Topic: 1978 CB750 Codename "Athena"

[MrJackLazarus]

I've always wanted a project with a code name... the original fairing on the bike reminded my of helmet that Athena is often depicted with... there is going to be very little wisdom or war going into this build  (thats why i need you guys)
I had already explained the acquisition of the motorcycle in my introduction post so I am just going to skip to the things i KNOW about it at this point.
-It hasn't been started in 10 years
-motor is free and will kick around
-I drained the oil in the case but forgot to empty the tank as well  so i completely overfilled it and contaminated my new oil with what was still in the reserves (I had car thinking, one oil plug)
-it has about 32,000 miles on it
-factory wiring harness is a rats nest because of splicing and dry rot.
-start button is missing
-choke is froze up
-front brake is froze up
-the clutch is free but ridiculously difficult to squeeze with one hand (it does return though)
-as far as i can tell, everything is there except for the headlight assembly and the front signals have been cut off to make room for the fairing it used to have.

I have a new main harness on the way.  I plan this coming weekend to go through the carbs, check coils, condensers, points, general timing set and verify spark.  Most of that list, i have only done on a car or truck or not at all.

[MrJackLazarus]

I have so much temptation to completely tear the bike down but i want to at least get her going before i dive in like that.  I am fortunate in how I am a process engineer for a company that does Electro Coating, Phosphate coating, Solid lubricant painting (teflon, graphite, moly).  I could completely break her down and phosphate and ecoat the frame.  phosphate and spray teflon on connecting surfaces...
I have to fight the urge though.
I know myself and I can see the various projects I have laying around the house that I had every intention on restoring from the ground up.  I need to hear her run and somewhat functional.  I still have the bike over at the place i got it from because I don't have access to a trailer yet to bring it home.  all work i have done was right where i found it.  I am hoping to con a friend into coming in with his trailer to move it for me, shes only a few blocks away from my house.  I was tempted to try to just walk her home but that front brake is seized for the most part and the tires won't hold air.  that would be a hell of a workout for me, I only weigh about a buck twenty five.
I think the direction i am going to take with the build is: I'm not going to be overly concerned with keeping everything stock.  I am going to just do what i like for it and just play to my tastes.  I have several 3D printers so I imagine I am going to end up printing a lot of custom plastics (might even consider a custom airbox depending on the exhaust route I take)

*be warned that i will more than likely use this thread as a complete journal for this build, thoughts and all.  I don't really talk to anyone aside from at work and I can ramble a lot in posts*

[newday777]

Well Jack you have a good plan to start off getting it running 1st and will have your hands full in this project.  It looks like it sat out in the weather for some time or in a damp building at the least.
Hopefully you will be cleaning the carbs more than just trying to spray clean them(some people have the notion that they can properly clean motorcycle carbs that way and learn the hard way.....) Ultrasonic cleaning will be the best way to get the old hardened gas stuck in the tiny inner ports of the carbs followed by spray cleaner.

Get an aftermarket replacement handlebar switch assembly to get the starter to work so you can spin it over to build the oil pressure before you fire it up. (Kicking it will not get the oil pressure built up enough.)
https://www.vintagecb750.com/products/5/electrical/90/handlebar-switches
Or you can jump the starter solenoid to get it to spin over with a remote starter switch if you just want to kick start the bike only later on.

Put some oil in the tappet caps to lube the cam with a squirt can before starting. (And drain the oil tank and check it for sludge in the tank, clean if necessary)

The 78 I picked up a week ago had fubared wiring at the side panel, thankfully I had another harness for the surgery or I would have bought a new aftermarket harness.I  did have another set of clean carbs that I put on the 78 and got it fired up to hear the motor running and it sounds sweet. The 78 carbs will need a good cleaning as it is molasses in them.... the tank too.....

[70CB750]

Get it on the road first.  My first SOHC4 I was planning to rebuild but I fixed her up and put on her 25 000 miles. 

[Stev-o]

As far as the front brake being stuck, loosen the two bolts that hold the caliper together, that should release it.  Rebuilding the caliper is very basic, just need to clean it and replace the seal  [but may want new pads too]

Do you have a new battery?  A good battery is essential for these bikes or you wont have spark.

