Topic: 1978 cb750 carb adj.

[eldar]

See not so hard is it! Just takes some time.

[lucky]

after the idle jets are pulled for cleaning, how are the internal passageways/slow speed circuits cleaned.  carb clean sprayed into the jet side, or something?  i'd like to avoid separating the individual carbs for soaking if possible.  bike takes a 3-4miles to warm up then runs great.  just trying to improve this a little.  thanks,
bobp     

You do NOT have to separate the carbs. It is not a car.

[lucky]

um, 78's have adjustable needles as well, you just have to separate the carbs fully to do it.

That is not correct.
The 1977-78 carbs do not have adjustable needles.

[bollingball]

I bet they figured this out FOUR years ago

[lucky]

PD41A and B had needle clip adjustments.
PD42A and B did not.

My 1978 carbs just say PD nothing else.

So does that mean there is PD, PD41A, and PD42A???

[TwoTired]

PD41A and B had needle clip adjustments.
PD42A and B did not.

My 1978 carbs just say PD nothing else.

So does that mean there is PD, PD41A, and PD42A???

On the right side of the carb bodies, just above the bowl interface and below the raised PD molding, is stamped the number series.
According to this chart, the PD41s had adjustable needles, but the PD42s did not:
http://www.motorcycleproject.com/motorcycle/text/specs.html

I was led to believe that the K models didn't have adjustable needles, but the F models did.  I know my 77 CB750F has adjustable needles.  But, I haven't checked my 78 CB750F for same.

Cheers,

Edit:  Forgot to put the year for the F models.  Sorry, was in a hurry.

[bollingball]

I know my CB750F has adjustable needles.  But, I haven't checked my CB750F for same.

TT read this I don't get it. My 78 750K does not have adj. needles PD42b I have a set of PD42a I will have to check them.

Ken

[Imago]

Just fired up the 750 from a year resto.  runs good better with a little choke and will not hold an idle, have to flutter to keep running.  Any secrets to adjust carb. before I go through the manual.   

            thanks Geno

I took my carbs off today for exactly the same reason. A wooden 2X2 about 3 feet long helped pull the carbs off their boots without damaging the engine. This link really helped me too, particularly if it's CB750F: http://forums.sohc4.net/index.php?topic=48858.0

[Spanner 1]

This thread is 4 years old........ the OP has not been active since Oct 2010...stop the insanity 
Plenty of actual ( now ) folks needing help... 'Lucky', why do you keep doing this again and again ( Pulling-up loooong dead threads )....