needle valve seat test - would it work?

[tab1324]

Would this be an appropriate test for the needle valve seats?

1) install the float and needle valve
2) install a length of hose on gas inlet 't'
3) plug the 2nd carb needle valve opening
4) blow on the length of tube and look and listen for leaks around the o-ring.

I tried this test tonight because I cannot for the life of me get the needle valve seats to budge but I'm still getting gas flowing out of the carbs and into the airbox. I have an 82 XJ1100 with the pressed in style seats. Also, I can't find the parts to replace the seats so any help on that would be great!

Maybe a better test would be to put some soapy water on the area like you might test for a gas leak in your home. This way, you could sense even very minute leaks by seeing bubbles.

Maybe these tests are no good and I'm just spinning my wheels - dunno. Any opions???

Another question. If by chance the o-ring did leak, could a guy put some form-a-gasket over the area (I know it's kinda a hack job but gotta get er running). Is there a possibility of the needle valves (even if they're new) not seating due to the float height not being set correctly? Could the seat be "reset" in the carb without removal?

So many questions - so little time.

Tom Brant
Brooklyn Park, MN

[Ken Talbot]

I hate to put a damper on this, but the other part of the reason you are getting gas in the airbox is because your octopus is not working properly. In an ideal world, just having the octopus working properly, or having all four float valves working properly together, would eliminate the possibility of gas in the airbox. It is time, grasshopper, to go back to basics and get your octopus working properly. It is easier to get one little part working properly, than trying to get four little parts all to work properly all the time...

[randy]

To add yet another damper on things, the kind of float and seat work you're talking about requires that you remove the bank of carbs.

There is no way IMHO you can set float hieghts with the carbs on.

For your seats, check Partsnmore. Do a search here, there's a thread with the link to thier page.

Randy

[tab1324]

carbs are off the bike so I should be able to set the float height this way and then bench test for leaks. I still can't find the seats on partsnmore. It's an 82 XJ1100 - of course they have them for a bunch of others but not that one. What to do with those blasted seats. I really wanna get them out and do this only once more - already reassembled and still leaks (w/o new parts).




Tom B

[tab1324]

Octopus - or not to octopus

I removed the octopus completely ala Mike Hart thread. Even with the octopus working properly, w/o float height set properly and the needle valve and seat working properly, there's still a potential flooding problem right?

Tom B.

[randy]

Tom, the parts for the seats are available on bikebandit.com.
Don't know what the dealer would charge, but you say you can't find them, so here's a viable alternative source.

They're pricey, though. The needle and seat set is $27.50, the o-ring is $2.76 and the filter screen is $8.23.


FYI, the Yamaha part # for the needle / seat set is: 3L1-14190-20-00.

HTH,

Randy

[POOLBOY]

needle and seat fix

Tom.
I polished my seat's by spinning them in a drill press, and going at the needle seat area with a wood "Q" tip soaked with "simichrom" polish.
Any brass polish should work.Then I cleaned the rubber tip's on the needles with acetone to remove the "shiny" rubber oxidation.
I got new "o" ring's from my local hardware store.
No leak's.
I dont think I would do this for a "paying" customer, but it worked fine for me.
***********************SPLASH*******************

[skids]

Re: needle and seat fix

I have conditioned a set in a very similar way. I think acetone is a bit too risky however. I rubbed the rubber tips of the needles (later carbs only) on a tee shirt with an area soaked with gumout -- NO, it wasn't on my belly!

Originally posted by POOLBOY
Tom.
I polished my seat's by spinning them in a drill press, and going at the needle seat area with a wood "Q" tip soaked with "simichrom" polish.
Any brass polish should work.Then I cleaned the rubber tip's on the needles with acetone to remove the "shiny" rubber oxidation.

[tab1324]

I tried again to get the seats out today and I'm getting close to ruining them. Coulnd't I use the polish on a cu-tip method while the seat is still in the carb?

Tonight, I measured the float height from the surface of the carb body to the high point on the float (upside down on bench). I've had a suspicion that they were set correctly. I've been reading posts on the forum and have seen 20-23 mm suggested (about 7/8-15/16" of an inch). Mine were at about 13/16" which I think is on the low side. So, I adjusted the tangs and installed the floats and bench tested for leaks. At first it leaked but then it nearly stopped - this is with the original needles installed. Maybe this is the problem. It can't hurt to reset the float heights anyway, the bike hasn't run well anyway due to the flooding carbs.

I can get the seats to turn but not pull out. The brass on the outside is getting marred up now so I think I may just install the new needles and see what happens. Maybe it will be solved with that and the float adjustment.

Tom B.

[nashville_bill]

I'm sure that www.motorcyclecarbs.com can get you the parts you need.

[John]

By handling the brass seats with a pair of pliers, it is possible to distort the the seat, and the needle will hang up and stick...open! Happened to me. If the seat will turn freely, then the O ring is probably bad and has a flattened out on the outer diameter. It will have to be replaced, to stop the leak. I, like you, am frugal, no I'm cheap, but sometimes we just gotta come up off the wallet, and buy new stuff.