Carburetor upgrade. 1971 CB350. Who's done it?

N

nobrakese28

New Member
Hey guys.
My carburetors are giving me problems. The bike runs pretty well, but after some tuning and investigating I discovered the carburetors are not same left to right. The fuel adjustment screw is different(the whole casting). Has anyone upgraded to flat slides or round slides? Did you pull them from a different bike? If so, which bike? How do you like it?
Thanks
-MV
 
yes. round slide vm30 mikunis.

way more time is spent figuring out jetting etc then you might want to spend. takes MANY hours adjusting jets to get them right.

i havent adjusted yet as my bikes still apart, when im running and tuned i could post my proper jet sizes, but for now i have a base line where you can start.

i recommend you get a sudco mikuni book for tips on tuning etc, as well as part numbers.

no matter WHERE you buy your mikunis from, they will be GROSSLY over jetted, even if they are "special set" or whatever gimmick the companies have.
 
Yep, I've got mikuni VM30's running really nice. It took awhile as Rocan said, but it was worth the effort. The main thing is to be sure you have the proper "air bleed" style emulsion tubes. Many companies ship them with the "primary" type that is used mostly for two stroke applications. Do a search of the site and you'll find quite a bit of info on the topic. member crazypj has post some great information that helped me a lot when tuning.
 
thats pricy... i got both carbs for 160 SHIPPED, from OEM Cycle. granted, it took them three months to ship (backordered) but they were the cheapest around, and they are legit.

even bike bandit has them cheaper then 350!

elliot... what jetting do you have in there? good call on the bleed type. i want to see how close my calculations are to actual real life jetting.
 
Rocan said:
thats pricy... i got both carbs for 160 SHIPPED, from OEM Cycle. granted, it took them three months to ship (backordered) but they were the cheapest around, and they are legit.

even bike bandit has them cheaper then 350!

elliot... what jetting do you have in there? good call on the bleed type. i want to see how close my calculations are to actual real life jetting.
Click to expand...

I'm on a 3mm overbore so it's a little higher then a regular 350. I'll have to check but I believe I'm on 130 hex style. I had so many different combinations I lost track with what I finally settled on. It's around there though.
 
If I were to but them from a different vendor would you gentlemen be so kind to help me jet the carburetors properly?
-Marco
 
nobrakese28 said:
If I were to but them from a different vendor would you gentlemen be so kind to help me jet the carburetors properly?
-Marco
Click to expand...

Of course, we don't have any allegiance to any particular shop or vender. There's already a bunch of info on here. Try a search on "mikuni VM30". It'll help you narrow down the questions you may have. Good luck.

FYI, I've been looking into 30mm Oko flatslides. Sound pretty cool so far. I'll probably start up a discussion on here to get some feedback.
 
djelliott said:
I'm on a 3mm overbore so it's a little higher then a regular 350. I'll have to check but I believe I'm on 130 hex style. I had so many different combinations I lost track with what I finally settled on. It's around there though.
Click to expand...

im overbored 1.5... 65.5 pistons.

howed you squeeze in 3mm over! :eek: and what pistons are you using?

my estimations put me at 140-160 large hex, so i wasnt TOO far off, and it makes sense as i rounded to the rich side of things.

what about the other jets? air jet, etc etc.
 
Rocan said:
im overbored 1.5... 65.5 pistons.

howed you squeeze in 3mm over! :eek: and what pistons are you using?

my estimations put me at 140-160 large hex, so i wasnt TOO far off, and it makes sense as i rounded to the rich side of things.

what about the other jets? air jet, etc etc.
Click to expand...

I used the actual honda approved Rocky S12 overbore kit (67mm) found a NOS pair on eBay. Sorry I forgot to look last night, I'll check when I get home to give you the exact jetting.
 
your liners must be crazy thin! any chance you have a pic of that?


thanks for jetting. take your time ;)
 
Actually not too thin. I'll see if I can dig up a picture. I think 67.5 is about as far as you can go.
 
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