Author Topic: CB750 Hardtail Build Journal  (Read 4888 times)

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Offline ECinCLE

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CB750 Hardtail Build Journal
« on: February 27, 2017, 11:03:44 PM »
To start things off....I'm not a builder. So I'd like to use this forum as not only a build journal of sorts but also a place to get some feedback and maybe trouble shoot a couple issues.




I got my first bike, a '72 cb350, last year (2016) and rode it all season. After a season of hard riding both on backroads and in the city, I decided I wanted more power.

The work I did on my cb350 was done out of a community garage based in Cleveland OH called SkidMark. (http://skidmarkgarage.com/) Very cool concept worth checking out if you're local or anywhere in NE Ohio.
The owner of SkidMark has stock piles of old Japanese motorcycles and parts so I was able to pick up a cb750 frame and engine for pretty cheap.


I'll spare some of the details to get the post up to speed, but here's some of the fun so far.

Ordered a hardtail section from voodoo vintage and early December it arrived. Completed frame to follow.


While the frame was out for chopping I went to work on the top end. I decided against cracking the case as it's a little above my pay grade and the engine seemed to be in relatively good shape when I got it.




An advantage to working in a community garage such as Skidmark is the access to tools and pieces of equipment you might not normally have access to in your every day D.I.Y. or home garage. One such piece of equipment is a vapor blaster. I'm no expert but it's my understanding that the vapor blaster uses compressed air to blast a water and particulate (in this case glass bead) mixture. Place a part in the cabinet and watch the grime wash away. Much like sand blasting there's a treatment process after pulling the part from the cabinet but nothing extensive.

Here's my cylinder bank before and after the vapor blaster. I also had these Honed.








Probably the best example of the vapor blasting success is the valve cover.


A few days later I get notification that the hardtail has been finished!


Look at those welds!!!


Got it back to the garage and threw the rear wheel, and front fork after getting the All Balls......just as fun to type as you'd think.....tapered roller's on the head stem.


SITTIN LOW!

Got a pretty wild hair about this interesting headlight surround I saw. and decided that I'd try my hand on fiber glassing something like it.

Inspiration


I've got a mold ready for the fiberglass but haven't committed to anything yet.




Found a tank and I think it fits.



I ordered a set of engine bolts from Dime City and was really happy with it.



Dug into the Head and began piecing it back together only to realize I was missing a Cam Tower Oil Jet! Oh yeah!!!! Of course its discontinued from Honda so our good friends at http://www.cyclexchange.net/ came through in the pinch.. If you have any SOHC questions Ken is the guy. $3.00 part from Honda cost me $15.00 plus shipping. Thanks HONDA!


Quite honestly putting together the top end was one of the most fun things Ive done so far. Very rewarding tangible progress.






Flipped 'er over and got after that ass after putting on some of the other vapor blasted covers.


I know this seems all over the place and I plan to start detailing progress a little better. I just wanted to get the post up to date to where I am now. There's of course some things that I've glossed over intentionally. I want to keep this light up until I have actual issues to be resolved. I've probably gotten in over my head but I think with some focus I can have this project done in time to ride this summer.


Offline iiAtlas

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Re: CB750 Hardtail Build Journal
« Reply #1 on: February 28, 2017, 07:25:21 AM »
Great start!  Good work and keep on trucking.  I personally can say not cracking the cases has saved you some headache...I am currently in high water regretting I hadn't done that!! Of course, of course, good to learn, clean, verify, and understand everything down there but it's really put a slow down on my build.  Anyways GOOD work and GOOD LUCK!  8)

Offline 754

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Re: CB750 Hardtail Build Journal
« Reply #2 on: February 28, 2017, 08:01:03 AM »
Welcome..great looking hardtail.. What do you have planned for rear motor mounts?
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #3 on: March 01, 2017, 03:11:26 PM »
Voodoo Vintage sent these with the hardtail kit. I'm planning on learning how to weld and will be installing these under supervision!




Thanks for the read!

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #4 on: March 01, 2017, 03:13:18 PM »
Great start!  Good work and keep on trucking.  I personally can say not cracking the cases has saved you some headache...I am currently in high water regretting I hadn't done that!! Of course, of course, good to learn, clean, verify, and understand everything down there but it's really put a slow down on my build.  Anyways GOOD work and GOOD LUCK!  8)


Hopefully I can get away with not cracking the case. It's my understanding that these things are pretty much bullet proof. fingers crossed!

Offline Ruckus2115

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Re: CB750 Hardtail Build Journal
« Reply #5 on: March 01, 2017, 06:17:40 PM »
Voodoo vintage does some nice work for sure. Should be a nice little hardtail. I'm in the same boat right now with a hardtail but having a full custom frame made up. How much ground clearance you have now? I think I am aiming for 5-6 inches of clearance. The low pipes on these 750s really eat up any clearance especially around corners.


