Author Topic: 1972 CB750 - Vermont Winter Project - Into the second Summer  (Read 16555 times)

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Offline VTCBike750

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1972 CB750 - Vermont Winter Project - Into the second Summer
« on: April 25, 2011, 09:32:27 am »
So here is my Vermont winter project. I wish I had started this posting sooner, but never really got a around to it. Back in October I bought a 1972 CB750 and decided to post my progression throughout the rebuild. I don't really have the time or money for a full restore. And I've tried to keep this project to a financial minimum, but exceeded the bank account just a little ;D!

Long story short my first bike was a 1977 CB550 that I sold before moving up here in June and regretted it ever since. One of those I'm moving, somebody wants to buy it, and the price was right sort of things.


We pack up everything, the 2 dogs, the cat, truck on tow dolly (dogs in truck), 16' moving truck and drive 31 hours straight to Vermont. Of course we get up here and my neighbors have hondas. I instantly want to get a another one.

I search craigslist on a daily basis for weeks. Nothing really comes up. Dont want to go smaller than a 550. There was a nice CB500, didn't get it, and still wish i had. So I put up a posting on CL that Im looking, and get a call from a guy in Franklin, VT (right up near Canada) with a 1972 CB750 for sale, with a 75 750 parts bike (seized engine), and a third set of carbs for $800. Why the hell not!

There are a few things wrong with it:

Front fork seals need replacement
Tachometer is missing a needle
Has a king queen seat
Bad looking Kreeme job
Left fork ear has been broken and welded
Missing a left side cover
PO says that the starter isn't hooked up

Thats it! Minimal rust for anything in Vermont. For those who dont know it Vermont has a large appetite for eating cars and the sort.

He swears to me that it runs and I grab it. So far everything that he has said has been spot on.



Get it home, unload the bike, and look at my new found treasure/project/headache/fun.






Suzuki turn signals (now belonging to a proud owner in brazil)

Early 750 tach without needle

First things first: New gas, buy a battery, and see if she'll start!


« Last Edit: July 16, 2012, 07:59:54 pm by VTCBike750 »
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline joeyputt

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Re: 1972 CB750 - Vermont Winter Project
« Reply #1 on: April 25, 2011, 10:00:39 am »
Brother VTCBike750 your 750 looks nice!
Joe - Owner/Operator of DWMS Racing World Class Engine & Motorcycle Building www.dwmsracing.com

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Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #2 on: April 25, 2011, 11:37:43 am »
Thanks Joeyputt. 

So I get new gas in her, charge up a new battery, and put in new spark plugs.  Ah, good news, the electronics work. Starter doesnt, but PO said it wasnt hooked up.  Headlight, check. Turn singals, check. Brake light, check. The instrument wiring is all messed up, the tach indicator lights are hooked up and half the lights on the indicator panel aren't. 

1st kick start, it feels good.  30th kick start im getting tired, but can hear it coming. So the PO wasnt lying she runs...rough. 1 and 2 arent firing.  Let the bike sit for a little and kick her over again.  All 4 cylinders firing and all 4 exhausts hot. Pull in the clutch, put her into gear, and she stalls. No matter what I do and she stalls. 

Being my first time working on any bike, its time to learn how to take the clutch apart give it a good cleaning and see whats up.
Clutch taken apart, cleaned, and reassembled. Clutch was in decent shape. 

Now for the first ride. 
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #3 on: April 25, 2011, 02:21:09 pm »
The first ride wasn't too bad.  Great to just be back on a bike. She rides a little rough, definitely needs the carbs cleaned, and an over all tune up.  But the biggest thing, the handle bars aren't straight when riding.  After looking over a few things, the forks need a little more than new seals!!!


The left fork is bent and probably the right.
I'm beginning to have that funny feeling that the bike got laid down. Given that the left fork is bent, left side cover is a replacement, the left fork ear is welded, and the stator cover is jacked. What ya think?
The Previous PO bought the bike with the same parts bike (last registered in SC)...Wondering when this bike was last registered, the Vermont sticker on the left fork tube was red? Anyone know what year that would be?

Took the bike down to the spray and wash, cleaned it up, and took it inside for a long winter.


