Author Topic: 1971 CB750 Project by Cedric (Read 3028 times)

WideAWAKE · « **Reply #25 on:** September 10, 2022, 07:24:41 PM »

What about the gasket??

I’m asking so that in the future it’s documented for other.

If the combo your running works.

I just got gaskets from CMS and they were THICK.

cfairweather · « **Reply #26 on:** September 10, 2022, 07:41:04 PM »

I can't measure it because it is already installed. The extra CB750 gasket set I thought I had was actually a set for a CB500. But, there was an extra o-ring in the set that I used just like the ones I installed, so I measured that one.

cfairweather · « **Reply #27 on:** September 20, 2022, 05:03:56 PM »

I started the engine today and ran it for about 10 minutes. It started immediately and it even idled without any adjustments, so I must have things set pretty close. So far, no leaks. Tomorrow, I will run it again and sync the carbs.
I wanted to share something that I do, when installing the head on these old cb750s. First, I use the heavy duty studs and torque the head bolts to 6, 12, 18 ft pounds and then I apply heat to the engine. I hold a propane heater in my hands and blow hot air on the engine for about 10 minutes. I try and get the engine about as hot as it would be if I ran the engine for 30 minutes. I attempt to spread the heat evenly across all the fins, then I let it sit overnight. Next day, I check the torque at 18 lbs and some of the nuts turned a bit, so this proves the heat helps "settle" the head gasket. Then, I do the final torque at 21 lbs. The picture is the left side of the engine and the other file is a 5 second video of the engine running.

cfairweather · « **Reply #28 on:** September 28, 2022, 03:40:35 PM »

I am putting the bike back together and making good progress. Notice the VIN plate that I bought on eBay. Looks just like the original; even the studs . I also installed the new third party wiring harness after I soldered all the crimped connections. I have learned it is wise to solder these connections to avoid issues down the road.

scottly · « **Reply #29 on:** October 02, 2022, 10:42:02 PM »

Hey Cedric, FIY: your front coil bracket is mounted backwards: the recess in the brackets face the coils. Also, it is supposed to mount on the other side of the frame. I'm not sure about the K1 harness, but some of the 750s have the harness green wire eyelet grounded to the frame at the front coil bracket bolt.

cfairweather · « **Reply #30 on:** October 03, 2022, 04:41:45 AM »

Scottly- Thanks for your advice and attention to detail. You are correct about the mounting of the original coils, but the Dyna style coils won't mount exactly like the originals due to their design and size. I am not quite done with the coils and will still need to verify I can mount the tank without touching the coils, but I will take a look at them and see if I need to change anything. On a GL1000, the the green ground wire attaches like you described, but at least on this K1 reproduction harness, it attaches to the rear part of the frame, near the battery, under the seat.

cfairweather · « **Reply #31 on:** October 09, 2022, 08:22:00 PM »

Update: Got the forks finished and installed. Also installed new wheel bearings. I ordered new Rising Sun aluminum wheels but after installing the spokes on the front, I decided not to use these cheap rims. I ordered DID original type rims this evening.

cfairweather · « **Reply #32 on:** October 13, 2022, 05:49:54 PM »

I have been working on the gauges and here are two pictures. These were in bad shape when I started including dents, rust, cracked faces, etc... I used Jet black urethane paint with hardener for the covers. I cut the chrome rings with a Dremel and then reattached them using JB Weld. The clamps are used to hold the rings securely in place overnight and then you can see the results in the second picture. Notice I reset the odometer to 0 as part of the process. I also made the wires look nice again but these are not shown. I also ordered new chrome rear covers and they should be here in a few days so the gauges should look nice on the bike.

cfairweather · « **Reply #33 on:** October 17, 2022, 11:26:23 AM »

Got the spokes in, wheels trued and lots of little details completed this week.

Stev-o · « **Reply #34 on:** October 17, 2022, 11:43:12 AM »

Lookin' good!

cfairweather · « **Reply #35 on:** October 20, 2022, 05:11:20 PM »

Got all the electrical work finished and everything works. Also got the front brake installed, the front fender installed and the pipes installed. I might finish tomorrow

.

scunny · « **Reply #36 on:** October 20, 2022, 05:34:05 PM »

getting close.

newday777 · « **Reply #37 on:** October 21, 2022, 02:19:20 AM »

Coming along nicely Cedric.

WideAWAKE · « **Reply #38 on:** October 21, 2022, 07:18:36 AM »

Nice work on the gauges!

Amazing what a little focus and elbow grease can do!

MauiK3 · « **Reply #39 on:** October 21, 2022, 08:05:00 AM »

Great progress!

cfairweather · « **Reply #40 on:** October 21, 2022, 10:25:15 AM »

Delay...I have to replace the starter button/kill switch control. Getting one on order today.

WideAWAKE · « **Reply #41 on:** October 22, 2022, 10:44:26 AM »

If yours are original and in good shape and want to keep ‘em original- repops seem to stick out like a sore thumb.

It’s pretty easy to swap the internals from your new one to your originals.

* if you’ve made it this far in the rebuild process I’m sure this is info you know or could intuit on your own, but just throwing it out there incase.

cfairweather · « **Reply #42 on:** October 23, 2022, 05:11:47 AM »

Not done yet but I did get the control fixed and installed the body parts. I took it for a quick ride and discovered the tachometer wasn't working. The problem is the cable was made too short. Ordered mirrors and rubber for the kick starter.
Here are a few pictures:

MauiK3 · « **Reply #43 on:** October 23, 2022, 07:51:05 AM »

Very very nice!

WideAWAKE · « **Reply #44 on:** October 23, 2022, 07:55:49 AM »

Is there play in the tach cable at the motor?

Give it a push and see if it engages.

I had that problem.

cfairweather · « **Reply #45 on:** October 23, 2022, 09:43:46 AM »

The tach cable was turning but was too short to engage the tachometer. I have run into this issue before with third party cables. I just cleaned up the original and it works fine.

cfairweather · « **Reply #46 on:** October 24, 2022, 06:51:55 PM »

Except for installing the rubber on the kick starter it is finished. Here is a link to all of the pictures I took during the build. Thanks for looking and I appreciate all the comments.

https://drive.google.com/drive/folders/1XeSFwW5ajdYvQajk5QpPAbKTnLkRU_9h?usp=sharing

Stev-o · « **Reply #47 on:** October 25, 2022, 07:06:09 AM »

Gorgeous! Nominating you for BOTM....

http://forums.sohc4.net/index.php/topic,180400.0.html

tshrey · « **Reply #48 on:** October 25, 2022, 09:32:58 AM »

Holy hell it looks like you just picked it up new from the dealer!

News:

Author Topic: 1971 CB750 Project by Cedric (Read 3028 times)