big-mike77

ive been offered a cb 750 custom by my girlfriends mom. it will be my first bike and my first restoration project. apparently the tires need to be replaced, the carbs need to be rebuilt and the magneto is malfunctioning (i know its not to specific but thats all i was told). basically im trying to decide on the most economical way to turn this old p.o.s. into something i dont have to worry about falling out from under me.

jtrouten

I just picked up a 81 cb750 last month, started pricing everything and it ended up being too pricey for me to consider. If you have the same electrical problems that happen to all these bikes you are gonna have to replace the rotor, stator, and reg/rectifier which is about $500 at the cheapest for all those. I have to do my wiring harness as well so I would check that if I were you. Carb rebuild, tune, and sync is gonna be at least $300 at a shop. Tires are gonna be around $200.

I am not saying this to discourage you, just know what you are getting into before you do it. I decided it is just not worth it to me to do, but you may be different. I don't know what year your bike is, but I am probably going to just part the bike out, so if you need pretty much any part from an 81' cb750 custom let me know.

lostsoul74

Contrary to the other posters reply, that bike shouldnt cost you more then 200 bucks to get up and running and in solid condition. Perfect rule of thumb, if your going to be a biker, plan on owning a tool set. If you have to take something to a shop, then you should go to a dealership and buy new. Theres forums available all over the net for any motorcycle you can think of, a bike is very easy to work on with some basic tools. Anything you dont know how to do, guys at the forums can help you out, or in most cases, you can go to youtube and teach yourself. Yes, a shop will charge you top dollar to clean a set of carbs, but theres no reason you cant do it yourself in about an hour, theres plenty of forums with how to pics and tutorials, and more videos on youtube then you can imagine walking you through every step of the way. For syncing, again, a shop will charge you top dollar, while you can go on youtube and see how to use a 2x4 and plastic hoses and sync yourself in 15 minutes. There really isnt anything complicated about a bike unless you have to get deep into the internals of an engine.
You can replace your entire electrical system on ebay for around 50 bucks, 12v is 12v, not too complicated, and tires shouldnt cost you more then 60 bucks a piece, or hit craigslist and grab a set of used with 80 percent life in em for 10 bucks.
Bikes are cheap, workin on bikes is cheap, if you dont know which way is righty tighty, lefty lucy, then yes, you should go to a dealership and get something new, but most of us able cats prefer the classics for various reasons, easy to work on, parts are dirt cheap, and they are 3 times more reliable then todays quality. Point in being, bikes from the 70's, early 80's, were built to last over 100k, outlast the rider, while todays junk has to be rebuilt every 20k. Companies learned long ago if they built something to last, they got less repeat business. I build/flip old bikes for a living, pick em up for a couple hundred, dump maybe 200 tops into customizing, cafe racers, choppers, bobbers, etc, and flip for 2500+. And believe me, I didnt know crap about bikes a couple years ago and started chopping right off the bat, chop the rear, drop the tail, throw a 25 dollar solo seat on, 20 dollar bars, cheap paint buffed out, and suddenly it's a hot hip style that brings a couple G's. I'll buy a tank off a yamaha to fit a suzuki to change the look and style, make it work!! lol.
so yea man, no reason you sholdnt have a good running depending ride for less then a couple hundred bucks and a few hours of your time, while updating it to your style along the way.

e

mccolo

I'd love to hear how the restoration went. I have a 1980 CB750 Custom and I love it. Been riding it for more than 20 years. Did you get yours running?

mccolo
Passes and Canyons, Motorcycle Touring in Colorado

Cappii

I am building my very first bike as well. It's an 80 Honda cb750F. There were supposed to be a lot of electrical problems with it, as well. I ended up re-wiring the gauges, which had all of the wires cut off, but for the most part, it's been very easy.
Some advice from someone in your same boat:
Get a wiring diagram online. Try to find a good copy with crisp colors.

Take off the cover for the alternator and take the rotor out. If it's rusty / nasty, sand it all down, and clean the stator with electrical contact cleaner. If the lights brighten up when you rev it up, you're likely in business, or at least a good bit closer.

Get an electrical tester and a good ohm-meter... you'll need it to test voltage and continuity... a lot.

Just about any information that you need will be found online. Google is your friend.

I hope that you enjoy working on yours as much as I have enjoyed doing mine. I am now a set of tires, and a custom set of turn-signal brackets away from being street-ready. Considering that the bike would not even turn over a month and a half ago, I'm proud of what I've accomplished, and will likely take better care of this bike (that I have almost nothing in) than any car I've ever owned.

Hatch R

I would like to know if any one has purchased (new) cb750k exhaust off ebay. If so are you happy with them?

Shagga

Bought my old 1979 boldor CB 900f last year, the motor blew up after 6 months and ended up transplanting a 750 motor. The bike had been sitting idle for 15years before I bought her and if its of any help, this is what I replaced to get it Roadworthy and Registed. Front tyre(bit hard to get as unusual size) Rear tyre, fork seals, front and rear master cyclinders, Stator and stator field, exhausts, all 4 manifolds, rebuilt carbies as they are vacuum and all the rubbers had perished. And one owners manual. Best money I ever spent

markus_s

While on the subject, does anyone know what year's cb 750's engine could go into a 80 cb 750. I am in the process of a restoration and my local dealer did not know.

PA_HD_Guy

Thank God for You Tube! I have save myself thousands, upon thousands of dollars with a a little hard work, and you tube videos. Everything from motorcycle repairs to home improvments

Jessigef

Take off the cover for the alternator and take the rotor out. If it's rusty / nasty, sand it all down, and clean the stator with electrical contact cleaner.

Wade_D_Wilson

SO I also just bought a 81 honda cb750k myself. Been slowly replacing crap as it breaks. When i bought, first thing I had to replace was the Point cover because that was broken. Then i finally replaced the entire wiring harness and battery. I finally got the main fuse replaced as well. Now, my battery is dead after a ride. I'm thinking it the stator and the rotor. The regulator has been replaced the battery has been tested and deemed that its been good. Any other ideas on how the drain might be occurring?