Tracking down problems

[Hoko]

I just bought this  bike recently (the one in my Sig) and am going through it to find and fix problems.  The PO said the charging system was not charging the battery.  I pulled the fuel tank and dumped out the 5 year old gas.  The inside of the tank looks like someone treated it with some rubber like sealer (probably for rust) but no foreign matter moving around with what gas is left in the bottom of the tank, probably usable.  The rod the throttle cable attaches to and connects all the carburetors to is very stiff and hard to move (I assume varnish from old gas inside carburetors, pull jets, needle valves and clean with carb cleaner?).  The front dual disk brakes fluid reservoir has this jello looking stuff in it partially crystallized (I assume jelled brake fluid?) funky, probably a lot of cleaning and flushing lines and stuff.  No real surprises considering how long its been sitting.  Im going through the manual and will use procedures listed there but if you know what the problems and solutions are likely to be, I will check those first. Thx
1) Charging system not charging battery.
2) Carburetor connecting rod hard to turn.
3) Jelled brake fluid in front brakes reservoir.

[pat english]

there is no bike in youre sig...what kinda bike we talkin about?
im sure youve herd of carb dip,but let me tell you,that stuff is awesome..take the carbs off and find a tupperware style shoe box(or somthing the carbs will fit in)and pour that carb dip in submerging the carbs..let them sit for a week then take them apart and clean everything..trust me.i learned the hard way that being patient with carbs is the way to be..these carbs were totally messed up..every throttle valve was seized.now they are awesome.

[shinyribs]

Well bud,since you do have auto mech. experience you probably already know the answer to your questions...dirty.  Cleaning the carbs thoroughly is a must. When you have them off for cleaning you will be able to address the sticky throttle rod. pat english just posted some stuff on how to remove and clean that rod. Your 'tank liner' could be a liner,or it could be old gelled gas. Sometimes that old gas can look like rubber. And your best bet on the brakes is to order a kit and rebuild them. A kit for your bike should run right at $45-50 to do both front calipers. Good luck and have fun!

[Hoko]

So put the whole carb assembly in the dip without taking anything apart?  I have a 78 CB750F SS.

[Hoko]

Thx for those tips Shiny.  I have no idea where to get parts for this bike.  There is a local Honda dealer, would they have parts for older bikes or is it better to order online?

[pat english]

oh ok.i have a 78 also..yeap put the whole carb assembly in the dip..it comes in a gallon can..the carbs will not fit into the can..so find some type of tupper ware that theyll fit in and pour all that carb dip in..let them soak before you even try to take them apart..trust me..let em soak for a week before you mess with them atall.

[shinyribs]

I get the majority of my stuff from vintagecb750.com .  partsnmore.com is good,too.  Ebay has alot of stuff also. Just search for honda cb750 .... than whatever part you need. Since your bike is a SOHC you can buy every part you could ever need,so no worries about parts. They are out there

[Hoko]

Cool, thx Pat and Shiny for that info

[Re-run]

Remove ALL rubber and plastic bits. Also, carb dips are mass cleaners but they do not get the small stuff such as the idle jets.
So, remove the float bowl gaskets, the fuel tube o-rings, I think there are a couple felt seals, And there are seals under teh top caps. Remove all these.

Pull the idle jets and clean those with a strand of copper wire.

[Hoko]

I've been looking for Carb Dip but cant find anything by that name.  I did find one called Chem Dip, is that the one you mean?

[Re-run]

Should just be able to go into a auto parts place and ask for it.

[Hoko]

Thx for that  info Rerun.   Do you mean remove rubber stuff, gaskets and seals before soaking the carbs in the dip or after to clean the interior of the carbs?

[TOOLS1]

Chem dip is good stuff. Just remove the rubber parts. It will swell them up. Also your carbs have an accelerator pump. This is tricky to clean. First remove the No#2 float bowel, and check the ball valve in it by blowing, and then sucking air through it. Air should only go one way. Then do the same thing with the pump cover located on the No#2 float bowel. If air does not go through one way, or not at all, you will need to remove the little plastic plugs, and clean the balls, and passages. To remove the plugs use a very small drill bit. I use a pin vise cutting torch tip cleaner. They come with little drill bits, and are great, for working on carbs. After drilling a little hole, screw a No#2 wood screw into the plug, and use it as a handle to work the plug out. Be careful, those little balls, and springs are only about a 1/16 inch, and just love to jump, and hide.
TOOLS

[Hoko]

Thx for that info Tools.  You didn't put a number on one of the bowls you mentioned.  I'm assuming all rubber parts and seals should be replaced right?  Is there a kit I can get that has all this stuff?

[TOOLS1]

Not every piece of rubber will need replaced. Most of the time I only replace the O-Rings on the fuel tubes. They are 10mm X 2mm. Any well stocked autoparts store should have them.
TOOLS

[Hoko]

Thx man.  Am I reading your sig right, you have 5 CB750's?

[pat english]

 http://www.berrymanproducts.com/Default.aspx?tabid=146.

^^^^^^^^^^^^^^
all auto parts stores have this stuff...or you could just order from them..get that big 5 gallon tub!!!..this stuff is reusable.

[sgtslag]

The ONLY thing to clean brake parts with, is fresh brake fluid of the type specified by your bike.  Do NOT use anything else to clean up that jellied DOT Fluid in there...  Tools uses an old-style, hand pump, new oil can (only use it for DOT-3 Brake Fluid), filled with DOT 3 Fluid, attached to the bleeder valve, with a hose, to pump Brake Fluid up the line, into the reservoir (need to pull the brake lever half-way to allow fluid to flow...).  This avoids air bubbles, as they want to rise, so this allows them to do so, and makes 'bleeding' unnecessary.  I like this technique better than I like SpeedBleeders, and I have several of them -- learned Tools' technique after I bought my SpeedBleeders (I really like SpeedBleeders, but this technique is even better!).

After you get the carbs cleaned out, get some SeaFoam, and use it in both the gas tank (will dissolve varnish deposits, won't damage the lining), and the crankcase (will dissolve carbon, sludge, and varnish deposits, within the engine, and the transmission -- drive it a short distance to warm up the oil, shifting through all five gears, to thoroughly flush it through the transmission!), making sure to change the oil, and the filter as soon as you circulate it through the system.  Cheers!

PS:

Forgot to mention the fork oil needs to be changed out.  Follow the book, but basically drain it, compress the tubes to flush it all out, then replace it with Dexron III-VI ATF (equal to about 8W fork oil, at 1/3 the cost), making sure to support the oil pan with a jack stand, as the forks normally hold the front end up!  It's in the FSM.

[Hoko]

Thx Sarge, thats cool stuff!

[Hoko]

Thx Pat!