Oh yhea and the original carb air box has been removed, someone put K&N filters on each carb intake but it has the original stock exhaust pipes and mufflers.
I have a 1982 Yamaha XS400 Special II. And it runs but ides high then low then high and sometimes acts like it wants to “Runaway” even after the engine gets piping hot. I cleaned the carbs (they were caked & clogged) I then had the carbs worked on, put new spark plugs in her, she showed no spark ⚡️ on either cylinders for a while there but cannot get both stabilized to run as a great pair. She seems very cold natured, new battery 🔋 easy to start now, I use only 90 octane non-ethanol gasoline, no gray or blackish exhaust, not running too rich ! Fellas I’m at my wits end 😢. What do I doooooo ?
I brought home an 82, cant wait ti get er running?
Oh yhea and the original carb air box has been removed, someone put K&N filters on each carb intake but it has the original stock exhaust pipes and mufflers.
1041 Original miles? Nice! I've got a 1980 Special II with 2800 miles, though some of them are aftermarket miles.
I have the same xs400. Also, had a similar issue. One cylinder would run and the other wouldn't. Luckily, mine got fixed with a new spark plug. 🤞🏼
Is there anyway for me to contact you
My XS400 is still sitting in my yard not running.
i cant seem to find the parts anywhere.
Mikesxs.net
I have a nearly complete parts bike available in central Florida.
I got one too,the same problems after 1500 km from new, this girls are cursed ,carbs constantly problematic.
Hello, What was the problem on this bike, mine is doing the same, and I am fully angry
I have a 1982 Yamaha XS400 Special II. And it runs but ides high then low then high and sometimes acts like it wants to “Runaway” even after the engine gets piping hot. I cleaned the carbs (they were caked & clogged) I then had the carbs worked on, put new spark plugs in her, she showed no spark ⚡️ on either cylinders for a while there but cannot get both stabilized to run as a great pair. She seems very cold natured, new battery 🔋 easy to start now, I use only 90 octane non-ethanol gasoline, no gray or blackish exhaust, not running too rich ! Fellas I’m at my wits end 😢. What do I doooooo ?
Does the revs go up if you spray carb cleaner on intake boots/inlet on engine as could be a leak from a cracked boot messing up the mixture?
It's running too lean
Actually, it was down about 40% on the compression on the right cylinder.
Idle should be 1200 to 1250 rpm, not 12,500!!!! Hahahaha
Did it blow up?