eastwood Exo-Armor. I know some have some strong feelings about clearing their polished parts but I know first hand how quickly aluminum starts to oxidize. I especially didn't want that to happen on my hubs I spent hours cleaning up, because once I lace them there's no getting back in there to polish them. I started searching online for a clear that wouldn't yellow when I found one that claimed to also be good up to 2000 degrees F so I figured I might as well do my engine covers. Hopefully this stuff holds up like it says it will, I guess I'll be the guinea pig for the forum.

[riverfever]

You did a great job polishing that stuff! Did you just use a proper buffing wheel or did you need to get into the nooks and sand? That's a good time.

[SOHC4 Cafe Racer Fan]

I clear powercoated my fork lowers after polishing them.  They are still shiny and no yellow.

[onetruepunk87]

You did a great job polishing that stuff! Did you just use a proper buffing wheel or did you need to get into the nooks and sand? That's a good time.

Thank You! I did both, i ripped apart my fingers sanding them all starting at 400 grit working all the way up to 3000. I picked up a couple different buffing wheels at harbor freight and threw them on an old bench grinder to finish everything off. Spent way too many hours than I want to admit sitting and polishing.

[onetruepunk87]

I clear powercoated my fork lowers after polishing them.  They are still shiny and no yellow.

Here's hoping this stuff holds up too!

[riverfever]

You did a great job polishing that stuff! Did you just use a proper buffing wheel or did you need to get into the nooks and sand? That's a good time.

Thank You! I did both, i ripped apart my fingers sanding them all starting at 400 grit working all the way up to 3000. I picked up a couple different buffing wheels at harbor freight and threw them on an old bench grinder to finish everything off. Spent way too many hours than I want to admit sitting and polishing.

Ahhhhhh.....reading this makes me feel good. Now I know I'm not the only that did this. That's precisely my routine. Start low, work high (200 grit or so steps along the way) and go until your hands cramp. I, however, did not clear coat. Perhaps I will wish I had at some point but, so far, none of the aluminum bits have oxidized whilst sitting in the garage . I did a set of mountain bike cranks years ago and worked for days on them until they had a mirror finish. They were/are stunning. I didn't clear them and they saw thousands of miles of trails in all conditions (including mud). They have picked up a few scratches over the years but they still look amazing after a quick polish with some Mothers.

[calj737]

Purely from an explanation: aluminum oxidizes almost immediately once cleaned, polished, machined, etc. The extent of the discoloration is purely down to how much neglect it encounters and/or the finish achieved when polishing, machining, etc. So a quick polish and buff with an alloy cleaner will help reduce oxidation, and discoloration, but the oxidation layer is still there as a natural result.

Pure stainless brushes help remove the oxidation before polishing if you want to try that before polishing for a mirror shine. But buffing wheels and rouges produce the absolute best finished result.

[onetruepunk87]

I did the same process on my CB500's engine covers (minus the clear coating) and it's been about two years since I polished them. They're still very nice looking but they've lost that mirror shine they had. I try to hit them with some car wax about once a month to keep them looking good but when they sit for too long, like in the winter, they start getting white powdery oxidation all over them that I need to rub off.

River, glad I'm not the only one who sacrifices my fingers to get aluminum nice and shiny. I usually do small 200 steps in the lower grits up to 1000. I switch to wet sanding from there on. I've got two buffing wheels, a harder one I use brown rouge on and then a very light flap wheel style one with grey rouge.


The clear took away a little bit of the luster but if it stays that shiny without needing any real up keep I'll be happy.

One of my best friends is a chemist and was trying to explain the whole process of oxidation to me, maybe it was all the beers I had but I couldn't grasp it.

[onetruepunk87]

Well crap, everything was going so smoothly until this happened.

Snapped the cam tower stud while reassembling the top end. Part #90055-300-000, which seems to be obsolete
I took the cam and rockers off to replace the pucks and o-rings under the cam towers just because I know they are the spot most prone to leak oil, I know my '77 leaks there.

Everything was going good, I was using Hondaman's book along with Dino's Hack-a-week video to walk me through it (which were both awesome help) I went to torque the nuts down with my torque wrench when the stud snapped off. I only had it set for 6lbs to start but it is a harbor freight torque wrench. Not sure which it was the wrench or the stud but the remainder of the stud came out really easily with some vice grips and was able to spin the nut back off the broken piece pretty easily too so i think the stud may have been weak to begin with.

I know i can probably DIY a new stud if I have to but does anyone happen to have some extras around in a spare parts motor I could buy off of them?

Some other stuff I've been working on. I laced up my brand new D.I.D. rims yesterday. Used this really helpful walkthrough http://forums.sohc4.net/index.php?topic=135846.0 and some old rusted out rims as a guide. They went together pretty painlessly. Now I've just got to decide if I'm going to attempt to true them myself or take them to someone to get done.


Also I got some brass swing arm bushings and installed them the other day!

[onetruepunk87]

Phew, problem solved. MRieck is hooking me up with some cam studs so I can get this motor back together.

[edwardmorris]

I probably have a set saved somewhere, I'll PM you if I find them tower studs.

Edit: Looks like you're covered, so nevermind.

[onetruepunk87]

Thanks Rafi, we must have posted at the same time. I'll let you know if I break anything else, haha.

[onetruepunk87]

I decided to true my wheels on my own and it really wasn't as hard as I originally thought it would be. I picked up this balancing/truing stand off Amazon for probably half the price it would have been to have each wheel done.

Also, I got my cam tower stud in from MRieck (thanks!) and think I've got everything tidy'd up. I've got one problem, though, that may actually not be a problem from what I've been reading on here.

I think my cam may be 180° out. Should I disassemble and redo it? I've read a couple threads that it shouldn't matter. With my cam in this position and the timing mark lined up on the 1-4 cylinders the tappet's that are adjustable are the ones designated with an X


If I turn it another 180° degrees with the notch in the cam at 6 o'clock then the tappets represented with O have the play to be adjusted.

Hopefully that makes sense to someone. This is my first time doing this so I just want to be sure I'm not going to blow my engine the second I turn it over. Thanks.

[onetruepunk87]

Ok, I've read a few more threads and got some replies that I should be fine. I think I'm safe to close it back up and get it in the frame.

[onetruepunk87]

Time to start putting it all back together!

[edwardmorris]

Congratulations on the milestone! Should be rolling quickly now

[onetruepunk87]

Hopefully, thanks Rafi!

[jerry h]

Beautiful looking engine.... it'll look great in your frame!

Putting it all together is the fun part (mostly)

[NobleHops]

Great project, great thread. The engine looks fantastic!

[edwardmorris]

Ok, I've read a few more threads and got some replies that I should be fine. I think I'm safe to close it back up and get it in the frame.

I wonder if this is what Mark explains in his book. Appendix C-1. I can't remember, but I may have run into this for my K2.

[onetruepunk87]

Ok, I've read a few more threads and got some replies that I should be fine. I think I'm safe to close it back up and get it in the frame.

I wonder if this is what Mark explains in his book. Appendix C-1. I can't remember, but I may have run into this for my K2.

It does sound like Mark's saying it could be either way, that's definitely some more reassurance.

Motor is back in the frame, officially into the reassembly faze. I used the trick of laying the engine on its side and lowering the frame onto it. I bubble wrapped the frame for some added protection and got it back in without a scratch.


I've got to order some tires and turn this thing into a roller. Anyone have any recommendations? I'm looking for something with a not to modern tread to go with the bike.