Author Topic: CB 750 K0 — Me and the dog are building a bike. Finished!! (Read 23405 times)

dolamike · « **Reply #100 on:** December 23, 2015, 08:45:27 AM »

Thanks for all the info on the exhaust mounts! I'll need to really think this through before I get them back on the frame!

dolamike · « **Reply #101 on:** December 31, 2015, 12:46:48 PM »

Happy New Years!

Latest progress on the build, parts are coming in and the frame is welded! The speedo and tach will need to be rebuilt with new faces, I just couldn't afford the mint ones... I got a really fair deal on everything in the photos. I also have a 2nd unicorn triple tree that I bought from Greggo, I'll save it for the K1.

My brother is a contractor, he always says when in doubt sub-it-out. I don't think my welding and fabrication skills were up to the task of getting the frame welded to the level of precision I would have liked. I had a well respected local fabricator help out. Fingers crossed I'll have original exhaust on this thing!

dolamike · « **Reply #102 on:** January 12, 2016, 10:32:32 AM »

Project Update: Engine Build and Powdercoat

I started the rebuild of the top end over the weekend. The head is on the engine, I'll tackle the valve train this weekend.

Parts Ready for Powdercoat

754 · « **Reply #103 on:** January 12, 2016, 11:18:01 AM »

Your first pic , is that a saw vise on the left. And what is that stand for ?

You may want to close the gap on sidestand a bit..
Battery box, did you get the rubbers out.. They are tricky.

You cylinder head. Is a later one, and maybe the swingarm as well.. The bike should have the short plastic chainguard, and it uses a different bracket on the swingarm.

dolamike · « **Reply #104 on:** January 12, 2016, 12:14:26 PM »

Quote from: 754 on January 12, 2016, 11:18:01 AM

Your first pic , is that a saw vise on the left. And what is that stand for ?

You may want to close the gap on sidestand a bit..
Battery box, did you get the rubbers out.. They are tricky.

You cylinder head. Is a later one, and maybe the swingarm as well.. The bike should have the short plastic chainguard, and it uses a different bracket on the swingarm.

That's the head of the stand in the first pic, it's a home brew bicycle repair stand. It just snuck into the photos, I didn't use it for the engine rebuild.

Thanks for the tip on the side stand, I'll have a look when I get home from work, that would be good to take care of before paint.

For now I'm going to powdercoat and use the later swingarm, I'm having trouble locating the earlier one. My plan is to swap out at a later date when I can get my hands on the appropriate one.

Unless someone has a K0 swingarm that they would be willing to sell me now... that would be excellent!! :-)

The motor in the rebuild photos is the K8 motor that I bought when I found the hole in the crankcase on the original motor. That should be the appropriate head I think...

I'm going to try and use the K8 until I do a complete rebuild on the original. That's going to be a longer term project as well.

I did however locate this, it should be shipping today!

I don't know if you remember, the bike actually came to me with a K1 motor, it will be cool to have a K0 serial on the motor if I'm able to use these cases. This will also negate the need and be cheaper than having the original engine cases welded.

Thanks again for all your help and info.

Please let me know if there is anyone out there with an earlier swingarm!

dolamike · « **Reply #105 on:** January 12, 2016, 12:16:21 PM »

One more thing, I was able to save the rubber on the battery box! One less thing to buy!

Thanks Frank.

754 · « **Reply #106 on:** January 12, 2016, 12:41:09 PM »

Good score on the lower end..is it still together ..looks like a lot of the top bolt are removed.
I would not sweat the swingarm too much if you dont have the proper chainguard, they can be hard to find
Giving youself time to find them , usually means lower cost....easy to change out later..

kmb69 · « **Reply #107 on:** January 12, 2016, 01:37:16 PM »

Quote from: dolamike on January 12, 2016, 12:14:26 PM

.....
I don't know if you remember, the bike actually came to me with a K1 motor, it will be cool to have a K0 serial on the motor if I'm able to use these cases. This will also negate the need and be cheaper than having the original engine cases welded.
.....

That may be a K0 serial number but they are not necessarily K0 cases. Could be replacement cases. That number has been re-stamped. It is definitely not the Honda font.

dolamike · « **Reply #108 on:** January 12, 2016, 03:31:52 PM »

Wow, that's a good catch. I actually compared the typeface to a couple on ebay and it does look off. It is also missing the hyphen between the E and the serial number. I don't think it's shipped, I'm getting my money back.

Thanks for the heads up, total bummer.

dolamike · « **Reply #109 on:** January 13, 2016, 09:36:29 AM »

This is cool.

dolamike · « **Reply #110 on:** January 13, 2016, 10:27:59 AM »

I'd love to, is there a link?

Tews19 · « **Reply #111 on:** January 13, 2016, 12:14:33 PM »

KMB is correct on the cases. Those are replacement cases. Had them on my K1

dolamike · « **Reply #112 on:** February 01, 2016, 05:56:22 PM »

Project Update

I got the frame and parts back from the powdercoat shop Friday. Spent the last couple of weeks finishing up the engine. Got the engine in the frame over the weekend. Everything went fairly smooth. The one exception is my lower triple tree. I'll need to replace it, one of the stops is bent back, probably from a previous fall. When I mocked up the tank the bars were able to hit it. Bummer. The tab on the frame is slightly bent up as well, I wish I had noticed before paint!!!

