Topic: DOHC CB750--new project/stuff to take up space in my garage

[jdigga]

My coworker's husband brought over his 79 CB750 today.  It's been sitting in the garage since 1991.    He just got a 2003 Yamaha V-Star 650 and was going to junk the CB.  I told him I was interested, and he said he'd just give it to me.    Yay, free bike!

It's pretty rough and missing some bits but the engine turns over.  I want to try to save it...

[bill440cars]

          Hey, that's not so bad. Now, if it's too much to handle, you can just pass it on to me and I'll take care of it for you.   Seriously, my 80' CB750 looked similar to yours except that mine was complete except for turn signals and the stock headlight. You see, mine had a Wind Jammer Fairing (explains why the stock headlight wasn't there), a shot King & Queen seat and a luggage rack with a helmet box on it. Oh, and it also had Jardine 4 into 2 exhaust (one of which had broken and had been brazed) I pulled all of that off, got a seat and a headlight off of ebay. Terry (cb650) gave me some stuff and the front turn signals in that batch, worked great. Got me a couple rear signals from another buddy and I made the rear mounts.

           Lots of luck with that one.

                                                       Later on, Bill  

[jdigga]

Thanks, Bill--I'll see how far I get and then I'll hand it over to you. 

I went over it and it's mostly there.  Other than the obviously missing seat, stator, and headlight, it seems to be pretty much all there.  There's even some '91 vintage gas in the tank. 

There's some questionable wiring in the headlight bucket, complete with dreaded scotchlocks, and the tank needs some attention as there's rust all over it and the petcock is stuck. 

The other thing that's stuck is the clutch--the darn thing won't budge.  I'm not sure what I'll find when I pop off that cover, but I'm not looking forward to it...

[bill440cars]

         Hey, that clutch problem may be just a stuck cable.   That wouldn't be too bad of a deal. I'm hoping for the best on that deal.   Sounds like you're gonna be hitting ebay soon. I've picked up a few parts on ebay for my 80' model for fairly decent prices. Main thing that I couldn't find was, rear turn signal mounts and I ended up making them myself. Bought a seat, headlight (in pieces from several different sellers, after I got the headlight bucket from a buddy). Take care and Lots Of Luck on that project!

                                                         Later on, Bill    

[jdigga]

The armature that sticks out of the clutch cover doesn't move--is it supposed to?

[jdigga]

Spent some quality time with the DOHC today.  Did a bunch of disassembly and ended up tossing a bunch of junk bits.  Turn signals are gone, headlight ears appeared to have been in an accident.  I took the clutch apart and the best I can tell is that the plates are stuck together.  I'm hoping I can resolve that.



My coworker said that she didn't really know why they stopped riding this bike so long ago.  Found this:



Something looks like it might be missing here.  Anybody know what it is?



I hope I can clean this up:



This looks icky (exhaust port):



What the hell is this all about?



Looks like I've got my work cut out for me, eh Bill?

[JSGAuto]

Sweet another DOHCer. 

That starter solenoid is missing the fuse.  It is a stupid piece of metal, for simplicity I just wired in an inline glass one, that way if I blew it (40amp) I would have no problem getting a fuse on the road. 

Looks like your charging system was the reason he stoped riding the bike (no suprise).

I have a lot of parts for that bike if you are looking for anything.....and a little knowlege if you have a question or two. 

Enjoy,
Jim
jsgauto@gmail.com

[jdigga]

Hey Jim,

Thank you sir; I believe I may have a big list for you.    I'll send you an email with what I'm looking for...

Regarding that fuse for the starter--is it this?



If it is, you're right--that is pretty dumb.  I think I'll do the glass one like you did.

[bill440cars]

           Jim & jdigga,

                        I've got one of those DOHC 750s (an 80' CB750K) and I'm still learning about mine so, maybe we can all get some education out of this.   Mine had a piece of copper wire where that starter solenoid fuse goes. I'm lucky something didn't fry! I'll be doing a fix on that one myself. Ever thought of using one of those newer "blade type" fuses? I'm going to look into that type myself.

           jdigga,   That exhaust port sure doesn't look good at all, you might be in for a bunch of work. The wiring looks like a fairing of some kind was on there at one time. I hate those kind of splices, they don't do the wiring harness any good.   Lots of luck on that one guy.

                                                    Later on, Bill
 

[jdigga]

Bill,

Regarding the exhaust port--you have idea what that white crusty stuff is?  Also that appears to be a rusty valve or valve guide, no?  Oh boy...  Well, I guess that's to be expected if it's been sitting for 17 or so years.

On my XS650 I ditched the entire fuse panel and went with blade fuses.  There was no space for a panel so I just wired up some connectors and plugged them in straight.  Pretty much what liaudio did in this thread except I used 90 degree connectors so the fuses could sit flat on top of the battery where the old fuse panel was.

Jay

[JSGAuto]

Oh yea, those stupid little pieces of metal....or fuses that they claim they are. 

There is a guy on ebay selling a solenoid with a blade fuse in it, I think the BIN is $25.  Seems like a good deal, its on my list of stuff to buy.  I have also heard that the CBR600 ones will work too (not sure if the wiring will clip in though)

I have 4 of these bikes...and love them.  Some stuff is easier then SOHC, some harder.  The power is nice! 

Next up for me is to paint my daily rider (1980 750F) then onto the electronic ignition upgrade on the 900F.  Lots of possibilities if you want to have moddifying fun with them, I installed CBR rims on the 900, handling is amazing.....and my insurance is still the same. 

Jim

[bill440cars]

        Jay, I can only venture a guess on the white stuff in the exhaust port. Could it be that moisture has gotten in there and caused oxidation of the aluminum? I mean, you've got rust on the valve stem. That'd be my guess on that one.   Anybody else?

                                                 Later on, Bill