Xj750 will not rev or will over rev

Hi guys I have a question I'm thinking there us just crap in the carb but I just picked up a 82 xj750 seca wen I first got it to fire it would only run up to 1000 rpm now I raised the floats a little and cleaned the main/ pilot jets and now it will start and over rev to 45-5000rpm I know nothing about the bike at all from previous owner if some one can send me in a detection I'd be great full I'm also in the NY area to

 

You really go through the carbs , full tear down and soak and ALL seals replaced , read in the Church of Clean ...spray cleaner will NOT cut I have a spare set of carbs on the bench right now I'm going to do full tear down and , will soak in Berrymans carb dip this the ONLY way to go , to replace butterfly seals you have to break the rack and pull the butterfly plates to remove shaft . If you try to soak with this installed the seals will swell or crack . Hogfiddles offers a carb service as well as a clinic in NY state .

 

Why did you raise the floats? and in reference to what?

Float height (really fuel height) is critical on Hitachi carbs, and there is a very narrow acceptable range.

Setting the fuel levels

+1 on making the carbs like new.

IN THE CHURCH OF CLEAN
Replacing your Hitachi throttle shaft seals

Also go through/inspect everything else. Never trust a prior owner's word or work.
The Information Overload Hour

 

I thought the float bowls where empting out faster but now I have them at the stock night and doing the same thing

 

Stock height by measuring the float level, or stock height by measuring the fuel levels in each float bowl with the carbs sitting level on a workbench?
It really does matter.


Be aware however that you likely have a vacuum leak (the excessively high idle is a clue), and one of the more common places to have one is at the throttle shaft seals (because it's very likely that they are the originals).
You can chase your tail trying to find the problem, and still end up needing to tear the carbs down and refreshing them.

Other things to look at:
What condition are the intake boots in? Are the vacuum port caps cracked? Is the vacuum line for the petcock in good contition? Have the throttle cable and enrichment cable been switched around?

I'm not familiar with NY state, but @hogfiddles might be local(ash) to you.

 

carb clinic coming up soon.

 

Central New York Carb Clinic #12 - June 8, 2019

 

Thanks for all the help ive checked everything you guys have said but it is still doing it but now its only when its warm I'm thinking its to lean I currently dont have the air box hooked up but I know it will not couse the issue that bad I did the same thing with my xj650 then just fine tuned after the bike was running better

 

You've torn the carbs down and replaced all the rubber seals and it still won't idle correctly?

 

Yes

 

When you did the work were the air jets returned to their proper positions (they will swap, and the photo in the manuals are labled incorrectly)?


I still think you have a vacuum leak somewhere, but the air jets can cause fueling issues if they are not in the right places.

Have you ever removed the gallery plugs for the YICS manifold?

 

Also make sure you haven't swapped the throttle and choke cables when you reassembled.