[MrJackLazarus]

                   ***I did order the starter trigger thingie**** thank you so much for that... I would have had to have the miss outside with me and she doesn't like it when I am obsessing about a project HAHAHa

The bike did sit outside for about the last 4 years... it had the slightest bit of an roof overhang above it and a giant pile of leaves and sticks around it, protecting it from the elements 

The carbs are definitely being removed, disassembled, cleaned, ultrasonic... etc.  (i worked in a tattoo shop for a time so i already had the ultrasonic)  I am pretty confident in my ability to get them as clean as humanly possible, I can get a bit meticulous... for example, every 3D printer I own is calibrated to within .09 mm tolerances lol (doing that with a stream of molten plastic is damn near a superpower)  My only slight worry is dialing it back in, I know i would have a ton of help coming from you guys so I am not too worried.  I know how they get synchronized for the most part.  I get the concept anyways.  I might not be able to pinpoint what is good and what is a bad sign like a lot of you will though.  I will probably throw pictures up when I have it apart just to get a general consensus over the condition. 
With a lot of the electrical components, I imagine I will go with a lot of aftermarket items.  I don't feel strongly one way or another about keeping it true to original (i just want to make it run and be safe as it could be)  This is more a lesson for me, I do not hold anything in higher esteem than learning. 
I did purchase a new battery for it this past saturday and I charged it an hooked it up... Nothing.  Not a single light came on but the cassette player in the fairing scared me to death with the sound of some AM radio LOL.  I later went on to discover that the the main fuse had no contacts left on it.  I used alligator clips to jump it and i touched the frame slightly with my wrist and got zapped.  So i unhooked the battery and thats when I ordered the new harness... and I swear to god... as i am writing this I just got the email that it has been delivered lol.
As far as the brakes are concerned, I am 100% comfortable getting those sorted out... I have done brakes so many times in my life over a huge variety of motored things that i feel that i am ready to take whatever they throw at me with a smile. (bet Ill be back here later asking a brake question soon)
So far my order of operation is going to be 1) clean the carbs. 2)change plugs. 3) Change oil in the reservoir.  4) check the charging system... rotor for resistance and stator for cont. 5) oil tappets 6) jump the starter a bit. 7) see if i have spark try to start her up
... then I will deal with things like timing or maybe I will just be trying to figure out what went wrong... who knows
Seeing that this is my first bike, if i get the urge to tear her down and do all the fancy stuff, I will just grab a second bike to do that with.  I should probably let her come to life the way she wants to.
since i have that harness now, it kinda makes me want to go to my buddys house and pull the carbs today.  The downside to doing that is that my buddy just recently went through a breakup so he can't help but to talk about her constantly (which is fine... but not when i am busting my knuckles and fighting wasp nests)

thank you everyone for being so awesome, its something that really is much appreciated

[newday777]

 #8- a shot of starter fluid in each intake port to see if it pops over. It'll give you a bit of incentive  when it pops over.

P.S. have fire extinguisher handy when ever starting up a new project bike.

[MrJackLazarus]

Got over to her today to pull the carbs off... I was heading home from work and stopped to get my friday beers and thought "...I need something to do tonight and probably the rest of the weekend.

pulling them was simple enough and I grabbed a few pics of what i have to deal with in the future. 

But... I was pleasantly surprised with what i found when i got them off. 

[MrJackLazarus]

So the carbs were surprisingly good from what i expected.  I knew that they were cleaned before it sat and it had only run a few times after the clean.  I have yet to crack them open, I need a beer or 2 in me first but I am pretty hopeful about it.

[MrJackLazarus]

bowls are decent

[newday777]

Definitely better than the one I bought......

[MrJackLazarus]

Definitely better than the one I bought......

Oh ouch!  Probably still not the worst you have seen though lol!

So i found out that my ultrasonic doesn't heat anymore nor does it sonic...  I work in a place with giant vats of near boiling alkaline cleaner and I am wondering if there is any reason that I SHOULD NOT just dip the entire carb system in there for an hour or so.  The cleaner is for metal of course, its to clean automotive service parts for zinc phosphating.  I know i need to avoid the acid tank because aluminum lol.  I am super tempted to dip it but i have a fear that i am overlooking a small detail that will screw me somehow.  The bath sits around 88C.
If anyone has any doubts about it or reservations please let me know lol.  I actually just replenished the bath this morning so it would be the ideal time for it.
I had ordered a rebuild kit for the carbs this morning (only using the gaskets out of it as everything else is still fine in the carbs) and I had to order the accelerator diaphram, current one is pretty crispy and I don't know that soaking it in fuel will help.

