Help identifying Carbs, frame, engine etc.

[Tim H]

My bike was bought as a half basket project and is obviously not numbers matching. Frame serial is S650 113xxx
Engine serial is 2F0-156251

From this thread http://www.xs650.com/forum/showthread.php?t=42 I think my frame is a 71-72 XS2 and my engine is a 78-79?

Reading through I believe my carbs are supposed to be BS38s? Is there a way to tell if they are the 'old style slide' or the 'new style slide' or narrow down the year a little better so I can use the chart referenced here http://www.xs650.com/forum/showthread.php?t=43 for stock jetting etc?

I'm still a little green when it comes to carbs but I'd like to get some rebuild kits and spare parts on order (new brass floats etc) from mikesxs and dive in.

Both carbs were on the bike and I pulled them off and tore one down to start cleaning. I only do one at a time as I like to have an example if reassembly finds my memory lacking. I can get pics of the one tore down if it helps. For now here are poor pics of the complete one:

Thanks for the help.

Tim

 

[Tim H]

Also how bad can these carbs get before its not worth rebuilding them? Just about every phillips screw is wobbled out as well as many hexs rounded, a couple of the tube nipples pulled right out of the body etc.

To me it looks like a small order from Mcmaster, some bead blasting, and a rebuild kit and the important stuff will be replaced. But like I said earlier I am green with carbs and only know what i've read on the internet concerning them.

The diaphrams both held well when I did the thumb over the oval port thing, that 's the first thing I did when looking at all 6 carbs my lot of 3 bikes came with.

 

[bluebikerblan]

That particular carb is a BS 38 type II, such as might have been supplied OEM on a 1978 or 79 E, F, SE, SF. There's a great carb guide in the tech section and Mikes XS also has tech info. to help you learn how to distinguish the types.

 

[weekendrider]

To fix the the tubes that sipped out you can put something solid on the inside and knurl the outside with a punch, nail etc.

 

[5twins]

Although those carbs appear to be a '78-'79 set for the most part, there is one oddity - that vent hose from the inner side of the body. That was eliminated for that carb set and the vent was moved to around the intake bell (as shown in Blue's 1st and last pic). Your set has vents in both spots. I suppose it's possible that yours is an early transitional set that retained some of the older features while having some of the newer ones as well.

You can tell which slide you have by how the needle mounts. The newer style will retain the needle with a snap ring .....

The older slides just use a large plastic disc over the needle held in place by the slide return spring.

Also make a list of the jetting and needle you find in there.

 

[XSLeo]

I was going to say they looked like a 76-77 set. They have the vent hose in the side.
If you pull the diaphrams and slides.
The 76-77 set have a thick plastic washer holding the needle in the slide.
The 78-79 used a different slide and they had an snap ring holding the needle in.
If you get the needle and needle jet out.
The 76-77 used a Z-8 jet with a 4M1 needle.
The 78-79 used a Z-2 jet with a 502 needle.
I have a set of the 76-77 carbs. A bit of a mix matched set up. The needle and needle jet are from a 74 carb set, a Z-6 jet with a 4N8 needle.
Once you get all the parte out and can see what they are you can figure out the year and what the stock jets should be.
The 76-77 should be a 122.5 main jet, a 45 pilot jet.
From everything I have studied they used a carb for two years, made changes, used two years. Making changes every two years.

 

[Tim H]

thanks guys. i have one apart i'll spread out all the parts today and get it narrowed down.

 

[5twins]

Your float bowls appear to be the '78-'79 style because they have no hose nipple on the bottom. That would mean they should have no brass overflow tube inside either. Pictured below is a '78-'79 bowl on the left with no brass tube, an earlier bowl on the right with the overflow tube .....

'76-'79 BS38s used the VM22/210 type pilot jet so the passageways would resemble those in the bowl pictured on the left. The '76-'77 set ran a #25, the '78-'79 set used a #27.5.

 

[Tim H]

Thanks for all of the replies.

The float bowl looks like the one of the left 5twins adn the pilot jet says 27.5 on the side. also there is no overflow tube as you said.

The needle is held in the slide with a snap ring though I keep forgetting a set of pliers from work to pull it and check the rest of that assembly.

The main jet is pretty chewed up but on the top I can read a 35, so I assume that is a 135 as listed in the tech section chart.

I think its safe to say its a 78-79 set of 38's so I will order the appropriate kit.

Is there anything else I should get on order that you guys think I may run across needing besides the mikexs kit #48-7879?

 

[5twins]

If you want the perfect pair of snap ring pliers for slide dis-assembly, get Mike's part #35-0009. This is a long reach right angle pair intended for use on the master cylinder but they work beautifully on the '78-'79 slides.