too much gas. flooding n what not.

[mikepointfive]

i gotta 1981 xs400 special.. i think i might have the wrong petcock because i ordered a rebuild kit and it didnt fit. i am getting too much gas. it floods out and dies. advise? quick fixes? anything would help. thanks.

 

[mikepointfive]

I just took off my gas tank and noticed that off my carburetor there is another valve for the vacuum tube that is capped off.. could this have anything to do with it?

 

[arfstrom]

Nope, The capped off intake nipple, is for carb balancing. nothing else that we need to worry about. till you get everything running. the second connection on the petcock only holds the valve open, when the bike is running, so that you are able to get gas down to the carb. so if you didn't do a good job in cleaning the petcock, you will have a leaking petcock. that will leak down to the petcock. if their is anything else wrong with the carb in example the float, valve assemble, it will leak into your crankcase/air filter. always check for smell of gas in the crankcase. (not good)

good luck, Tobie

 

[mikepointfive]

Thanks Tobie. yes I do have gas coming into my air filter.. what do i do?

 

[arfstrom]

For my bike it ended up being a 2 to 3 more carb type inspections. I finally figured out I had a hole in one float. But previous to that, I was doing the Carb float height check, I have photos in my album that shows me testing it. or I created a thread doing float checks. One day, I got it close to right, then the next day I would get the flooding fuel out the airbox/filter and possibly via the crankcase oil. I thought I had done a float check in a pot of water, but I didn't do it for long enough. The Float had a hole in it, it just the timing of everything. by the time the I disconnected the carb, and strip out the stuff from the carb, and then put everything together, the carb had emptied, then test fine, then then next day would fail.

I suspect/know my petcock rebuild didn't work either, but the floats should still stop the fuel from going anywhere till there is a need. I figure when I take my bike out of service for winter break, I might redo the petcock cleaning up. It would be nice not to have fuel leak ever time I take off the tank, (one of few reasons I haven't done the 1/4 turn on my left carb) (excuses, excuses.) There are some really nice ones out there,
Start with this one, then google some others yamahaclub, and someothers have some really great photos, and suggestions
http://www.xs400.com/forum/showpost.php?p=83915&postcount=1


Good luck

 

[drewpy]

floats aren't meant to stopping fuel entering the floats bowl under pressure, but to maintain the correct level of fuel in the chamber.

If that was the case, there would be no real need for a fuel tap!

 

[arfstrom]

I have to bow out to Drewpy, he has been doing this longer than I have, I am just happy to be able to help out, when possible, and hopefully help others save $$

 

[mikepointfive]

alright.. i got my carb off. now what? and where can i find a good rebuild kit? im pretty sure i got the same carb shown in Tobie's pics.

 

[arfstrom]

I have been wanting to update some of my stuff as well, Mikes has everything you need.

Carb parts MIKESXS web site
Gasket, Float bowl 3F7-14984-00-00 20-5020 $4.50 * x2
Needle Valve Set 25G-14107-20-00 48-1445 $11.00 * x2
Oring for needle valve set 8F2-14147-00-00 In kit
Rubber plug 3F7-14991-00-00 48-5002 $4.50
Carb Slide Diaphragm 40-4820 $69.00
Carb Slide Diaphragm 3f7-14940 20-6028 $90.00
Carb Holder • 2A2-13586-00-00 40-4850 $48.00
• 2A2-13596-00-00 Same Same
Float bowl Drain Screw 2L1-14191-00-00 48-0778 $4.50
Carb rebuild kit • 5V4-14902-00-00 48-1408 $13.50 (Msg MikesXS to see if the parts listed, are the same as in the kit? Its hard to say for sure, then its only $27.00 for both carbs.)

Carburetor Rebuild Kit - Fits: XS650SG-SL (1980-84) stock Mikuni 34mm. CV carburetors Kit Contains : Push-in Float Valve assembly with O-Ring, Carb rubber passage Plug & Float bowl Gasket 3F7. Made in Japan - 1 kit required per carb. Also works for: XS400 SE '82, XS1100 SG '80, XS1100 LG/LH/SH '80-'81


http://jbmindustries.com/Yamaha650.html (Carb Slide Diaphram) * x2
This company sells the rubber portion for 20 bucks,

Look up FUBARS posts
http://www.xs400.com/forum/showthread.php?t=8398

This company makes the products out of Aircraft rubber
http://jbmindustries.com/HOLDERS.html
CARB Holder for $64.00 pair *

Of coarse there is ...
eBay
http://www.ebay.com/sch/i.html?_nkw=xs400+carburetor&_sacat=0&_odkw=bs34cv&_osacat=0&_from=R40

So I would recommend *

Most of the other jets, and other brass parts should be fine. just clean them with any of the forums favorite methods, (Lemon/vingar boiling) Ultrasonic if available. If you dont' need a screw dont screw your self out 5 bucks for a new one, I replaced my shot screws from my local ACE hardware for the allen head screws instead of the phillipps, and tried to replace the group of them, so I wont need different tool just to take apart the carb next time. The carb holder if you dont need it, save your $$, The choose of Mikes or the other website, is intriguing, 48 at mikes, 64 at the other site, Fubar like the other site one, If you need it, (I am tempted for th $64. pair) Then eBay has bunches as well, perhaps same/or not (didnt look long, maybe cheaper) Good luck

 

[drewpy]

good info Tobie

 

[mikepointfive]

wow Tobie! very thorough!

 

[arfstrom]

You ought to see what I am doing for the upcoming clutch/seal replacement. I have been tracking what I want, trying see if there are any trends. 3 different columns with past local purchases tracked as well. So far Its just waiting for there to be enough $$, to start the purchases, and trying to leverage, the most for the shipping costs. So like Powersportsplus, they want 10 bucks for the first $100. so I need 50 to 60 for the clutch's, and then all the other stuff 10 for the clutch rod seal, kickstart seal needs replacing. Now just to have the $$. Now I need a new tire for an additional 50 dollars. Life goes on. Thanks

 

[mikepointfive]

alright... so i bit the bullet and took it to a mechanic. =(

 

[arfstrom]

The local guys didn't want to touch mine, (when I was looking for a Crankcase Bottom end rebuild.) Took me longer, but I didn't know what I was doing, so its suppose to take longer. . So you will be able drive it sooner then! Let us know what the verdict was! Tobie