1974 CB750K Project Bike

[cdaiscool]

Too bad you don't have a DOHC. I'd pick up that bracket from you. :D

[Scrappyike]

Ok, think I did something stupid and I blame it on lack of sleep.  I saw that the turn signals were not connected so I took them off.  I kept going and saw this



I figured it was just wiring for the lights on the fairing and I began disconnecting so I could take the headlight cover off.  I noticed that alot of these wires led to thick harnesses and then realized that this could be essential wiring needed in starting the bike!  Urgh!  Does this look familiar?  Hope it's not needed in starting the bike of which I was going to do this weekend.  

I am stopping now and not doing anything else until I get to starting it.  Grrrrr.  

Additional note:  As for posting pics, for some reason I have not figured how to do it.  I have uploaded them to photobucket but the url did not work even when putting it between the <nabble> </nabble>.  Anything I'm missing?  Thanks again

[cdaiscool]

In the reply box, you will see 'insert image'. Looks like this:



Click that, and you get this box:



In the 2nd line down, where it says "Or copy an image from the internet" put the .jpg link into that box. Put the ENTIRE .jpg link. Looks like this:

http://sphotos.xx.fbcdn.net/hphotos-snc6/255023_10100221064926032_12101664_49841870_1667851_n.jpg

I use FB, but you can use anything. Just make sure it ends in .jpg.

Finally, click 'okay' and it will come up with the following code:

nabble_img src="255023_10100221064926032_12101664_49841870_1667851_n.jpg" border="0"/

Except it will have greater than and less than symbols around it so Nabble can understand it's code. And this is what you get!

[cdaiscool]

And I'm going to defend my car quick: it'd just come out of like 6 months of hibernation. See that metal on the front of the motor? That's not a normal exhaust header

[Piute]

 Don't panic about the wire's but yes you need them ,Some where's ,get a good look at specs ,The headlight bucket is the junction area for ,ignition/idiot lights,wire from bars ,wire's,tach,wires very simple to navigate ,just intimidating is all,All color coated ,take yo time.IF WRONG go to
 http://www.oregonmotorcycleparts.com/diagrams.html

[Scrappyike]

Thanks CDA....How did I miss that button

Piute, I kinda figured afterwards.  Definitely a spaghetti mess in there.  Back to the drawing board.  Sticking to the plan from now on.  

[Scrappyike]

Found some time to do a little bit of work on the bike.  Having problems getting the plug out.  For some reason the socket will not go down far enough to catch the plug.  I can't see anything down there like a rock or dirt.  The other thing I found is when removing the oil filter, yellowish liquid was coming out.  Did not smell like gasoline.  When draining the oil it looked dark and thick but the stuff coming out of the filter was thin and streamy.  The oil cap was missing and the PO kept it in a barn but do not know how the owner before him kept it.  I suspect water but did not see any coming out of the sump.  There was oil in the filter and it was brown and sludgy...possibly caused by the thin liquid mixed in.  

Sooooo, is this something serious?  I have not put oil in but did replace the oil filter.  I have not started on the wiring fiasco but that is next so I can see if she starts.  

[Scrappyike]

Ok, tried to start it.  New plugs (except for one I could not get out), new oil and filter.  Hooked up temp gas source.  Got wiring hooked up (without lights).  Hooked up battery from my other bike.  Starter button worked.  Bike turned over beautifully.  No start though. No sputter.  Seems like not getting gas.  Think next step is to pull the carbs and clean them.  I take it engine turning over and starter working is a good sign?  Hopefully it's just the carbs.  Will be searching the forum for good method to clean the carbs.  Wish me luck.

[shinyribs]

I have one socket in particular that will not go down on the plug like you mentioned. I found the reason why is the end of the socket has a real long taper/radius where the flats roll out to the edge. Some sockets are just made a little different than others. I have one that fits and one that doesn't.

That does sound like water in your oil.Gasoline in your oil will not make it turns colors like that.Since water is heavier than oil it will settle to the lowest part of the motor.Probably the reason it showed up in your filter and not in the sump is the filter element probably absorbed the water into itself and when the engine stopped it was able to drain down and create what you saw. I wouldn't be concerned with it personally.

Good luck on your wiring!

