Topic: 78 750 Carb rebuild questions

[KB02]

Okay, here are a couple of quick (hopefully) questions as I am tearing apart my carbs for a cleaning and rebuild.

First of all, how do you get this bar out of the Carb?
There is a Shear pin in the red circle, and the part in the blue circle looks like it is held in place by a set screw, but with this set screw removed, the part still does not want to budge. Which end should I tackle?


Second, I know that every time that someone tears into one of these carbs they are told to watch out for pin holes in the Diaphragm on the pump. My question is, Where? In the two red circles, there are some small holes. Should they be there? Is it just the big part to worry about?


As you can see, I have these carbs all apart. Next step is a good, thorough soak and cleansing.

[russouno]

Take the set pin out of the spring assembly and the whole shaft should slide out to the right..
I recently rebuilt my carbs on the same year bike.(actually every nut & bolt up on the thing:) )

[eurban]

Fuel needs to flow through those holes in the accelerator pump so yes there should be holes in the rubber diaphragm.  If yours are tiny then you will need to open them up to essentially the same size as the holes in the carb body/bowl.  Remove and clean your pressed in slow jets if you haven't already. Bench synchronize the carbs prior to reinstallation.  You also may want to check the actual level of fuel in the bowls by using clear tubing on the overflow nubs.  Level the carbs, hold the tubing up along the carb body, connect a fuel supply to the carbs, open up the drain screws and observe where the level of fuel settles out in the tubes.  Should be at or just below the carb to bowl seam and should be identical all the way across.  While you have fuel in the carbs pull open the throttle as quickly as you can to observe whether or not each brass nozzle (located at the bottom of the bore next to the choke plates) squirts fuel into the bore of the carb.  It may take a bit of priming to get things going.  These are the accel pump nozzles by the way. Have fun.

[KB02]

Fuel needs to flow through those holes in the accelerator pump so yes there should be holes in the rubber diaphragm.  If yours are tiny then you will need to open them up to essentially the same size as the holes in the carb body/bowl.

SO, in other words, the hole should look a little more like the one on the right, rather that the one on the left. (Ain't Photoworks great?)

[KB02]

Mine are the brass.

[jtb]

KBO2,  I took the throttle linkage off of mine (blue circle) remove the lock nut and the allen set screw and it should slide off.  A couple of taps with a rubber mallet might help.

John

[KB02]

I decided to go with the shear pin as the linkage wasn't moving. BUT, as I was banging it out, the linkage decided it was time and just slipped right off. So, I got the whole rod apart and it was much easier to clean that way.

The whole set is apart now and cleaned up. Now I've just got to get the slow jets out and cleaned up.

I spent about $15 at the hardware store buying all new stainless, allen head fasteners for the carbs. Those nasty old phillips screws need not be put back in.   

[Lumbee]

FYI

http://blog.360.yahoo.com/blog-Sg4KjsE8erQjVxgd6tTWVeKm_ww-?cq=1