[MrJackLazarus]

Woke up around 3am sunday morning so I could go through and clean/label my replacement wiring harness.  It looked like it was in pretty good shape save for a few connections that needed polished up.  Checked everything for continuity.  I had a little help from my Priscilla.
I went over to the bike around 2pm and wanted to check to make sure the starter was ok.  I had gotten my remote trigger a few days back and I put the battery back on the charge for a bit.  She turns over... a little more slowly than i think she should but i haven't replaced any of the wiring at this point so there may be a bug in there yet.  Big thing was that starter motor was usable.  After that, I started to go through and undo the old harness (started at the tailight end) and I made it to the fusebox area before rain cut loose on me.  I plan to go back the next few days and continue.  I have a lot of stuff to rewire altogether and a lot to trace.  I should get a different tail light/turn signal assembly as mine is trash almost but I'm not overly worried at the moment.

[MrJackLazarus]

went back out to continue wiring but I started running into issues...

the start button was out, so i assumed that they kick started it but no... i found a little tiny switch tucked into the triple tree...

[MrJackLazarus]

I am not crapping on anyone for improvising btw... I have had to do it more times than i can count... its when you have something new and you get to discover how it worked.  The last 2 owners didn't even know the switch was there lol.  Also if anyone has anything... I am more than willing to purchase parts from whoever lol...  looking for the headlight assembly (preferably with a visor) looking for the ricks equip.  and also looking for the complete front forks assembly.  They are in sad shape currently and someone did a pretty bad weld job trying to possibly weld the turn signals back on at some point... I don't know how they were originally attached but theres a half inch stem and then a bunch of goober welds on the end of it.  I will try to take pictures tomorrow.

[Stev-o]

Y2KCowboy just sold a Ricks Rectifier, try starting a thread in the Parts Wants section. 
Most of us have spare parts that we are willing to sell for a reasonable cost to fellow members.
And nearly everything you may need is on eBay.

[MrJackLazarus]

Y2KCowboy just sold a Ricks Rectifier, try starting a thread in the Parts Wants section. 
Most of us have spare parts that we are willing to sell for a reasonable cost to fellow members.
And nearly everything you may need is on eBay.

Yeah i need to start paying better attention to what is out for sale one here loll.  I am not even sure of what i will NEED to replace right away.  I am waiting on my accelerator diaphragm and then i can finish up the carbs. I will probably be super eager to try to start it once they are back in.  I am going to be mindful of all the suggestions i have gotten from everyone too.  Oil on the tappets, fresh properly gapped plugs, petcock open (HAHA yeah I've done it), starting fluid probably, in neutral... probably will only take a million kicks.  I know that the starter motor works but i don't trust it yet.  Should I set the points gaps and check valve clearance before the first start?  or should I just say screw it and try it as is and hope for the best?  I know the smart thing would be to check it all but the impatient kid in me says go start it now lol.
The diaphragm will  be in by Friday i think, I can probably get all of that checked out before then.  I am going to try to get the first start on video just in case something unexpected happens.
If there's anything else I should be mindful of please let me know.  Most of my engine experience is on cars and lawnmowers (and its not much)  I know an engine is an engine but its shaped kind of different and it throws me for a loop sometimes... if that makes sense lol

[MrJackLazarus]

Got to go over and do the plugs... noticed a pattern and im hoping someone knows what to think about it.  I know it means  something.

Plugs 1 & 3 are a bit s*** compared to 2 & 4... or maybe its the other way around, I don't know what it means. 

[Stev-o]

1 & 3 look a little rich.  An engine that is set up properly will have tan colored plugs.

Have you confirmed you have genuine Keihin jets in the carbs?  Aftermarket parts can have you chasing your tail....

[MrJackLazarus]

From the ones I have pulled so far, looks to be.  I'm not doing the complete tear down and clean until I get the diaphragm and gaskets so I haven't pulled needles and slides yet.  If I tear it down now and clean then wait 3 days to put it back together, I will miss something.  I have to do it all in one sit.  When I do the rebuild, I am of course making sure of manufacturer settings so I guess that will give me a baseline to start from.  For soaking the jets and other parts, anything recommended?  Ultrasonic is out of commission and I doubt I will be able to afford another one this week lol... unless harbor freight has one uptown. 

