Leaky Carbs

[Roy]

Is it possible to get carbs not to leak when you leave the petcocks on? The needles and seats look fine, and the floats are set at exactly 25mm. I ordered new needles and seats but they sent the wrong ones. It's not a big deal to just shut the gas off. I was just wondering. My bike is a 71 xs1-b with 38s.

 

[nj1639]

One of the reasons I do the ol school 'on, off and reserve' petcocks, when they're off they're off.

 

[5twins]

It's best to use factory float needles and seats. The aftermarket ones are "hit and miss" on quality, so much so that my dealer won't even use them anymore (too many returns with leaks that he had to fix on his dime, lol). But, that being said, the float needle isn't meant to be an absolute shut-off. A full tank of gas exerting pressure on even a good float needle and seat assembly may leak some.

 

[bosco659]

It's best to use factory float needles and seats. The aftermarket ones are "hit and miss" on quality, so much so that my dealer won't even use them anymore (too many returns with leaks that he had to fix on his dime, lol). But, that being said, the float needle isn't meant to be an absolute shut-off. A full tank of gas exerting pressure on even a good float needle and seat assembly may leak some.

5T, did you have any success with your testing of Viton tipped needles?

 

[Melnic]

5T, did you have any success with your testing of Viton tipped needles?

Hmm, who has viton tipped needles?

Even so, who has rubber tipped ones, MikesXS one I got is all metal.

I use only ethanol free so I may not be afraid to use a rubber one.

I have rubber tipped ones in both my XJ and don't expect they are Viton. Both are manual right now and I have accidentally left them on all night but do expect they would not last forever.

 

[5twins]

Well yes, kinda, lol. I tried some from Honda VT600C rebuild kits I got for a song off Craigslist. They fit and worked OK so I ordered just a pack of the needles. Both were the K&L brand and supposedly the same needles, but the "new" ones are a little longer so may induce some float tang issues (bent too steep). To solve that issue, you can put sort of a "Z" bend in the tang instead of just the normal angle. I plan to modify a pair of cheap HF pliers for this but haven't gotten around to it yet. DogBunny had a good thread on this, and his solutions .....

https://www.xs650.com/threads/rubber-tipped-bs38-float-needle-answer.59064/

I don't see the point in replacing a good working (not worn) steel needle. If I encounter worn ones, I will switch to the Viton rubber tipped needle.