[Scrappyike]

Thanks Shiny.  The first socket was just a deep 18mm socket.  Worked for the other 3.  I bought a 18mm spark plug socket, with the rubber sleeve inside, and that still did not get it.  Perhaps when I pull the engine out I will be able to see what's up.

As for the water in the oil, I kinda thought it would not be a problem.  Since the oil cap was missing, I just thought condensation caused it.  Just wanted to make sure.  

Taking all day today (taking my time to do it right) to remove and clean the carbs. Will post pics.

[TOOLS1]

It is tough to get a socket on the plugs. I have found the plug socket that comes in the Honda tool kits works the best. I have an extra one I keep in the tool box.
TOOLS

[LukeM]

I use an 18mm 6 point deep well socket.  Works fine.  The 12 point socket is a bit too thick to get inside the channel.

It's possible there's something else in there that's preventing the socket from seating all the way.  

Sounds like you're making progress. Keep us in the loop. Don't get discouraged.  It WILL live again!

Luke M

[Scrappyike]

Thanks Luke.  Learning a lot of patience.

Ok, electrical is not my strong point....so here goes a dumb question.  Do all of the wires need to be connected?  I had taken off the speedo, tach and lights up front.  

I hooked up everything else but I seem to be missing the green/yellow wire from the stop switch.  If this is not connected, would it keep the bike from starting?  

My guess would be yes.  I tried kickstarting but nothing. I am using the wiring diagram found on the HSMCB750_5 PDF provided here.  

I will still be cleaning the carbs as I think they will need it anyway.  Thanks again

[Scrappyike]

Ok, another challenge encountered.  While cleaning the tank I discovered two holes.  One small one and a rather large one.  

This is the small one



and here is the large one



Any ideas on patching or should I just write it off?  

"Never give up....never surrender"

[Scrappyike]

Second challenge of the day.  Removing the carbs.  Going by the instructions I unscrewed the throttle valve from each carb.  Now what is in the pic is not what mine look like.  Mine have some kind of rubber boot ontop and I can't see what's underneath.  The ring is unscrewed all the way but I can't pull the carb towards the rear to remove it from the engine nor can I pull down on them to remove them from the Throttle assembly (my words).

[shinyribs]

Your carbs and your "throttle assembly"(your words) come off as a unit.

You don't have to unscrew the tops off of these carbs to pull them off. The carbs that require that will have a cable going into the top of each individual carb. Yours has a solid linkage connecting all the slides,or throttle valves, to a common cable.

Go ahead and screw those caps back on for now just to prevent anything from getting there.


Your carbs are called roundtops. Leave the rubber boots on the head tight and loosen the clamps on the carb side. Leave the boots on the head,that way when you go to install them back they will already be rotated for proper alignment. You'll have to remove the tank to get at the throttle cables. There should be two of them right under the backbone,which is the largest diameter piece of frame tubing that is in the very center of the bike. They will come off after you remove those two items.When I do mine I just sit on the bike and push pretty much straight down while rolling them backwards. It takes a fair amount of pressure but they will pop out. The whole assembly will come out on the rack. The factory service manual calls "the rack" the stay plate. There are two screws on each carb that holds it to the rack. Under those rubber boots are the forks which raise the throttle slides ( throttle valves) when you twist the throttle. They are just there to help keep dust out of the forks. Here is a pic that might help it all make a little more sense.

If you look at the part of the carb that goes into the boots you'll notice a groove that runs around the circumference.That groove is what makes the carbs sit so tight in the boots.

A little better look at the forks without the dust boots

[shinyribs]

Scrappyike wrote

Ok, another challenge encountered.  While cleaning the tank I discovered two holes.  One small one and a rather large one.  


Any ideas on patching or should I just write it off?  

"Never give up....never surrender"

 Someone just recently posted a link on how to solder up a hole like that. I think it was rrgunslinger? You might want to check that out. It seemed to work real well for him. If not a have a 100% rust free tank that will fit your bike for salebut its rough on the outside

[shinyribs]

Here is the link for soldering a gas tank. Good luck!

http://honda-cb750-s.456789.n3.nabble.com/Gas-Tank-td3844291.html

[Scrappyike]

Cool Beans.  That makes more sense.  Thanks Shiny and I will look for the post on the tank.  

[TOOLS1]

I would clean it out with Muratic acid, and then use JB Weld on it.
TOOLS