Author Topic: 78 CB750 Bobber Project  (Read 23250 times)

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Offline Nick_701

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78 CB750 Bobber Project
« on: June 15, 2010, 12:35:38 AM »
Hello,

New to this forum, just thought i would share my first bike project and the progress i have made.

So i got this bike for 100bucks at a yard sale down the street.  Purchase date was June 5th so i have had it for about two weeks now.  After another 20bucks i had it running and so i really started to get into it after that.  Here is what i have so far.

My 100 dollar yard sale find


30 min later, already tearing it apart



Cleaning the motor


Time to figure out the perfect ride height, before cutting

After cutting

Feels pretty good


Need an oil tank now.... yeah that will work






As of now I am trying to get the home made oil tank to seal and my welding is not perfect. 

Any one have any ideas to seal it?

Offline rippy154

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Re: 78 CB750 Bobber Project
« Reply #1 on: June 15, 2010, 09:34:23 AM »
If it is leaking through the welds I would grind out your welds and reweld it, maybe you have a friend who welds or find a vo-co school that offers adult ed classes in welding, if your new to welding please take care on the frame as proper welding and fiting is what will give you all your strenth, where do you live???

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #2 on: June 15, 2010, 10:24:13 AM »
Yeah it leask through the weld, but just slightly,  When i put the tank in water i can see the weld get damp (change to a darker color) in the inside.  It doesnt pour in but i would think this would still be a problem.  On the other hand, oil is thicker than water, wonder if it would leak... I would feel better if it did not leak anything though so will probably re weld.  I think a problem i had was the 'cap' i put in the tank and the drain tube.  do not fit perfectly so I kinda 'filled' in the small gap with the welds.

I have actually been looking at classes for proper welding education.  I dont want to pick up bad habbits,  below are some of the welds i have done on our gocarts and my welding cart.  Never had a problem with the go cart frames and they are abused, yet they are lighter and dont to 70mph+ (I understand the higher risk involved in the bike build, i do appreciate the concern and will always keep it in mind).

First week of welding

Later on

Go Karts

Welding cart


I live in Northern California, 30 min north of Sacramento
« Last Edit: June 15, 2010, 10:33:02 AM by Nick_701 »

Offline kck3

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Re: 78 CB750 Bobber Project
« Reply #3 on: June 15, 2010, 12:05:18 PM »
$100 bux?  Wow you scored.  Who was selling it?  Angry wife?  Old mans daughter?

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #4 on: June 15, 2010, 12:23:51 PM »
Just an old guy who never drove it anymore, it sat for about 7 years.  He also had a 74 cb350 that i was tempted to pick up , 100bucks for that one too.

Offline sangyo soichiro

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Re: 78 CB750 Bobber Project
« Reply #5 on: June 15, 2010, 12:53:53 PM »
Just an old guy who never drove it anymore, it sat for about 7 years.  He also had a 74 cb350 that i was tempted to pick up , 100bucks for that one too.

Run back there and grab that one too!  Now!  Di di mau!  Most ricky-tick!  Andele!  Mush!
1974 CB 750
1972 CB 750 http://forums.sohc4.net/index.php/topic,57974.0.html
1971 CL 350 Scrambler
1966 Black Bomber
Too many others to name…
My cross country trip: http://forums.sohc4.net/index.php/topic,138625.0.html

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #6 on: June 15, 2010, 02:54:11 PM »
I was gonna but when i went back the next day he had sold the CB350 the day before.  Wish i knew then what i know now.  O well always keeping my eyes open for good deals.

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #7 on: June 15, 2010, 10:42:50 PM »
Worked on the seat tonight, this is what i got

Used this steel pipe in my garage to make the bend




Think i am gonna put a little more arc into it

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #8 on: June 16, 2010, 09:29:01 PM »
I cant believe it, i saw the CB350 that i found at a yard sale for 100bucks, found it on craigslist for 700. i sure am kicking myself now.

