CB350 Carb jetting...yes, this again

[lbaker]

Ok guys, I know experienced DTT members love seeing this post, but I'm lost after reading thread after thread on the issue here. Long story short I have a 72 CB350 that needs the carbs rebuilt and the side covers are damaged, so perfect time to remove the stock air boxes right? Maybe not. It's not a looks vs performance thing, but if I can get some solid suggestions on aftermarket filters whether they be pods or whatever I'd appreciate it. I've heard on here a wide ranging set of opinions, I'm running the stock carbs. If I choose to not order new side covers I would like to clean up that area which would mean bringing in some pods. To that option I've heard I'm screwed unless I really know what I'm doing, while I'm learning all that I can I would say that is not true and I need help. I've read that buying some vm30s that are "pre jetted" is bs and I will still need to tweak. If I keep the stock carbs I need to contact so and so on DTT because they are a wizard...on and on. Since I'm rebuilding the carbs and want to construct my own rebuild kit, can anyone offer jet size replacements they have used along with filter types on the stock carbs they've used? Fitment issues you've ran into, etc.
Thanks

 

[teazer]

That's easy. Stock side covers and filters - O R send the carbs to PJ and have him modify them to run with a good set of pods.

 

[alzcbz]

If you go the Mikuni VM route, let me know, I'm looking for a set of stock carbs.

 

[lbaker]

That's easy. Stock side covers and filters - O R send the carbs to PJ and have him modify them to run with a good set of pods.

Ah, another send them to the wizard. Who is pj and what does he do, just change jet sizes?

 

[mydlyfkryzis]

CrazyPJ is the wizard.

He has a little magic left in his fingers. The problem with CV carbs is that they have more than fuel jets. They also have air jets. The Keihin CV carb uses "emulsifiers" that premix air and fuel, like the aerator on your kitchen faucet. Too little air, and the fuel is in droplets rather than a froth. Too much air and the fuel is restricted. The jets are based on the smooth flow of air from aitbox to carburetor.

Pods do not deliver smooth flow. The turbulent flow means the air jets are not given the right pressure air.

CrazyPJ only sets the carbs up for K&N pods. The Emgo little cones restrict air, block air passages, and deliver really turbulent flow. The CV slide works less well, as well as the emulsifiers.

Crazy has found the right mix (pun intended) of fuel and air flow to allow the CV carb to work with a K&N pod reasonably well..

You will arrive at the right tune far faster with CrazyPJ's help than on your own.

 

[lbaker]

And with that...pm sent to crazypj

 

[crazypj]

CrazyPJ is the wizard.

He has a little magic left in his fingers. The problem with CV carbs is that they have more than fuel jets. They also have air jets. The Keihin CV carb uses "emulsifiers" that premix air and fuel, like the aerator on your kitchen faucet. Too little air, and the fuel is in droplets rather than a froth. Too much air and the fuel is restricted. The jets are based on the smooth flow of air from aitbox to carburetor.

Pods do not deliver smooth flow. The turbulent flow means the air jets are not given the right pressure air.

CrazyPJ only sets the carbs up for K&N pods. The Emgo little cones restrict air, block air passages, and deliver really turbulent flow. The CV slide works less well, as well as the emulsifiers.

Crazy has found the right mix (pun intended) of fuel and air flow to allow the CV carb to work with a K&N pod reasonably well..

You will arrive at the right tune far faster with CrazyPJ's help than on your own.

It isn't that they are CV carbs but they are 3 jet carbs with transitional circuits.
The pilot and primary main jet are linked for total fuel delivery, the secondary main jet starts delivering fuel much earlier than expected and causes a massively rich mixture if jetting is (theoretically) correct for full throttle/max rpm (motor can't pull through the rich area to get to max rpm though)
Leaning out jetting to get rid of rich area makes it way too lean to run over 7K
You will need K&N filters, Uni's work but are slightly more restrictive so tend to run a little richer, even after modifications

 

[mydlyfkryzis]

It isn't that they are CV carbs but they are 3 jet carbs with transitional circuits.
The pilot and primary main jet are linked for total fuel delivery, the secondary main jet starts delivering fuel much earlier than expected and causes a massively rich mixture if jetting is (theoretically) correct for full throttle/max rpm (motor can't pull through the rich area to get to max rpm though)
Leaning out jetting to get rid of rich area makes it way too lean to run over 7K
You will need K&N filters, Uni's work but are slightly more restrictive so tend to run a little richer, even after modifications

Doesn't change your wizard Status 8)

I wasn't all that specific, but the Emgo pods do block the atmospheric ports for the CV Diaphragm....

 

[crazypj]

Myd, you need to get a spare set of carbs, K&N filters and the 'race' baffle for MAC.
Even though you've had the 360 a while, you would be astounded how fast it can get up and go

 

[mydlyfkryzis]

Myd, you need to get a spare set of carbs, K&N filters and the 'race' baffle for MAC.
Even though you've had the 360 a while, you would be astounded how fast it can get up and go

I have the 750 to ride fast. Buddy with a Ducati who lets me ride it. The cb360 is plenty fun as it is. If I make it fast, I'll ride it fast. Prolly kill myself.

I can ride the 360 hard and not even exceed the speed limit. .

At this point, it runs better than it ever did. I like that

Also, to the OP, sorry for the thread jack.


Sent from planet Earth using mysterious electronic devices and Tapatalk

 

[lbaker]

haha thread jack away, I'm just appreciative for being put in touch with PJ. He's currently taking me to school.

 

[mydlyfkryzis]

PJ has forgotten more than I know...