Topic: 1972 CB750

[pszeliga]

Hello

My name is Paul and this last weekend, an older neighbor of mine gave me his 72 cb750 for all the house work i helped him do over the years, making me promise that i wouldnt part it out or sell it. That being said, I'm fairly new to motorcycles. I bought two en450s 2 years ago and put parts together to make one and it runs fine.

However, this project seems a bit more involved. There is rust all over and gasoline had been sitting in the tank since 1999. Looks pretty rusty. The front brake is frozen(or seized) and i tried the kickstarter with no battery and nothing happened(bad idea?). Perhaps the motor is seized also? Gears shift fine and clutch is super smooth. I'll be buying a battery today after work to check out the electronics.

I was hoping for any bit of help or even better, a direction as to how i can begin. After looking around on forums for quite some time, i see that many people disassemble everything but i'm not sure why or what to look for as i'm doing it.

Thanks in advance for anything and everything.

[Whaleman]

I would not spend money on a battery until you have the engine broke free. Dan

[70CB750]

Welcome, Paul!

Pull plugs, see what they look like.  You can try the kick start again, rock it back and forth a little.  If you free it, drain the oil, pull the oil pan and check what is stuck at the oil pump screen.  Also what - if any - is on the bottom of the oil pan.

If it turned over, oil pan is clean, put in new oil and filter and try to start it up.

I know lot of ifs and be prepared for more.  Even if you get it on the road, it will take some effort to work out all the bugs, but you know that, since you done it with that 450.

Good luck and post pictures when you can.

[70CB750]

Also, download a manual from here:

http://forums.sohc4.net/index.php?topic=17788.0

and check out the 3000 miles service; that's what you want to do, all of it, if you get her to start.  3000 miles covers tappet adjustment, cam chain adjustment, idle setup and vacuum synchro, basically all you need to make the bike run smoothly.

[pszeliga]

Thank you very much.. will do

[Don R]

While the plugs are out spray some good penetrating oil in the cylinders. It will help when breaking it loose.

[Johnie]

Welcome to the board. Upload a pic when you can...we like pics here. You tried the kickstarter and nothing happened...you mean it will not kick over? If so then the motor is froze and you hopefully can free it. Take a real good look in that tank. If there is rust and dirt in there I would not want to run that crap into the carbs. A good tank cleaning and maybe a liner would be needed. Also, it is very easy to take a carb bowl off. Just snap the hold strap back and tap the bowl off. Take a look and see if there is a bunch of dirt in the bowl. Take a mirror and see what the slow and main jets look like. If he left fuel in those bowls they are likely needing a good cleaning so there would be no reason to try starting it before that is done. Just no need to rush it. These bikes are very reliable even after sitting a real long time. I like to do the work before I try to start it and give it the best chance to see the road again. Doing the work up front also reduces the chance of damaging something by rushing it. Good luck and let us know how you come out. Oh...and those pics

PS If that front brake is seized and preventing you from moving the front wheel just take a rubber mallet and give the caliper a couple wacks. That should free it up so you can at least move the bike around. You will need to rebuild the caliper and master cylinder which is not a big deal the with the help from the guys here.

[Tews19]

I may be misunderstanding but you stated you tried kicker starter but nothing with no battery. Did the kick starter at least move or is it solid?