What year carburator is this BS38?

Terrible1

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Can anyone ID this carburetor? I'm trying to rebuild them and see that the model breakdown is not as simple as the BS34.

The two were not linked together, both had separate cable pulls. I think it's the 70-75 according to the rebuild guide but then when on 650central there's kits with in those years.

I do currently have them apart and soaking so if anything else is identifiable let me know. Thanks !
 

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Assuming it's original, no swapping of the top cover (minus the Solex name), I'll guess it's from July, 1974 to 1975. Comparing the jetting to the charts would help.
 

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My best guess would be a '74-'75 set as well. Earlier sets had a raised floor in the main bore which yours does not have. Also, the throttle cable arm where the cable attached was a double "claw" style instead of the double ring type you have .....

g9j2FOS.jpg


Yes, check the jetting, especially the needle. Mains and pilots are often changed so may not tell the tale, but needles were rarely swapped. Do you have 4N8 needles in there?

7wbHkpb.jpg
 
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Thanks Twomany/5twins.

The mains are 127.5 with 45 pilot's and 4N8 needles. So yes they fall into the 74/75s.

Damn you guys are good.

Well the float bowls from any bs38 work for any year bs38s? I think I've got one that is beyond clean up.

Thanks!
 
Thanks guys. The Tops were aluminum with Mukuni stamped in the top, choke only on one of the two, and the 4N8 needles. Now I just need to source a float bowl!!!
 
No, the float bowls differ over the years. You pretty much have to stick with what matches how the carb sets are broken down in the chart above. '76 and newer bowls use a different style of pilot jet (the VM22/210) so that rules them out. '73 and older bowls had changes done to the overflow tube height and the choke tube location so whether they worked or not would be a gamble. Here's an I.D. page from the Australian site. In the text below the chart, it spells out the little float bowl changes .....

http://www.xs650.org.au/Technical Info/XS-TX650 Carburetor Evolution.htm
 
No, the float bowls differ over the years. You pretty much have to stick with what matches how the carb sets are broken down in the chart above. '76 and newer bowls use a different style of pilot jet (the VM22/210) so that rules them out. '73 and older bowls had changes done to the overflow tube height and the choke tube location so whether they worked or not would be a gamble. Here's an I.D. page from the Australian site. In the text below the chart, it spells out the little float bowl changes .....

http://www.xs650.org.au/Technical Info/XS-TX650 Carburetor Evolution.htm

Thanks 5twins. I'll read up and start looking.
 
Good Afternoon. I'm working on my '74 TX650A. When I bought the bike it had later model paired linkage carbs installed, and I want to install the correct configuration. I received these carbs in the photo with the extra parts from the PO. Are these in fact 1974 carburetors? I know that I'm missing a brass connection where my finger is pointing, but can someone please help me identify the hose connection configuration with these carbs - where do the hoses go and how do they link together with hoses? My Haynes manual is not that specific about the year.
Thanks for your help!
 

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The fitting you are missing is for the chock crossover.
upload_2020-2-24_10-1-24.png

The 2 open fittings go to the gas tank petcocks. The hose below them is for fuel crossover. The 2 hoses pointing down are for venting.
upload_2020-2-24_10-2-11.png

If you are going to use them I would advise going to the Tech section and reading the threads on cleaning and rebuilding them.
upload_2020-2-24_10-10-8.png
 
Thank you very much for the photos and explanation. The small plastic fittings on the bottom of the float bowl are for overflow and also vent to the ground? I've read the threads and am in the midst of rebuilding these carbs.
Another question is that with the Keyster carb rebuild kit from MikesXS Canadian affiliate, I received a 130 main jet and a 42.5 pilot jet, plus the incorrect jet needle. I can reuse the correct longer needle I have from the later carbs, but am concerned those jets will be too lean. The stock carb specs are for 127.5 and 45 jets, respectively. I am hoping to run with the MikesXS pod air filters (just because I already have them with the bike)
 
74-75 BS38s.JPG

In general small pods are a problem on CV carbs many here have tried and discarded pod type filters. The vacuum chamber above the piston needs a relatively large air volume inside the filter to dampen pressure fluctuations and reduce CV piston "flutter", flutter makes a carb run like well you know, and will increase wear.
 
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Thank you. I have read several times that the pods can be problematic and yet others seem to have success. I have the original air boxes so will fix them up and make/buy the new parts to properly seal them, and put the pods aside. Any feedback on the quality of the aftermarket air filters available at MikesXS for these original air boxes? I have not read anything specific on that.
 
Van Islander, Cool Bike and what a great place you have to ride eh ? Hey, in the Seattle Craigslist "motorcycle parts" there is that guy near Seattle selling XS stuff. He has pics of new in box K&N air filters for sale. (One pair) that's close to you other than that darn border crossing lol.
-RT
 
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