Author Topic: Bessie, my first rebuild: 78 CB750F3 (Back in the shop 2014-04-21)  (Read 22410 times)

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Offline wohali

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Hi there,

The rebuild that I was going to do last year is now underway. The main reason for the rebuild is to teach myself how to wrench well, from the ground up.

She was riding fine over the summer, until the battery died, the brakes started to seize up, a bubble appeared in the tank paint job I did previously and I noticed she'd drip gas from the carbs if the petcock was open. I figured it was as good an excuse as any!

Galleries so far:

Me after wrestling the engine out (thanks for all your help doozer!)


Top end off, ready to remove the head
« Last Edit: April 21, 2014, 09:18:36 PM by wohali »



Offline bluesmoke69

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Re: My first rebuild/restore ever: 77/78 CB750F2/F3
« Reply #1 on: December 03, 2010, 10:53:27 PM »
Let me be the first to say welcome, and good luck with your build. This board is a wealth of knowledge. ;D



Offline tweakin

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Re: My first rebuild/restore ever: 77/78 CB750F2/F3
« Reply #2 on: December 04, 2010, 11:58:24 AM »
welcome to the forum, good to see another 750f getting worked over.



Offline tango911

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Re: My first rebuild/restore ever: 77/78 CB750F2/F3
« Reply #3 on: December 04, 2010, 02:52:02 PM »
looks like a great start!!  congrats and welcome.

CURRENT STABLE:
1965 Sears Allstate Puch 250
1969 Honda Dream 305 (black)
1974 Mach III kawi 500 smoker
1974 CB750 (project)
1978 CB750 SuperSport Custom
2006 CRF250R



Offline BruceDeuce

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Re: My first rebuild/restore ever: 77/78 CB750F2/F3
« Reply #4 on: December 04, 2010, 02:54:26 PM »
Hi Joan, from NJ
78 Honda 550 Four (K)
79 XS650 Special
72 Suzuki TS400J Apache
72 Kawasaki G3SS 90
73 Aermacchi X90
86 Honda 450 Rebel restored
03 HD Deuce Screaming Eagle
Yamoto 50cc Quad
06 Loncin 110 Quad
85 LT250EF Quadrunner



Offline SOHC Digger

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Re: My first rebuild/restore ever: 77/78 CB750F2/F3
« Reply #5 on: December 04, 2010, 03:15:31 PM »
I am just winding down on my 78F rebuild.  If you have any questions, feel free to ask.

By the way, take those two little oil restrictors on top of the head near the cam chain and put them in a SAFE place!

And if you don't have an impact screwdriver, I would strongly recommend getting one.  It will make your life significantly easier!
« Last Edit: December 04, 2010, 03:18:46 PM by SOHC Digger »
The surest way to learn is to make a mistake.
1978 CB750F Chopper/Digger
The Next Chopper Project



Offline wohali

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #6 on: December 05, 2010, 01:32:00 AM »
SOHC Digger: Are those the 4 O-rings on the top near the nuts in this picture? Yes, I have an impact screwdriver :)

More pictures - Gallery 3! I got the head and cylinders off today. Took nearly 4 hours to get the cylinders off with gentle prying and wooden shims! I think it was jammed due to corrosion on the studs. DEFINITELY getting those replaced!

Previous owner said there was a problem with cylinder 3 not firing, I think because he didn't have the proper wrench to replace its plug. Got it working 5 years ago, but you can still see the uneven wear.

Underside of head, cyls 1 (R) and 2 (L)


Underside of head, cyls 3 (R) and 4 (L)


Augh, those studs!


Tomorrow: splitting the crankcase, maybe valve removal.



Offline brandEn

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #7 on: December 05, 2010, 01:45:27 AM »
making progress! Good to see you posting pics and good ones too. You must have a nice camera. Mine is real POS. Anyway If you decide to remove those cylinder studs be VERY careful removing those 4 in the middle that are corroded. They will be stubborn and could break and then you have real battle on your hands. I just went through that and I consider myself lucky to have gotten them out.



Offline SOHC Digger

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #8 on: December 05, 2010, 01:46:12 AM »
SOHC Digger: Are those the 4 O-rings on the top near the nuts in this picture?


