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1980 KZ750g BS38? carbs

  • tdogm6@yahoo.com
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13 Jun 2021 23:04 #850170 by tdogm6@yahoo.com
1980 KZ750g BS38? carbs was created by tdogm6@yahoo.com
undefined So, I just finished going through the carbs on my (new to me) bike. They weren't real dirty, and now the bike runs pretty good.  I noticed two things. 
1- the mixture.screws for both carbs were still sealed with the Welch plugs ( I left them as they are)
2- the bowl drain screws, and jets underneath them are physically two different sizes.  The diaphragms for each are the same diameter. But the bevel on the bevel on the slides
are different too.
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Is this normal?
I ordered rebuild kits before cleaning, but now fear that one can't be totally rebuilt when the time comes. 
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1980 KZ750G

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  • DoctoRot
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  • Oh, the usual... I bowl, I drive around...
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17 Jun 2021 08:44 - 17 Jun 2021 10:30 #850310 by DoctoRot
Replied by DoctoRot on topic 1980 KZ750g BS38? carbs
If the plugs are still there then I would guess that’s how those carbs came from the factory. Do you have pics? Its possible someone mismatched parts from a different BS38 setup. Many Yamahas of the era use the same carb bodies but had different setups.

The 1980 carbs are one year only carbs. The pilot screw and carb body  is unique to them, so if you drill out the plugs do not discard the pilot screws as they will be very difficult to replace. If you have a 40 pilot jet i would recommend going up to at least 45 or 50. these were way too lean from the factory.
Last edit: 17 Jun 2021 10:30 by DoctoRot.
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17 Jun 2021 20:09 #850342 by tdogm6@yahoo.com
Replied by tdogm6@yahoo.com on topic 1980 KZ750g BS38? carbs
 There's no Chance of mixing the Drain plugs, main or needle jets between the two. they are different sized threads. One looked "newer" than the other.  
   I'll post some pictures the next time I pull them off the bike.

1980 KZ750G

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