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #9 on: June 18, 2010, 10:51:24 PM »
Making some progress, waiting for my sportster tank to try that fit.  Shortened the bars today than kinda put it together to see how it looks. 







Offline bikeme2001

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Re: 78 CB750 Bobber Project
« Reply #10 on: June 19, 2010, 05:54:35 AM »
Cool build.

Offline captaincrash80

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Re: 78 CB750 Bobber Project
« Reply #11 on: June 19, 2010, 11:58:08 AM »
I'd ride it :D

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #12 on: June 19, 2010, 07:46:42 PM »
Thanks I cant wait to ride it myself, got some more work to do before i get that far.  Thanks for the comments so far.

traveler

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Re: 78 CB750 Bobber Project
« Reply #13 on: June 20, 2010, 07:57:20 AM »
eBay those bags and fairing...generate some money for the build.

just .02

~Joe

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #14 on: June 20, 2010, 02:59:38 PM »
I'll take your 2 cents, lol and i totally agree about selling the extra stuff i have, but wouldn't shipping be a pain in the butt with this stuff.  Hmmm maybe ill try craigslist first, than worry about shipping

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #15 on: June 22, 2010, 08:44:33 AM »
Got my Harley sportster tank and test fit it on the frame.  I want it to sit lower on the frame so im gonna have to do some mods.  i was close to driving it if i was gonna use the factory tank, now i need new drag bars or broomstick bars and a pipe bender so i can fit the tank. Also decided to extend the frame and build a full solid rear frame, no more swingarm.




Offline Cbowers

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Re: 78 CB750 Bobber Project
« Reply #16 on: June 22, 2010, 10:02:21 AM »
Great build, love the stance of the bike. cant wait to see the harley tank on it.

If you still have those saddle bags and seat I would be interested if they were on the cheap!!

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #17 on: June 22, 2010, 01:42:21 PM »
I still have the seat, luggage rack, passenger backrest, side bags and front windscreen.

Sent you a PM

Offline 75cb550 (kyle)

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Re: 78 CB750 Bobber Project
« Reply #18 on: June 22, 2010, 02:26:26 PM »
i like it

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #19 on: June 23, 2010, 08:06:02 PM »
Got my tail light today so i built a licence plate and tail light bracket instead of buying one, here it is.  I'll prob paint it black or whatever i paint the frame.




traveler

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Re: 78 CB750 Bobber Project
« Reply #20 on: June 23, 2010, 08:16:24 PM »
A standard frame of measure is 4 inches stretch.  Any more than that, and the chain has a tendency to flop around when riding.

So, block the bike up, move the rear wheel back 4 inches, and redo the rear tubes.  you could always do a quick 4 inch extension on the swingarm to get het wheel back, and then put in your tubing, then get rid of the swingarm in the center.

All this welding....sure hope you are using slugs between the tubing....otherwise she may come apart at speed and kill you!

P.S.  Get rid of the King sporty tank, and get a small "peanut" sportster tank.

~Joe

Offline 75cb550 (kyle)

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Re: 78 CB750 Bobber Project
« Reply #21 on: June 24, 2010, 06:09:58 AM »
nice job on the tag bracket. that would have saved me some $$

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #22 on: June 24, 2010, 01:43:28 PM »
Thanks, it really wasn't hard at all and took all of about an hour.  i was thinking of making more considering how much these things go for online. 

Offline 75cb550 (kyle)

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Re: 78 CB750 Bobber Project
« Reply #23 on: June 24, 2010, 01:45:23 PM »
Thanks, it really wasn't hard at all and took all of about an hour.  i was thinking of making more considering how much these things go for online. 
plus your's will probably fit the axle bolt.

Offline Nick_701

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Re: 78 CB750 Bobber Project
« Reply #24 on: June 24, 2010, 03:00:10 PM »
Yeah i drilled it to fit perfectly