CV pistons not actuating

I mean like squirting carb cleaner in the jets. I figured it out. I have confirmed that carb cleaner sprays out the small three holes when the idle screw is seated and sprays out all 4 when it is open.
 
I cant hold a quote, this is from "yamaha club"
http://yamahaclub.com/forums/topic/27374-i-think-xs-250-has-beaten-me/?p=155075
by HoughMade dtd June 2011
Thank you Google

As for cleaning the carbs, if they are like those used on the XS400, the idle circuit passages can be finicky. Here's how I clean them (this is for BS34s, hopefully yours are similar). With the carbs off (you can leave them attached to each other) take carb cleaner and spray it through the air jet at the mouth of the carb. With the idle mixture screw in, but at the setting for running (try 3 turns out to start) a strong stream should spray out from the hole beneath the idle mixture screw. Turn the carb over and take the idle jet out and clean it and shoot carb cleaner up through where the jet was. You should have a strong stream out the same hole. Then screw the idle mixture screw in and lightly seat it. Spray the carb cleaner in the air jet while holding the carb butterfly open. You should see 3 strong streams coming out of 3 small holes just above where the butterfly rests. Turn the carb over and spray carb cleaner up the idle jet from below and you should see the same thing.

Spray until you can see the carb cleaner flowing in strong streams as noted above. If you can't see that, you may need to strip and boil the carbs (my preference...'cause it's cheap) or have them ultrasonically cleaned. If you can see the carb cleaner spraying out basically unimpeded, then the idle circuit is clean because you have cleaned it from both directions.
Click to expand...


I am still looking for a pic, I have seen one. it shows, its probalby on this website, just not metadata right.
 
Update: still no dice. I'm still getting the popping out the carbs sometimes it pops out the exhaust at idle. I'm going to clean it ONE MORE TIME! Im posting a video of the streams as well just to prove these suns a guns is clean
 
Remember, inspect the needle valve set. Mine was seventy indented. So bad that the OEM guy local had never seen valves imprinted that bad. Now that I have my petcock fixed, I bet that problem solved. Out nerve know, till you inspect. Use that free manual listed here.
 
I'm sorry i didn't understand your post. Needle valves indented? Also i noticed something. When both idle screws are seated on of the needles sticks out the hole more.
 
Here you go.
 

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When both idle screws are seated on of the needles sticks out the hole more.
Click to expand...

That is by design. there are alot of people have learned the hard way, and had to replace those Air Mix screws (Pilot) spin those I mark mine where each one bottoms out at, with a permanent marker, and spin it out 3 full times.

It gets a little fuzzy, as you zoom in, but you can still see the marker lines, and the screw slot.
 

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Ok i spun them out 3 turns after bottoming out. I just wanted to make sure it wouldn't be better to match there lengths. Im going to inspect the carbs like crazy and will supply a bunch of hq close ups.
 
Willem had posted a know it all, map to all the "How T0's" Miss spelling on purpose.

http://www.xs400.com/forum/showthread.php?t=10715

We have the photos, its just hard to index every photo, and when you do a dump from a camera the system will ask to identify each photo. So if your interested, you can go ball's to the wall, and include part #, and other identifying info. When you start to do it, then you realize life happened, and you have no time, and you end up pushing the system cookie timeout time frame, for development of a decent thread, Luckily, you can come back and update later, as you have time. and you don't have to make them public, till your ready for them to be. Like Forest Gumps said, Life happens, or was it Sh1t happens? :D
 
how fast are the slides supposed to fall?

Mine fall slow but steady and both dont fall at the same speed. one is slightly faster than the other.

is this going to be an issue? slides seem to be pricey...
 
It is possible that the needle and the jet that the needle slides in, is gummed up. which could slow the one side down. (If the diaphragm are in good repair, and no leaks) The barrel could be gummed, but there is no reason I can think of for fuel to get to that part of the item, to gum it.

So my recommendation, is to just pull the top part apart. Really easy, 4 screws, and diaphram, (if its a new one with out the OEM dog-ear, make sure you have a paint stick to mark the placement of the earmark. (new ones are uniformed circle all the way around, the original one will have a fatter spot on the rubber that is key'ed for proper placement if you remove it. then use something to clean the parts, (carb-cleaner spray with googles or glasses) vinegar ...( your choice!) Then you do have to pull out the jet noozle part 32.
Thank you Boats.net for the diagram
http://www.boats.net/parts/search/Yamaha/Motorcycle/1981/XS400SH/CARBURETOR/parts.html
Thank you Ebay for the photo.
http://www.ebay.com/itm/YAMAHA-XS40...Parts_Accessories&hash=item43beead00b&vxp=mtr
 

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well i recently took the carbs apart to clean and boil them. I could not for the life of me get my needle jets out even after boiling. The center passage seems quite clean not sure about the holes on the sides of the jets.

The diaphragms are in good condition no holes or tears. I did have a VERY hard time getting the diaphragms to sit back in when i reassembled them. so maybe the seal isnt perfect....
 
Youtube, it was done by one of us. 9 minutes a piece. Keywords XS400 Carb
His carb is that from a 78. There is very subtle differences between years and carbs.

Part 1
Part 2


I don't know which one will work for your system, he tells you everything. in what appears to be 2 short videos.
 
you know I made a video, apparently I forgot to save it to the forum.
this is my diaphragm release. It is pretty fast.
 
yea ive seen the carb basics vid, im just concerned about the difference in speeds that mine fall...

im going to play with them tonight, even though they did not have holes, maybe the diaphragms are shot( since i did have a ton of trouble getting them to sit back in the the seats, had to little pieces of tape to hold them in.)

they fell steady and in unison before i opened up the carbs and boiled them
 

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