78 CB750K Carbs Help

[Brandonb028]

The carbs on this barn find are in pretty bad shape. The screws that hold down the float bowls are all stripped out and the main jet port on the carb is half broken off. Like to just get a new set of carbs or newer and better shape then whats on it. Found a few on eBay but they don't look to be in any better condition. i fond some rebuild kits for them but don't think thats going to do me any good since the float bowls screws are stripped out. does anyone know where I might find a good set of carbs? Price doesn't matter as long as it not to crazy. Thanks for the help.

 

[madmtnmotors]

Reach out to this guy:

http://harisuluv1.imgur.com/

He is the resident carb guru over at SOHC/4.net. If the main jet port is indeed broken off at the port then at least that one carb body would likely need to be replaced. I have had good success with heli-coil repair of stripped bowl screws:


Completed repair:

Chasing the new threads to insure there are no surprises. It was this step where the tap grabbed a hold of one of the extra threads that protruded beyond the carb body. I was able to recover by trimming the excess with the proper diamond stone in my Dremel tool, but the 4mm long repair insert would have avoided the extra work:

Between the last photo and this photo you can see one coil of thread protruding above the carb body. The repair coils I used were 6mm in length. I recommend using repair coils that are only 4mm in length to prevent the repair from protruding beyond the carb body. I ended up trimming mine down:

And finally, the completed repair that encroaches on the screw boss for the carb plate (the holes overlap, but the new threads do not extend into this screw pocket):

 

[amc49]

Or, you can carefully mike OD of the OEM screw then again carefully pick a bigger thread screw maybe in SAE that then drills and taps in to have just a slightly bigger screw used and no helicoil at all. I've done that before too. I use allen head socket screws there, but one has to keep the material in mind, you can strip threads there the first time you tighten if you are a torque butcher. With an o-ring being sealed there then extra force does not aid sealing at ALL, you simply pull up to the hit solid and then a wee bit more to lock the screw from backing out, no real torque used there at all. In fact, torque used there can pull the corners of carb in to have four high points and the rest lower and does not seal as well.