Time to take it apart.  I was hoping to use the front forks off the parts bike, but learned the very tedious way that they are not compatible.  DUH!





The bottom tubes are from the 72 (not too bad ???), top tubes are from the 75 parts bike


Grabbed a set off ebay and ran them through electrolysis to remove the rust.


Polished the lower fork tubes the best I could without a polishing wheel and reassembled the forks.
Crappy cell phone picture, but you get the idea.





« Last Edit: April 25, 2011, 03:47:11 pm by VTCBike750 »
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #4 on: April 25, 2011, 07:14:15 pm »
Started looking at the very chunky kreeme job.  The slightest touch compressed the kreeme revealing nothing but rust underneath. Peeled out what I could.





After a good sloshing of acetone... Empty, Filter, Repeat.  Electrolysis, more Acetone, and some scrubbing with a toilet bowl brush...I thought about adding some loose change to the tank.  Maybe use pennies, seal the tank, and shake.  Well this caused a chemical reaction, built up pressure on the inside, and blew out the petcock caulk plug. Next time Ill use nickels or nuts. The acetone breaks down the caulk, but at a very slow rate compared to the kreeme. I also put a small piece of masking tape over the caulk to just hold it in place, no leaks.



There are a few smaller pieces of Kreeme Stuck in the corners and on the bottom.  A little fresh acetone, should do the trick.

 
« Last Edit: August 21, 2011, 07:51:05 am by VTCBike750 »
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline MasterChief750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #5 on: April 26, 2011, 06:43:36 pm »
copper shouldnt vigorously react with acetone. but it will react with some acids. did you maybe have acid in there?
1978 CB750 K - Project Red Headed Step Child
1976 CB750 K - Drag Bike
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Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #6 on: April 26, 2011, 07:44:39 pm »
No acid in the tank, thoroughly washed out and dried. Dont know what to say. I was a little surprised by this myself.  Maybe something from the kreeme being dissolved into the acetone that I reused? Some of the pennies had their tarnish removed.
« Last Edit: April 30, 2011, 06:08:27 pm by VTCBike750 »
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #7 on: April 27, 2011, 02:02:00 pm »
So experiment, the pressure has nothing to do with the loose change. Put the new acetone in it and it builds up pressure.  ????
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline MasterChief750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #8 on: April 27, 2011, 06:17:53 pm »
ah acetone evaps rapidly
1978 CB750 K - Project Red Headed Step Child
1976 CB750 K - Drag Bike
Some things i know, others i dont.
I AM THE STIG
Sam is THE STIG
he said i can be STIG3 tho

Offline KB02

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Re: 1972 CB750 - Vermont Winter Project
« Reply #9 on: April 30, 2011, 05:14:41 am »
Good looking project. I live in northern Vermont - Burlington area. Where are you?

I had to take out a bad kreme job and used M.E.K. with good results.
1978 CB750K Project
2000 Ducati Monster
...and a pedal bike

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Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #10 on: April 30, 2011, 05:48:12 pm »
Good looking project. I live in northern Vermont - Burlington area. Where are you?

I had to take out a bad kreme job and used M.E.K. with good results.

Thanks KB02, Im in Burlington.
So far Ive gotten most of the kreeme out.  There are a few smaller pieces that Im hoping to get out tonight and then seal the tank.  Wondering if MEK would of been a better option though.
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #11 on: April 30, 2011, 06:07:36 pm »
So far Ive been able to:

- Cleaned and Polished 90% of the bike
- OEM front turn signals
- unplugged everything and hit every electrical connector with dielectric grease
- Used 72 seat on Ebay
- Found a tachometer on Ebay (wasnt the easiest find)
- Repainted front brake caliper
- New front brake pads
- New left fork ear
- Used fork tubes off Ebay, run through elecrolysis.
- Tach cable support mount (need to put on the Gremlin Bell)
- Cleaned the carbs (not too bad)
- New fuse box and rewiring. Bike was wired without fuse box and the starter cable connected directly to the battery, bypassing the solenoid
- Key for Rear Seat lock and Steering lock
- New ignition switch rewired for round plug
- Dropped exhaust, rust removed with naval jelly, elbow grease, and polished.
       - #1 exhaust wet...Need to look into that.
- Started treating tank with acetone to remove old Kreem and run electrolysis to remove rust
- patched 1 mm x 1 mm hole on top of tank with JB Weld