The restrictors are the little aluminum orifaces inside the o-rings next to your cam chain (two of the four mentioned o-rings)

Good start.  My 750F had the same problem with disassembly.  I had to fight a long time to get the head and cylinders off.  The same four studs had heavy rust as well.  Those are the four studs with cap nuts and copper washers.
The surest way to learn is to make a mistake.
1978 CB750F Chopper/Digger
The Next Chopper Project



Offline Really?

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #9 on: December 05, 2010, 01:52:12 AM »
tagging along.



Offline wohali

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #10 on: December 05, 2010, 01:55:13 AM »
The restrictors are the little aluminum orifaces inside the o-rings next to your cam chain (two of the four mentioned o-rings)

Ah of course! Yes, once the O-Rings come out, they'll come out too, and get bagged. Actually, I have a very old parts drawer unit (OD green, all metal, maybe from the 40s or 50s?) I am storing everything in. Really convenient!

Zzzz....



Offline wohali

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Boo.
« Reply #11 on: December 05, 2010, 12:55:53 PM »
These four screws have completely seized up. #3 JIS impact driver not getting me anywhere. Trying some penetrating oil for the next 24 hours since I have other commitments for a bit. After that it'll be heating a rod, applying to the head of each in turn until the oil smokes, reapplying oil and letting cool before trying to remove.




Offline brandEn

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #12 on: December 05, 2010, 01:33:58 PM »
You may not be hitting the impact driver hard enough. I literally had to hit mine as hard as I could and they all broke loose with a satisfying 'snap'. Also make sure you have the driver so it is turning the right way when you smack it. They are able to loosen or tighten either way.



Offline pearsonm

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #13 on: December 05, 2010, 01:36:22 PM »
So how heavy is that lump of a motor? Is it possible for one person to wrestle it out? (I'm guessing not.)
Bikeology: '78 CB750F, F4i #2 (track); DR-Z400SM (traded); SV650S (sold); F4i #1 (RIP); R6 (traded); YZF600R (sold); ZR-7S (sold); Bandit 1200 (RIP)



Offline GammaFlat

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #14 on: December 05, 2010, 02:17:48 PM »
So how heavy is that lump of a motor? Is it possible for one person to wrestle it out? (I'm guessing not.)


about 200 lbs.  They can be removed by one person if you get a little creative.  One way is with support from above -straps holding it up while "sliding out" the frame.  Another way is to lay the bike on it's side. 

These four screws have completely seized up. #3 JIS impact driver not getting me anywhere. Trying some penetrating oil for the next 24 hours since I have other commitments for a bit. After that it'll be heating a rod, applying to the head of each in turn until the oil smokes, reapplying oil and letting cool before trying to remove.




Impact driver should do it.  Are you "pre-loading" the impact driver... press down real hard and put rotational pressure in the direction you want the screw to go... Another important consideration... make sure what you're hitting is extremely stable.  In other words, The engine shouldn't be hanging from chains.  The slight amount of give that is given up if your target is unstable makes a huge amount of difference. 

If your problem is corrosion (a general notion regarding seized parts), a 50/50 mix of acetone and ATF works really nicely.  There was a study posted here somewhere that indicated it was a lot better than any of the "known solutions" like liquid wrench, PB Blaster, etc.  I've had great luck with it myself. 
K4 - hmmm.  after K6 is done. 
K6 - Get all the king's horse's and men
K7 - my 2nd love (did I say that?)
K8 - Prolly the next SOHC I have on the road
05 KLR650 - Don't knock 'em 'til you try 'em.  685 might be in order.



Offline SOHC Digger

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #15 on: December 05, 2010, 03:19:17 PM »
+1 on trying the impact driver again.  My general rule of thumb is that if I haven't broken the driver bits yet, I can still hit it harder. (It's nice to have lifetime warranties).
The surest way to learn is to make a mistake.
1978 CB750F Chopper/Digger
The Next Chopper Project



Offline Damfino

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #16 on: December 05, 2010, 03:39:31 PM »

Coming along for the ride.... :)

Oh, and welcome to the forums Joan.  ;)

After looking at your profile, I guess I should make that a belated welcome. ;D
« Last Edit: December 05, 2010, 03:43:18 PM by Schmthaus »
You can still call me 'Schmitty'

1976 CB 750
2014 CB 1100DLX



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Offline SOHC Digger

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #17 on: December 05, 2010, 04:08:34 PM »
By the way, it's good that you have a nice camera.  The shift linkage is where I seem to have the most problems figuring out on reassembly.  No diagram I have seen helps.  Take good pictures in this area so you know how your springs go!
The surest way to learn is to make a mistake.
1978 CB750F Chopper/Digger
The Next Chopper Project



Offline GammaFlat

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #18 on: December 05, 2010, 06:18:16 PM »
By the way, it's good that you have a nice camera.  The shift linkage is where I seem to have the most problems figuring out on reassembly.  No diagram I have seen helps.  Take good pictures in this area so you know how your springs go!