All in all good progress, new triple tree should be in the mail tomorrow, in the mean time there is plenty other work to be done.

BTW, this Park Tool for tightening old bicycle bottom brackets works great on the triple tree, perfect fit.

BPellerine · « **Reply #113 on:** February 01, 2016, 06:04:46 PM »

you will have a nice bike,looks clean.bill

SOHC4 Cafe Racer Fan · « **Reply #114 on:** February 01, 2016, 08:40:47 PM »

Coming together nicely, DM.

pipeguy · « **Reply #115 on:** February 02, 2016, 11:09:21 AM »

Very nice job so far.

ogsmakdade · « **Reply #116 on:** February 02, 2016, 01:35:55 PM »

Love the progress, the dog has been busy!

dolamike · « **Reply #117 on:** February 16, 2016, 09:38:20 AM »

Build Update

I got some work in on the bike over the three day weekend. Really happy to have the bike up and rolling! I sourced a new lower triple tree last week and had it powder coated to replace the bent one. No more issues with the bars being able to hit the tank!

Next up, get the carbs clean! One step closer to the first start.

I'm going to post in the parts wanted section but will also post here.

I'm looking for a correct airbox with mounting hardware for my project.

This bike came with pods and after reading many, many , many, posts on pods, I would really love to get this bike the proper stock airbox.

Any help would be greatly appreciated!!

Thanks for all the help and support.

dolamike · « **Reply #118 on:** February 20, 2016, 07:32:56 PM »

Turning Point...

Now that I have the K8 motor rebuilt and in the frame I just happened to come accross a set of K0 engine cases locally.

They're farm fresh for sure.

My plan was to get the project up and running this winter and then collect all of the correct bits needed and finish the restoration next winter.

I'm having second thoughts, would be nice to get the right engine in there, I know myself and I won't be happy with the K8 engine in this bike for long. On top of that I picked up some early forks, so I'm inching closer day by day.

If everyone remembers, the bike came to me with a K1 engine that had a hole in the cases from a broken chain. My plan would be to to use that as a donor to build up the K0 engine cases.

I read here that there were some changes so this wouldn't be a clean swap...

http://www.sohc4.net/cb750-faq/indexphp/cb750k-and-cb750-engine-differences

I'm just wondering if anyone has attempted to do something like this? Any advise from the old timers would be really helpful!

seanbarney41 · « **Reply #119 on:** February 20, 2016, 11:38:16 PM »

save lots of money and get really familiar with Ebay...or ride your bike everyday and who cares about all that bullcrap

dolamike · « **Reply #120 on:** February 21, 2016, 09:28:26 AM »

Will the K1 engine bottom end work in the K0 cases?

seanbarney41 · « **Reply #121 on:** February 21, 2016, 09:43:17 AM »

I know little about K0's because I have never found one I could afford, but I have not heard of any design changes between K0 and K1 that would prevent this.

mystic_1 · « **Reply #122 on:** February 21, 2016, 12:15:16 PM »

You should have no real problems. Check to see if the cases are machined the same way for the final driven shaft, that area went through some changes in the early years. Not really a problem, you'll just need whatever final shaft and bearing that your case is machined for (in the case of K0, a single-row bearing with a half-circle locating ring with the matching "notched" bearing - later cases used a dual row bearing with a full circle locating ring outboard of the bearing).

mystic_1

dolamike · « **Reply #123 on:** March 09, 2016, 06:55:13 PM »

Here's something funny.

Last weekend I did some restoration on the rubber carb boots for my project. I used acetone and wintergreen oil after reading about it on some posts here. The good news is that it worked great, really brought them back and I did a second set that I picked up when I bought my motor.

Soooooo... then last night I was cleaning up an airbox that I bought on ebay, the rubber boots were hard as a rock! I said what the hell and threw them into the jar before work this morning, I just checked on them when I got home tonight...

Totally crazy, I think the solution got stronger as the week went on, totally turned them into mush!

dolamike · « **Reply #124 on:** March 14, 2016, 11:34:26 PM »

Hey all, I've been making slow but steady progress, carb rebuild is done and airbox mounted. I ended up using a later airbox, I'll post pics soon, not correct for the year but will get me rolling for the summer!

I'm staring to route all of my oil and engine venting tubes and had a question. I read a really great explanation of how this should work by Hondaman on this thread...

http://forums.sohc4.net/index.php/topic,147504.msg1680491.html#msg1680491

I think I have a good understanding of how these should be routed. I'm running into one small problem.

I have a K8 engine and an earlier 1969-1975 oil tank. It looks like the port at the back of the K8 engine was made larger than the diameter of the tube coming off the oil tank.

I'm wondering if there is a way to splice a larger hose onto the smaller one to make the fit? Also curious to know if this is under any sort of pressure?

Any help or advice would be greatly appreciated.

Thanks!

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Author Topic: CB 750 K0 — Me and the dog are building a bike. Finished!! (Read 23405 times)