O ring size on BS38 needle jet

cjrenick

XS650 Enthusiast
Messages
40
Reaction score
0
Points
6
Just wondering what the size is on the needle jets? My carbs are BS 38 1972. I hate to pay $12 shipping for $1.50 o ring. Hoping maybe I could go to my local hardware/automotive store and get the o ring. I noticed that they do not include this o ring in the rebuild kits either.
 
It's 1mm thick by 4mm I.D. You can get a 25 pk. from McMaster Carr cheaper than what Mike's wants for 2.
 
Thanks to 5twins for the size. I got a pack from Grainger for my recent BS38 rebuild. PM your address and I'll send some for free if you want...
 
5twins, for those needle jet o-rings from McMaster Carr, I see the 1mm by 4mm ID rings, which compound have you found works best?
 
I've only tried and used the Viton ones but I'm sure the Buna-N ones would be fine too. I think that big carb o-ring place, Cycle O-rings.com, sells strictly Buna-N o-rings and there are no complaints. They've probably sold thousands.
 
Reviving an old thread here, but since I just had to search - here is the part # from the McMaster Carr website for the Vitron 0 Rings: 9263K284
 
I too have a few extra of these on hand for the same McMaster Carr package size reason. PM me an address and I'll be happy to put a couple in an envelope.
On that note, thanks to 5twins for the part # which I got from a previous thread.
Yamimoto
 
Pardon my thread jack, but do you think the o rings not allowing the jet to seat would cause many many headaches for me such as only being able to idle without the choke? I've read all the other posts over and over and it's never come up as a solution to an issue.
Thanks
 
Pardon my thread jack, but do you think the o rings not allowing the jet to seat would cause many many headaches for me such as only being able to idle without the choke? I've read all the other posts over and over and it's never come up as a solution to an issue.
Thanks

Yes, I believe so. Mostly because it may not allow the float bowl to properly seat.
Check this out: http://www.xs650.com/forum/showthread.php?t=36764
 
Pardon my thread jack, but do you think the o rings not allowing the jet to seat would cause many many headaches for me such as only being able to idle without the choke? I've read all the other posts over and over and it's never come up as a solution to an issue.
Thanks
You only think the jet is not seating, but it actually is.
The float bowl will push the nozzle (needle jet) into place when it is placed on the carb body. Note that there is a tiny depressed lip in the float bowl that matches with the step in the nozzle. Tightening the 4 float bowl mounting screws will push the nozzle into the main carb body and will fully seat it.

Maybe you can describe your "many many headaches." Not being able to idle without the choke is usually a clogged pilot jet or pilot circuit.
 
The Z-2 needle jet used in the '78-'79 carbs is usually not a problem. The o-ring groove on it is far enough away from the step so that the jet can usually be seated into the carb body with a little lube applied and a twisting motion. The Z-6 and Z-8 jets used in the earlier carbs are another story. The o-ring groove is pretty much right next to the step. They usually won't push into the carb body, but as DogBunny said, installing the float bowl will press them in. If you were to remove the bowl in a day or two, you should find the jet fully seated.

cyGGqbT.jpg
 
Last edited:
Back
Top