I'm about to tear into my K6 engine to determine what a phantom noise is about... so thanks for the heads up on the pictures.  I'll be sure to get good pictures of the transmission.  And now that you mention it, there have been folks here on the forum that have had gears in backward or spacers in the wrong spot.... And it's not like I haven't regretted missing opportunities to document how things have come apart :(

[CAUTION... EDITORIAL ALERT! :)]
Joan's using an Olympus c5050z which is not a bad camera but if she's half as skilled as I suspect (and she were impolite like me :)), she might tell you that the nice pictures have little to do with the camera and a lot to do with the person behind it. 

I have done a lot of photography work and have spent more than I'd like to admit on cameras but I can pick up my $100 digital point and shoot camera and make excellent pictures.  Better cameras do give you more flexibility/functionality and a $1200 Nikon DSLR probably has a better chance of making a better picture but... If I hand that $1200 rig and a part to a non-photographer... then give the same part and a Canon Sureshot to an experienced and trained photographer, who do you think will have a better picture?  The results will be phenomenally different.  The better camera will not win.  I'm kicking around the notion of putting together a tutorial for photographing bikes/parts etc. since our reliance on pictures is huge here.  For the moment, I'll rant about the 2 most glaring errors I see here. 

  • For close-ups, make sure you're in focus.  Most people get the camera close to the subject for a close-up.  Not too good when you're beyond (inside) the camera's focal range - the fix is to move back and crop the photo or select a macro mode which sometimes gives you the ability to focus closer. 
  • Lights!  Use lots and lots of lights.  Getting light from multiple angles is a good thing. 

Stay tuned... not sure yet where I'll post the "photo tips". 
[EDITORIAL ALERT END :)]

SOHC Digger - I see you're in the Chicagoland area.  I'm pretty close (NW Indiana).  Maybe we can catch a ride some time. 


K4 - hmmm.  after K6 is done. 
K6 - Get all the king's horse's and men
K7 - my 2nd love (did I say that?)
K8 - Prolly the next SOHC I have on the road
05 KLR650 - Don't knock 'em 'til you try 'em.  685 might be in order.



Offline joeyputt

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #19 on: December 05, 2010, 06:24:53 PM »
You picked an awesome bike to learn to wrench on! Nothing better than a sohc Honda! Pic's look great too! Keep up the hard work!
Joe - Owner/Operator of Joes Performance & Polishing/DWMS Racing

Polishing - Engraving - Engine Restoring/Rebuilds & Complete Custom Bike Building & Restorations.

Website - www.dwmsracing.com



Offline SOHC Digger

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #20 on: December 05, 2010, 08:10:23 PM »
[CAUTION... EDITORIAL ALERT! :)]
Joan's using an Olympus c5050z which is not a bad camera but if she's half as skilled as I suspect (and she were impolite like me :)), she might tell you that the nice pictures have little to do with the camera and a lot to do with the person behind it. 

SOHC Digger - I see you're in the Chicagoland area.  I'm pretty close (NW Indiana).  Maybe we can catch a ride some time. 

You are correct about the person being behind great shots, not the camera.  My wife is a perfect example.  She takes beautiful pictures and has never owned a camera that cost over $100.  Maybe I should have her take my bike pics.

Yes, let's catch a ride!  I think we should wait until all the lake-effect snow that you are blessed with is gone.
The surest way to learn is to make a mistake.
1978 CB750F Chopper/Digger
The Next Chopper Project



Offline wohali

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #21 on: December 06, 2010, 12:24:03 AM »
Hey guys - thanks to everyone for stopping by and following me! Stay tuned, I'll head back with the impact driver tomorrow, and turn the engine on its side so I can impact straight down without the engine sliding away.

