need XS2 carb advise

[tmikeyb]

Yes the seal is in with the lips facing outward. Also, the total movement back and forth is .005. That would make the actual clearance .0025, unless I'm thinking completely wrong. On the old Linkert carbs that I'm more used to working with, they used pressed in bushings which were reemed to size, as someone mentioned. So, assuming that this is caused by wear, I'm assuming that the wear would have to be in the carb body, not the shaft. Am I right on that?

 

[GLJ]

I would say your clearance is .005. Just like when a piston and cylinder are measured.
I've rebuilt 3 or 4 sets of XS2 carbs. I lube the seals with high vacuum grease. It's a very thick silicone grease. It's made for sealing vacuum which is what you are trying to do. I do not know how much is too much clearance. I will admit I have never measured the shaft clearance. I just do it by feel.

 

[GLJ]

Also make sure the small orifice in the left float bowl that lets gas into the enrichment circuit is clear and the passages in he carb body are clear.

 

[Niels B]

I find it hard to believe that the shaft or the carb body has been worn very much since new - I know these are old ladies so it could happen - it’s just like an area that does not have a lot of pressure to it - and most of these bikes hasn’t run that many miles compared to their age - many below 40k mile - all the once I have none had over 35k most in their teens and low 20ties. I honestly think you can seal your shaft- the idea of vacuum grease sounds like a good option - never heard of it but I’ll have to look it up - like the idea

 

[GLJ]

https://www.amazon.com/gp/product/B00CLGS92M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[5twins]

I guess it's not unheard of for the shaft to wear the hole in the carb body, and it mostly happens on the one near where the cable connects. That hole is subjected to more side forces than the other one because of the cable pulling up on the shaft.

I've taken to packing my shaft seals full of red rubber grease. I think it helps both seal and preserve them .....

 

[tmikeyb]

I would say your clearance is .005. Just like when a piston and cylinder are measured.
I've rebuilt 3 or 4 sets of XS2 carbs. I lube the seals with high vacuum grease. It's a very thick silicone grease. It's made for sealing vacuum which is what you are trying to do. I do not know how much is too much clearance. I will admit I have never measured the shaft clearance. I just do it by feel.

 

[tmikeyb]

OK, I understand the clearance explanation. I think I'll try the grease. It makes sense, and it's worth a try.

 

[tmikeyb]

I guess it's not unheard of for the shaft to wear the hole in the carb body, and it mostly happens on the one near where the cable connects. That hole is subjected to more side forces than the other one because of the cable pulling up on the shaft.

I've taken to packing my shaft seals full of red rubber grease. I think it helps both seal and preserve them .....

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What exactly is "red rubber grease"?

 

[5twins]

It's a grease made specifically for use on rubber. It's vegetable oil-based, not petroleum. It's not readily available in the States here it seems. The couple cans I got I bought off eBay from England.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=red+rubber+grease&_sacat=0

 

[jetmechmarty]

It's a grease made specifically for use on rubber. It's vegetable oil-based, not petroleum. It's not readily available in the States here it seems. The couple cans I got I bought off eBay from England.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=red+rubber+grease&_sacat=0

Parker O lube will do the same job in this instance.

 

[tmikeyb]

Thanks guys, I'll add some of that to the hundreds of other jars and tubes of stuff in my shop.

 

[tmikeyb]

OK, I packed the throttle shaft seal that I suspected of leaking very well with high vacuum grease, put everything back together and started the bike. How frustrating, it is no different from when I started. Bike runs only on left cylinder until about 2000 RPM. Carb is cleaned, carb holder is new, seals are new, and now are greased, carbs are synced, and idle screws are properly set, and I still have an air leak. Spraying carb cleaner around the intake area will cause it to fire, but I guess I just haven't been precise enough with my spraying to pin down the exact location. I know that nobody can fix this from far away, and that it's my problem to figure out, but if any of you have any more ideas or suggestions, I'd be very happy to read them.