Topic: First Post/First Bike: 78' CB750A, 2100 Miles

[JohnCurW]

Just bought my first bike ever about a week and a half ago, its rained every day since...

Like the subject says its a 1978 Honda CB750A, I'm the third owner, and it only has 2100 miles on it.  Its almost flawless but I'll go ahead and list the flaws here to see if I can get some input.

1. Small amount of surface rust on the exhaust where the four become two (awkward spot to work with really).  Any treatment suggestions?

2. Small amount of rust in the gas tank, I've done some research and as soon as I have some time I'll be treating this with a some abrasives and a coating (which coating does everyone here suggest).

3. Cold blooded as all get out, and the choke doesn't seem to stay where I put it; bike has died on me multiple times at the first intersection I get to only for me to find out that the choke lever has sucked itself all the way in.

4.  Erratic Idle, both in nueteral and in first, though not as bad in first.  Sometimes in nueteral it will rev itself so high that I can't shift it into first without a violent lunge forward which I'm sure is great for my tires/brakes.

I just bought some seafoam and dumped it in my tank to try to clean out my carbs a little, if that doesn't work I might have to start tinkering with the carbs, I've never worked on a carburetor before so I'm a bit nervous about it (I'm 23, so carbs were a bit before my time).

I'll put some pictures up once the sun finally comes out, looking forward to hearing from you guys.

-Curtis

[hoodellyhoo]

Welcome!

As far as the surface rust, I like to use either 0000 steel wool or a brass wire attachment on my dremel tool. Neither will hurt the chrome.

[BVCB650]

I think it is Mothers that makes a foam type polisher that is cone shapped. Fits in a drill and you apply some chrome polish to it and it cleans things up nicely. Even though your bike is low mileage, chances are it was not stored properly during it's life. I would suggest getting a Clymer repair manual and go through your bike referencing it. Carbs will probably need to be cleaned but fear not...the book is full of easy to follow directing and has good pics.

[1974CB750rider]

As far as the rust in the tank goes do a search on the forums here for cleaning it. There are several good methods. If you can get it clean and there is no actual holes in it you may not have to coat it.

[CBdave76]

I have a 1976 CB750A.  I have replaced the points ignition with a Dyna S type.  I replaced the field coil in the alternator.  The alternator was not charging the battery and I think some of the running issues I had were due to it being a battery powered bike.  I changed the rear sprocket to a 38 tooth and it really helped with the Rpms at highway speeds.  I start out in "L" and shift to "D" at near 40 mph.  I also have added a tach and volt gauge to give me some clue as to what the bike is doing.  Be careful what you put in the gas tank to address the rust issue, some products (I.E. Carb clearner) will cause more problems than they fix.
David

[Spanner 1]

John...point#3...when you pull-up the choke knob,turn the nut ( has a rubber cover over it ) to the right to grip the choke at whatever setting you want...stops it from returning by itself.
point#4....this is symtom of carbs needing to be synchronised...also, don't forget you have an idle adjust for both N and L/D. Read all info you can about the A, different in many ways to the F or K bikes.

[JohnCurW]

Thanks for the advice!