Carb ID. Mikuni CV's, BS38, BS34, 70-84

[Manic]

New member here! I Really appreciate all the time and effort put in by the community. Thank you. This carb breakdown along with the VIN i.d. Section have helped me uncover my mystery project XS650. The Registration from previous owners stated it was a 1979 but upon investigation of the 3G0 Vin on the frame and engine and BS34 Carbs with brass floats it seems as though I have a 1980 XS-G. Wish I hadn’t bought a jet kit for a ‘79 with BS38 carbs!

What Vee said! Thanks all for this great thread!

 

[Manic]

Does anyone know a good supply for Mikuni parts for the BS-38 carbs? I’m aware of NicheCycle.com. And Mikes XS (won’t be using them again). But seems a lot of genuine Mikuni parts are hard to come by for these carbs. I know there’s a lot of aftermarket stuff available. But after wasting $82 at mikes on the Keyster kits, I’m wary of going that route again.

 

[Jim]

@650Skull ... I looked through Tech and didn't see this thread in there. Was it never put there or am I just blind?

 

[Jim]

Does anyone know a good supply for Mikuni parts for the BS-38 carbs? I’m aware of NicheCycle.com. And Mikes XS (won’t be using them again). But seems a lot of genuine Mikuni parts are hard to come by for these carbs. I know there’s a lot of aftermarket stuff available. But after wasting $82 at mikes on the Keyster kits, I’m wary of going that route again.

https://www.jetsrus.com/

They have OEM Mikuni and the repop stuff and It's easy to get confused. Make sure you're selecting the OEM.

 

[Manic]

https://www.jetsrus.com/

They have OEM Mikuni and the repop stuff and It's easy to get confused. Make sure you're selecting the OEM.

Thanks Jim! Yes, I’ve already experienced the “confused” part. I’m hoping now that I’ve been directed to very helpful threads, I can shop with a little more knowledge now!

 

[Jim]

Thanks Jim! Yes, I’ve already experienced the “confused” part. I’m hoping now that I’ve been directed to very helpful threads, I can shop with a little more knowledge now!

I'm a bit embarrassed to admit that I ordered the Chinese ones on my last order with 'em. Putting "OEM" in the repop column is a bit deceiving.... even after I've bought from 'em before.

 

[jetmechmarty]

I'm a bit embarrassed to admit that I ordered the Chinese ones on my last order with 'em. Putting "OEM" in the repop column is a bit deceiving.... even after I've bought from 'em before.

View attachment 340413

Not on that site, but I have been guilty of just clicking away on cruise control with less than desirable results.

 

[650Skull]

Yes, you can retrofit the plastic floats to the 1980 carbs if you like, and it's what I'd do if the original brass ones ever went bad. The plastic ones rarely go bad and can usually be found for a few dollars cheaper than the brass ones. And the Suzuki equivalent is even cheaper than the Yamaha float .....

View attachment 339175

View attachment 339176

@5twins Are these exactly the same.?? Reason i ask is, if they are slightly different, (size/Shape), then the Factory float height might/will b off.

Use of a site tube to set them would bypass any concerns.

 

[Jim]

@650Skull ... I looked through Tech and didn't see this thread in there. Was it never put there or am I just blind?

For the short answer..........No,

@Travis ?

 

[Travis]

@Travis ?

I can't believe this isn't in there. I'll add it.

 

[Jim]

I can't believe this isn't in there. I'll add it.

Thanks. It really is good info.

 

[5twins]

Yes, the Suzuki float is exactly the same, it's the same part. I did a very close comparison between it and an original Yamaha one .....

It even has the tube "shim" insert for the pivot pin, something that's missing from many of the aftermarket offerings. That makes them a loose, sloppy fit on the pivot pin, and they often stick or hang up .....

 

[5twins]

As far as jets go, Mikuni sells their mains and pilots in 4 packs to cater to all those Jap UJM 4 cylinder bikes out there, and they're usually cheaper this way (about $3 to $4 a jet), so that's what I get. I'll search eBay from time to time because good deals often pop up there .....

https://www.ebay.com/itm/313150761736