Off Parts Bike
- Rear Seat Lock (someone took out the 72's tumblers)
- Headlight bucket repainted (72's cracked on left)
- Ignition switch mount
- Negative battery ground cable
- Positive battery cable
- Rear shocks
- Stator cover
- Starter cover
- Right foot peg (72's was bent forward?)
- Battery drain tube and associated washer on center stand
- Misc bolts and etc.

Left to do
- Remove residual Kreeme from tank and seal with POR-15 Tank Sealer
- Remove rear wheel and check brake shoes
- Adjust valves
- Adjust cam chain tensor
- Adjust chain

Long term goal
 - Repaint tank and get a left side cover, $$$$$
















-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline jumpnkill

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Re: 1972 CB750 - Vermont Winter Project
« Reply #12 on: April 30, 2011, 09:51:27 pm »
It's looking good!  You got a much better deal than I did so you're starting off right.  Do your bikes have the starter safety units still installed, or were those removed?  Show some pics of the new fuse setup too!  Keep at it...it only feels better once they get closer to finished!

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #13 on: May 01, 2011, 01:31:03 pm »
Adjusting the  valves today...for the first time!
 
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline jaguar

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Re: 1972 CB750 - Vermont Winter Project
« Reply #14 on: May 01, 2011, 07:10:17 pm »
looking good.
i have some good friends in burlington and go over and see them often.  nice town

im in northern NY for school right now and its a terrible place to live....lol

Offline KB02

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Re: 1972 CB750 - Vermont Winter Project
« Reply #15 on: May 02, 2011, 06:39:26 pm »
Long term goal
 - Repaint tank and get a left side cover, $$$$$

Check out LMP:
http://lpmreplicaparts.com/honda/CB750K1/sidep.html

Great prices and a good product. Those are what I have on my bike.
1978 CB750K Project
2000 Ducati Monster
...and a pedal bike

Join the AMA today!!

My project thread Part I: K8 Project "Parts Bike"
My project thread Part II: Finishing (yeah, right) touches on Project "Parts Bike"

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #16 on: May 03, 2011, 05:33:20 am »
Do your bikes have the starter safety units still installed, or were those removed?
I dont think the 72 has ever had one, someone correct me if I'm wrong. The wire diagram doesnt show one. Where would it be? 

Got the battery charged up and most things are working great. I was a little worried that the starter motor was shot, bc I never saw it work, but it works great. Ill have to test the blinkability of the turn signals once I get the bike running.  The only things not working are the high beam, neutral, and oil pressure indicator lights. Ill have to dig a little deeper and see whats going on with them.

Check out LMP:
http://lpmreplicaparts.com/honda/CB750K1/sidep.html
Thanks, Ill check them out. Hey you been riding yet this spring, when its not raining? I cant wait to get out there.
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline KB02

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Re: 1972 CB750 - Vermont Winter Project
« Reply #17 on: May 03, 2011, 06:11:43 pm »
I've been riding a little bit. Not too much. Too cold, too much rain, and a 9 month old that needs a car seat.  ;)  I haven't had the CB out yet, though. Still been doing a little work to it.
1978 CB750K Project
2000 Ducati Monster
...and a pedal bike

Join the AMA today!!

My project thread Part I: K8 Project "Parts Bike"
My project thread Part II: Finishing (yeah, right) touches on Project "Parts Bike"

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #18 on: May 06, 2011, 07:04:34 am »
looking good.
i have some good friends in burlington and go over and see them often.  nice town

im in northern NY for school right now and its a terrible place to live....lol

Yeah, Ive never been up there, but Ive heard less than great things about it.
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline jaguar

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Re: 1972 CB750 - Vermont Winter Project
« Reply #19 on: May 06, 2011, 03:07:48 pm »
im at school in potsdam NY(clarkson)
being from outside of NYC im going mad with all these trees and such.

if your looking for covers a member here is making them.
im planing on getting a set for both my 750s.

