1979 gs750e carb questions

[acmemetalfab]

hi everybody. i build bike frames and do metal fab as a sideline, as a day job i'm a synthetic chemist. the new thing that customers have been asking me for is to take older honda and suzuki motocycles, get them running properly, and then take the motor/trans, brakes, etc... all the reusable parts off the donor bike and put them in custom frames. this is a good way to get a really nice custom or chopper for little money, because with my shop rates (40$ an hour) the frame and the sheet metal and paint come cheap and it's the huge cost of harley drivelines that hold people back. anyhow, i know lots about welding, some about machining, and not near enough about carbs. all of a sudden i live in a world dominated by these four-wide banks of japanese carbs, and i don't know how to adjust them or synch them. here are the questions:

1- the current bike i just got running is a 1979 gs750e with 22k miles. the airbox is gone and pods installed, the pipe is aftermarket 4 into 1, after removing and cleaning the carbs thoroughly (and i do mean thoroughly- synthitic chemists make REALLY good carb cleaner, lol) i reassembled the carb bank and installed it. the bike fired right up, but it appears to be running a little cool on the second cylinder from the starboard side. also, the thing idles at 3k rpm, and i'm guessing that's 2k rpm too high. the idle adjustment that is ganged to all four carbs is fully turned out and therefore has no effect on idle at the moment. there are two adjustment screws on each carb- one on the side, easy to get to; and one on the bottom, more of a pain to get to. what's the best way figure out what beginning screw settings should be? once i have a good beginning point i should have little troble tuning and synching.
2- the kit i got for synching is mercury based and rather flimsy, not a good combo. will buying four of the dial type like this:

http://www.jcwhitney.com/autoparts/Product/Pr-p_Product.CATENTRY_ID:2008076/c-10108/Nty-1/p-2008076/Ntx-mode+matchallpartial/N-10108/tf-Browse/s-10101/Ntk-AllTextSearchGroup?Ntt=carb+synchronizer

work well?

thanks!

 

[acmemetalfab]

btw, i ordered new o-rings and intake boots already.

 

[christopher_2]

Check the throttle cable to make sure it has slack you should be able to turn the handle say 1/16 or 1/8 " and not change the idle. If you can back the throttle adjustment out some. The idle should come down.

 

[acmemetalfab]

thanks, that's the first thing i did (make sure the cable had the proper amount of slack).

 

[Guest]

I'm no carb guru, but I can give you a few suggestions. The idle problem could be several things. Did you bench synch the carbs? They could all be set too high to start. Make sure your slides are closing all the way. It could also be an intake leak. You mentioned new orings and boots on the way. That would fix that problem.
Set the side air screws at 2 1/2 turns out, and the pilot screws at 1 3/4 turns out. Make sure you don't over tighten the pilot screws... they have sharp points on the ends and can easily break off (I know from experience). Lightly seat them and count the turns out. If not already done, remove the carb vent tubes from the rack and leave open.
Once you get it running and idleing properly, set the side air screws for highest rpm and vacuum synch the carbs.

That's a start. See if that helps.

 

[acmemetalfab]

"Set the side air screws at 2 1/2 turns out, and the pilot screws at 1 3/4 turns out." That's exactly the kind of info I was looking for. Thanks, I'll post the results when I get all the parts beginning of next week.