Engine shuts off when throttled

[Wr3cKli5s]

Hey guys, new to the scene here. Just bought my first bike the other week, 95 Honda Nighthawk 750 with 9500 miles. A little background on the bike, the spark plugs were recently replaced and it has a brand new battery. When I got the bike it wasn't running although I had physically seen it run before. Troubleshot down to a vacuum tube to the gas tank, reconnected and took a few turns but she starts right up every time now (for whatever reason it was connected to the carb drain screw). The issue is now that the engine completely shuts off as soon as any throttle is applied. It idles just fine but only with slight choke applied. Any suggestions? Bad vac to Petcock restricting fuel flow to carb? Think carbs just need a good cleaning?

Also, another separate issue that I was made aware of prior to purchasing and confirmed once I got it started, cylinder 4 is not firing which I believe may also be attributing to the inability to idle without choke applied. Any suggestions for that?

Any help would be greatly appreciated guys. Thanks.

[stevo as b4]

Get the carb's off and into an ultrasonic bath ASAP!

That sound's like blocked jets more than anything IMO. You can always pull off the fuel feed pipe and do the run it into a jar test to see if the flow rate is ok, but I'd bet it's the carbs at fault here.

[Wr3cKli5s]

Thanks, cleaning the carbs was my next plan of attack. Do you think an ultrasonic bath is necessary or in your opinion do you think a good carb cleaning would suffice? I may or may not have the tools for carb cleaning but I most certainly do not have the equipment for the ultrasonic bath.

The original owner was saying it sat for a number of years in his garage prior to selling, so I'll check the fuel feed pipe but I think your right that the carbs are probably the issue.

[el_oso]

I ended up fixing my gixxer which had the same issue by resetting the postions of the two throttle position sensors and upping the idle speed very slightly. All were just slightly low on the tollerance settings. Reset them all to the smack bang in the middle and runs better than ever.
____________________
Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L