carbs

[urumqi]

Help!  I'm new at this website, so excuse me if I goof.  I am restoring an 82 vision, and once I got it running ok with the original carbs I decided to replace the carbs with 'rk' model Mikunis.  So far I have purchased two sets on ebay, rebuilt them both with kits purchased on ebay, but the bike just refuses to run with them.  The only adjustment is the pilot screw, which the rk shop manual says not to fool with.  The bike will "vroom vroom" when I pump in gas with the accelerator pump, but then it stops running. If I try to start it without twisting the throttle it backfires, which to me means a lean mixture.  All the vacuum lines are hooked up and there are no manifold leaks.  The last set of carbs I got seem to be brand new, but I cleaned them thoroughly anyway, every passageway was squirted through with carb cleaner and blown out with air.  The floats aren't sticking.  The fact that both sets of rk carbs behaved the same way seems to indicate something is fundamentally wrong.  Aren't the rj and rk engines the same except for the carbs, and if they are, why should rk carbs not work on my rj?  Should I be fooling with the pilot screw, or maybe re-jetting?  Speaking of jets, the jets specified in the rk shop manual are not the same size jets that came with the rk rebuild kits, and the jets that are actually installed in the carbs I own are different yet!
My thinking keeps coming back to the same basic thing-the carbs are running too lean, but why shold this be?  I hate to go back to my rj carbs, but I have spent lots of hours trying to get the rk carbs to work and I am getting very frustrated.
Anybody got any ideas?

[YellowJacket!]

Woahh.... you found two sets of 83 carbs on ebay and one of them seens "new"?!!!  Son, you have struk gold!
There are a few members here who are running 83's on their 82's, Lucky is one of them and is one of our resident carb guru's here - there are several who will chime in soon with some advice for you.
Did you have to modify your airbox or motor mount to get them to fit?

David

[urumqi]

Thanks David-Are you a Ga Tech yellow jacket?  Yes I did have to modify the back head brace to install the 83 carbs.  I don't know yet about the air box, actually I have both 82 and 83 boxes.  The 83 has a vacuum operated intake flap. Could it be that I need to install the air box to get the carbs to work?  But then why do the 82 carbs work without the airbox?  It just gets more confusing.

[QBS]

'83 owner here.  Mediocre carb guru.  But, Vs' don't run right without their air cleaners/boxes in place.  Test with it place then analyze what transpires.

[Lucky]

since you had them apart for cleaning, you need to synq the carbs & set the pilots.. do a search on here for $4 manometer

[YellowJacket!]

Thanks David-Are you a Ga Tech yellow jacket? 

LOL!   Heck no, I'm a TN Volunteer.

The YellowJacket avatar is from the Seabee's - there's another guy here that has one similar to mine.  Mine was modified slightly to give it a more distinct look.

The nickname came out of necessity (I used to be "DaveTN") because my bike and riding gear are yellow and black.  I got tired of being called a "bumble bee" so I came up with the nickname "YellowJacket!" with the exclamation point for emphasis.  It didn't occur to me at the time that I'd be taking on the name of another SEC team.  I get some ribbing from my Vol fan friends about that.

David