Honda VF500f Interceptor engine problem

Hi everyone,

I have a '85 VF500F that is experiencing problems. I did these jobs:
-cleaned the carbs and did the valve adjustment in January
-the air filter is off so no restriction
-spark plugs and cables checked and are good
-compression is at 135psi at all four cylinders
-fuel pump is good and brings fuel to carbs
-fresh fuel in auxiliary tank so its not the problem
-drained the carbs so no water or contaminents
-choke and thottle cable checked and ok
-battery checked and filled (with distilled water)

It ran and started like a charm last week. I came to start it today and it turns but doesn't start. It did three or four backfires during the starter turning.
Sometimes it sounds like one or two cylinders are having combustion but nothing else. I checked only one cylinder for fuel (the only easy one to check) and didn't seem to have fuel in it. What could happen in one week to make it like this?

Thanks in advance!

Yoann

PS: One of the pictures is my setup when the bike ran well (with the red fuel tank on the side)

 

There are alot of things in a carb that may need cleaning that many are unaware of. For example, if you didn't remove the idle mixture screws and shoot carb cleaner + compressed air in the holes, that could be a problem. (Best done while idle jets are removed.) U're using FRESH fuel ?? Checked for healthy, fat, blue sparks. Battery is at at least 12.6 volts ?? Choke is working ?? Plugs are cleanish and properly gapped ?? If carbs are lacking fuel, could be debris in tank, kinked fuel line, plugged fuel filter, bad pump (if you have one) or pump relay, or simply not enough fuel in tank to flow out well.

 

Yes I opened my carb and cleaned every thing in it with carb cleaner but didn't compress air in it. I'm using two week old 91 octane fuel that I checked by pooring some on the floor and lighting it. The sparks are nice and my battery got checked last week by an aircraft electronics technician. The choke lever moves freely and I here when the engine turns that the choke does its job. I drained the carbs then turned the engine and fuel went in the carbs son no pump or fuel line problems. Also the pump gives a good fuel flow. But fuel doesn't seem to get to the cylinders... should I open the carbs again? Its just weird because I ran the bike for 45 minutes just a couple of days ago and worked just fine...

Thanks!

Yoann