The adventure of a first bike and the young guy that owns it

Just wanted to say thanks to everyone who posts on this site. I rode my xs400 into work today and everything was working great! Couldn't have done it without this site.

Not only does it run great though but I now feel confident in my abilities to keep it doing so for a long time.
 
Spoke to soon :/

Sorry this may get a little wordy but I don't know what went wrong so I figure I'll just tell the whole story.

Alright so it rode great for two days. Not long trips by any stretch of the imagination but 3 miles between work and home and 5 miles to get some coffee (at See See motorcycle coffee (a must visit location if you're ever in portland, or.) after work tonight when I went to ride home it didn't start 1st kick like it had been. After a couple more kicks I realized I was in gear and that's why it wasn't starting (it didn't help that a pretty drugged up guy was trying to panhandle me while I was trying to start it). So I found neutral (which is reasonably easy when it's running but takes some finesse when not) kicked it and it started right up, but sounded a little off (low idle maybe one cylinder?) so I gave it some throttle and it responded well, sounded right, but then went back to sounding odd. Pulled the choke and it picked up again so I let it be and put on my helmet and gloves. Pushed the choke in and it was idling a little low maybe 1000 instead of 1200ish. I was riding it home and it seemed like it wanted to die at stops. So I would give it a little throttle and it would be ok. Rode it about 2 miles like that then it died. I tried to start it again a couple times but no go. Lights were still on and bright. Ended up pushing it home the last 1/2 mile. At one point I glanced at the oil glass and it looked low. It was on the center stand but it may have been on a slope. There was gas in the tank and the fuel line. Up until this is was riding great, shifting great, revving as it should (I was shifting between 4-5k), I've never noticed an oil leak on the bike. The ground is always clean and dry under it when it's parked. I've done zero to the electrical system the bike has a bit of a drain like .10-.30 lost every couple weeks.

I'll be checking the oil again tomorrow and I'll check the spark plugs too but other than that I'm at a bit of a loss :shrug: the carbs have been cleaned 4 times (carb dip dunk and carb spray which shot out of all the holes it should) brass floats set to 26mm, synced with a homemade manometer (thanks xs400.com!).

Any ideas would be helpful!
 
image.jpg

*As a bonus*
Here's a picture of the bike at Coffee (note that the bike next to it which is fitted with a surfboard rack has the same xs tank)
 
Left looks a bit lean and the right a bit wet. I would do a compression test to see what you get there. What jets are you running and where are your idle mix screws set at. When you clean your carbs you need to put high pressure air( 125-160psi) through every little hole. When you dipped them did you remove all the rubber parts ( butterfly seals, idle mix screw o-rings ect.)?
 
It's been a while but I'm 90% certain that I'm 2.5 turns out on the air screws (the ones on the rear of the carb) and 2.25 turns out on the idle mixture screw (the one on the engine side top of the carb)

Currently all the jets are stock as is pretty much everything else.
The right side exhaust makes a rattling sound like something broke off inside is and I have new ones but haven't switched anything yet.

I'm fairly certain I removed anything that I could when I dipped them.

Did a compression test not to long ago (a month?) and both were over 140 and within 5 of each other

Does this seem more like a carb issue than electrical?
 
First pic is the idle set screw and it should be turned only to set the idle of the motor when warm to 1200 rpm's. Second is the carb sync screw which is used to balance the carbs when hooked up on a manometer with the engine warm and after the valves have been set. Third is the idle mix screws. These are for getting the proper fuel/air mix at idle to 1/4 throttle. These get set around 3 turn out from seated on most stock bikes. The o-ring goes bad in these and should be replaced from time to time. Also make sure they are assembled correctly. Last is the butterfly seals. If you don't remove them when dipping carbs they will leak air bad and will need to be replaced. They are on each side of each carb. Dipping carbs are only good for surface gunk. A sonic cleaner or soda blasting will get the more fine areas and blowing high compressed air through all the passages will clear them fully.
 

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Thank you so much xschris this bike would probably never run without your help.

Do I need four total of the butterfly seals (two per carb)? Or just two total (one per carb)?

My friend must have thought they were the idle mixture screw when he told me to back them out. The air screws are not seated on my carbs right now. Could that be causing some of these issues?
 

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