removing needle valve seat, 82' XJ1100

[tab1324]

Are the needle valve seats pressed in? It looks like there might be a very thin o-ring around the seat ass'y. How do you remove the seat? Where can you get new seats?

I cleaned up the needle valves, floats and all that but the carbs still leak gas back into the airbox bigtime.... I'm going to replace the needles but is there anything in the seat that could be causing this?

Thanks,

Tom B.

[jboughto70]

the needle jet is for mid range operation. The float should cut off all flow to the carbs so this is where the problem probably is. In theory, you should be able to leave your fuel valves on all the time and the float should cut off flow. The spider is an added security to stop the flow of fuel even if the float does not stop it. More than likely, your problem is in the needle and seat that the float operates.

[Ken Talbot]

Yes, the needle valve seats are pressed in. Remove the screw and retaining clip:
[IMG]/forum/images/tips/20040329-dscf0112.jpg [/IMG]
and you should be able to pull the valve seat assembly out gently with a pair of needle-nose pliers.
[IMG]/forum/images/tips/20040329-dscf0113.jpg[/IMG]
The o-ring on the body of the assembly should give some resistance but it will pop out:
[IMG]/forum/images/tips/20040329-dscf0119.jpg[/IMG]

If the o-ring is shot, it could allow gas to leak past the body of the assembly even if the float and needle valve are working properly.

[nashville_bill]

My needle valve seats were stuck and I had to drill them out. Just use a drill bit smaller that the opening in the carb body and be careful.

I had to drill even though the PO said the carbs had just been "gone through". I think they were probably "gone through" at the Yamaha factory in 1981.

[tab1324]

drilling needle valve seats

Mine are stuck and I don't want to ruin them by trying to pull them out with a needle nose... You mentioned drilling them but obviously then you'd be replacing the whole ass'y. Where did you find the part? I can't seam to find it online. Haven't checked with a local dealer yet.

I tested the O-Ring by installing a float and needle valve and then a small lgth of tube hooked up to the gas inlet. I blew on the tube and plugged the other carb with my finger. I didn't hear or feel any leakage through the o-ring. I bet a better test might be to put soapy water on the area and then blow. In this case, do you think I still need to replace the seats? Or maybe just the needles (new needles are on the way).

Tom B.

[Ken Talbot]

The problem with not removing the float valve is you then have no way of checking and cleaning the fine mesh screen on top of the assembly. Invariably, especially with an abused ride, these screens are completely plugged and varnished up. Missing a step like this is why so many guys have to back into their carbs so many times before they finally get them clean enough to run properly. Try some penetrating fluid around the body of the assembly, and some pliers to turn it inside the carb body. That little bugger has to come out..

[John]

carb parts

You can find the flaot needle and seat assy's at partsnmoreonline.com, or motorcyclecarbs.com. I know for sure that 'pnm' has them, as I ordered four of them for a 78E a few months ago, and 'mcc' has a LOT of NOS OEM stuuf. I got four pilot screws for a 78E from them a couple of months ago also.
Try sparying some wd-40 or similar product into the fuel T's to allow it to seep around the seats from the top side. That may help free them up. Try heating the area around them with a propane torch. It won't get hot rnough to melt them, but it will melt the o ring around the seats if it gets too hot. If they are this difficult to remove, then you will probbaly end up destroying them to get them out. Instead of drilling, try using an easy out screw extractor. When I ordered my saet assemblies from 'pnm' they6 were packaged and sold as an overhaul kit. It was about $12. Make sure you specify what year your bike is, as the 78-79 had screw in seats, and the 80-81 had pushed in seats.

[xj11john]

Are the 82 xj pressed in?

I just made another tread on this and then rezarected this one, I was looking on partsnmore and couldnt determine if those assembly (needle and seat) wold fit my xj1100?

[xj11john]

Partsnmore

when I enter the year model of my xj1100 only needles come up for it on partsnmore?

[xj11john]

Mikesxs.com

MIkesxs has them and so does Partsnmore the assembly (needle and seat combo) is the same for the 650 '80-'84 as for the
82 xj1100,

The advantage to ordering from Mikes (esp. if you are as poor as me right now) is there is no minimum order so 4 needles costing $4.00 USD total $16.00 + 4.00 shipping total was $20, instead of having to spend 35.00 with no shipping from Partsnmore.

I used the yamaha parts catolog online to find out that the needle and seat assemblys for xs650(80-84) and the xj1100 (82)
were the same.

[fxrer]

I had trouble getting my seats out, too. As TC said, lots of varnish is the usual culprit. My technique was, after removing the set screw and collar tab, I gripped the outside of the protruding part of the seat with vice grips, then twisted to break it free. Then, with a large screwdriver, carefully pry underneath the vice grips, while wiggling it back and forth. This gradually lifted the seat out of the carb body. Be careful and do NOT exert any pressure on the float needle post or you may snap it off.

BTW, is there a source for the rubber o-rings that seal the seat, other than buying the whole kit?

[turbopete]

Tab1324: every time I work on my carbs I fit them back onto the bike and they leak pertrol firt time I fill them with fuel. A small tap with a hammer stops it leaking and it never happens again. I think the floats must stick against the bowl slightly when they are empty of fuel.

MY xj carbs were absolutely seized solid - even the floats were seized on the pins, the slides stuck down, the float valves were stuck fast in the seat and the seats were all stuck in the throttle bodies. Even the springy pin in the top of the float needles were atuck. I got them all out without damaging any of it. To remevoe the floats and pins I sprayed them with carb cleaner and wiggled the floats until I could get the hinge-pins out. I removed the float valve seats from the carbs using an air line - I just put air pressure into the fuel inlet and blew them out. The first one that popped out I fitted back in and held it with the clamp and then blew the other out. I then submerged the whole seat+valve assembly in cellulose thinners overnight, and used air once again to remove the float valves from the seat.

Fxrer: I got some standard o-rings to replace the perished ones from the a spares shop. They had an assorted box of them.

[xj11john]

O-rings

Fxrer, I got some valve stem seals out of a assorted stock at a Napa auto parts store (any auto parts store should have them) I'm not sure air conditioner o-rings are impervious to gasoline so I made sure and got valve stem o-rings that I am sure are.

[fxrer]

Thanks John and Turbo for that info. NAPA, here I come.1

[xj11john]

Not so sure about the napa valve stem seals now (5/2010), last time carbs were pulled some of the rubber was flaking off the 0-rings!

I will be replacing them with a true gas impervialbe 0-ring this time.

I usually have to learn the hard way, unless I find the answer on here, this place has saved me from I'm sure alot of banging my head against walls.