Carb confusion

[kevinl]

Any ideas on how vacuum/vent lines with the hitachi carbs? I'm struggling to find info and the only port I see on the carb is the fuel T

[chuck hahn]

I dont recall how the Maxim was set up. I guess if you could find an XJ 650 or 750 manual to download the carb section may answer that question.

[kevinl]

I dont recall how the Maxim was set up. I guess if you could find an XJ 650 or 750 manual to download the carb section may answer that question.

Searching the web it seems that the xj's of the era receive petcock vacuum via the 3rd intake boot. I can't find any information about any vacuum or vent lines on the carb itself - is it possible that there is none?

[chuck hahn]

I can take a look at the ones i have tomorrow. came off a 82 XJ650

[bobgroger]

Here you go, there are 3 sets around the same price. But wouldn't an 80 be CV carbs?

https://www.ebay.com/itm/80-SUZUKI-GS550-CARBURETOR-CARB/162775674415

Edit: Yes, this.... https://www.ebay.com/itm/Mikuni-Carb...s/263397828395

I just got a set of BST38s on ebay for $25. I don't need them but couldn't pass it up.

[chuck hahn]

Should be BS32 carbs I think. The ones in the first link are for a 79 or later. 80s had CV carbs..the ones inn the second link should be then right ones.

[kevinl]

I can take a look at the ones i have tomorrow. came off a 82 XJ650

Thank you!!

Here you go, there are 3 sets around the same price. But wouldn't an 80 be CV carbs?

https://www.ebay.com/itm/80-SUZUKI-GS550-CARBURETOR-CARB/162775674415

Edit: Yes, this.... https://www.ebay.com/itm/Mikuni-Carb...s/263397828395

I just got a set of BST38s on ebay for $25. I don't need them but couldn't pass it up.

Is there any real reason to switch to the OEM carb? My only hesitation is that the hitachi carbs on my bike have been jetted already and appear to be in good condition

[chuck hahn]

First thing is that the Mikunis were designed and engineered to make your bike work and perform optimally. Second, has your bike ran with the Hitachi ones???

[Nessism]

Is there any real reason to switch to the OEM carb? My only hesitation is that the hitachi carbs on my bike have been jetted already and appear to be in good condition

Since you are building a cafe I assume that means a modified exhaust and pods right? Given that, you will have to play with jetting regardless of what carbs you use. For a stock bike using the airbox a set of stock Mikuni's would be the easiest way to assure the jetting is correct. Those Hitachi's may be fine all things considering but just plan to do some jetting work before the bike is running the way it should.

[Steve]

Is there any real reason to switch to the OEM carb? My only hesitation is that the hitachi carbs on my bike have been jetted already and appear to be in good condition

Functionally, you could make almost any carb work, within reason. However, almost nobody on this forum has experience with Hitachi carbs on a GS, so we could only offer general suggestions, and they will have to be based on your observations. If you had Mikuni BS32 carbs, we could say "try this as a starting point". With the Hitachis, we don't really have a clue.

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