74 CB750 ENGINE REBUILD...

[cityslicker]

Ok. It's time to get the engine worked out.
I have the ENTIRE shop manual from here printed out and bound in my shop.
But I am still suuuuuuuuuuuuuuper nervous about getting into this.
Any tips or info that you guys may have for a never tore and engine open before guy; would be very very much appreciated.
I think I have to do this so there is really no choice in it.
what kits should I buy?
is there a tried and true way to keep track of all the parts?
ETC.
if I get the top open and things look good can I just jump to the lower case? I definitely have to see why I'm missing spots in my shift pattern. so the lower has to be opened.

[shinyribs]

I am not gonna be able to help at all,im just gonna stay out of the way here.I am eager to see what you find so that i can learn something from this.Main reason for posting this,don't be nervous.If those assembly line guys could slap them together 30+ years ago,i am sure that with your common sense,and being cautious,that you will be just fine.God luck to ya Mike,you can do it













....man.....i sure am glad its not mine......just kidding

[Daddyman]

If it makes ya feel better I rebuilt one of these when I was 15 years old and didn't have a book to go by.  It is still running today, so don't sweat it.

[Piute]

  Go to cheepo store and get dot stickers or some thing to use # or letters for some bolts ,baggies work for some that are all the same put yoursticker on it ,wright it all down on note pad and copy on sepperate pad every night so the oily one in shop can stay in tool box.
  I did my 1st build by myself 350 chevy and did this,don't think that "O" i can remember that ,you can't 3 months down the line,
   push rods and such need to go in same place if not replaced,(i believe)you say getting new one's then find out you can't get them BUT already mixed them up,GET THE IDEA ? mark / save everything.
  leave note's for yourself,were wires go and how routed,"O" there in the book but this 1 "I'll remember" that 1 wire can blow your "what ever"

[LukeM]

If you are after the gear bits in the lower case, you'll need to take apart the upper parts to get to it.  While you're doing this, look over every bearing, ring, and seal on the upper section.  It would be prudent to replace that stuff that looks old or ready to go.  I had the opposite situation: the long cam chain on my DOHC 750 broke, and the mechanic I was working with wanted to replace all sorts of pieces in the upper and lower sections, using the "Well, as long as we're here..." argument.  The piston rings didn't look bad, and the bearings were just starting to show some wear.  I parted mine out.  I applaud your decision to rebuild. There are plenty of SOHC 750 guys on this forum, so support shouldn't be a problem.

Also, take LOTS of pictures with a digital camera.  It's an easy to document the process.

So, I'd recommend looking everything over, and if it looks suspect, replace or recondition it.

My 3.7 cents worth.
Luke M

[TOOLS1]

Unless your top end needs rebuilt don't mess with it. You can work on the transmission with out removing the top end. Just mount the engine in a stand (Shiney's method will work perfect), and remove the lower half of the case.
TOOLS

[cityslicker]

can you link me to shineys method? how can i know if the top is ok though? maybe just remove the rocker cover and have a look?

[ksharp]

the rocker pannel wont tell you another about the cylinders because you wont be able to see inside them besides the spark plug holes, i would suggest spending the fifty dollers for a gasket kit and a enginer screw set, never know when you strip somthing taking it off and have to re tighten it back in and just thinking to your self shit ima have to pull that off one day lol. its a super easy engine nothing to it, if your even thinking about taking it apart then you already have the skillz

[cityslicker]

well,.,,, I want it to run... I know that. and I'm spending alot of time meticulously sanding cleaning and painting the rest of the bike, the engine should be done right too I figure. Thanks for the Confidence everyone.

[TOOLS1]

Haven't, you had it running? How do, you know it will not shift? If, you have not had it running, you can do a compression check. That will tell, you if the top end need rebuilt.
To see Shiney's method just look at the Water buffalo thread, and look at how he has his engine mounted in the engine stand.
TOOLS

[cityslicker]

I haven't had it running. there seems to be pressure when I crank the engine by hand. I can feel and hear air through the spark plug holes.
so will it not shift to all the gears without it running? thats interesting.

[TOOLS1]

They do not shift very well unless they are running. Also any time, you are trying to shift gears without the engine running DISENGAGE THE CLUTCH! Since the gears are not spinning the teeth can catch on the sides rather then sliding together. If they are forced. The shift forks can be bent.
TOOLS

[cityslicker]

well it is disengaged, but thats good to know, I guess, what I'll do is build a mount for the engine, and hook it up so I can turn it over. then go from there. perhapse I'll find the engine is in good working order.
does anyone here have a diagram of what I'll need to set up to have the engine running off the bike?

[TOOLS1]

Set it in an old car tire. Block it up with scrap wood if necessary. Hook it up to a gas can, and a 12 volt power supply. Crank it over. It should run.
TOOLS
P.S. What do, you mean the clutch was disengaged? Were, you pulling the clutch lever, or was it just disconnected? The clutch is always engaged unless  the lever is pulled, or it is disassembled.
 

[cityslicker]

I was holding the lever in

[cityslicker]

just 12 volts to the coils? to the plugs. and thats all it'll  need to crank? thats awesome, I'll give it a whirls once I get some coils.:)

[LukeM]

Love the low-tech TOOLS methods.  You know it works, because TOOLS has done it before.

Just remember the 4 word mantra when it comes to Otto-cycle engines:  Suck, Squeeze, Bang, Blow. Toss some gas and air into the equation, and you have a working engine.

Luke M

[TOOLS1]

It's sad, but I just don't have all the toy's Shiney has. However I am catching up.
TOOLS

[shinyribs]

I may have some tools,but you have all the know-how and experience

[shinyribs]

cityslicker wrote

can you link me to shineys method? how can i know if the top is ok though? maybe just remove the rocker cover and have a look?

http://honda-cb750-s.456789.n3.nabble.com/One-man-engine-removal-in-ten-minutes-td3248305.html

I know you already got the motor out,but how i mounted it is down a few clicks