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Offline budman

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CB750 Hardtail Build Journal
« Reply #6 on: March 01, 2017, 06:19:08 PM »
Looks like you're off to a great start.  Subscribed.
Bud

1973 CB750K3 Chopper
2021 Indian Scout

Offline ChromeDreams

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Re: CB750 Hardtail Build Journal
« Reply #7 on: March 01, 2017, 07:40:44 PM »
headlight shroud looks cool! also dig that engine stand

Offline palepainter

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Re: CB750 Hardtail Build Journal
« Reply #8 on: March 01, 2017, 08:19:17 PM »
That is a really nice hardtail section!  Pretty cool set up that they have there at Skidmark.  I like the concept.

Offline catsoup

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Re: CB750 Hardtail Build Journal
« Reply #9 on: March 02, 2017, 05:35:08 AM »
Very cool - not a build we see here very often. Making good progress too!
78 cb750f

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #10 on: March 02, 2017, 10:34:04 AM »
headlight shroud looks cool! also dig that engine stand



Pictures of the engine stand for you. Apparently Low Brow is going to start selling this type over the next few months.

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #11 on: March 02, 2017, 10:37:15 AM »
Voodoo vintage does some nice work for sure. Should be a nice little hardtail. I'm in the same boat right now with a hardtail but having a full custom frame made up. How much ground clearance you have now? I think I am aiming for 5-6 inches of clearance. The low pipes on these 750s really eat up any clearance especially around corners.


Sent from my iPhone using Tapatalk

I'm not sure the ground clearance. I know that the stock four into one that lines under the frame will not fit. I've seen some cool ideas for the exhaust. I'll try and post some that i'll be using for reference.

I'm thinking just extending the individual headers down and out a little....

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #12 on: March 02, 2017, 12:36:36 PM »
So I got tired of looking at the engine on the bench.....



Most likely will not be running the mag wheels.

Offline 754

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Re: CB750 Hardtail Build Journal
« Reply #13 on: March 02, 2017, 01:02:40 PM »
Your best bet right now..buy the high pipe from Ricky Racer and get it to work..
 HighPipes Rule on Choppers......then you can still corner pretty good..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #14 on: March 02, 2017, 06:50:01 PM »
Started digging into eBay a little bit and I think there are some really great options.
Cycle x also has some very cool looking stuff if you have the dollar.

Im thinking about some drag pipes but I may be getting ahead of myself.
I'm picking up some carbs tomorrow.

Offline ChromeDreams

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Re: CB750 Hardtail Build Journal
« Reply #15 on: March 04, 2017, 09:55:54 AM »
headlight shroud looks cool! also dig that engine stand



Pictures of the engine stand for you. Apparently Low Brow is going to start selling this type over the next few months.

killer thanks for that info, i'll keep an eye out for availability

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #16 on: March 05, 2017, 04:31:21 PM »
I picked up a carb bank from a buddy from his old '72 CB750 for $100 bucks.

Need some cleaning up and probably a full re-build but I really enjoy carb work. I don't know....maybe I'm crazy. Also got the cam chain tensioner push rod in the mail yesterday. Again another Honda part that's been discontinued. Ebay to the rescue.





Under first inspection boots aren't cracked, but they are very stiff. I've heard submerging in boiling water helps.



I'll really be digging into these this week.

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #17 on: March 08, 2017, 12:14:27 PM »
Started carb work.
1972 CB750 Keihin Carb bank from what I know.
Pulled float bowls and saw about what I expected. Gasket’s in really poor shape.  Worse on one side since they sat on a parked bike that was using the side stand I’ve been told. Pretty gross but I think they’ll clean up.



Bottom end disassembly
•   Main jet
•   Pilot jet
•   Float Pin
•   Floats
•   Float Valve

After properly taking apart the first three L to R on bench, R to L on bike I’ve come to the conclusion that the fourth is probably not salvageable. I believe I’ve identified it as the #1 L to R on the bike. The stem where the float bowl pin sits is actually corroded away to the point that I’m worried I’ll break it even taking the float pin out. I think I should be able to find an empty carb body to replace it. I’ll start a ISO in the WANTED section and do some searching online.




« Last Edit: March 08, 2017, 12:17:02 PM by ECinCLE »

Offline ECinCLE

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Re: CB750 Hardtail Build Journal
« Reply #18 on: April 28, 2017, 11:06:49 AM »
Big update coming soon. Stay tuned! ;D

Offline Ruckus2115

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Re: CB750 Hardtail Build Journal
« Reply #19 on: May 02, 2017, 02:12:15 PM »
hows the build coming along?