1E1 Carb issues

[Andy1]

Got job of building set of XS650C carbs.

After receiving the bits i had a closer look at them and found a few things i did not like;

first off these are parts from a keyster kit; needle came with Y5.5 on it , i queried this and was told that is the norm now? i was looking for a "4M" needle id?
Next the float needle kit did not have the viton tipped float jet, just the plain steel one. i thought these became obsolete years ago? The emulsifier tubes i received have holes in it that are a different size to the original item i am replacing, the quality of the tube was naff in otherways. i found burrs and a rough finish inside, is this the norm for keyster kits, is that all they have on offer these days?

My other queries are to do with the rebuild; i could not get the emulsifier tube to stay in place, the o ring stopped it seating. This meant that the float bowl was jamming it into position, which could mean i get a leak round the bowl gasket. Is this usual to find difficulty seating the tube?
Do you people think it vital to replace the choke shaft seals , because i really do not want to remove the shaft at this stage?

Finally can i expect good results from these carbs , not super performance , just to start, idle and good pickup

 

[5twins]

The '76-'77 carb set is a very good one, some think one of the best of the 38s. The Keyster kits are of questionable quality. There really isn't a good kit out there. That's why I recommend time and time again to just buy any individual parts you may need.

The needle and needle jet you got are some generic type. I wouldn't use them. Clean up and reuse your originals if possible or buy new 4M1 needles and Z-8 needle jets from Mike's or his Euro partner. The needle jet not seating immediately with a new o-ring is common. The o-ring groove on this particular needle jet is very close to the shoulder it stops at when fully inserted. I lube it up good with WD40 or some other light lube, install the bowl, and let it sit. In a day or so, the o-ring will usually work it's way into the carb body.

Viton tipped float needles were never made for the 38s. Any kit will have metal tipped ones and that's what a genuine replacement would be as well. Some have used viton needles from other bikes. The GL1100 Goldwing one is supposed to work but I've never tried it.

 

[gggGary]

Do you people think it vital to replace the choke shaft seals , because i really do not want to remove the shaft at this stage?

Finally can i expect good results from these carbs , not super performance , just to start, idle and good pickup

Do you mean throttle shaft seals?
I'm guessing you do and we are talking about 40 year old rubber, You can guess my opinion. I wasn't replacing them, but now I do. The OEM yamaha seals are the Only way to fly about 3.50 each at boats.net Yes BS 38's work well. actually any stock carb 76 up will work well if properly and completely overhauled.
PS. believe everything 5twins says, you heard from the expert first.

 

[Andy1]

Thanks for that, i am not sure what to do at the moment, i do not fancy stripping down the "throttle shafts, i always end up drilling the screws out and making a mess. As for using the old needle, well that answer is a surprise and there does seem to be wear visible, that is if the patination is anything to go by?

 

[5twins]

You can easily inspect the condition of the left seal on the left carb and the right seal on the right carb without removing the butterfly shaft. That should tell you if the other 2 require replacing.

I said reuse the needles if possible. If you think they're worn too much, replace them. Clean them really well. What you're seeing may just be gas residue.

 

[Andy1]

I looked at the throttle shaft seals and change one, the old one was intact just age hardened a bit. the needles i will stay with the new ones and keep in mind if i have 3 quarter throttle issues. The emulsifier tubes, well i removed and greased with petroleum jelly and put the float bowl back on without the gasket to force the tube in . left it for a few hours and re tightened the float bowl screws . i will wait a few more hours to see how it has progressed.

 

[5twins]

Compare the length of your original needle to the kit one. If they're the same or close to it, the new one may work. If there's several MM difference, it probably won't work.

 

[Andy1]

same length , emulsifier tubes fitted now thanks for tip.

 

[5twins]

A report back on how those kit needles and needle jets work would be appreciated. No doubt others in the future will encounter this same dilemma.

 

[Andy1]

No problem, but don't hold your breathe, i am snails pace progress .lol