Need Help. Cleaned carbs now no starting

Gents,

I've got an 84 GPz 750 as you might have guessed from my username. I last had it running about 7 years ago and then stored it away until this spring. I did not take the proper care to get it ready for long term storage so this spring I started cleaning it up and one of the big projects was fully disassembling the carbs and cleaning them up. I used Nessism's carb guide to remove and disassemble my BS34's. 

I cleaned them in my ultrasonic cleaner with diluted simple green and verified all passageways were clear with carb clean. Got them buttoned back up with new orings and gaskets and got them reinstalled with new fuel and vacuum lines three weeks ago.

The issue I am having is when I push the start button, I get cranking but nothing more. I verified spark and opened the drain screws to make sure the bowls had fuel. I got the airbox hooked up fully and sprayed some carb clean into it and the bike fired up for about 20 seconds then shut off. I pulled the carbs off to check float heights with the clear tube method. All were 2-3mm below the bowl deck so I put them back on the bike. 

I need some direction or insight. I'm seemingly not getting fuel into the motor but its getting to the carb.

Thanks

What sort of condition are the carb to head rubbers in (a significant air leak will stop the carbs drawing fuel from the float bowls) and also what condition are the diaphragms in ?

@Wookie58 the carb to head rubbers are new replacements. The diaphrams seemed to be in okay condition and I made sure to take precautions to get them sealed up well to the groove. I also made sure the diaphram needle when pushed up came down slowly as if working against a vacuum rather than dropping down quickly. 

When I was initially trying to start the bike, I had the rear up on a stand. Today I tried getting it off the stand and balanced thinking the unlevel-ness of the bike was the issue and it didn't help. Today, even spraying carb clean into the carb intakes didn't get the bike to fire either. I pulled the new NGK BR9ES plugs and put in the old mismatched ones that the bike had when I bought it and still no fireup.

Did you perform these two steps?  The first is actually backwards: put the spray nozzle down into the hole on the bottom of the cavity.  That's easier to do that spraying into the choke pickup tube.

The reason for these checks is to make sure the carbs have clear choke passages.





 

Yeah @Nessism I did both of those things from your guide. It took quite a bit of cleaning to get the spray to come out of the passage in the float bowl but I got all 4 to flow. If I need to disassemble and check everything again I have no problem doing so. At this point, I am just eager to ride the bike so I will do whatever I can to do that.

Have you checked compression (if it's been standing for 7 years the rings could be "stuck") ultimately you need three things
Spark (at the right time but your ignition isn't adjustable)
Fuel (you have already tried spray as a substitute)
Compression
Sounds simplistic I know but you need to identify which one you don't have

@Wookie58 I hadn't thought of that yet. I will try to rent a compression tester tomorrow morning and see what I can find out. I did spray fogging oil into each of the cylinders about 4 months ago hoping that would help once it was ready to fire up.

Since the engine fired on carb spray, the compression must be okay.  

make sure all of your hoses are routed correctly.

Checked compression this morning. 1 & 2 were at 120psi, 3 at 125psi, and 4 was 135psi. I’ve got carbs 1 & 4 vacuum ports to the T up to the vacuum canister. Carb 2 vacuum line goes to the petcock and carb 3 vacuum port is capped. The center fitting on the air box side has the fuel line and the outside two ports between 1 & 2 and 3 & 4 are overflow lines running up and back down behind the air box. 

Could my symptoms point to weak spark? Maybe the ignition coil is going bad? 

What is the voltage at the coils when cranking?
Compression is enough to run and if it was fuel you would expect it to show some enthusiasm on the spray

Nessism wrote:

Since the engine fired on carb spray, the compression must be okay.  

Completely agree Ed, I only suggested the compression check as it seemed to have lost interest in the spray after the first attempt