CB350F vs CB400F Carbs

[AshimotoK0]

I bought a set of rebuilt carbs from a CB350F done by Gerben off a member on here for my 400/4.
I was hoping it was just a case of swapping the slow jet for a #40 (from #38) as the mains are #75 for both models. Plus I already had four sets of carb repair kits from Yamiya and those kits cover CB350F and 400F but only have one needle/jet type in the kit.

However .. I just cross checked and each model has a unique part no. for the needle jet 16012-333-004 (350F) 16012-377-004 (400F)

Yamiya mentions a difference but says the kit one (primarily intended for the 400F model)  can be used on a 350F but has different diameter. Also I can't find reference to the clip position for the 350F (its 3 down on 400F I believe).

I also noticed that Gerben has fitted aftermarket jets but I gather he fits Keihin ones now.

Problem is it looks a real PITA to swap the needles or change the clip position on these carbs.

Anyone know anything about this .. If I have to strip them I think I will just fit a set of original Keihin parts that I have.  but the intention when i bought them was that I woud just have to change one jet.

Any hints & tips much appreciated.

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[Nurse Julie]

All the people I have known that have used the same carbs but have swapped them from a 350 to a 400 have only ever changed the slow jets Ash. No one has ever mentioned changing anything else or adjusting the needle position. Why don't you ping an email to Gerben to confirm?.

[AshimotoK0]

All the people I have known that have used the same carbs but have swapped them from a 350 to a 400 have only ever changed the slow jets Ash. No one has ever mentioned changing anything else or adjusting the needle position. Why don't you ping an email to Gerben to confirm?.

Ta  Julie .. I didn't buy them from him though  Just noticed  he's a member here but only 1 post in 3 years ? Can try a pm I guess.

[Nurse Julie]

All the people I have known that have used the same carbs but have swapped them from a 350 to a 400 have only ever changed the slow jets Ash. No one has ever mentioned changing anything else or adjusting the needle position. Why don't you ping an email to Gerben to confirm?.

Ta  Julie .. I didn't buy them from him though  Just noticed  he's a member here but only 1 post in 3 years ? Can try a pm I guess.

I will PM you over his email Ash.

[royhall]

Ash. Gerben assured me that the only change is to the slow running jets. Gerben appears to be an expert on these things so I don't doubt him.

[gerben]

Hi Ashley,

I understand your concerns about the difference between CB350 and CB400 carbs. The only difference is the size of the main jets.
You just have to change them for the correct size and try the set on your engine.  For the CB350 it says to set the air screws on 1 7/8 turns instead of 2 turns for the CB400.
The final tuning has tobe done using a vacume set (4) to synchronise the 4 carbs.
Just try this.
I have never heard any issues about changing the main jets and after wards problems occurred.

Regards   Gerben

[AshimotoK0]

Hi Ashley,

I understand your concerns about the difference between CB350 and CB400 carbs. The only difference is the size of the main jets.
You just have to change them for the correct size and try the set on your engine.  For the CB350 it says to set the air screws on 1 7/8 turns instead of 2 turns for the CB400.
The final tuning has tobe done using a vacume set (4) to synchronise the 4 carbs.
Just try this.
I have never heard any issues about changing the main jets and after wards problems occurred.

Regards   Gerben

Thanks Gerben .. I understood from the Honda manuals that both models had the same main jet size of  #75  but the 350 has a smaller slow running jet. Size of 38 as opposed to #40 on the 400F.  ... does anyone know the 'standard'needle clip position on the 350?

[royhall]

Did I say slow running jets, you know I meant main jets. Senior moment.

[AshimotoK0]

Did I say slow running jets, you know I meant main jets. Senior moment.

No I think you are right Roy if you go by the manuals it's the slow running jets you need to change, the main jets are supposed to be the same. Evidently, according to a guy who's really  into his 350 fours & CB92's the castings are the same but drilled differently. I am going to give them a whirl on my mates 400/4 tomorrow that he's just rebuilt.