82 xs400 issue

[Shawn Pickering]

Im having a odd problem with the starting and how the bike revs .

Its hard starting , when i do get bike started it idles fine then struggles to get to 2000rpm , twist on throttle nothing happens then all of a sudden 4500+ rpm .
I have cleaned and set the carbs and the problem remains .

The bike was parked for a few years and the previous owner said it was hard starting and had to warm it up for awhile every time it got started

Im wondering what else i should look at

 

[NewHavenMike]

Misfiring?

 

[opcracer212]

Is it possible one carb is empty at startup, then when it fills and that cylinder kicks in the motor revs up? While it is initially idling, check to see if both headers are heating up evenly.

 

[xschris]

Post some pics of the bike so we can see what your are working with. Any modifications to the intake or exhaust will cause lots of issues.

 

[NewHavenMike]

My bike will sometimes run on one cylinder when the temps are a little low and engine is cold. I need to let it warm up for 2-5 mins before releasing the choke/enrichment or this happens.

Pull the plug on the secondary carb and see if you get gas.

The plugs may tell a story...

 

[Shawn Pickering]

Ill pull the plugs next time i get it started ...looks all stock

 

[Shawn Pickering]

Ill pull the plugs and check exhaust temps when i get it running .
It looks all stock

 

[Shawn Pickering]

I pulled old plugs and they were wet and black .
Put new ones in it fired right up ran for a bit then died . fire it up then dies again