Should I order the carb (jets) rebuild kit? (have a look)

[tor_bjorn]

Hi everyone. *Short time lurker, first time poster.

As well as replacing the diaphragms, I'm trying to figure out why the left are right carb aren't identical when I open up the float bowl. It's a '72, xs2, bs38 CV carbs,

(image attached?)

One has a main nozzle, the other has no main nozzle but has another nozzle. Please help me identify these parts. If this is way off and they should each have these parts, funny thing is the bike's been running for at least a month (just took it on myself), but the problems were REALLY starting to show up so I took it apart finally.

The kits are available for me at xs650direct (Canada), and hell it needs a new gasket anyway. Let me know if the Rebuild Kit (#48-1918) will do it for me: http://www.xs650direct.com/products-36.html

Thank you! You guys are awesome here. Replies are friendly and timely.

 

[DogBunny]

You are missing a nozzle. The nozzles that come in the rebuild kits for your year are a generic substitute, and are not the same as stock. If you are going to use a nozzle out of a kit for your year, then you should buy 2 kits, and replace the other nozzle too, so that your carbs are consistent. Or, you can PM me, I'm sure I have the correct nozzle for you, as well as the nozzle o-rings and whatever else you need.
The little pipe (#1) is your choke circuit pick-up (enrichener). You only have one choke, so you only need the pick-up tube on that side. In other words, that part of your carb is normal.
Same with the lack of a "sync mechanism." You have un-linked, dual-cable carbs, and the only way to sync them is by adjusting the idle stop screws.

 

[5twins]

..... and throttle cable freeplay. You want equal amounts of freeplay in each throttle cable. That way the butterfly plates will begin to open at the same time as you open the throttle. They will also be open the same amount at any given throttle position. So, to sync these, set and match idle speed on each cylinder, then match freeplay in the cables.

To maintain sync, in the future if you need to adjust the idle speed, be sure to adjust the idle speed screw on each carb equally. If you adjust only one carb, that will change the amount of freeplay in that cable and throw the sync off.

 

[tor_bjorn]

5twins: Ah yes, thank you. I've been doing it that way. Do we want the butteflies to be barely open at idle, or well-sealed at idle? i hear so that "you can barely slide a strip of paper from under it".

 

[tor_bjorn]

Thanks for the reply DB! Yes I agree I should replace em all to retain consistency. As for the needle jet (nozzle i'm missing) I may as well order two new ones while I'm at it for consistency too, thanks for the offer though.

Additionally, do you have any suggestions on how to get a stuck pilot jet out?! the head of the screw is so worn that i can't screw the darn thing out. Am I going to have to resort to drilling? (arggg)

Finally, &How do I get 5twins to see this too? >> I noticed in another old thread you were describing how to properly work with needle jet screw heads. Do the passages have to be facing the holes in the float bowl? I notice in the main jet maybe the positioning should matter (?) does the groove need to be facing the engine?

 

[angus67]

http://www.xs650.com/forum/showthread.php?t=43
click the first link in this thred. its a pdf. don't know how to link directly to it. extremely usefull info here.

 

[5twins]

None of the jets are installed so they are oriented a certain way or anything. The mains and pilots simply get screwed in a little bit past snug, not super tight. You're dealing with what happens when someone puts them in too tight, not a pretty picture is it. The needle jet has an o-ring on it to seal it into the carb body and is just a snug push-in fit. The float bowl holds it in place once installed.

 

[DogBunny]

Thanks for the reply DB! Yes I agree I should replace em all to retain consistency. As for the needle jet (nozzle i'm missing) I may as well order two new ones while I'm at it for consistency too, thanks for the offer though.

Additionally, do you have any suggestions on how to get a stuck pilot jet out?! the head of the screw is so worn that i can't screw the darn thing out. Am I going to have to resort to drilling? (arggg)

The secret to removing stuck pilot or main jets, and I have done this many times, is to put the float bowl in a 200 degree oven for 20 minutes. This does two things: It softens the dried fuel varnish which has "glued" the jet in place, and it causes the bowl to expand around the jet so that the jet is not in so tight. This has never failed me.
If the head is already buggered, then you have to resort to using a properly sized screw extractor (along with the 200 degree oven). Using a screw extractor requires a bit of skill and finesse, so if you have never used one, see if you can find a tutorial on-line.
As far as I know, new nozzles for your year carb are unobtainable. I am pretty sure I have the correct nozzle for your year, along with nozzle o-rings, float bowl gaskets, and whatever else you might need, PM me if interested.

 

[5twins]

Mike's does carry the long Z-6 needle jet for the '70-'73 carbs (and I see they finally corrected their description as to what it fits). What isn't available is the short Z-6 as used in the '74-'75 carbs.

 

[DogBunny]

All of the needles that MikesXS sells are counterfeits. On the left is a genuine Mikuni 4M1, and on the right is a counterfeit MikesXS 4M1.
The worst thing about the fakes is that the diameter of the e-clip slots is too small, so that the e-clip does not firmly grab the needle. Additionally, the height of the slots is too great. Combined, these two deficiencies result in the e-clip slop that you can clearly see in my photo.
It is easy to tell the difference between the counterfeit "square-within-a-square" logo and the real thing. The fake is more like a rectangle-in-a-rectangle.
If they got that much wrong, they probably got the taper wrong too.

The package that the MikesXS needles come in say "Made in Taiwan", not Japan.

 

[5twins]

They say Taiwan now but it wouldn't surprise me if they eventually come from China too. I recently installed a new front cam chain guide in a guy's motor and, you guessed it, it was made in China. I hope they got that part right because it's a little more involved than changing a slide needle, lol.

 

[5twins]

When you get your new jets, you will probably have difficulty locating good fitting screwdrivers for the screw slots - and this is critical. That's because they are metric sized slots. I've taken to grinding my own to get that perfect fit. I use the readily available 1/4" insert bits. Some grinding of the hex shaft is usually also required to access the recessed mains in the BS38 float bowls. The single bit to the left has not been ground and as you can see, it's a very sloppy fit .....

For removal, I like to use a T-handled holder. You can generate incredible torque with these things and also hold the bit down into the jet very tightly .....

For install, I only use a stubby, or the knurled bit holder I got from Sears. This guards against making the jets too tight .....

I absolutely DO NOT use the T-handle for jet installation, or float bowl and carb top screws either. All carb assembly is done with the stubbies.

 

[tor_bjorn]

Luckily I don't need the needles at this point. Phew, good to know though.

BUT what I do need to check now is that the guy I bought the bike from is running the 45 Pilot Jet so I have to make sure the needle is adjusted right for that.