Carbs backfiring?

So I just bought my 1993 XJ600 for 500. It has low miles but it was sitting for months and wouldn't rev past 1500 and would barely run. So, I took the carbs apart and found them filled with varnish. I cleaned them and now they are back on the bike.

The problem:
The bike starts only with the choke pulled all they way out and then revs to about 4000 then back down to 1000 rpm and dies when i let it go. It won't rev at all and the bike sounds like it's taking in a lot of air. Then when I let go of the throttle there is a backfire of some sort that comes out of the clamps that are on the bottom of the carbs. I experimented with setting the pilot screw 1, 1.5, 2, 2.5, and 3 turns out and nothing changes.

I looked over about half of all the threads the pertain to carbs and could not find an answer. Could it be the float level, or another screw that was adjusted incorrectly? I really appreciate any suggestions. Thanks

 

What did you find when you punched-out the Emulsion Tubes?

Are the Diaphragm Piston Bores cleaned and refinished?

Perchance, do you know the results of a Compression Check?

If you've been all over the map and are not getting any results from changing the Pilot Mixtures ... there's a good chance the Pilot Jets aren't letting the fuel get to the top.

You might have to do a Pilot Air Passage flush-out.

When the Bike ONLY starts with Enrichment and dies out when the Throttles are closed ... that's a pretty sure sigh that the Pilot Jets aren't passing Fuel to the Top End.

 

One thing I forgot to mention. Yesterday when I was working on the bike and trying to tune it, it was working really well. I could rev it and even take it off the choke. Since the battery is dead from trying to start it so many times, I use the boost setting on the charger.( this is why it would rev to 4000-6000 rpm and when I cut the power to the charger it would drop back down to 1000 rpm with the choke on). I believe it is an automitive charger that can boost a 6 and 12 volt battery at 12A. Could using this setting repeatedly have destroyed the ignition coils, cdi, or other electronic parts? Or can it only be a problem with one of the carbs or all of them.

As to what RickCoMatic said: I didn't really do any of those things. All I did was take the carbs apart, clean them with carb cleaner and compressed air, and put them back together just like they were. I am 18 with no previous experience and with limited knowledge that extends to the hanyes repair manual that I have.

 

Hi Stan, you realy need a fully charged battery, I wouldn't recomend running the bike with one of those booster chargers.
Make a propper job of cleaning & setting up the carbs, if you PM RickCo Matic & make a donation to his feral cat fund, he will give you the "old school guide" to cleaning & sync'ing your carbs. Believe me the finished result will be well worth the effort. Wiz.

 

Having to run the bike with the CHOKE ON is "A-symptomatic" of a Fuel Delivery problem. You are NOT getting the right volume of fuel to run the bike without Enrichment.

You need to revisit why you aren't getting a sufficient supply of fuel without opening the Enrichment Circuit.

Before you can begin doing any fine tuning ... you must get the Bike to Idle.
The Idle Circuit is comprised of:
The Pilot FUEL Jet.
The Pilot FUEL Passage
The Pilot AIR Jet
The Pilot AIR Passage
The Pilot MIXTURE Screw
The Pilot Air~Fuel Opening.

These Jets and passages have to be clean and free flowing.

Be careful with hooking-up that Battery Charger to a Battery struggling to keep-up with repeated use and not having the opportunity to get leveled-off from a long, deep charge.

You never know how much Hydrogen Gas has formed in the void between the Battery Fluid and the top of the Battery Case.

The right amount of captive Hydrogen and the introduction to a spark from a Battery Charger alligator clip will cause that Battery to explode.

The consequences of that happening could be very, very bad!

Or worse ...

 

Thank you rick and wizard for your quick responses even though it is 2 in the morning.

I will definatly check all the passages again since my tank has rust in it. I just wanted to see if it would run since it is my first bike.

So to recap, you guys don't think that I messed up the electrical system in any way right?

Also, what causes the backfire from a carb. I don't know if thats what it is called, but for some reason my bike started to.

Lastly, one of the carbs was damaged by the pilot screw and I think I fixed it. Would the bike not rev past 1000 if one of the pilot screws was messed up?

Thanks

 

so what do you guys think?

 

I'm agreeing with the thoughts that you need to get back into those carbs. Won't rev past 1000 makes me think fuel starvation. How much gas is in the tank? Is it set on ON, PRI, or RES? I stranded myself on the side of the road a couple weeks back trying to figure out why my bike wouldnt rev up enough to ride home .... turns out i was wicked low on gas and forgot to switch to reserve.