Carb/fuel issues

So i have a 1982 xj 550 mxim just rebuilt the carbs because i was having issues where it would flood, after rebuilding the carbs (bowl side jets except mains/floats) it flooded again, adjusted my float heights to 21.5mm dry as i recall seeing in another post but now i have to run with my fuel select to prime vs run because it won't pull fuel through the vacuum. Also my bike currently idles around 1k i dont know where it should idle but when i go into 1st its wanting to idle all the way down to around 500 and die on me now i know i can just load more on the throttle to keep that from happening but it will die when trying to down shift into a turn aswell. please help thanks!

 

Per the Haynes manual the float height should be 17.5mm +/-.5mm and idle speed 1050 +/-50 rpm.

Have you synced the carbs?

 

Question, where did you get the parts to rebuild the carbs?
I have now rebuilt 2 carb sets recently and the float needles are very important. Depending on where you get the kits, some don't have the rubber tip and some do. Also, some , the little thin capture wire on the bottom end (top when you are rebuilding it upside down) have TOO much free play (not related to your problem).
If you took pictures during your rebuild (EVERYONE should be taking LOTS of pictures during carb rebuild for this very reason and to keep track of what it looks like as your tearing it down and how it looks when your building it back up.

I had to replace my petcock. If you did not at least pull it from the tank and test the vacuum function, you should do that anyway.
I arm running a manual petcock but I did test a replacement vacuum petcock by lightly sucking on the vacuum line and watching the fuel flow out of the tank into a gas can.
I have been running my bike enough to know everything is working so I can put the new vacuum petcock in.

Note: there are LOTs of vacuum petcocks out there that say they are for XJ bikes but don't work right. If did find 1 manual and one vacuum petcock that works on Amazon/Ebay.

You also need to wet measure the floats on the bench for best accuracy. If your floats are not bent up or damaged, dry measuring the 17.5 will make them come out very close, at least that is what I found with the 2 carb sets (8 floats) I did. I had one float that was bent which messed up a wet measurement and when I pulled it apart I saw it was bent (both floats need to be inline with each other or the dry measurement won't be valid)

 

Make sure the floats are not in upside down..............it happens! Especially w/o taking pictures.....

 

So when i set my dry floats at 17.5 it wanted to flood out and i found a post somewhere on here saying 21.5 was a good set height for them and its been okay since, my fuel/air mix was only set at 2 turns from closed so i backed them out to 2.5 (factory specs 2.75 which i may go to she seems lean on the low end) and she seems to be doing okay, as far as the parts i used to replace mine i got a factory oem slow jet/needles/needle seats and thats as far as i went in replacing everything got everything snugged down not over tightened, and i think its come down to a petcock issue because its not pulling fuel in when its on the run position so if you could send me the link to the one you replaced yours with that would be fantastic, the BIGGEST issue im running into now is i set my idle to 1100 or so and anytime im going into first gear (if i dont add throttle) just easing out of the friction zone it was to drop way down in rpms and die so it makes slow maneuvers difficult without having to keep on the throttle even after being warm

 

they arent upside down lol i made sure to put everything back in very meticulously and methodically i'm ocd in that department so no issues there, as far as the floats though i made sure they well, floated lol and everything was good on that end

 

and my wet measurements were spot on with where it needed to be so good there

 

i did a bench sync but it wouldnt hurt to get them properly synced thats my next to do

 

Have you considered just rebuilding the petcock? Very easy.

 

This is what is in there now, It is a manual petcock (I have the vacuum line capped off):
https://www.amazon.com/gp/product/B01LN7WF24/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1


This is what was on my bike when I purchased it. It was faulty though, It is what I plan to put in next.
https://www.amazon.com/Petcock-Yamaha-Virago-1988-1997-3AL-24500-00-00/dp/B0BKLHK89Q/

I did rebuild my original petcock, used sealall to put the tubes back in. It worked but because my screens were messed up in the carb, I took it off to put the manual in while troubleshooting.
I'll keep it as spare parts. The amazon petcocks are cheap anyway.


If you pull your carb apart, take pics and post them.