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #20 on: May 07, 2011, 06:22:11 am »
Weekend check list:

Reassemble petcock
POR-15 tank sealing
repair new cracks in seat (not too happy about this, but it was used off ebay)
Swap out oil pans (current one is cracked)
Put on carbs and Airbox (wish my knuckles luck)
Enjoy some beer
« Last Edit: May 07, 2011, 09:23:57 pm by VTCBike750 »
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #21 on: May 20, 2011, 07:38:36 pm »
So its been a couple of weeks and Ive been able to get a few things done. The biggest pain in the A$$ was getting the old Kreeme out of the tank. The POR-15 tank lining wasn't bad, just took a long time. Be prepared to spend a lot of your weekend working on it though.  I followed the instructions posted by Tim. http://forums.sohc4.net/index.php?topic=1586.0;nowap

But so far Im happy with the results



I left the tank to drain overnight and had a little pooling by the petcock area, but I've let it cure for 2 weeks so far.
But Like I said so far I'm happy with it, give it time and we'll see how long the happiness lasts.


Swapped out the oil pans and started to give the rear brakes a look over. So far this is what Ive been able to come up with.


From what I've read, arent the punch marks are supposed to line up? Mine are off set one step. The brakes only work when set up this way. Ive tried adjusting. I checked the brake pedal, those punch marks are lined up properly. Is this something I should be concerned about?


I couldnt figure out to remove the chain. I started to undo the master link, but from there it looks like I need to break the chain.  Something I couldn't figure out. Oh well, no forcing or twisting, just slide the wheel forward.


Maybe someone can give me some insight on the hub's diameter. It has a diameter of 181 mm and is fairly smooth, no gouges or ruts. Does anyone know what is the inside diameter of a new hub?  The Clymer manual says at 183 mm the rear wheel hub needs replacement. Is the hub close to wearing out? Maybe thats why those punch marks dont line up? Any ideas? The pads are 7 mm thick. Well reassembled things and the rear brakes work well, just wondering if they are wearing out.

Now its time to get the carbs and air box on the bike. But first Im gonna give that whole wintergreen oil a shot at softening the carb boots.
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #22 on: May 21, 2011, 06:42:36 am »
Show some pics of the new fuse setup too!  Keep at it...it only feels better once they get closer to finished!


Here it is in the beginning. The negative starter cable goes to the battery not the solenoid, There is no negative battery cable to the frame, and no fuse box.


Not too impressive, but here it is. A little wire switcharoo, negative battery cable from the parts bike, and a new fuse box.
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

Offline KB02

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Re: 1972 CB750 - Vermont Winter Project
« Reply #23 on: May 22, 2011, 10:42:17 am »
Stayed with the glass fuses, huh? I've been thinking about doing the blade fuse conversion on my bike.
1978 CB750K Project
2000 Ducati Monster
...and a pedal bike

Join the AMA today!!

My project thread Part I: K8 Project "Parts Bike"
My project thread Part II: Finishing (yeah, right) touches on Project "Parts Bike"

Offline VTCBike750

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Re: 1972 CB750 - Vermont Winter Project
« Reply #24 on: May 22, 2011, 03:47:00 pm »
Well the wintergreen oil worked great on the boots. They're a lot softer. Added 2 oz to about a gallon of water, go it to a boil, dropped boots in, and took it off the heat.  Every 20 minutes or so Id bring it back to a boil and then off the heat for about 2 hours.

Mounted the carbs and air box, new fuel lines, charged the battery, got some gas and took her out for the first ride.  Started up on the 5th kickstart. An awesome bike. The 750 doesnt feel as big as I thought it would. Great bike to ride.

Need to work on a few things, turn signals arent flashing and it could use a carb sync.  #2 is running lean, but #1 is firing without a hitch.

When I first started riding there was a clicking noise coming from #1 (around the top), but it went away after a few miles. Any thoughts? Sounds great and should sound better after the sync.




« Last Edit: June 03, 2011, 06:01:56 am by VTCBike750 »
-Adam

1972 CB750 (current project)
http://forums.sohc4.net/index.php?topic=87951.0

 

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