1983 CB750 DOHC Build

[ljonny18]

At this point, seeing although I am this far (and the bike had a knocking noise coming from the engine when running) I thought it made send to go the whole hog and also check the bottom end of the motor to make sure there are not "bigger" issues related to the camshaft / connecting rods etc  before I continue ... it's also pb best as the bike has 60,000km (40,000 miles) on the clock and it appears the the previous owner(s) did not look after it too well :(















Now I have hit a wall and cant continue until I get / make a tool to take this nut off:

[motogrady]

Sorry to hear about the knock guy.
But I wanna see the gut's of that engine.
Keep the pics coming, all the way thru, you take great shots.

[shinyribs]

That nut on the clutch is not very tight. That's why it has the retainer plate with the bendable ears to hold it in place. Now,if you are not comfortable with this-dont do it!- but I knock mine loose with a long flat head screwdriver and a hammer. The longer the screwdriver,the more angle you can get on it. Either way:good luck !

[ljonny18]

shinyribs wrote

That nut on the clutch is not very tight. That's why it has the retainer plate with the bendable ears to hold it in place. Now,if you are not comfortable with this-dont do it!- but I knock mine loose with a long flat head screwdriver and a hammer. The longer the screwdriver,the more angle you can get on it. Either way:good luck !

Cheers,, thats what I was currently thinking !! My mate has a Honda tool / socket from n MX bike that he thinks may fit.... will give that a go first !

[ljonny18]

ljonny18 wrote

shinyribs wrote

That nut on the clutch is not very tight. That's why it has the retainer plate with the bendable ears to hold it in place. Now,if you are not comfortable with this-dont do it!- but I knock mine loose with a long flat head screwdriver and a hammer. The longer the screwdriver,the more angle you can get on it. Either way:good luck !

Cheers,, thats what I was currently thinking !! My mate has a Honda tool / socket from n MX bike that he thinks may fit.... will give that a go first !

Here is the tool :



Although its too small :( @shinyribs, im going to give your idea a go :)

[ljonny18]

I eventually got impatient using "shinyribs" method - I took a hammer and long screw-driver to the clutch bolt :S and decided it would be easier and faster to simply replace the bolt with a new one on the re-build (it looks although someone has already take a hammer to it anyway):

[ljonny18]

Moving on:

[ljonny18]

I could not seem to get the alternator rotor off... After a while of trying I thought I would leave it for now and do a bit a research before I broke something :(

[ljonny18]

As I am now a bit stuck with the alternator bolt :(

A lot of the engine is already apart and space in the garage is slowly getting less, I thought it was a good time to have another clear up and organize everything... I have learnt (in my case at least) keeping  your space tidy and organizing your parts / tools etc make the whole process a lot easier ....

[ljonny18]

I got it - I manage to (eventually) get the alternator off with a little help from brute force :S :







prepare the rest of the engine for separation.... :











Upside down and ready for separation (I hope) :)

[ljonny18]

sump off:

[ljonny18]

This does not look too hot :S





Anyone know how much I should be worried with such shards of (I think rubber / plastic) ??? I think they may even be from one of the chain tensioners...

[ljonny18]

onwards :)















Removing the final bolts for separation:

[ljonny18]

Stuck :( the casings do not want to seperate ....



I have tried loosening the seal with both a rubber mallet and also using a larger hammer and wooden block, but the seal does not want to break :( I am pretty sure I have removed all bolts (maybe there is one hiding)

Would it help to heat the seal / casings up ? would this help the separation ???

As always, any advice is welcome and appreciated.

[ljonny18]

I finally got the engine casings separated, after heating the seal and using further persuasion with a wooden block, hammer and heat gun:





Note: if you have any issues seperating the engine, I found heating up the seal very effective... :





Separated :)




oooo interesting :)

Before I get carried away and continue any further, I am going to have to spend some time doing my reading my Haynes manual and doing homework / research and learn whats what before I get too deep and break things :) watch this space ;)

[Hoosier Daddy]

ljonny18 wrote

sump off:

Check for metal in that sludge... don't just trust a magnet, some important stuff is non-ferrus. Especially bushings / bearings.

ljonny18 wrote

Anyone know how much I should be worried with such shards of (I think rubber / plastic) ??? I think they may even be from one of the chain tensioners...

Most likely you are correct if it is rubber / plastic. Inspect your tensioners.

[seestheday]

First off, awesome thread.  I'm really impressed at how fast you've been able to work.  You started Nov 17th by replacing the battery, and it's a week later and you've completely torn down the bike.

Really digging the pics, this will be very useful when I tear down my 81K engine this winter, although I don't plan on going nearly as far as you have as mine is a daily rider.

Looking forward to seeing more progress.

[shinyribs]

Nice pics! I cant believe how massive that primary chain is Hoosier gives good advice on inspecting the contents of that sump.BTW,that sure is a used up tire under that sump

[motogrady]

What about the knock?

Grab each connecting rod where it bolts around the crank and see if you can feel
any up and down play, in any of them.

[ljonny18]

seestheday wrote

First off, awesome thread.  I'm really impressed at how fast you've been able to work.  You started Nov 17th by replacing the battery, and it's a week later and you've completely torn down the bike.

Really digging the pics, this will be very useful when I tear down my 81K engine this winter, although I don't plan on going nearly as far as you have as mine is a daily rider.

Looking forward to seeing more progress.

Hi - thanks, however I started the project a while ago, I have only just started documenting it on this thread recently - im not that fast ;)