Thanks for all the kind statements about my photos. We should start a separate thread for photo tips, I think, don't you?

But since you asked here, I'll give 3 quick tips.

  • Since someone asked, I like my Olympus C5050Z. I also own some C3040Z and C4040Z cameras, all between 8-10 years old; if you can find any of these on eBay, snatch them up. (I see a C3040Z on there for $0.99 right now!) I love them for two great reasons. First, they're small and run on 4xAA batteries - cheap and easy to find anywhere I might be. Second, the (built-in) lens is capable of going down to f/1.8. This means that the lens itself doesn't absorb a lot of light, so it's really great in low available light situations. As long as the camera is held steady, is on a tripod or resting on a surface, I don't need a flash. C#0#0 cameras after the C5050Z don't go down to f/1.8 so don't bother . So what if the C3040Z is only 3.3 Megapixels -- that's still higher resolution than this forum allows you to embed anyway. ;)
  • One of the main challenges in photographing motorcycle bits is all the shiny metal. The reflection of the flash tends to wash out large areas of detail and skew the light distribution, making it hard to achieve good exposure, or to correct the exposure after the fact in photo editing programs. There's ways around this (bounce the flash, use diffusers, etc.) but I think it's just easier to use a camera where I don't have to worry about all of that. In fact, all of the photos above are taken in my workshop, which is only lit by 10 48" fluorescent bulbs, all about 4m / 12' up. Only about half the pictures posted use a flash.
  • Don't be afraid of the "digital darkroom." iPhoto, Office Picture Editor, or my favourite, Lightroom, all give you great tools to get the most out of your pictures. Once you learn how to use a tool, you'll spend less time cleaning up your pictures than it takes to upload them to your favourite gallery.

Oh, here's a sample low light picture from one of my C3040Zs, no flash, from 2002. Not my best shot ever, but you get the idea!
« Last Edit: December 06, 2010, 12:32:28 AM by wohali »



Offline BruceDeuce

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #22 on: December 06, 2010, 07:51:27 AM »
looks like a pretty good shot to me and oh the quality of the pic is great as well  ;D
78 Honda 550 Four (K)
79 XS650 Special
72 Suzuki TS400J Apache
72 Kawasaki G3SS 90
73 Aermacchi X90
86 Honda 450 Rebel restored
03 HD Deuce Screaming Eagle
Yamoto 50cc Quad
06 Loncin 110 Quad
85 LT250EF Quadrunner



Offline wohali

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #23 on: December 06, 2010, 09:54:47 PM »
OK enough photography yammer. I'm mad as hell. Begging for help here. I guess I need to go to my Screw Outs? The driver won't even stay lodged in 2 of the 4, and none are budging. I tried a nice claw hammer and a 3lb sledge. No dice. Yes it's preloaded, and yes it's set the right way, it won't let you preload if it's set the wrong way.

These ARE normal left-handed screws, correct? Can someone give me measurements in case I need to drill it out?




« Last Edit: December 06, 2010, 10:09:37 PM by wohali »



Offline GammaFlat

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Re: My first rebuild/restore ever: 78 CB750F3
« Reply #24 on: December 06, 2010, 10:54:24 PM »
If the motor moves at all while you are striking, all is lost.  The "object of your frustration" must be solidly against a wall or floor - preferably something concrete or steel - not on wooden blocks or a workbench where it can slide.  Any give at all will make it much much more difficult to break loose.  If you are doing everything correctly, you'll eventually break the screw.  I highly suspect they're not corroded to that point... based on where they "live".  I've seen that happen on screws that hold exhaust flanges (same size screw I think).  

In my experience, when your work is solidly in place, you're holding the impact driver firmly and strike like you mean it, the head of the screw will not get damaged.  Softer strikes will mangle a head - NO TAPPING.  The bit wants to "stay in there" when there's a powerful strike.  I have seen screws in worse shape than yours come out with an impact... especially with a #3 bit. 

Good luck.
« Last Edit: December 06, 2010, 11:05:37 PM by GammaFlat »
K4 - hmmm.  after K6 is done. 
K6 - Get all the king's horse's and men
K7 - my 2nd love (did I say that?)
K8 - Prolly the next SOHC I have on the road
05 KLR650 - Don't knock 'em 'til you try 'em.  685 might be in order.

 

Honda