Carb Rebuild Question

I'm guessing that this has probably been answered several dozens time already, but I can't seem to find the answer.
I just acquired an 82 XJ750 Maxim with 11k on the od, that has been in the back of a garage for about 8 years or so. Now form what I have read I know the basic things I have to do to properly service and get the bike to living status again, I'm ready to start in on the carbs (thanks to those who say to document everything so that I may preserve what little hair i have left). I know that the rubber pieces and gaskets need changed and possibly the diaphragms (please no), but is it necessary to change the float needles and pins or the float needle valve assembly?
Thanks!

 

Although not an "expert" (I've only pulled mine apart twice) the metal components of your carbs should all be reusable, unless there is severe corrosion or damage upon disassembly. There are several threads on this site that provide GREAT instructions on carb rebuild. I suggest you read them completely before getting started so you have a reasonable idea what you will come up against. They were a big help for me. Do not skimp or skip steps. Make sure you install a fuel filter before reattaching the tank or you'll be pulling the carbs apart a second time...... ask me how I know!

 

If you can run to new new float needles & seats it would be a worthwhile investment, the old ones can be cleaned & polished, I have had patchy results re-using the old ones & they do seem to settle down, once the motor has been running for a while, but they can give you grief in the meantime, especially if you have any petcock issues as well.

 

It's possible though pretty unlikely that you'll need to replace the diaphragms. It's amazing how well those hold up, actually. Once you get them out, take a flashlight with a lens about the same diameter as the diaphragm, go into a dark room, then hold the diaphragm tight against the flashlight to see if there are any pinholes. If not, you're good to go.

If there are, some people repair them with liquid electrical tape-type products. A good alternative is to buy another set of used carbs on eBay or through the classifieds on this site. Either way, you won't need to buy new diaphragm assemblies at $229/ea. or whatever ridiculous price they're going for now.

Many on this forum will strongly encourage a person in your situation to buy new carb parts. A set of four float bowl rebuild kits for your bike (from XJ4ever) run $69-88. The advantage is that, if you do have any trouble getting the bike going, you'll know you have the right parts installed and that they should be functioning properly.

The bigger question is whether or not to replace the throttle shaft seals because it means breaking the four carbs apart from the rack rails that hold them together. With your bike sitting for 8 years (or so), those seals are probably toast which means the bike will be very difficult to tune. The seals plus new fuel tube o-rings will run less than $40 from the same source.

The advantage to doing the FULL rebuild is that you will get a real education that will help you understand how the carbs work and will aid in future troubleshooting. It's not a simple task, but people on this forum will help you.

Good luck!

 

Advisable.
Not necessary.

Remove the Float / Float Pin and Valve Seat.
Carefully, Don't break a Float Hinge Pillar.

Hold the Pin with Tweezers or a Hemostat
Brush with a Nylon Bristled Tooth Brush.

Spray the Seat's Cylinder
Bunch Q-Tips and Burnish the Seat clean with Polishing Compound.

Be sure to also:
Remove Center Emulsion Tube
Clean Interior, Exterior & Probe Air Ports.
Refinish/Polish Diaphragm Piston Bores.