Hi! New to the Forums, new to bikes, proud owner of a CB750 dohc!

Hello!

As the title might suggest, I'm new here! I've ridden quite a few motorcycles in my life but I've never owned one until now! About a month ago I picked up a 79 Honda CB750k for $500 on craigslist. The guy who owned it before me put it together in his kitchen after painting it (badly) with no intention of ever riding it. it was about 3/4 of the way put together, the few things that were obvious right off (and the PO was honest about the whole thing,) no speedo cable, no receiver gear for the speedo cable, no headlight or blinkers, 1 of 2 throttle cables and not the important one , choke cable housing was cracked, and no front caliper, rotor or brake hose at all.

Before I bought it
http://i1288.photobucket.com/albums/b483/makspya94/20170317_191343_zpsjokd5yfd.jpg[/IMG]]
My dad upon me bring it home.
http://i1288.photobucket.com/albums/b483/makspya94/20170318_174653_zpsufknwcrg.jpg[/IMG]]

After getting it home there's a couple more things that came up. Shock are dead front and back, petcock valve was smashed and it didn't have a ground cable at all.

Soooo first thing's first. I pulled and inspected the gas tank and there was some less than desirable stuff hanging out in the so I'm in the process of cleaning it. Got a rotor, caliper, hose, extra master cylinder and petcock valve at ye olde junkyard. Only thing that doesn't match is the rotor but that's for a different thread. While I was waiting on those parts to come in I painted the tank and side panels

Before:
http://i1288.photobucket.com/albums/b483/makspya94/20170321_220707_zpsy8nl6rw4.jpg[/IMG]]
After:
http://i1288.photobucket.com/albums/b483/makspya94/20170326_120529_zpsje2azykh.jpg[/IMG]]
http://i1288.photobucket.com/albums/b483/makspya94/20170323_190623_zpsydt0u071.jpg[/IMG]]

I haven't cranked it over by hand yet but when I replaced the spark plugs I stuck my boroscope down into all the cylinders and 3 were great, one was meh. I think if I spray some pb blaster or dump a litte fresh oil into the combustion chambers the starter should be able to crank it just fine.

So yea that's all I've got for the bike. As for me I'm a 22 year old dude, living in Maryland, who's mostly into rally and cars (particularly Audi and BMW,) I've got too many cars and I've always wanted a motorcycle but I've never been able to stop buying cars long enough to get a bike. Since I have all the projects I can handle, I finally sprung for a bike! I've ridden every from tiny pit bikes to massive flipping Streetglides and quick as hell BMW s1000rrs so I think a CB750 is a good starting point for me and it's something I can work on. Hopefully with some help from you guys and she'll be on the road again in no time!

Thanks for having me!

I’d get on the cb750c.com and cb1100f.net forums. You’re going to find tons of info there from some exceptionally knowledge people that can help with all aspects of your project. You can probably find parts from some of the guys at a better price than ebay. Good luck with you bike!

Welcome from Montreal mate, I'm working on my first bike which is also a cb750 ('81) - nothing like it, looking forward to seeing how yours shapes up =)


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Thanks for the replies guys! I tried to get on the cb1100 forum but for some reason I was denied an account, I'll give the cb750c forum a shot tonight. To be honest there's only one model specific thing I need to know and it has to do with the front wheel. Everything else that's left is wiring and cosmetics once I get the front brakes figures out.

The 1100 site is a bit troublesome...it took me a few tries efore it worked for me. As for cb750c.com, once you're signed in, you have access to download .PDF scans of the Honda Factory Service Manual and all of the FSM addenda (updates) for your specific sub-model and year. Very handy stuff! It's also nice to have all of the factory wiring diagrams to chase electrical gremlins!

There will be gremlins


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Ugh. So many gremlins!

Something I thought of last night as well: clean your carbs. If they've been done already then clean your carbs!

Also, synchronizing them is a good idea. If you don't have a good sync tool, Here's a YouTube video for bench syncing them which should get them close:

https://youtu.be/oVlLitzF38I

When I pulled the carbs apart they looked pretty damn clean, but it definitely can't hurt to tear them all the way down, especially since now I have to source a front wheel, I've got some time. The one thing carb related I want to do for sure is replace the Philips head screws that hold the carbs together to something that sucks less. And that video is fantastic! No need to buy a $100 carb sync gauge! What kinds of electric gremlins do you mean? I'm pretty good with wiring and this wiring harness is about as complicated as a brick so I don't see anything that can't be done. A custom harness for this thing would take me half a day so I could do that if necessary. So far I haven't noticed any fraying, but to be fair I haven't really been looking for that, I've been focused on other stuff. Like having to rebuild the ignition cyilnder because it was all sorts of jacked. I'll find out later if it works and if the electrics want to do anything funky haha but if anyone could give a couple examples of these gremlins that would be lovely

MaksP said:

The one thing carb related I want to do for sure is replace the Philips head screws that hold the carbs together to something that sucks less.

Click to expand...

SeanG over at cb750c.com sells a stainless, allen-head screw kit for our bikes; decently priced as well!
He also has a free to download, .PDF carb manual and tuning guide.

MaksP said:

And that video is fantastic! No need to buy a $100 carb sync gauge!

Click to expand...

Not quite. Having it done with a gauge is a good idea; doing the bench sync is a ballpark starting point. If you dont want to spend $100+ on the gauge set, there are videos on diy versions. Or a competwnt bike shop should be willing to do it for under $50.

MaksP said:

What kinds of electric gremlins do you mean? ...if anyone could give a couple examples of these gremlins that would be lovely

Click to expand...

Voltage drops. Every terminal is likely to have some corrosion or looseness in it. The added resistance adds up in a hurry and makes the gremlins angry. Pull all connectors apart, pull the male pins out and clean them one at a time, then do the same with the female pins and tighten them with pliers. You want some good pin drag. Clean and polish all your grounds.
Remember that when your bike is running, the charging system won't break even until about 3000rpm. You'll be shooting for 14.1v @5000rpm.

*EDIT*
Wow look at me, almost sounding like I know what I'm talking about!

Thanks for the info Cookie! I'll be on the lookout for corrosion when I'm inspecting the harness. I'm still planning on getting a carb sync gauge in the future because I want MORE BIKES! I'll definitely get that bolt kit asap. My throttle cables are coming in the mail today so if I can actually get the gas tank clean, which is an infuriating process for me in this Maryland humidity, I'll should be able to try to run her at some point in the near future