Re: 79 CB750F That has been in storage for 28 years

Posted by sgtslag on
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/79-CB750F-That-has-been-in-storage-for-28-years-tp4003715p4021924.html

Check the level of the oil, before you try to turn it over...  It should have a dip stick, left side, round, black knob which twists open.  If the oil level is good, then go ahead and try to fire it up.  As stated already, the carbs are likely a mess, and it is doubtful that gas will flow through them.

Go to YouTube.com, and type in "motorcycle carb cleaning":  this will give you many videos to choose from, but there is a three-part series which I am following, with great success, thus far.  The wire to use, to poke through the jets, to open them up, is just some 14 GA, stranded wire -- strip around 4" of bare stranded wire, separate out a single strand, and poke it into the jets, twisting the wires/jets, so as to clean all of the gunk out.

I did not use carb cleaner, as it will destroy rubber, and possibly plastic parts.  I used Citrus Blaster degreaser/cleaner, available at auto parts stores, and maybe Wal-Mart's auto supply section.  It is rubber, and plastic safe, and it won't leave a residue.

Once you get the engine running, buy some SeaFoam Engine Treatment, Wal-Mart, around $9/can.  Follow the directions, and add it to the crankcase oil.  Run the engine for five minutes, on the center stand, idling(!), shifting through all five gears, letting the rear wheel spin freely; then put it in neutral, and shut it down.  Change the now-coal-black oil, and filter.  The SeaFoam in the crankcase oil, will dissolve varnish, and carbon deposits, within the engine, and the transmission (that's why you want to shift through all five gears, while idling...).  A lot of the crud will be caught in the filter, so you need to get it all out ASAP.

Fill with a good quality oil, and a new filter.  Shell Rotella T6 Synthetic Oil (~$21/gallon @ Wal-Mart) is a diesel oil, rated SN for cars, no friction modifiers, so it is safe for wet clutch motorcycles.  It has high detergent levels, so it will keep your bike's engine nice and clean (should never need to SeaFoam the engine/transmission again...).  It is also 5W-40, so it is perfect for easy starts, in any vehicle, or engine, in any climate (I use it in every engine I have).

Come back here with any questions you may have.  Best of luck!  Cheers!