1982 cb750 nghthawk mini project help

[ProfessorDingus]

Hey guys! New to the forum and new cb owner (1 month into this).  I purchased a project '82 cb750 nighthawk about a month ago.  The guy i got it from had pod filters and repainted the whole bike with rattle can paint, removed all unnecessary components (speedo, tac, turn signals etc...).  I have put the old airbox back on, cleaned the carbs somewhat, lubed the throttle cables, new throttle tube and she runs great now.


The only thing left to get it ready for the road is to rebuild the master cylinder and bleed the front brake.


I have run into a problem now that i've put the stock airbox back on.  The oil breather tube is hissing when the bike is shut off after running.  Sounds like alot of pressure built up in there.  It was not doing this with the pod filters on it.  I think that the airbox is smashing the oil breather tube.


There is nothing tube wise connected to the airbox right now, it is simply connected to the carbs.  I have a feeling the previous owner re-routed some tubes to clean up the empty section after the airbox was removed and the pod filters were put on.



Also, after removing the pod filters and taking the tank off, i found 2 tubes that are disconnected at the ends, just freely hanging.  They were wrapped up under the fuel tank.  I cant figure out where they are supposed to connect to, or if they are even necessary as the bike sounds good and idles fine when running.

Any help is greatly appreciated, thanks!

ps. i apologize in advance if i am mis naming tubes and parts, i am new to working on motorcycles.
-Ross

[Rodgil]

You should have two crankcase breather hoses coming off the top of the gearbox housing each side, just behind the cylinders. They go to a rubber tee piece, at the upper front of your airbox. The hose you are holding looks like the condensation drain tube, which is normally plugged. It sounds like your crankcase breathers have been blocked off.

[ProfessorDingus]

Thank you for your help Rodgil!  I took the airbox off last night and connected all hoses to their appropriate homes now.

I have run into a new problem (seems to be the pattern with these things).  My starter wont work...The bike has started first time everytime since i have owned the bike.  Now, nothing.  Battery is fine, headlight turns on when i turn the key.  When i press the starter button, the headlight dims like it would if the bike was starting normally, but instead it is just silence.

Literally touched nothing except for the airbox and breather hoses since I last started it, which was about a week and a half ago.

Any help is greatly appreciated!

-Ross

[shinyribs]

Welcome in Prof. Dingus.

Headlight dimming when you push the button is a good sign that the button is OK. Could be a neutral safety switch/wire problem. That's how these bike's act if you try to start it in gear and with the clutch lever out- headlight dims,but no cranking.

Does the solenoid click?

[Rodgil]

You can try putting a screwdriver across the large terminals of the solenoid to see if the starter motor  is working. If it is, You can use a test light or multimeter to see if current is getting to the small terminal at the solenoid when you are trying to start.If there is current there, the solenoid is faulty.  Possible causes, if no current is getting to the small terminal are the neutral switch (behind the front sprocket cover) the clutch switch, or the kill switch. I hope this helps you.