1981 Honda CB 750 K

[ezimmerman]

I have only started my bike up once this winter. Its has been sitting in my Kitchen for a couple months.  It ran perfectly fine before storing inside for the winter.  I charged the battery up and put it back in.  I then backed the bike out of my back door and attempted to start several time.  I believe I may have flooded it but then it turned over and started up.  The left exhaust pipes were blowing out  white and black smoke.  Also the bottom of my left carb was squirting fuel onto the ground.  Whats going on here? Old fuel that needs replaced?  New Fuel and see foam do the trick?  

Any suggestions would be appreciated.

[seestheday]

The fuel squirting out of the carb - is it coming from the nipple on the bottom of the carb (a hose is likely attached to it).

If so, this is probably a stuck float valve, caused by having old gas sit in the carbs over the winter.  Did you put fuel stabilizer in before you stored it?  Seafoam might fix it, if not, you need to pull and clean those carbs.

Black smoke usually means an excessively rich mixture.  Too much gas and not complete ignition.  You stated that you likely flooded the engine with gas before it fired, this likely caused the black smoke.  That might work itself out after a short run.  Don't do a 100 mile trip or anything like this though as you'll get excess carbon build up.

[ezimmerman]

Thanks a lot man, I appreciate the help!

The fuel was definetley squirting out of the little metal nipple on the bottom(just the left one though).  There are no tubes connected to these metal nipples though, Is that bad? There hasn't been tubes connected to them since I last had it serviced at a vintage motorcycle shop a while back.  

I did not put any stabilizer in it before I stored it.  About a half a tank of gas has been sitting in there since December. I have started it maybe three times since then.

As for the black smoke, that sounds like and accurate assesment.  You are suggesting the carbon build up will only take place if the bike continues to emit black smoke from the exhaust? Once that works its way out and there is no more smoke I shouldn't have to worry about carbon build up correct?

Thanks again!

[seestheday]

Not a huge deal if you don't have a hose attached to the nipple.  It basically just means that fuel will dump on the engine as opposed to the ground.  As long as it's not dripping, it is fine.  If it drips for a long time, fuel will eat into stuff, cause discolouration etc.  Tubes are cheap...

You're having trouble because you didn't properly winterize your bike.  Tank should have been full, and fuel stabilizer should have been added.  Hopefully you don't have bad condensation in your tank or any rust that formed.  Here is a thread on how to winterize your bike for next year: http://honda-cb750-s.456789.n3.nabble.com/Winterizing-the-bike-td3433181.html

Yes, as long as the black smoke clears it shouldn't be an issue.  The carbon buildup would be caused by running it really rich for a long period of time.

I would start with seafoam and good gas.  Giving the carb with a stuck float a little tap might also cause whatever is causing the float to stick to resolve.  

If it were me I would pull the carbs and clean them, but I like really clean carbs and a very well running bike.  

[ezimmerman]

Thanks! That really helps me out.

[ezimmerman]

I have this speedometer and was wandering if it would work on my bike.  I looked at some of the schematics people have posted and they all seem to almost make sence but there a few colors of wireing that don't seem to match up.
 

[seestheday]

Is that an electric speedometer or a mechanical one?  Looks like an electrical only from the wires, but there could be a spot for the mechanical interface on the back that I can't see.

If it is mechanical and has the right ratio it should work (CB750 Speedo  2240:60  Tach 4:1).  Wires could be just for idiot lights, which you should be able to wire up correctly, just follow what is already there.

If it's electric only, you'll need to add more stuff to make it work.

[seestheday]

Thread on how to get an electronic speedo to work (http://forums.sohc4.net/index.php?topic=95342.0).

If it were me I'd just stick with a mechanical speedo or upgrade all the way to a gps one.

[ezimmerman]

THANKS AGAIN!  Yeah it is mechanicaly driven.  Also the ratio is 2240:60.  

thanks!

[seestheday]

You're welcome. If you haven't already you should check out the cb750c.com and cb1100f.net sites. Tons of great info on them.