[MrJackLazarus]

I really need to brush up on air/fuel ratio info and balancing a healthy, fire breathing carburetor.  I still basically remember how everything works mechanically but its all the other factors that i trip over.  With aftermarket jets, are they mostly a problem because poor quality? or bad tolerances? Both?

[MrJackLazarus]

I finally got my carbs done... had to replace the acc pump diaphragm, a #$%* ton of O rings and gaskets.  I cleaned and polished the brass and reused it.  I think... I should be about to a point to where i can try to turn her over tomorrow i hope. 
Wiring Harness-check
oil change- check
new plugs- check
clean carbs- check
oil cylinders-check
oil tappets- will check tomorrow
bought a new can of starting fluid- will check tomorrow
battery charged- check
gallon of premium @ $6 a gallon... - check 

I had a slight bit of paranoia when installing the accelerator pump diaphragm bc I recalled so many people on so many forums complaining that they would be dead in the water because of a replacement.  Fortunately i did find the thread about it on here and made sure i cleared all passages and installed all o rings. 
I have to finish hooking up the harness in the morning before i check it out (most of it) 
I also have the small detail of getting the bike home as well lol... as it turns out, I don't have a ton of friends with trailers.  The front wheel is locked so i have no real hope of pushing it 6 blocks and I have reservations about calling a tow truck for that kind of money.  I have a decent job but i am not in a place to where i can throw around couple hundred dollars for something like that.  So if anyone knows someone in the central ohio area (dayton/ springfield/ marysville) area that wants to make 40-50 for a short haul... please let me know.  My other option is to buy a hitch for my kia soul or put a driveshaft in my equinox.

[Stev-o]

 The front wheel is locked so i have no real hope of pushing it 6 blocks

Most likely, the front caliper is locked up.  If so, loosen the two bolts and the bike will roll.

[MrJackLazarus]

 The front wheel is locked so i have no real hope of pushing it 6 blocks

Most likely, the front caliper is locked up.  If so, loosen the two bolts and the bike will roll.

coincidentally I did end up doing that (you told me to the last time i mentioned it and I forgot completely until i got back on here lol) now I think theres a problem with the rear drum or perhaps the bearings bc it took all of me to push it 8ft out of the sun yesterday.  Tyres are half flat and rotten so that didn't contribute much to my effort.

yesterday i got my carbs back on and kept on with my wiring.  most of my connectors crumbled as i touched them which is a bit disheartening, I kinda blew my budget i had for the bike this week on bullet connectors, choke cable, carb kit and a new torque wrench (i only allow myself "X" to spend a week on this project, or else i would spend all my extra cash on it and be screwed everywhere else)
Most of the front end wiring was replaced at sometime or another and various other connector types were used and different wire colors than original so I have to do a lot of tracing.  As i said before, there was a lot of splicing done to put the fairing in and some was done correctly and some was done with the blue wire splicer and some was cut, twisted and taped together.  I am starting to consider just cutting everything out and running new wire.  It would save me a ton of headaches but probably screw the next owner (if i ever part with it, very doubtful)
I have to hook up the throttle cables still.  I didn't really pay much attention when i removed them so im sure that will be a nightmare as well (naturally)  really was hoping to get to the point yesterday to where i could try to kick her over but I don't know how much of the wiring HAS to be connected for the engine to do its thing and the kill switch and starter button is part of the wiring mess up front.  I thought it best to get that done before trying to start so i don't misdiagnose a "no start" when its bc my killswitch or something is grounded out.
During this whole heartache yesterday I had my "friend" hovering over me telling me about how i should have bought a Triumph 

Im hoping today goes a bit smoother for me and I hope I at least make enough progress to see a result.... hell even a neutral light would make my day.

Happy Fathers Day to all the fellow Father's out there as well!!  I hope you all have a great day

[newday777]

Well the no roll can be the flat tires or bearings yes or stuck back brake(pull the wheel off to find the cause...) or a stiff or rusty chain(can be loosened up by cleaning and the lube as a temporary solution or removal of the chain)